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Artistic License – Biology

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Obviously, there is no real life "X-Gene" that gives you superpowers.note 

"This movie is too dumb on too many levels. I mean, why does everything on Earth freeze at night? Wouldn't that kill all the greenery, and the animals? And speaking of animals, why does that eagle adopt Jaden as one of its young, then commit eagle suicide to save him from the cold?! It hasn't figured out how to live in the cold over the last thousand years of being an eagle?! Seriously?!"

There are cases where the MST3K Mantra certainly applies, especially if the entire world of the work of fiction is pretty crazy and, thus, all bets are off in terms of good science. Therefore, most of the examples below are culled from series who were at least trying to be taken seriously (so please keep that in mind before adding an example on this page).

A subtrope of Hollywood Science and supertrope to Pregnancy Does Not Work That Way. Contrast and compare Improbable Taxonomy Skills. Also a deeper trope than Informed Species, which is more of a general trope for characters that look absolutely nothing like their species.


Works with their own pages:

The following examples do not fit any subtropes:

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  • In an H2OH commercial, the narrator's voice comments how cool it is that nature gave spikes to the hedgehog, instead of you (human). In the video, though, the guy shoots spikes all around. It's said that porcupines can shoot their quills — porcupines are not hedgehogs, however, and the popular belief is in fact false. Porcupines may have their spines dislodged while swinging their tails around because the spines are very loosely attached to the porcupine so that they'll come out once they've been lodged in another creature's skin; however, they don't deliberately shoot their quills at a target. They're much more likely to reverse into your leg and fill it with hooked barbs.
  • Yellow, the peanut M&M from the candy commercials, messes up when he and Red show off their muscles. Yellow boasts "Check out my adenoids!", but adenoids are tonsils, not muscles. Probably more of a Genius Bonus since neither of the M&Ms (especially Yellow) have ever been portrayed as incredibly smart. Of course, candy obviously doesn't have muscles (thankfully), so there's that.
  • Lots of ads and other kinds of artistic portrayals show "parrots" that don't exist in nature, with bizarre coloration, patterns, etc. Oh well. But even depictions which were obviously done with good attention to detail, including real-life parrot coloration, feather layout, anatomy, etc. still often mess up the feet. A very large fraction of all parrot artwork gives them "chicken feet" (with three toes facing forward, one facing back) instead of real parrot feet (which have two toes forward, two toes backwards). Corona Beer ads are especially bad about this. The same problem often crops up in depictions of toucans, woodpeckers, cuckoos, and roadrunners, which also like parrots have zygodactyl feet.
  • Most commercials for hair care products use words like "nourishment" or "healthy hair." One commercial years ago even went so far as to call hair "a living, breathing part of your body." Too bad that the part of the hair being "treated" is biochemically dead. The only part that's actually alive is underneath the skin, in the follicle.
  • There's the "oxygenated water" thing. Drinking water with more oxygen packed into it is good for you, right? Well, only if you had fish gills in your stomach. If your stomach and intestines could perform that sort of gas exchange, Coke and Pepsi with their carbon dioxide would be a deadly poison. Lungs do that function excellently, thank you.
  • There's one vitamin commercial that claims that it helps repair your "cell walls", a feature not found in mammalian cells. Even if they're just trying to put "cell membrane" in simpler terms, those terms only exist in biology (nobody knew about the things to name them before the invention of the microscope), so their technical usage is their only correct one.
  • Many "Blue Wilderness" dog food packaging show an adult wolf note  with digitally altered blue eyes. Adult wolves do not have blue eyes. Puppies do, but they change before they reach that age.
  • In a Dettol (cleaning product) advertisement, it claims to kill "99.9% of all bacteria", including, among others, the flu virus. Viruses are not bacteria.

    Anime & Manga 
  • Case Closed: Conan repeatedly knocks out people with a needle coated with some sort of general anesthesic. Not only would this require some sort of dissolving agent to get rid of the needle, possibly causing minor acid burns from repeated exposure (especially Ran's dad), but the side effects of long term anesthesia are nothing to sneeze at.
  • Cells at Work: Baby!: In the real world (and other Cells at Work! spinoffs), the "child" equivalent of a red blood cell would be an erythroblast, which the RBCs in Baby! clearly aren't. However, they are portrayed as children to show that, like the cells of real-life newborns, they haven't entirely grown into their roles and are somewhat inefficient in their jobs.
  • Doraemon: A major plot point involves Sewashi changing the past by sending Doraemon back to the 20th century to improve Nobita's future, resulting in his great-great-grandmother being changed from Jaiko to Shizuka. He demonstrates that no matter who Nobita will marry, he will always be born which is not possible due to 1/16th of his genes being different, thus, he will cease to exist. The fact that this doesn't occur in any of the mangas or adaptations so far suggests that there is something that Sewashi didn't tell or either the authors just didn't think about this.
  • Dungeon Toilet: While the manga does offer some real information about toilets and toileting, at times it doesn't let said facts get in the way of a joke. For example, in one chapter Yotaro is shown pooping out something that was all the way up in his stomach only moments before, which would be impossible under almost anything resembling normal circumstances.
  • Hetalia: Axis Powers: An in-universe example. The most prominent female character, Hungary, used to think that she was a boy and that penises grow as you age, which would "explain" her... lack of one. And she laughed at Prussia for "not knowing."
  • In Baki the Grappler, in addition to all the other insane/biologically impossible things that fighters do, Shinogi Kanno can rip out nerves with his bare hands. In a fight with Baki, he blinds him by ripping out his optic nerves; apparently unlike all other humans, his optic nerves are located in his neck. Baki then temporarily repairs them by knotting the nerve endings. Of course, he makes a full recovery. Somewhere, a neurologist is weeping.
  • In Demon Slayer: Kimetsu no Yaiba, “Breaths” are the center of all techniques performed by human demon slayers in the series. While learning how to breathe effectively is a real thing among athletes and martial artists, in here it is taken to a whole new level, proper breathing can make the characters have unprecedent control over their bodies, it can freely control their blood flow to make their muscles have super strength, it can push their bodies to move faster than bullets, it can outright stop hemorrhages by focusing hard enough; even so the series pushes Breaths as something that is not supernatural at all compared to actual demons who can cast magical demonic arts.
  • Hand Waved in Digimon, anything impossible that a Digimon (or the Digital World) does is explained away by saying "they're just data".
  • One chapter of Gon set in The Amazon Rainforest has an arapaima falling prey to a shoal of piranhas, which eat it down to the bone as traditionally expected from piranhas. Arapaimas have extremely tough scales that even piranha teeth cannot pierce through, and if anything, they eat piranhas as snacks. Ironically, this is what exactly happens with Gon, who no-sells the piranha bites and eats the predatory fish.
  • The Keeper Wants to Build a Zoo in Another World, so He Tames Monsters: Zig-Zagged. As expected of a zoologist, Ikuhara is correct on several topics, like when he explains gynandromorphy or mimicry to Merou. However, he also talks about Alpha and Beta Wolves, which was debunked years ago (it could be true for hellhounds, but he should know it isn't for real wolves).
  • Love Hina: Ken Akamatsu seems to have been blindsided by myths about eyesight. Supposedly, Naru 'ruined her eyes' by studying so much for her entrance exams, and towards the end, Keitaro has developed night blindness, unstated but implied to be from going on so many digs with Seta. While these things are possible, they would require our fun couple to do most everything by dim candlelight, never get enough Vitamin A in modern culture, and seems a combo of somewhat realistic biology and old wives' tales. Maybe this was meant to symbolize their blindness about their mutual feelings, but genetics also plays a huge role in eyesight.
  • Naruto:
    • Naruto was born the day of the Demon Fox attack. But at the time of the sealing, he is shown without an umbilical stump. That usually doesn't happen until ten days after birth.
    • Surgery in Naruto tends to work a bit like LEGO with anyone being able to put pieces of other people onto themselves with minimal effort. Eyes are repeatedly removed and given to other people. In one case a character manages to pluck out another character's eye by apparently just grabbing it with their bare hands when running past them during a heated battle. Even better, said character just plops the eye into their own socket and is immediately able to use it perfectly. Another character managed to pull out his own eyes and put them into someone else's head without that other person noticing what had happened. Human-to-animal transplants are apparently flawless, too, as seen when Itachi transplants one of Shisui's eyes into a crow. The one-time eye surgery is portrayed somewhat realistically, requiring a lengthy recovery period, it is used to temporarily write a character out of the plot.
    • The cells of Hashirama Senju can apparently just be implanted willy-nilly into anyone for various effects. Madara Uchiha discovered their power when, for some reason, he used pieces of Hashirama's flesh to patch his wounds. Worse, he'd bitten off and swallowed said flesh, only to spit it out hours later, when it should have been dissolved by his stomach acid.
    • The same thing happens with Orochimaru. Late in the story Kabuto injects Orochimaru's blood into his body and it gradually infests his body like a cancer while also giving him Orochimaru's abilities. He also does the same with the Sound Four abilities. While not too ridiculous for the ones with implied or explicit bloodline abilities, it also works for those like Tayuya who just use ordinary jutsu.
    • Plenty of characters suffer significant burn injuries, but only to their skin and body. Their hair and clothing (usually) remain intact.
    • In the sequel, Sarada can use her sharingan as a microscope to see viruses. Regardless of magnification, such a feat is impossible with visible light as viruses are just too small. Such a feat would require special dyes, ultraviolet light, or an electron microscope.
  • Tsubasa -RESERVoir CHRoNiCLE- features, to make a long Mind Screw short, a My Own Grampa situationnote  where all involved have the same DNA, despite the presence of a non-blood-relation mother. This may be because of the laws of reason, i.e. cause and effect, falling apart.
  • When Tetsuo from Yuureitou is unable to use testosterone for several weeks, his voice starts reverting to a more feminine pitch. In real life going off testosterone doesn't do that to trans men. It might affect other parts of your body, however, your voice changes are permanent.
  • In Tokyo Shinobi Squad, one of En's first displays of the Technique of Remembrance is memorizing an entire petabyte of information. Computational neuroscientists estimate that the brain can only hold anywhere between 1 terabyte to 2.5 petabytes, meaning that En would already be halfway to maximum capacity at best without taking any of his other life experiences into account. Hand Waved by the supernatural nature of ninpo techniques.
  • It's alright that biology isn't Paru Itagaki's forte, but as illustrated in Beastars, it seems to be her pianississimo:
    • There is a plot point that Legosi seems to dislike his grandfather due to the fact he isn't a wolf, and Legosi and his mother are half breed wolves (quarter in Legosi's case rather.) It turns out his grandfather is a komodo dragon. Ignoring the impossibility of a mammal and a reptile having children, Legosi looks like he has only inherited a few reptilian traits from his grandfather: small pupils and immunity to komodo dragon toxins.
      • And it eventually comes out that Legosi's mother developed scales similar to her father later in life that was the contributing factor to her suicide.
    • As revealed in Chapter 124, Legosi isn't the only halfbreed in the series with the introduction of another hybrid character called Melon. A serial killing Leopard-Gazelle hybrid, who is forced to hide his heritage.
      • This was even hammered home further with the introduction of the hybrid Daycare in Chapter 142.
    • This series also gets several other things wrong about biology although some of them may be intentional. For example, it greatly exaggerates the deadliness of Komodo dragon venom. In real life they are not a very venomous species, but the series depicts Gosha has having to be extremely careful not to accidentally poison people and dripping large amounts of venom from his mouth when excited, and when he is especially upset his venom acts like Hollywood Acid. It also gets where they secrete the venom from wrong. In real life Komodo dragons secrete venom from a pair of sacks in their lower jaw, not from the upper jaw like Gosha does.
    • In Chapter 154, some of the history of this civilization is revealed. Apparently when the carnivores or "life animals" first encountered the herbivores or "nature animals", some form of magical "survival instinct" triggered causing the carnivores to view the herbivores as objects of protection, rather than potential meals even though the historical account just established that the carnivores would eat each other to survive. It remains to be seen how much of this account is factual versus mythical versus revisionist history but, needless to say, the current story flies in the face of established predator/prey behavior observed in nature.
    • Towards the climax of the Melon arc, some traits ascribed to some species cross the line from exaggerated to purely fantastic. Apparently, a few drops of venom from a strong komodo dragon is enough to melt a huge hole through a building wall in a matter of seconds; they can also bristle their scales like a mammal would bristle their fur. Leopard spots move on their bodies based on their thoughts or emotions. And more.
  • In Jewelpet, Sango is a cat who absolutely loves to eat sweets. In real life, cats are incapable of sensing sweet tastes.
  • In Nectar of Dharani, black keels are clams that produce spiky pearls. The reason why clams (and other shellfish) produce pearls in the first place is to deal with irritating particles, so it's illogical for any clam to produce spiky pearls.

  • Charles Darwin once famously pointed out that the way Laocoön's eyebrows bulge in Laocoön and His Sons is physiologically impossible.
  • The Raft of the Medusa: Due to the elements of Classicisim Géricault employed (which focused on, among other things, idealized human forms) the passengers are still rather muscular and healthy-looking for people who've been starved and dehydrated for almost two weeks.
  • The flowers in Ophelia don't all bloom at the same time. The reason for this is that Millais painted them all from nature over a few months.
  • Michelangelo is normally strict about adhering to human anatomy, but he deliberately made the hands and head of the statue David overly large, most likely so that people viewing it from far away in a chapel could distinguish these important elements easily. This break from reality is also a result of the original placement of the statue on a rooftop. Looking at it at that height and at that angle, the excess height, head size, and hand size are actually correct.

    Asian Animation 

    Board Games 

    Comic Books 
  • In the Buffy the Vampire Slayer miniseries "Viva Las Buffy", in which our heroine travels to Las Vegas, the villains are two twins joined at the hip: the man's a vampire, the woman's a mortal with deadly aim. One problem: their joining was so minor (both had full limbs and organs), any sane doctor would have separated them at birth. Also, Conjoined Twins are identical and not fraternal and would therefore necessarily be of the same sex. Having one of the twins be Transgender, as is the case with the (real life) Schappell twins, is as close as you're going to get to opposite-sex conjoined twins. This being Buffy (and as such, anything can happen), a wizard probably did it.
  • The DCU:
    • Batman's physical capabilities are supposedly natural, without any artificial or supernatural enhancements, but his feats are greatly embellished. For example, he's able to bench press 1,000 lbs and fight for 28 hours straight. Even when Batman's feats are within the bounds of human achievement, they will clash with each other. The physiques required to be the best powerlifter, boxer and marathon runner are all completely different. Also consider that athletes who make record-setting achievements have carefully regulated their training for weeks or months beforehand to "peak" at just the right moment to perform. One cannot stay in a constant state of peak performance.
    • Swamp Thing:
      • In the Wham Episode, it is revealed that Swamp Thing is actually a plant, not a transformed human. Fair enough (stranger things have happened in the DC Universe). The thing is, we're told that his memories were transferred to the plant in the same way that planarian worms can learn how to run a maze by eating other planarians that solved the same maze. While it is, admittedly, a fantastic idea for sci-fi writers to play with, it's too bad the planarian worm experiment from 1962 was faulty, to begin with, and has since been discredited. The new worms in the maze were actually following the slime trails left by the old ones, rather than relying on transferred memories. Placed in a fresh maze, they performed no better than the old ones. (Funnily enough, the scientist saying this in the story is, at his best, not quite right in the head. And later, Moore does, in fact, reveal that A Wizard Did It.)
      • The conclusion to the Woodrue storyline has Swamp Thing pointing out that, without animals, there'd be nothing to turn oxygen into carbon dioxide for the plants to use. Fungi are perfectly capable of carrying out this task, as are the plants themselves when they switch from daytime photosynthesis to nocturnal aerobic respiration.
    • Superman:
      • The explanations for Superman and his family's abilities combine Artistic License — Biology with Artistic License – Physics to a staggering degree, raising such questions as "How does he cut his hair?" and "How does his sperm not drill through Lois Lane's flesh like a sandblaster?" Some stories actually attempt to answer some of these questions, though not the latter.
      • In The Leper from Krypton, Lex Luthor mutates an Earth microbe into an alien pathogen called Virus X, which causes an infection compared with leprosy... which is not caused by virus but a bacteria (although it is eventually clarified the name is a placeholder, and the pathogen is indeed a bacteria). Later, though, the Virus X is killed by exposure to white Kryptonite, whose radiation kills all forms of plant life. Though, bacteria are not plants (albeit, to be fair, they were once regarded as plants).
  • How to tell the birds from the flowers. A manual of flornithology for beginners by R.W. Wood parodies semiliterate "botanics" books:
    Some are unable, as you know,
    To tell the Crocus from the Crow;
    The reason why is just be-caws
    They are not versed in Nature's laws.
  • In Invincible, the genetic dominance of the Viltrumite race is simply absurd, early in the series it seems the viltrumites have just been lucky enough to have found a compatible genetic structure in humanity in order for Mark to exist through Nolan and Debbie, the average case of a fantasy hybrid; later on this is expanded to a much grander degree by revealing the viltrumites actually have super powered genetics capable of breeding with any species in the universe, no matter how different at first glance their partner may seem, as long as the race has a concept of fertilization and gestation it seems anything goes, and the resulting child will only look slightly different at first (like skin color), when they get older their viltrumite blood will overtake any genetic trait from their other race heritage, basically becoming 100% viltrumite in their adult years, looking indistinguishable from someone who was born a pure blood viltrumite. In short the Viltrumite empire has potential to convert a good portion of the universe into their race at a genetic level.
  • Marvel Universe:
    • In the Marvel Universe, humans apparently evolved around 1,000,000 BC. Needless to say, Homo Sapiens didn't emerge for at least another 650,000 years - though this is eventually nodded to by one of the Judgment Day (Marvel Comics) tie-ins, which states that a bunch of modern humans fell through a chronal rift at some point.
    • Marvel officially lists the Kingpin at 6'7" and 450 pounds, but he is frequently depicted as looking more like a refrigerator than a human being. He claims that only 2% of his body mass is fat; while that is physically possible for bodybuilders to achieve, with the build that he has it is certainly impossible. For real-life comparison, a sumo wrestler with 10% bodyfat would be extremely low, with most being closer to 30%. Sometimes, he is depicted as a fairly realistic albeit very large person, but he's often drawn several feet taller than anyone around him, including Daredevil and Spider-Man (both of who are fairly average height). His hands in particular are frequently drawn as larger than Spidey's head or chest by a large margin. His feats of strength are certainly beyond what are humanly possible, even at Olympic weightlifter levels: he's been shown casually lifting, swinging and throwing objects that weigh hundreds of pounds with no apparent difficulty at all, as well as crushing thing like concrete with his bare hands.
    • When Warren Ellis wrote Iron Man: Extremis, he explained the eponymous magic bullet (a single injection which turns ordinary mortals into supermen) as a "Data package contained in a few million carbon nanotubes, injected directly into the brain". The information package would then rewrite the repair center in the brain — that is, the part of the brain which keeps a complete 'map' of our organs and functions. "The brain is telling the body is wrong"... and it compliantly changes according to the Extremis instructions. Perhaps needless to say, there is no "repair center" (although the "sensory homunculus" seems a little bit like what is described). Later writers retconned Extremis into a viral package, which is at least borderline believable.
    • X-Men:
      • While mutants are supposedly "the next step in human evolution", a claim which in and of itself shows a lack of understanding of the concept of evolution, absolutely none of their powers work without liberal use of the MST3K Mantra. Also, the fact that one mutated gene can apparently do so much and the constant claims that mutants are not humans show a clear misunderstanding of what the word "mutation" even means. The vast majority of mutants have absolutely ludicrous powers, hand waved by the Celestials inserting the x-gene in humanity millennia ago, known as the celestial seed.
      • After Warren Ellis explained the difference between normal and artificial mutants in his first Astonishing X-Men story, people pointed out that genetics don't work that way. Ellis admitted his mistake.
  • Nearly the entirety of issues #3 and #4 of Marville is loaded with completely asinine science, with a particular focus on evolution. All to set up a joke that Wolverine was the first human, evolved from an otter.
  • Poison Ivy (2022): Ivy's new plan involves the use of spores to sprout fungi in people. The issue is her powers come from the Green (plant life), whereas fungi are an element of the Grey, a completely different force. Despite this change and her not hearing the Green anymore, no mention is made of this shift, as if treating mushrooms as always in her power set.
  • In the crossover issue of Planetary with Batman, Elijah uses his powers to give someone what he calls "an ice cream headache." A real ice cream headache occurs when blood vessels in the roof of your mouth are suddenly pinched by very cold food. What Snow actually does is freeze a portion of the person's brain. Which would either do nothing (since the brain doesn't have sensory nerves), lobotomize them, or just kill them outright.

    Comic Strips 
  • Calvin and Hobbes: The Chocolate-Frosted Sugar Bombs cereals make Hobbes gag for being too sweet even though felines can't taste sweetness. Ironically, Calvin is the one who thinks the cereals are a little bland without adding them extra sugar. This might be justified by Hobbes possibly being imaginary.
  • The Phantom: One issue featured a criminal called "The Man Who Never Sleeps", who had his eye lids sewn back so they could never close, thus preventing him from ever falling asleep or having to close his eyes for even a moment. In actuality, his eyes would dry out and he'd go blind very quickly. And even if it would somehow keep him from falling asleep, the lack of sleep would at best have significant negative effects on his cognitive abilities (issues with speech and memory and hallucinations have been known to be caused by severe lack of sleep) or at worst lead to death (case-studies on fatal familial insomnia suggests that humans can survive at most 6 months without sleep).

    Fan Works 
  • The Bolt Chronicles:
    • Bolt and Mittens cry and shed tears, which real dogs and cats cannot do.
    • Bolt and Mittens have sex lives that are far more human than animal in nature. For example, Mittens does not go into heat like real cats do.
    • In "The Protection Payment," it is revealed that Kelvin the labradoodle can't swim. In real life, all dogs of his type are able to do so. His pigeon friends in fact express surprise at this inability.
  • In Cinders and Ashes: the Chronicles of Kamen Rider Dante, Hoshi receives bullets that contain the body heat of animals. However, a few of those bullets are of cold-blooded animals and insects, meaning they do not have body heat to begin with.
  • In-Universe with CWCollateral: A Tale of the Resistance, the author goes to great lengths explaining how many sacrifices had to be made to bring a Sonic the Hedgehog-type character into the real world, and exactly how the trope contributes to the chus' Uncanny Valley appearance and Made of Plasticine disposition. An Ancient Artifact that had been turned into a "creation engine" figures heavily into their creation.
  • In The Darker Knight Batman's Batarang hits "Too-Face" in non-vital organs... like his liver and intestines.
  • There is a rather prolific author on who seems to believe that the male and female genitalia differ In Name Only.
  • Full Metal Dragon doesn't even have to start before this happens. Jake's mom had an affair while she was still pregnant with him. resulting in two infants. Jake stayed with them while the other child went with his father, Hoenheim of Light. While this is possible (it's called superfetation) it's also ridiculously rare — there have been only ten known human cases.
  • This is averted in the Gensokyo 20XX series with Ran's suicide attempts, as they were noted to have failed because she probably wasn't cutting in a way in which that hit the major arteries and the fact that she did so in the snow, the cold of which caused her blood vessels to pull back.
  • Hans Von Hozel:
    • In The Raven, the titular raven is being hunted for its fur coat.
    • Also, the Glee fanfic involves a banana forest growing as a result of Produce Pelting. Edible bananas have no seeds.
  • There is one Harry Potter fanfic that places Draco's penis at a minimum of 42 inches longnote . The quantity of blood required to get something that long erect would cause the rest of the body to die from lack of blood instantly. He'd have it dragging against the ground wherever he goes. He better be asexual, or else he's going to live a life of forced celibacy, or have to romance giantesses.
  • Several Inuyasha fan works feature Kagome and/or Sango going into heat. Humans don't go into heat, they have a menstrual cycle. Inuyasha and his brother, Sesshoumaru, are male dog-demons, so a number of fics have them going into heat because of their dog natures; male dogs do not go into heat. Similarly, some stories have a demon being able to smell that they or their mate is pregnant as soon as a few minutes after having sex.
  • In Light and Dark The Adventures of Dark Yagami, Dark shoots and kills Watari on his way out of the "Whammy" house. Watari returns six chapters later, having been revived by CPR — even if he hadn't been killed, CPR could not have saved his life.
  • The Simpsons fanfic Lisa is Pregnant has Lisa describe men as having "dominant" sexual organs and women as having "recessive" sexual organs. Sexual organs are not determined by a dominant or recessive gene.
  • In The Loud House fanfic Loud Farts, Lisa claims that women are gassier than men. How gassy someone is can depend on diet, and occasionally genetics, but not sex.
  • the man with two souls, a RWBY fic, depicts Jaune's evil split personality as being physically stronger and more martially skilled than him. Despite sharing the same body.
  • In the Percy Jackson and the Olympians fanfiction Moon Daughter:
    • The author believes that kissing causes you to lose your virginity. A virgin means someone who's never had sex before, not someone who hasn't had any kind of intimacy.
    • And this line: "I kicked him in teh cocanuts so he could never conceve." While a blow to the reproductive anatomy can sometimes cause a man to become sterile, it's exceedingly rare.
  • In Lethal Species:
    • Xenomorphs can hatch from demons just as they can hatch from humans (although the resulting aliens will be slightly different from the standard version), and at least one hatches from a vampire despite a vampire being incapable of sustaining ‘life’ normally.
    • Rather than hatching as a Queen from the beginning, the first xenomorph to arrive on Earth goes through a period of metamorphosis where it creates a cocoon for itself so that it can transform into a Queen.
  • In The Lion Guard, the eponymous lions have hands. And fingers. This defies both real biology and the source material, in which lions have very obvious paws.
  • A Fanservice-crossed-with-disturbing The Lord of the Rings fic featured the protagonist sustaining the Fellowship when they ran out of food by breastfeeding them. Human females do not produce enough milk to feed nine adult males at once. Someone on a badfic-sporking community pointed out that they'd do better to kill and eat her. Even if she could produce enough milk, human breast-milk has very little nutritional value to a human older than, say, 8 years old (this being the absolute upper limit).
  • In the Ghostbusters (1984) fanfic Massage, Egon is mentioned to have never gotten an erection outside of sex before, and that's portrayed as a sure sign he's in love. In reality, erections don't require sexual attraction; they can happen due to something touching the area, waking up in the morning, or even for no reason at all.
  • Also from Dakari-King Mykan, in My Brave Pony: Starfleet Magic:
    • In general, the Space Ponies have this trope in regards to their own physiology. According to Word of Godinvoked, when Celesto lost the use of his front legs, learning how to run with just his hind legs made him much faster. This is the opposite of how it actually works: a good reason as to why horses (and just about any quadrupedal animal, for that matter) can run so fast is because they use four legs to run in the first place. Their bodies are essentially built for running. An equine losing the use of two legs is more or less equivalent to a human losing one: it handicaps the individual rather than strengthens them. Even if we're talking about Celesto's descendants, it would realistically require immense physical training for a regular Space Pony to outrun a unicorn, let alone a pegasus or an earth pony; it would not be a natural advantage.
    • In one chapter, Fluttershy has to go to the hospital, because of her appendix. The author at first thought that ponies don't have one and admitted he knew that, but he was too lazy to think up something else to make Fluttershy sick. When he found out that, not only do ponies have an appendix but it is essential to their survival, he changed the line which handwaved them having one by Anthropomorphic Shift into said shift making the appendix unessential.
    • Cadance is rendered infertile by the pillar that falls on her and causes her to miscarry. An impact strong enough to cause that much damage to the female reproductive system would realistically cause much bigger problems than just sterility. And that's not even getting into the matter of the stillborn child staying in her room for the rest of the season; decomposition isn't even brought up in the slightest.
  • Somehow, My Immortal confused magic with "advanced biology" when the protagonist was narrating about what is ostensibly transmogrification.
  • In the Crack Fic of The Simpsons, Ned Flanders Takes the Biggest Black Pill of All, Ned is described as being "mildly dehydrated", which causes him to either die or pass out. While death and unconsciousness can happen as the result of dehydration, neither can stem from mild dehydration.
  • Invoked in-universe by Elizabeth in The New Retcons to try to explain why she and her husband (both light haired) produced a dark haired baby. Unfortunately for her, Anthony paid attention in biology, and that coupled with the baby's darker skin tone tipped him off that the baby's not his.
  • The Chip 'n Dale Rescue Rangers fic Offensive Care sees Chip and Dale discover that there is a strange anomaly in their blood that makes standard blood transfusions impossible except between each other, even though they aren't biologically related. Dale eventually realies that this is because of the past accident where Nimnul's teleporter caused the Rangers to switch heads; as he and Chip switched with Gadget and Monty respectively, they retain some mouse DNA even after switching back, which also has the long-term benefit that Dale and Gadget can have children (based on tests Dale carried out before proposing to Gadget after Chip falls for his doctor during his time in the hospital).
  • The Sailor Moon Legend of Zelda:
    • Dakari-King Mykan gives us this gem, where a character seems to have biology and geology a tad confused:
      Melvin was most outraged by that. "How can you girls say that?!?" he spat. "Biology is all around us, the singular sciences of how our glorious Planet-Earth is formed and runs.
    • Moments later:
      "Now, I understand your teacher has had you investigating the science of sound."
  • In Shinra High SOLDIER by Sephirothslave, Hojo ends up pumping ten 500 ml (5 liters/1.32 gallons) mako injections into his body one night. The average normal adult has roughly 5 liters (1.3 gallons) of blood in his body, meaning that he basically replaced almost all his blood with mako.
  • There's a particularly bad 6teen fic where the author states that Niki's twin is such because doctor's put her dad's eggs in Niki's mother.
  • Zigzagged in Sonic X: Dark Chaos. Most of the biology behind the Shroud and the resulting Body Horror they cause on their victims are physically and anatomically impossible. It doesn't make them any less gross and terrifying though, and is entirely done for Rule of Scary. Lampshaded by Chris in the rewrite, who states that everything about the Shroud goes against every biological law as humans understand them, and it's the reason he's utterly terrified of them.
  • Subverted in the Danny Phantom/Gargoyles crossover, A Wish Your Heart Makes. Titania gives Vlad a vision of what his life might have been like if he had stayed friends with Jack and Maddie instead of turning evil. This leads to Vlad becoming Danny's biological father to prevent him from being born with hemophilia (Jack and Maddie had just discovered that Maddie and Jazz were carriers for it). Once Vlad wakes up from the vision, he reminds Titania what almost anyone who knows anything about hemophilia would have already noticed: because it's carried on the X chromosome, any child of Maddie's would have had the same chance of inheriting it no matter who the father was. Titania admits that she included that error on purpose so Vlad would know for sure that it really was All Just a Dream.
  • At least two Yaoi Genre Fan Fic / Slash Fic featured someone with an anal hymen, and many others have featured pain/bleeding/difficulty in penetration as somehow part of normal anal sex between men. The anus does not have a hymen, as anyone who has ever had a bowel movement should understand. Also, pain beyond slight burning or difficulty penetrating means that something is wrong (usually, the receiver isn't relaxed or prepared well enough if either happens), and bleeding means something is really, seriously wrong that may require immediate medical treatment and means STOP RIGHT NOW (at best a bumped hemorrhoid or the top has too-long/sharp fingernails, at worst something has been torn or ruptured or cancer is present).

    Films — Live-Action 
  • 28 Days Later: The rate at which the Infected vomit blood should kill them from dehydration and/or blood loss within a matter of hours. There's also the speed at which the virus infects its victims. A virus that induces intense rage is theoretically feasible, but infected victims are shown to take less than a minute to go from normal to mindlessly enraged. In reality, even an exceptionally aggressive virus would take several days to infect a victim to a point where their behavior would start to change.
  • In After Earth, humanity's former homeworld Earth is depicted as having changed dramatically in the thousand years since humans left the planet. Since then, the planet's rainforests have overgrown the continents, the weather changes from warm to ice cold every night, and "everything on this planet has evolved to kill humans". However, evolution does not work that fast. Biological changes on the scale depicted take millions, not thousands of years, and most plants and animals would have gone extinct trying to adapt to temperatures that fall far below freezing each night. In the time it would take for animals to change that much, humans would have changed significantly as well. Also, there'd be no reason for the animals to continue evolving abilities to efficiently kill humans since humans don't even live on Earth anymore. The primary predator of the film, the Ursa, is a blind creature that hunts by smelling the pheromones produced by fear. This is not a great feature for a predator; most predators hunt by ambush since prey goes down faster if it doesn't know you're there. But if the prey is displaying fear, it likely knows the predator is there and so has a chance to run or fight back, which would only make things more difficult for a fear-smelling hunter. Also, being blind is a huge disadvantage for an animal that lives on the surface of the Earth and would make it very difficult for a large, active predator to simply navigate, much less hunt, given that it would be unable to see any obstacles in its path like trees or cliffs.
  • Alien: Resurrection:
    • The plot hinges on creating a clone from blood samples to harvest the completely separate lifeform hiding out in the original Ripley's chest. Furthermore, red blood cells don't even contain DNA (though, white blood cells do contain DNA, so that might explain it).
    • Supposedly Aliens bond with their hosts at the genetic level, hence all the weird superpowers Ripley got from the genetic mutations caused by the Alien (like the corrosive blood). That doesn't make very much more sense, but hey, it's Alien.
  • In another '50s B-movie, The Alligator People, a physician uses hydrocortisone injections to induce accident victims to regenerate damaged body parts. While cortisones do reduce inflammation (swelling), and can, therefore, make injuries feel better, they actually slow down the healing process.
  • '50s B-movie The Amazing Colossal Man has one of the doctors tending to the eponymous rapidly-growing man describe the human heart as "one big cell." As Tom Servo says, "You're not a real doctor, are you?"
  • Oh so very much in the killer snake movie Anaconda, all in the name of the Rule of Scary. Among other things:
    • Anacondas get huge, but they spend the majority of their time in the water, only going on land if necessary. Water provides the buoyancy to allow them to grow massive (and never to the size of the snakes in the film, but the entire point is that these are special species that do. Problem is, they'd die if they tried to be arboreal.)
    • Its worth noting that their have actually been reports and claims of giant anacondas going back to the colonial times, which is what the film is probably based on. These giant anacondas are classed as cryptids and are thought to either be oversized green anacondas or a new species entirely. There is at least one species of prehistoric snake which did grow that large, Titanoboa, but it went extinct about 58 million years ago.
    • They don't move at the speed of a cheetah in a chase. They can strike that fast (i.e have their head and a small portion of the supporting body lunge forward), but not chase things that fast, even in water. And the gigantic snakes depicted in the movie have no business moving that fast with all that mass.
    • They don't predominantly prey on humans (though it has happened), especially after encountering life-threatening resistance each time.
    • They don't eat multiple prey the size of a human being one after the other. After consuming a meal like that (which can take hours), the snake will find a secure location where it will remain immobile for months to digest its food.
    • They certainly don't regurgitate their prey just so they can hunt again out of sheer sadism. They sometimes do this for safety purposes, such as when they're threatened by a predator and they can't afford to be lethargic by having such a big meal in their stomach, or if they find their meal is too big to eat.
    • The faces of the movie anacondas look more like the faces of vipers and other venomous snakes than actual anacondas or other pythons because the former look more intimidating.
  • Aquaman has made many mistakes regarding sea creatures:
    • Sharks don't roar. And they would never slam their noses into glass hard enough to break it, since their noses are extremely sensitive.
    • We see familiar fish in Aquaman's army, except fish that exist that deep tend to be blind and super-ugly.
  • Despite some scientists trying to handwave things in Arachnophobia, no species of giant spider could possibly exist in the real world.
    • While there really are species of spiders that live in colonies, none of these are male-dominated colonies, nor do they have a singular "queen" like ants or bees.
    • Arachnids breathe through their skin, and there simply isn't enough oxygen in the modern world's atmosphere for them to get any bigger.
    • Scientists use a paralyzing agent to make spiders fall out of a tree in the film. Despite falling more than a hundred feet, the spiders survive. In the real world, that fall would have killed each and every spider; their bodies simply could not handle that much force.
  • Mice live a very short life — 3 years at the most, but in Cinderella (2015) Gus Gus and Jacqueline are shown to have long enough lifespans to witness Cinderella growing up from a little girl to a young woman.
  • In The Cleaver Family Reunion, Grandma Cleaver reveals that she's been white all of these years, but has been taking melatonin to make her look black. Melatonin doesn't work that way... The correct term is "melanin". Melanin is what causes pigmentation of the skin. Melatonin is a natural sleep aid.
  • Doom has the mutant monsters come from the genetic experimentation of long-dead human Martian Precursors. Fair enough. But it turns out that the mutations are caused by there being a "gene for evil" in the "poorly understood 10% of the human genome" which the genetically engineered chromosome reacts to. Now, when one of these mutants bites a healthy human, it infects them like a virus.
  • Elysium: After his accident, Max says that he has so much radiation in his body that he is probably irradiating people in close proximity. Carlyle makes a similar claim when he worries about having to replace the sheets in the factory medbay, due to Max's skin falling off (which doesn't happen from radiation poisoning, either in reality nor in the movie itself). Both are wrong because radiation can only be emitted by radioactive material; human tissue does not qualify. There are excuses for both, though; Max was trying to intimidate someone and may not even know better, and Carlyle is just a jackass.
  • In The Final Destination, a girl is slowly pulled into the machinery of an escalator. As soon as her feet get crushed, she starts spewing blood all over her boyfriend. No reason for that, really. No digestive or respiratory organs in the feet. However, it is possible that getting her legs crushed between those cogs and gears caused her blood pressure to skyrocket, which would pop blood vessels (starting with the very weak ones, such as the capillary bed in the lungs). Imagine rolling a tube of toothpaste starting from the bottom up.
  • In The Fifth Element, the head scientist, while referring to the still-a-sample Leeloo, says "I can't wait to meet him.", even though he has complete access to her DNA, so he really should be able to notice the lack of a Y chromosome. So he either a) misled the general for no good reason, b) gave Leeloo a Gender Bender for no good reason or c) he's incredibly incompetent and has this job.
  • A Syfy remake of The Fly has a man crushed in an open-shafted elevator (literally, the elevator "shaft" is a chain fence with no gate), it causes his eyes to bulge out while his face turns red, until his head pops and deflates like a whoopie cushion. Where is his skull? Never mind the weight of an open-air elevator being lowered that slowly wouldn't be enough to cause that much damage, most likely just pressing the lungs until he asphyxiated.
  • Godzilla: Along with the breaking of the Square-Cube Law preventing a monster that looks like Godzilla from reaching that size, various movies have additional examples:
    • Godzilla:
      • Godzilla runs at a rather high speed, at one point chasing down an attack helicopter. Coinciding with the Square-Cube Law, large real-world creatures a fraction of Godzilla's size would splatter if they ever tripped moving that fast. And this ignores the physics of getting a creature with that much mass moving at that speed using anything close to real-world biology.
    • The reason why infrared-guided anti-aircraft Sidewinder missiles fired from AH-64 Apaches failed to lock on Godzilla is because it's "cold-blooded". Cold-blooded creatures don't literally have cold blood. They lack built-in mechanisms of keeping their body temperature at a constant level, independent from the environment.
  • The "Reproduction" song in Grease 2 (in which the teacher attempts to begin the sex ed class by talking about flowers, but the teens rapidly relate this to the advanced topics) has a girl singing "Make my stamen go beserk" and a guy singing "I got a pistil for you right here". This is exactly the wrong way round; the stamen is the male part of the flower and the pistil is the female part. (Since they're not paying attention to the actual lesson, it arguably makes sense that they'd get it wrong...)
  • A woman is cut in half at the waist in Hillside Cannibals; her intestines spill out of her lower half.
  • In The Horror of Party Beach, a doctor explains that the monster is actually a dead human whose organs were invaded by aquatic plants before they had the chance to decompose, and calls the result "a giant protozoa." Protozoa are single-celled lifeforms, and "protozoan" is the word for describing one in the singular. Also, algae are not "aquatic plants". They're algae. But they're often referred to as aquatic plants, so that one gets a pass as "one character simplifying the truth to explain it more easily".
  • House Shark: Pretty mush everything about the shark in this movie SCREAMS this trope.
    • For starters, no shark in existence can fit inside a toilet drain, or SWIM THROUGH WOOD.
    • And only the shark in this movie would react to plutonium in the manner it does.
  • Independence Day: Resurgence sees Brakish Okun waking up from a 20-year coma and is able to walk around and talk as if he had just woken up from a nap. After being asleep for that long, his muscles would be suffering from muscle atrophy and would barely be able to talk.
  • Interstellar has, as a major plot point, a world-scale blight wiping out all plants and thus depopulating the world. Such a situation is impossible in Real Life. Historically, blights of this nature only happened on a much smaller scale (such as the potato blight which caused the Great Irish Famine in eastern Britain and Belgium; the mainland cultivated multiple crops whereas one-third of Ireland had been forced to rely on potatoes through mainland-government policies. In comparison, two-thirds of the entire world at present is dependent on wheat, rice, and corn). Moreover, crop scientists are always specifically aware of the potential of disease, and develop new varieties to deal with them, even in crops which are all direct clones (such as common fruits like bananas, apples, and oranges). And the blight shouldn't be so devastating towards wild plants, since wild plants have greater genetic diversity (giving them greater potential to develop resistance) and tend to grow in mixtures of multiple species (making it harder for diseases to spread, compared to the monocultures that many crops are grown in).
  • Iron Man: The shrapnel working its way toward Tony's heart is held back by an electromagnet that is somehow just powerful enough to hold it in place but not powerful enough to pull it back toward the magnet over time even though jagged metal would tend to shift and thus cut through body tissue pretty readily as Tony does active superheroics.
  • Island City a 1994 made-for-TV movie, had the few remaining regular humans living in a small enclave surrounded by animalistic mutants. The mutants were called 'recessives' because the trait was inherited that way. One of the characters was — get this — HALF RECESSIVE, with all the increased strength and toughness but without the bestial aggression and reduced intelligence. Also, the inhabitants of the city wore colored crystals making their genetic status clear, to prevent the wrong kind of couple forming and producing the wrong kind of offspring. That would be fine, except there were THREE colors (should only be 2, carrier or not) and people were forbidden from mating with anyone whose crystal was a DIFFERENT color (should be, 2 carriers may not mate).
  • James Bond:
    • In Goldfinger: A Bond girl is asphyxiated by covering her entire body with gold paint. Bond explains that people need at least a small patch of bare skin at the base of the spine for their skin to "breathe." This isn't true. At the time the novel was written, "skin asphyxiation" was taken seriously, at least by the public. The studio had a team of doctors on hand while shooting the death scene, and left actress Shirley Eaton's stomach unpainted to make sure she could breathe. In reality, death could result from heat exhaustion if the paint interfered with perspiration, or exposure to toxins if the paint were unsafe, but it would take a very long time.
    • In Moonraker, Drax designs a chemical that will kill humans but not animals or plants. Humans actually are animals and a huge chunk of animals roaming the world have similar respiratory systems, meaning that they'd be killed too.
  • Jaws:
    • This film and its sequels are infamous for depicting sharks as relentless man-eaters. Great white sharks do not see humans as food due to lack of enough fat to provide them calories and usually (usually, not always) attack if provoked, smelled blood, or in a case of mistaken identity. They also need much of their energy to maintain their body temperature. Being opportunists, they will eat most things they can catch, but they don't specifically target people. Also, according to scientists in the 2000s, another reason sharks don't attack people is sharks apparently don't like the taste of human meat. After all, humans don't live in the ocean.
    • Jaws 2 has an orca that is mauled to death by the great white shark, and the supposed marine biologist claims that there are far greater marine predators than it, referencing the shark. In real life, orcas are capable of killing great white sharks and the only predator (besides humans and other great whites) that preys on great whites. There have even been cases of entire populations of great whites fleeing from an area due to orcas preying on one individual. Even a fully-grown shark would not bother attacking an orca as it is still less than half the size of the mammal.
    • Jaws: The Revenge has the shark roaring, which sharks are incapable of due to lacking vocal cords (or lungs, for that matter).
  • Jurassic Park contains a few:
    • One character who is supposed to be a paleontologist saying "Dinosaurs and man. Two species separated by sixty-five million years." The problem being that dinosaur is not a species designation, but a much higher taxonomic rank. There are currently known to have been more than 1,000 species of dinosaur. Furthermore, most of these species have been extinct far longer than 65 million years (and most paleontologists would argue that some dinosaurs live to this day — these dinosaurs are technically known as "birds"). It's almost like Dr. Grant knew he had to say something for the movie trailer.
    • Another scene has him holding a baby dinosaur in his hands. "What species is it?" he hisses to a nearby geneticist. "It's a Velociraptor," responds the geneticist. Neither of these trained scientists who really ought to know these things picked up on the fact that Velociraptor is the genus name. This is averted in the book, where the baby is identified as Velociraptor mongoliensis.
    • An early scene has the paleontologists digging up a Velociraptor mongoliensis in the Montana badlands. As the name implies, they lived in Mongolia, and not Montana. The misidentification of Velociraptor was actually due to Science Marches On — the original book based its research on a (now debunked) palaeontologist who argued that Deinonychus antirrhopus was, in fact, a species of Velociraptor, which means what they were digging for in the novel (which the film did not correct) was a north-American Velociraptor antirrhopus. Every instance where the book and the film use Velociraptor is therefore in actuality a reference to Deinonychus antirrhopus. This does not take into account the lack of feathers and an egregious misunderstanding of Deinonychus anatomy, but this could be explained away (at least in the book) by the knowledge that these aren't "real" dinosaurs but a facsimile created by geneticists working with patchwork DNA and a flawed understanding of the beings they're trying to re-create. The cheetah speed (the actual speed was closer to that of a wolf, or only about half this) and chimpanzee intelligence (they were very smart, but not that smart) can at least be filed under artistic license.
    • The premise of the movie (and the book). If the amber-preserved blood was any more than 1 million years old, the DNA would have been irrecoverably decomposed, no matter what it was preserved in. Cloning extinct species from before 1 million years ago is impossible. Also, if the DNA were available, we have absolutely no idea how to turn that DNA into a viable dinosaur egg. You'd need complete information about how the oviducts of that particular species operated even to get started, and we don't even have any fossils of dinosaur oviducts, let alone a clue as to their gestational duration, average internal temperature, etc.
    • The Lysine plan. A plan to limit the growth of the dinosaurs by making them dependent on the amino acid Lysine, by taking away their ability to produce it themselves. Lysine is an essential amino acid. Most modern-day vertebrates (including crocodiles and sharks; superorders that existed in the Jurassic period) can't produce it either. And we make do without it because we get Lysine from our gut flora or by eating things containing Lysine. The Lysine plan is a great way to limit the growth of genetically modified bacteria, which depend on Lysine in the media if they can't make it themselves. For vertebrates, that obtain it from eating things anyway, it's not. The book at least acknowledges this as an in-universe whopper by InGen's scientists, as it turns out it was no hindrance to the dinosaurs whatsoever.
  • Little Sweetheart almost avoids this, until the last few seconds. Elizabeth has taken a bullet to the arm, a bullet to the gut and then spent at least several minutes face-down in either the Pacific or the Gulf of Mexico. She's easily being moved by the ocean and she's not moving. A band-aid to the head is all you need!
  • In The Matrix, Agent Smith gives a Breaking Speech on how humans are viruses because they don't instinctively develop an equilibrium with their environment like other mammals and instead breed until they can't support themselves. In reality, animals do not instinctively find an equilibrium with their environment; it's forced upon them by outside factors. We see invasive species of animals run rampant in new ecosystems all the time. The only difference with humans is that we have the power to push past most opposing environmental limitations. On the other side, there are plenty of viruses that can inhabit a host but not kill it and form their own equilibrium.
  • Mission to Mars:
    • One character arranges Skittles in the air in microgravity in the shape of about ten base pairs and declares it's the genome of his "perfect woman" (the human genome contains about 3.2 billion base pairs). Another character eats a couple; apparently, it's now the genome of a frog. Easily written off as a joke, until later in the film: after seeing about five base pairs on a screen, a character declares that it "looks human". Five BP on their own would tell you nothing whatsoever about what you're looking at, not even which kingdom it belonged to, never mind species. Perhaps more egregious in this particular scene is how the floating candy DNA chain somehow rotates on an axis.
    • The writers clearly lacked an understanding of genetics. To start with, one of the characters constructs a model of a DNA molecule from supplied spacial coordinates, then Jim is able to look at a (very small) string of computer-generated DNA, and see that it "looks human". This is impossible, because a) you can't tell what species a sequence came from by looking at such a small sample and b) spacial coordinates that form a double helix say precisely jack shit about what bases (and, by extension, what genes) are contained in the DNA sequence. Then someone mentions it's missing "the last pair of chromosomes," when the simulation makes it readily apparent it's missing the last pair of bases. To top it all off, the coloring of the bases appear to suggest that a base pair is made up of two identical bases, which is just wrong.
  • In Monster Trucks, not only do Creach’s species ‘eat’ oil, but it is noted that Creach basically becomes hyper when he is fed petrol because of the additional chemicals in it compared to standard oil.
  • The Spleen from Mystery Men is an in-character example, as he named himself for an organ that has nothing to do with his Fartillery superpower.
  • A minor case in Mystery Team, but it is somewhat unusual that Jason can bike several miles with one flat tire without showing any signs of fatigue.
  • The African Mammals exhibit in Night at the Museum includes an ostrich, which is not a mammal. Error or not, this is an actual part of the real museum exhibit.
  • Nope
    • The Chinese Praying Mantis depicted in the film is diurnal and wouldn't have been active at night.
    • Jean Jacket's ability to recognize faces, specifically eyes, shouldn't be possible, even though it's an alien. Natural facial recognition comes from centuries of evolution and is dependent on the fact that most mammals and many other animals have the three main elements of a traditional face: eyes, nose, and mouth. Jean Jacket's only visible facial feature is a mouth, making it highly unlikely that it would have evolved to recognize a traditional face.
  • The low-budget monster flick Octopus attributes its giant cephalopod's prodigious appetite for meat to a severe deficiency in iron, such that eating iron-rich flesh is all that's staving off its death from anemia. Mollusk blood uses copper, not iron, as an oxygen-carrier, so if anything it should have been chewing on the imperiled submarine's electric wiring, not its crew.
  • Piranha 3D: The Piranha survived two million years in an enclosed cavern through cannibalism. Every predator gets about 10% of the energy his prey took in. So, every generation of piranha should have lost 10/11 of their population. Even assuming they magically preserved 90% of the energy, they wouldn't have made it that long without producers in their food chain! And just to add insult to injury at the end of the movie we find out they've been fighting the babies, which are apparently as big as their full-grown prehistoric ancestors. So, apparently, this process made them bigger.
  • In The Predator, a major plot point hinges on Autism being treated as the next step in human evolution. On top of being quite cringeworthy Flawless Token, the premise is flawed for two major reasons: firstly that it hinges on the Evolutionary Levels fallacy, and secondly that the characteristics of the condition (troubled social interaction and impaired communication skills) work precisely against what evolution stands for (better adaptation to the environment and better chances to survive and reproduce, which in humans is parallel to social functioning, and humans are social animals - romance is one thing autistic people notoriously struggle with).
  • Push has the lead character inject soy sauce directly into his bloodstream with no side effect at all.
  • In the low-budget monster flick Razortooth, the giant killer eel breathes air and slithers like a snake. It's also alleged to be incapable of metabolizing glucose "like a diabetic": a double error, as A) diabetics can metabolize glucose, they just don't do so at the right rate, and B) any animal with a nervous system that can't metabolize any glucose would be dead, as neurons quickly die from accumulated waste products if they have to subsist on fatty or amino acids instead.
  • The Reaping: Members of the Satanic cult sacrifice all their children to Satan, except for the firstborn, who are inducted into the cult, to ensure the cult itself can survive. In reality, you would need (on average) two offspring to survive (and reproduce) per couple just for the population to remain stable. Even if the cultists recruit outsiders to marry the kids they don't sacrifice, attrition would still wipe them out, as some of each generation are likely to die, fail to reproduce at all, or leave the cult.
  • Reign of Fire: A whole species consisting of thousands of females and only one male? It's actually not impossible in real life: Blue-Headed Wrasses (a fish) have a reproductive pattern where they live in large schools of females led by a single male. When the male dies, one of the females actually switches sex and becomes the new male. In the film, though, killing the male results in the extinction of the species.
  • Resident Evil Film Series:
    • In Resident Evil (2002), the Red Queen explains that zombification works by exploiting the cellular activity that continues after death, supporting the idea by stating that hair and nails continue to grow after death. No, they don't, and considering the fallacy is spoken by a supercomputer that really should know better and is used as the main rationale for including zombies to begin with.
    • When Major Cain tries to persuade Alice to cooperate with Umbrella in Resident Evil: Apocalypse, she calls herself a freak. Cain's reply? "No. You're not mutation, you're evolution!". If Alice were to breed and pass on her mutation, then it would be evolution.
    • Resident Evil: Extinction goes so far as to have most of the world's water supplies go dry due to a virus. It apparently infected and killed the water. For your own sake, don't try thinking too hard about this.
  • Revenge (2017): Let's just say that, from a medical point of view, very little of what happens to the characters after Jen's rape makes scientific sense.
  • In the Syfy movie Robocroc, CGI sequences show how the film's nanite-infested crocodile has her physiology transformed, bit by bit, into that of Mechanical Lifeforms. One of the first such scenes shows her red blood cells being converted by the nanites... biconcave red cells without nuclei, which are found in mammals but not reptiles. Presumably, the writers figured audiences wouldn't recognize blood cells unless they looked like the sort humans have.
  • Sherlock Holmes and the Curse of the Spider Woman Holmes meets Spiderologist #1 who recommends that Holmes visits Spiderologist #2. Meanwhile, criminal has murdered Spiderologist #2 and is impersonating him. Holmes spots the fraud because the criminal uses the wrong terminology. Meanwhile Holmes, Spiderologist #1, Spiderologist #2 and Criminal all call spiders "insects".
  • Silent Running is set in a future where the Earth's entire biosphere was destroyed, save for a handful of domes out in space. Simply put, this is impossible. If the Earth's biosphere were destroyed, we would go with it. We cannot survive without the environment. (There are a few lines that can be interpreted as humanity starting to die out, though.)
  • Snakes on a Plane plays fast and loose with biology, mostly for laughs.
    • The snakes are shown as shockingly aggressive, actively pursuing prey, whereas most snakes (including those shown in the film) are relatively sedentary; the snakes in the film bite repeatedly for no apparent reason, simply killing without eating the people or defending themselves, and then move to attack and kill other people who are neither a threat nor viable prey. The snakes are described as being so aggressive and violent because they are being stimulated by sexual pheromones, except that snakes are not praying mantids or black widows and do not kill their mates while they have sex. If snakes were to be brought into a violent frenzy when in the presence of sexual pheromones they would require separate pheromones for each individual species and would be just as likely to attack each other as humans, as any other species would be as much of a threat/competition as the people would.
    • The Burmese python practically growls and flashes fang like an aggressive dog. Then it manages to kill the jerkass in moments when in reality it would take much longer even if the guy had a heart attack almost immediately. Finally, the python has no problem getting human shoulders down its throat. A real python would need a few moments to unhinge and stretch out its jaw, and then would probably need some time to properly position a meal that wide. Assuming a snake that size (about 16 feet) could get its head over an adult male's shoulders in the first place; even most potentially man-eating snakes (over 20 feet) will have trouble consuming a large person and take hours to do so. Yes, there were time constraints, but still. At least the python seems to still have been working on its meal when the poor thing got sucked out the window.
  • Starship Troopers. The bugs are referred to both as "insects" and "arachnids" throughout the movie. Apart from those being mutually exclusive terms, it's unlikely that alien creatures from across the galaxy would belong to any terrestrial animal class. The film also ignores the square-cube law that would make those giant bugs collapse under their own weight.
  • While Super Size Me contains plenty of questionable science behind the "30 days of eating nothing but McDonald's" experiment, the one thing that's blatantly incorrect was the DVD extra where a McDonald's burger and fries were allowed to sit on a counter with food from other restaurants to see how long they took to decompose. The other sandwiches and fries showed signs of decay and mold before accidentally getting thrown out, while the food from McDonald's was virtually unchanged the entire time, with the implication that they're artificial to the core and pumped with preservatives. The real reason they didn't grow mold was that they were thin, greasy, and salty; what little water they contained evaporated quickly, leaving no suitable environment for mold to grow. It's the same reason fresh bread in a sealed bag will become moldy, while bread sitting on the counter will simply dry out and turn stale.
  • In Teenage Mutant Ninja Turtles (2014), given, they are mutant turtles, however in the case of great blood loss as the turtles experience, giving them adrenaline would definitely give them short-lived pep but it would be short-lived and not last as long as through the end of the movie. The amount they received on their dangerously low blood pressure should also have given them heart failure within minutes.
  • A scene in the bad Canadian vampire B-movie Thralls features the lead villain vampire punch another man through his stomach, tear part of his spine out and show it to him as the now-spineless man merely stands there. And then, rather than break in half where his spine used to be... he just collapses.
  • In There Was a Little Girl, Julia's uncle James claims that Mary is no longer her identical twin due to having been disfigured by her skin condition. Unless her DNA has also been altered by said condition, she's still identical to Julia genetically even if she no longer looks identical.
  • When Taylor goes into a doctor's appointment for a check-up in The Trump Prophecy, the doctor tells him that he has "the hormones of a 70 year-old." While PTSD in real life is related to a hormonal imbalance, specifically stress hormones, that has nothing to do with a person's age.
  • The Waterboy: Bobby tackles his biology professor over the fact that alligators get ornery because of their enlarged medulla oblongata, leading to more aggressive emotions, instead of Mama Boucher's explanation that "they got all them teeth and no toothbrush". They're both wrong, because the medulla oblongata has absolutely nothing to do with emotions, being responsible for breathing and heart rate. The amygdala is responsible for emotions. In fact, Bobby's answer is more correct than the other. Infected/damaged teeth and gums are one of the primary reasons for some predators to become more aggressive and developing man-eating behavior. Furthermore, the premise that alligators are unusually aggressive is false. In fact, among large crocodilians, alligators are comparatively docile.
  • In The World Is Not Enough, Renard has a bullet lodged in his medulla oblongata that is "slowly killing off his senses". No One Could Survive That!! This is credited with removing his sense of touch, despite this not being where the sense of touch is in the brain. The sense of touch is in the parietal lobe (mostly) which is at the top back of the brain. The medulla is at the bottom of the brain. While some have survived with bullets in their brains, such as Kiran Prajapati, who they were likely thinking of, if a bullet was damaging your medulla your heart would quickly fail, you would stop breathing, and your sense of touch would be fine. Until you die. Not to mention the absence of a sense of touch would produce a profound loss of balance. People who genuinely lose their sense of touch have to learn how to balance themselves all over again. And even then it's a tricky thing thereafter — every time Bond hit him, he would lose his spatial awareness and have to reorient himself, or he would keel over.
  • The X-Men Film Series has a whole collection of offenses.
    • Mutants cannot be called another species, given that they can still interbreed freely with normal humans. There is also the continuous reference to a so-called "mutant gene". In reality, any gene in the genome has the potential to be mutated. Even if you don't have a biology diploma, it ought to be obvious that there could be no universal "cure" that suppressed all the flashy mutations (but not "regular" ones like, say, heterochromia?) on any given mutant without affecting anything else, and certainly not in a matter of seconds.
    • Invoked for the purpose of goading someone in X2: X-Men United, as when discussing the mutant gene, Pyro says that it is passed on by males. This implies that the gene is carried on the Y chromosome, which if it were true, would mean that there would be no female mutants. However, the scene makes it clear he just said this to get under Mr. Drake's skin.
    • The iron injected into the prison guard wouldn't have gone unnoticed, least of all by the guard himself. Iron injections have a risk of anaphylactic shock — high enough that many doctors won't prescribe them unless the patient has no other option — and are incredibly painful.
    • Not to mention the entire idea of a genetic mutation causing things such as the ability to control the weather...

    Live-Action TV 
  • The 100: The Mountain Men, whose ancestor survived a nuclear apocalypse from inside a bunker, are unable to metabolize radiation the same way that characters who were born in space on the Ark or on the radiation-soaked ground can. When exposed to radiation, the Mountain Men break out in instantaneous lesions and bleeding wounds, which are treated with blood transfusions from Grounders or citizens of the Ark. The blood transfusions not only prevent further damage from radiation, but heal what wounds they have already sustained. The Mountain Men later move on to bone-marrow transplants from the Arkers they have in captivity, as the bone marrow allows the Mountain Men to metabolize radiation on their own. Their bone marrow plot seems to be "take someone's bone marrow and stick it into anyone else," which is hardly the case in real life. Donor and recipient have to be matched, and with only about 50 donors for 400ish recipients, you'd be lucky to find even one match for people who are not directly related. Justified, the Mountain Men are explicitly stated to be able to modify blood and marrow to make any doner/recipiet pairing work. This comes up as a plot point later on when the Grounders are angry at the Arkers for continueing to use Mount Weather.
  • Alma Gêmea: In real life, breeding roses can produce yellow, orange, pink, red, and white flowers, but not purple/blue ones, because roses lack the genes to naturally produce such pigmentation. "Blue" roses (which are actually mauve-colored, just like in the show) were first created in 2004 through genetic engineering of white roses, but in the show, Rafael somehow manages to create that kind of rose in the 1940s through traditional rose breeding.
  • And Then There Were None: Blore casually calls Lombard aside and asks him to confirm by smell that Marston died by cyanide poisoning. Given that the ability to smell cyanide is genetic and only shared by 40% of the population, it's more likely than not that Lombard wouldn't have been able to confirm this. Justified, as it's unlikely that Blore knew this.
  • In Season 5 of Angel there is a scene in which someone looks into a microscope and tells Fred he can see that the disease-causing agent is a retrovirus. Not only would he be unable to see something this small without an electron microscope, but there is no easy way to tell by looking whether it is a retrovirus or not.
  • Animal Planet really, really should know better...
    • An episode of Animal Planet's: The Most Extreme was about modern day animals and their ancient ancestors. Fair enough...until they start talking about the Komodo Dragon and state that its ancestor was the Tyrannosaurus rex. If the producers of the show had done even five minutes of research on the Internet (or even just read a current book on dinosaurs), they would've realized that Komodo dragons and the Tyrannosaurus rex aren't even closely related to one another. A more true ancestor for the Komodo dragon would be the ancient Mosasaurs (sea-dwelling reptiles that lived around the same time as the dinosaurs, and close relatives of monitor lizards). This is Artistic License – Paleontology — your common farm chicken is more closely related to the T. rex (birds are theropods) than the Komodo dragon is. Not to mention crocodilians are the closest living relatives of dinosaurs, including birds.
    • As a lead-in to some trivia about prairie dogs, the narrator of 50 Outrageous Animal Facts speaks of how mammals can sometimes be found in large groups. As he talks, shots of animal crowds appear on screen, including a beach full of walruses, a field full of wildebeest, and... a lake full of flamingos. Large groups of mammals, right...
  • The Barrier: One plot point of the series is that the Always Identical Twins Julia and Sara were both injected with a subcutaneous chip of unknown nature during the Distant Prologue. In the present day, Sara is dead and her daughter Marta now has her chip. Because of another plotline, Julia needs to pretend to be Sara for most of the series and fools plenty of people. After Julia and Marta turn out to share a very unusual trait, a scientist who has just discovered they aren't actually mother and daughter comes to the conclusion that the trait must not be of genetic origin, which means they have something else in common. The women about whom he makes that conclusion are still aunt an niece by blood and again, Julia and Sara were twins. Marta and Julia sharing an unusual trait shouldn't be considered odd at all.
  • Battlestar Galactica: In season 2, episode 13, the supposed genius Dr. Baltar heals president Roslin's cancer by injecting her with some cylon/human hybrid blood that is more resistant to diseases because it has no antigens (which means it has bloodtype O) and therefore it has no blood type. Therefore it is somehow capable of destroying a cancer in a very late stage. Furthermore, cancer cells (or any other animal cell type) aren't cultivated in a petri dish and on agar, as it is shown on the pictures Dr. Baltar has, but are instead cultivated in cultivation flasks in a fluid.
  • Sheldon in The Big Bang Theory. Yes, Sheldon. When he is unable to learn to drive on a driving simulation without crashing into a pet store or ending up on the second floor of a building, he claims that because he is the next stage in evolution of humanity, citing his small incisors and his massive brain, he does not need to learn how to drive, because the task is beneath him. Evolution does not work that way! Sheldon Cooper is also egotistical and occasionally delusionally convinced of his own superiority. He has been known to occasionally ignore various scientific principles in order to win arguments, particularly when it comes to superhero physics. Given that humanity is still evolving, every generation is a new stage. Sheldon's only mistake is that he overexaggerates his own significance in the process. He is also missing the point of natural selection. Because of his psychological quirks and self-centeredness, his "fitness" level currently appears to be very low (moreover he has a very low interest in finding a mate in the first place, much less conceiving and raising a child). Unless his attitude changes completely, he is going to be naturally selected against, and not pass on his genes. Evolution favors those who have multiple children. Though really, it was just an excuse for not being able to learn to drive, rather than him making a definitive statement about his evolutionary significance.
  • Bones:
    • In "The Dwarf in the Dirt", Dr. Brennan tells Sweets the chunk of brain Booth is missing would in no way mess with his aim because it was taken from his Frontal and Parietal lobes (which according to her only deal with memory). She then states that only the Occipital lobe (sight) and Cerebellum (coordinated movement) have anything to do with aiming a gun. The part of the Frontal lobe closest to the Parietal lobe is called the "Motor Cortex" and, oddly enough, is in charge of motor control. The Parietal lobe (which is a major part of spatial relations) has a part next to the Motor Cortex called the "Sensory Cortex" which, you guessed it, is about feeling ones body. Moving, feeling and spatial relations have nothing to do with aiming a gun... Nothing at all...
    • The frontal and parietal lobes are the largest two lobes of the brain, so it depends on which parts were taken. But the motor cortex and sensory cortex are right beside each other, straddling the border between the lobes, so it's hard to imagine how a single piece could be removed that incorporates both lobes and not involve the motor and sensory cortices (in which case Booth would have troubles far more than just aiming a gun — he'd be liable to be paralyzed on one side of his body in at least one limb). Also, the part of the brain most involved in memory is the Temporal lobe. And in a later episode they show an MRI scan of Booth's brain, and the missing part is most definitely not anywhere near the frontal or parietal lobes.
    • In a minor example, one episode starts with a human falling to his death and landing in a field of cows. The witnessing cows just stand there placidly, and politely keep their distance from the investigators. Real cows tend to be curious, so would gather to see what was going on.
  • Buffy the Vampire Slayer:
    • "Some Assembly Required'' would have been a lot easier to swallow had there been a mention of the guys using magic to augment their biology work, but there wasn't anything said about it. First, it's highly unlikely that all three dead cheerleaders would have had the same blood type and been compatible enough for their parts to be grafted together. Second, there's no way any of their cells would have still been living by the time the bodies were recovered and used. (ditto with the dead football player who was brought back). Third, no one seems to recall that heads can't be transplanted without severing the spinal cord and resulting in complete paralysis. It's hard to imagine that's what the re-animated dead kid had in mind when he wanted a girl built for him.
    • This trope is occasionally lampshaded in the scripts. A line in the script for "Some assembly required" written by Ty King describing a medical drawing reads, "it's of a woman's body, with muscles, joints, all kinds of equations and science type stuff (English major much?) scribbled all over it". Joss Whedon's script for "Graduation day, part one" has the stage directions "swabbing blood off the tip and putting it on a slide. That sounds real sciencey! Did I mention I was an English major?"
    • Somewhat justified since Sunnydale sits on top of a Hellmouth, which constantly leaks magic (and attracts supernatural creatures) — this probably allows a lot of people to do what they want to do, if they want it badly enough, even if normal biology wouldn't permit it.
  • Catastrophe: The sex of the baby can already be seen on the ultrasound, even though it's only been just over a month from the likely conception date (Rob is told by Sharon that she's pregnant thirty two days after, and goes immediately to London). Fetal genitalia don't even develop until around the ninth week, and can't usually be seen until twelve weeks at the earliest. Sharon should only be in the fifth to sixth week at the most.
  • On one episode of Charmed, an inspector at an autopsy appears to believe that a woman with "high levels of testosterone" in her bloodstream is a biological anomaly, rather than a statistical outlier. "Testosterone? How's that even possible?" It's as if the writers believed that women normally have no testosterone in their bodies at all (in actuality, they do, and some have more of it than others). This might be an in-universe error, as the inspector wasn't a biologist and was generally portrayed as a perverted fool, but the coroner he was talking to certainly didn't bother to correct him.
  • Chuck:
    • An enemy agent injects herself with a sizable amount of ricin so that she will not talk. That's all well and good, as ricin has no antidote...but it also takes days to do its dirty work. She died instantly (cyanide is a better idea).
    • On the third episode of Season 3, a foreign leader requires a blood transfusion and has AB Negative blood type. Captain Awesome is trying to find someone with AB- blood type; even though people with AB bloodtype can receive A, B, AB, and O blood types as long as they are negative. AB- people can also receive red blood cells from all other blood types, however if it was a whole blood transplant, as would happen in an emergency, the sera (which contains antibodies) could cause major problems if not also from an AB- donor, as it would "attack" and cause an immune reaction against the recipient's own cells.
  • In The Tag for an episode of Community Abed, Troy and a character played by Betty White rap the biological classification of human beings with a remixed "Africa". While the song is catchy, there are two minor mistakes when the last 's' is dropped from Primates and Sapiens.
  • In the CSI episode "Crash and Burn," the suspect says, "I have to feed my fish. Clown loaches, tetras, angelfish..." when the aquarium clearly contains goldfish, angelfish, and a couple other species (possibly tetras in there somewhere). There are, however, no clown loaches — probably because they're best kept in groups of 5 or more, in tanks over 100 gallons, which the tank in the episode definitely was not.
  • CSI: NY:
    • "What You See Is What You See": The femur being the strongest bone in the human body, there's no way Sheldon could've twisted it to make the lodged bullet fall out.
    • "What Schemes May Come": A laboratory mouse is used to demonstrate how an apparently dead victim had been put into an experimental state of hibernation. The mouse is hooked up to a heart monitor, which can be heard slowing as it enters hibernation and then speeding up as it revives... but only to a (human) rate of ~75 beats per minute, rather than the 500+ beats per minute that would be typical for a mouse. A mouse with a human's heart rate would have to be in hibernation just to be alive.
  • Something similar to Chuck occurs in the first season of Dexter, when Dexter has a flashback to being sick enough that he needed blood. He apparently has an extremely rare blood type that meant donor blood was in short supply, and they had to find a close biological relative of his to donate. That blood type? AB negative. While this is the rarest blood type, it's also compatible with any other type of blood, as long as that blood is also negative, to the point that AB people are referred to as "universal recipients." That said, there are extremely rare blood types... they're just not the ABO system types that everyone's heard of (in particular, there's an Oh type that's both very rare and which can't accept even the so-called "universal donor" O-type blood).
  • Doctor Who has many, many, many examples shown over the years. Some of these can be handwaved in one of three ways: 1) The TARDIS doesn't give a literal translation of the Doctor's biobabble, it instead renders something the companions can understand, even if it's wrong. 2) The alien physiology/technology in question works differently from our understanding. 3) The Doctor makes it up 'cause it sounds cool.
    • "The Invisible Enemy" beggars description. The Big Bad is a prawn-shaped space virus which spawns... let your imagination fill in the blanks.
    • "New Earth" has the Doctor discovering a lair full of cloned humans infected with, in his words, "EVERY DISEASE IN THE GALAXY." They don't die since all the diseases keep each other in equilibrium but if they touch you, you die instantly and painfully. How does the Doctor cure these poor souls? Why, he douses himself in ten or so intravenous solutions designed to cure the diseases, then transmits the cure by touch. One of these diseases, called "petrifold regression," turns you into stone.
    • "Daleks in Manhattan"/"Evolution of the Daleks": The Daleks are using a giant lightning rod to power their genetic experiments. Okay. The Doctor mixes his own DNA into the results by hugging the lightning rod as it's struck by lighting. Whu? DNA is conducted by electricity now? This one actually has a degree of In-Universe plausibility (albeit very, very thin), as Time Lords are repeatedly shown to be able to transfer regeneration energy, which can and does alter DNA — though that, in itself, is a case of this trope.
    • "The Lazarus Experiment": The weird scorpion monster that Professor Lazarus transforms into is said to be an evolutionary possibility that humanity rejected long ago but has remained locked in the genes.
    • "Planet of the Ood": Mr. Halpen is constantly downing hair tonic which turns out to be Ood-secretions that TURN HIM INTO AN OOD. Complete with the external forebrain, which can apparently break through the hard palate to come out his mouth.
    • "The Hungry Earth"/"Cold Blood":
      • While explaining that the Silurians aren't aliens, he calls them "Homo Reptilia", which implies that reptilian aliens are the same genus as mammalian humans, which is impossible in Real Life.
      • The procedure Mo was put through and that Amy is nearly subjected to is referred to as "dissection", which while understandable in non-doctor Mo's case is rather less so when coming from Malohkeh, since he was actually vivisecting them.
    • "Time Heist": The Teller's ability to reduce its victims brains to soup somehow also caves in their skulls, the bone going from a nice convex dome to a concave section where the forehead and front half of the top should be. It makes the victims actually look like their heads are empty, and is all the more horrifying for it.
    • "Kill the Moon" features giant single-celled prokaryotic spiders. Not only would this make eating and web production very difficult, not only is it outright impossible, but the Doctor apparently cannot pronounce "prokaryotic". Throw in the spiders being instantly killed by a spray of disinfectant, the Moon being an egg that somehow gains mass, and the hatched Moonling instantly laying another moon-sized egg exactly where it was before, and the show hit a new low for biological (and scientific) plausibility
  • Eleventh Hour likes to screw up cloning (at least the clones are born as infants and not carbon-copy adults with complete memories). In the first episode, Jacob Hood insists that cloned pregnancies are more dangerous to the mother carrying the clone and that you need the "real scientist" at the birth, when in fact a cloned infant poses no more threat to the mother than an in vitro pregnancy, which is scarcely more risky than a natural one (and in fact the mother's health is only in jeopardy if her own body is incapable of carrying a pregnancy; if the baby is unhealthy it will simply miscarry). Then in a later episode, he makes the claim that clones are born genetically the same age as the original that they were copied from (so even though they look like babies, their genes are actually adult or even geriatric), stating that the telomeres which break off each time a cell replicates are severely shortened. However, scientific research measuring telomere lengths has proved this to be false; the developing embryo somehow "knows" how long its telomeres should be and resets them to this length with the enzyme telomerase.
  • Friends:
    • Rachel is pregnant for at least fifteen months, being already pregnant at Chandler and Monica's wedding (May 15th) and going on maternity leave in August the next year. Not to mention the episode with Emma's first birthday party airing in the fall.
    • Despite many season premieres taking place within minutes or even seconds of the previous season finale, hair has somehow managed to grow several inches. That's why they don't film entire scenes before the season is over. That way, the audience has a summer to "forget" what the characters looked like and will accept the changes with little fuss.
    • Ironically enough they also lampshade plot devices like this through Joey's work on Days Of Our Lives: his coma-bound character gets a brain transplant that turns him into the donor's character in a new body. Later, he somehow reverts back to his old character (Drake Ramoret) when his body rejects the brain.
  • In the Fringe episode "Bound", the Monster of the Week is a fast-moving, foot-long slug that turns out to be an engineered cold virus. Walter attempts to Hand Wave this by stating that it isn't entirely unprecedented since large ostrich eggs are single cells... except viruses aren't cells. Cold viruses are strands of genomic DNA contained inside of a protein coat, and entirely unable to move under their own power. Saying that it was a "giant" cold virus makes as much sense as a "giant" hemoglobin molecule.
  • Game of Thrones universe:
    • Game of Thrones:
      • We're told that the Targaryens often married brother and sister to keep their bloodline pure over their 300-year reign, with an inference that they'd been doing it prior to Aegon's conquest, as well. In reality, severe mental and physical debilitation would result from this level of inbreeding (Charles II of Spain is a good historical example of the result). Instead, the Targaryens are physically flawless and only suffer from occasional instances of madness. It's implied that there's more than a little magic in their bloodline, which might be a mitigating factor.
      • Without testicles secreting testosterone, the muscular development shown by some Unsullied borders on unnatural. (This is actually addressed in the original novels: single Unsullied are not very formidable opponents, but an army of Unsullied is lethal due to their discipline and tactics making up for their lack of physical strength.)
      • The many foramina in the human skull would make it very impractical to use as a container for wine the way Karl does in "Oathkeeper".
  • Dr. Holt (A Gifted Man) had apparently never heard that you're not supposed to diagnose paternity based on ABO groups when he told an AB- man on the spot that his son, O+, wasn't his biological child. Although it is rare, the man could have been cis-AB and had an O child.
  • This is seen frequently in Helix, in spite of the attempt to ground Plague Zombies in epidemiology, using fictional CDC employees.
    • The CDC team accepts injected RFID chips from a shared device. This is risky, considering that this could be a method of transmission of The Virus, and they don't know who are asymptomatic carriers, including the device's handler.
    • Arctic Biosystems designer lab rats, who lack sex organs so they're more docile, are a solution in search of a problem, since lab rats are already docile, and removing sex organs removes both avenues of study (effects on reproduction, etc) and ability to compare or extrapolate from research on non-customized rats.
    • Less than a day is insufficient time to determine, via rat observation, if The Virus is airborne. Even if true this shouldn't be cause to remove a Hazmat Suit, as it could be absorbed through the skin, and bodily fluids can aerosolize.
    • Mutagens are, in and of themselves, not so disturbing to work with as Julia and Hatake say. They're used in cell biology.
    • Alan is frightened that an infected Peter will be killed by halothane gas, and wants him alive because he may have developed antibodies which takes five days, while Peter's had The Virus for three.
    • Viruses are not typically searched for by shape, and when Julia says she's searched for all of them, "even isocahedrons" she's treating the most common shape as though it were unexpected.
    • The Zeiss phase-contrast microscopes depicted can't produce such animated images, much less show a virus that's smaller than usual. (viruses also don't move like protozoa). They'd need electron microscopes to see such small objects.
    • In "Vector," Julia says rabies "doesn't include a compulsion to spread the disease" but that's exactly how rabies works. This error is odd since Peter's first symptoms are a supernatural exaggeration of rabies. His frightened refusal of water mirrors its hydrophobia, and the neck pulsations evoke the painful throat spasms that happen after those with rabies try drinking.
    • Isolation and safety protocols are more talked about in the abstract then abided by. Isolation facilities should be larger and more secure given Arctic Biosystems extensive work with pathogens. In "Vector" Dr. Bryce is correct that he and Sulemani should be separated from the sicker Haven, since late stage infectees are super strong and violent. In "274" Daniel is likewise correct when he thinks now-symptomatic Sulemani and Bryce should stay isolated from the asymptomatic in quarantine, and Alan's failure to account for this violence results in Bryce and Sulemani's deaths.
    • By the same token, the switch, over the course of three days, from Hazmat Suit to face shield for interacting with infected is unwise, given that, in "274" its easy for a Vector to slip one off mid-assault, and one strain is known to be hemorrhagic and lethal. Even face shields aren't employed consistently.
    • In "274" That the rapid response test wouldn't work is almost a Foregone Conclusion, given that Sarah sampled too few people to be assured of its efficacy, even given a limited population and time frame to work with.
  • Henry Danger: After watching a horrible cartoon, Ray complains that frogs are vegetarians. This isn't true. In fact, most are carnivorous.
  • House: In one episode, the title character triumphantly demonstrates a tick that was causing the Case Of The Week; in a close-up, one can clearly see it has six legs, as every insect does... but ticks are arachnids, and, like spiders or scorpions, they have eight legs.
  • iCarly:
    • In-universe, with this exchange:
      Spencer: Do girls have bladders?
      Carly: "Do butts have muscles?"
    • Maurice the Chicken. Called a male name. Makes rooster sounds. Yet actually a hen, a female chicken.
  • In From the Cold: Obviously, shapeshifting like the show depicts is not even remotely feasible, particularly not beginning in the late 20th century.
  • On Discovery Channel's I Shouldn't Be Alive, the narrator explains the effects of hypothermia on human cells, using the term "cell walls", in one episode (and is sure they have used it other times). Animals do not have cell walls (in fact, Animalia is the only kingdom where they are absent). Yes, they probably just don't want to explain what a cell membrane is/assume the audience won't understand the explanation, so they use a term the audience will know. Considering Discovery's association with fact and science, it seems like they would be willing to spend an extra ten seconds quickly explaining what it is.
  • A Korean drama special entitled Last Flashman has a girl find out a shocking birth secret (that she's an alien or something) because she has blood type O but both her parents have type A. Most of the people are shocked and confused and maintain strongly that it's impossible to have blood type O from A parents. In fact, this is something that is not only possible, but actually happens all the time: — the gene for type O is recessive, so a person with type A blood can still be a carrier for the O gene (allele pattern AO), and if both parents have this pattern and the child gets an O from both, the child will be type O. It would be true if it was the other way around (two Os giving birth to an A), if the A parents had a child who was B or AB rather than O, or if one or both of the parents were AB rather than Anote , but the situation as it's written (A parents, O child) isn't even all that rare, let alone impossible.
  • One episode of Law & Order: Special Victims Unit that has blood type as a plot point ("Stranger") has a doctor first make the claim that a child of two parents with type A blood can only be type A, and then that a type A mother could not give birth to a type B child (the latter being to rule out the possibility of the child being a product of an affair). Apparently the doctor forgot that recessive O genes exist: if both parents have a recessive O gene, they have a 25% chance of having a child with type O bloodnote , and a type A mother with a recessive O gene and a type B or AB father could have a type B child if the child got a B gene from the father and an O from the mother.
    • At least two episodes make mention of a woman undergoing a medical exam showing that she's a virgin — except that there's no medical way to prove that a woman is a virgin; the closest they could come is to rule out clear evidence that she isn't (e.g. showing that she's never been pregnant and is negative for STDs), but that's not the same as clear proof of virginity. One of the instances is potentially excusable as the detectives bluffing to make a suspect think they can disprove her story (she's using her supposed role as a sex worker to explain why she was in an apartment where bomb-making material was found), but in another episode, the "revalation" that a girl is a virgin is a major, plot-changing twist.
    • In an in-universe case, one episode has a defendant in a rape case mount a defense based on the idea that women can't get pregnant from rape, and therefore, since his victim is pregnant, it proves that it was consensual sex. The main characters know it's complete nonsense (especially given that one of the protagonists is actually a Child by Rape), but the defendant spins the story well enough to deadlock the jury.
  • Life After People just lapsed into this trope, showing footage of Volvox and Paramecium — two well-known varieties of protist — while discussing how living bacteria might've hitched a ride on one of NASA's deep space probes. Protists are more closely related to us than to bacteria, and the types shown would die just as quickly as we would in hard vacuum.
  • Nobody expects a fake-cryptid-sightings show like Lost Tapes to keep up scientific credibility, but the statements of their bogus "experts" can contain such idiocy it makes you wonder if they're doing it on purpose. When discussing werewolves, a fake biologist cites instances of a chameleon or octopus changing color as examples of "metamorphosis".
  • In Lucifer (2016), the Biblical Cain has blond hair, blue eyes, and light skin, traits that did not exist in humans at the time of his birth; however, to attempt reconciliation between known human genetic history and a show-universe in which the actual, Biblical Adam and Eve and their children definitely exist is to open a jumbo-sized can of potentially flammable worms.
  • Monk: A woman kills a billionaire by poisoning a death-row inmate, thus ruining the kidney he was going to donate to said billionaire. They both apparently have the "rarest blood type in the world" — "AB Negative with D antigen." Except that the Rhesus D antigen is what we mean when we say "positive" or "negative." No wonder AB Negative with D Antigen is so rare... it doesn't exist! "AB with the D antigen" would mean he's AB+... and therefore can accept any blood type! Also, only blood expresses the Rhesus antigen. All that's required to match in organ transplantation is the ABO blood type; all the recipient needed was another AB-type kidney.
  • A suspect on NCIS told Ziva that his aquarium held clownfish, triggers and lionfish. The fish in the tank are clearly clownfish, porcupinefish and surgeonfishes, and keeping lionfish in the same tank as smaller fishes is a great way to get the latter envenomated or swallowed.
  • New Girl: In the final season, Winston is revealed to be colorblind, and he sees all colors as shades of brown. Actual colorblindness is being unable to distinguish between a few specific colors.
  • Norsemen has a 780 AD slave state that urine is sterile, which is a common modern misconception. While urine is sterile in the body, the moment is passes out a urethra it stops being sterile. However, it's Rule of Funny just for a Dark Ages slave to be aware of the concept of sterility to begin with.
  • The Outer Limits (1995)'s Season 7 "Flower Child" was a flagrant offender in this category, featuring Violet, a plant lifeform taking the form of a hot chick via stealing human DNA. At the end of the episode and when her plans are questioned, she reveals her plans for Earth — to the human male who "fathered" her family of spores, no less — with the words "A new species, part you but more of me. To spread across this land, to become many. To become dominant." Isn't the whole point of inherited genetic characteristics that each parent contributes HALF of their DNA to the child, and not more than half? But even more so, since Violet's human form isn't 100% E.T. by default, isn't the new species going to be more him?!?
  • The Power (2023): The titular power is thousands of times stronger than the stated natural equivalent (eels) and it does whatever the plot requires, e.g. will strike distant targets, rather than flowing via the shortest path to earth, like any normal electricity. Further, the electricity organs in eels take up much of their bodies, while here the skein is small, no longer than the collarbone and have somehow remained dormant without previous signs or detection. In-Universe, nobody finds this odd, but it goes against everything known of how this works biologically and would overturn a lot of our existing scientific models.
  • The creators of Primeval do this knowingly and willingly for the sake of Rule of Cool.
    • Most notably, the Dracorex looks less like an ornithischian dinosaur and more like a dragon, with wing-like dorsal crests, exaggerated horns, and no cheeks.
    • Also, while the time for tranquilizer darts to take effect varies, it's usually more than ten minutes, as opposed to less than five seconds.
    • In the first episode, Cutter comes across a human skeleton. He is initially worried that it may be his missing wife, but he soon realizes that it's a male skeleton and thus can't be her. Fair enough, but the way he checks is by counting the number of ribs. Never mind that this is based solely on the Biblical account, which even then only affected one individual from who knows how long ago (it was never said to be a hereditary trait). Checking the shape of the hipbones would be easier.
  • QI:
    • In an episode about animals Sean Lock, either as a joke he kept up all evening (claiming that he learned everything he knew about animals from glamour-model Katie Price), or through what he professed to be sincere ignorance, was unable to score a lot of points. Among other "facts", he claimed that Rhinos are dinosaurs, because he thought they were called "Rhinosaurus".
    • In another episode, host Stephen Fry rather patronisingly "corrects" Jimmy Carr when the latter suggests that marsupials are mammals, which they are.
  • On Rides, the build team works to incorporate a real human skull into a spooky-themed vehicle's sound system. The narrator constantly refers to the skull as "he" and "Don", yet the numerous close-ups show features that suggest it's really a "Donna". Granted, the show's cast have no training to recognize this... but you'd think the suppliers who provided the skull would've mentioned it.
  • In the third episode of Sanctuary, Zimmerman claims that the last major outbreak of the Bubonic Plague was in 800 AD (the end of the Plague of Justinian). Leaving aside for the moment that he should have said "AD 800," the last major outbreak of the plague was in 1945. He was only off by about a millennium. Even ignoring the occasional outbreak in modern times, he's completely missed a little thing called "The Black Death" in the 14th century, the most famous plague outbreak in history, where it killed one in four Europeans.
  • In one of the early episodes of Smallville (which, admittedly, is not well-known for scientific accuracy), an embittered loner entomologist decides to take out his newfound mutant aggression on his mother. He blames this on his nifty bug genes, but rather than describing a real critter, he likens himself to the fictitious pharaoh spider. The fact that this creature exists in Sphinx and the Cursed Mummy is either a coincidence or a Shout-Out, as the game wasn't released until two years later.
  • The entire StargateVerse is filled with terrible biology.
    • In Stargate SG-1 and Stargate Atlantis there are many references to humans not being as evolved as other alien races. Plus how you ascend, you have to evolve into it, or jump into an evolution machine, or have your brain operating at a certain "wavelength" or whatever happens to be the trope of the week.
    • The Asgard have a serious problem — they are all clones and because they simply clone their last body their DNA is degrading! It seems that nobody had the bright idea to not copy the last clone, but just use the original copy every time. Though this is actually the point — they do not have any original from back in the time when they were still well enough. They found some ancient frozen Asgard, but those were not yet ready to be used as "hosts". There is no saying what the requirements of the clone are — possibly, the mind transferring process isn't actually as simple as they make it to be — possibly, the body has have some compatibility with the "transplantee". By the time they realized they have a problem, it was already too late. Yes, they could have bought some time if they stored some current copies for later use, but at the end of the series, they made it clear they do not want to protract their "death" as a species any longer, when there are no advancements in their condition.
    • In Stargate Atlantis Dr. Becket concludes that the Wraith evolved from the Iratus Bug by using every trope in the biology book. The DNA of the Iratus Bug mixed with human DNA, and because parasites are normally identical to hosts they feed from, the Wraith were born.
  • Too many Star Trek episodes to name (some are covered on the subtrope pages).
    • Star Trek: Enterprise:
      • An Ensign has a slug-pet that is not faring well on board ship, so they drop it off on a planet. Not its native planet — just a planet. Admittedly it won't have any breeding stock, but still...
      • The Doctor mentions that human fingernails continue to grow after death. They only appear to grow because the skin around them recedes.
    • In the first season of Star Trek: Deep Space Nine, Dr. Bashir mentions how he missed being valedictorian at Starfleet Medical Academy because he mistook a preganglionic fiber for a postganglionic nerve — even though, as it turns out, a first-year med student wouldn't make that mistake. After this is pointed out by the fans (and the wife of one of the writers), later seasons revisit this and reveal that Bashir deliberately got it wrong to hide the fact that he received illegal genetic enhancements as a child.
    • Star Trek: Voyager:
      • In the episode "Macrocosm", we have viruses(!) which can grow in size — up to a meter, fly, and hover in the air. It turns out that they somehow could do it by taking an alien growth hormone.
      • The way the Occampans (Kes' race) reproduce makes no real sense. The child can only be delivered standing up (the baby coming from the back), maximizing the chance of mortality from the baby falling to the ground, sex (or at least reproduction) is a very complicated procedure which includes foot massaging, and they only become able to bear children once in their lives. Even if both the men and the women of the species had babies with a 0% mortality rate (and none of those babies die between birth and having their own child) that means they can only maintain their current numbers. The expanded universe explained the first point by saying that twins and triplets are common among the Ocampa, but it still doesn't excuse the fact that they can only give birth while standing up, increasing the chance somebody is going to drop the baby upon delivery. note  Perhaps those are limitations caused by the dependence from the Caretaker.
      • In the second episode, Kes asks for soil samples to help her in setting up a hydroponics bay. Hydroponics is the means of growing plants without soil. Possibly excusable if the samples were being analyzed to determine the right proportions of minerals to add to the hydroponic fluid.
    • Star Trek: The Next Generation:
      • "The Chase" attempts to cure at least three problems at once... by making all of the Alpha Quadrant's DNA part of a message by a progenitor race, also humanoid, that "seeded" planets with their genetic code in the hope of more sentient humanoids like themselves popping up, an original idea that inspired a lot of 'ancient ancestor' settings. The original humanoids found that their home galaxy (not just one quadrant) contained no life that was like them. Their own extinction fears drove them to seed the Milky Way and as a result encourage humanoid life to develop. The code was like a signature for them — they wanted the Milky Way races to find out their origin to encourage cooperation... which, of course, implies that every non-humanoid carbon-based life form in the Star Trek franchise, from the grape vines in the Picard family vineyards to Captain Archer's beagle, is essentially doing it wrong.
      • In "Genesis", switching on Barclay's T-cells causes the Enterprise crew to — sigh — devolve to a variety of different species... most of which have common ancestors diverging HUNDREDS OF MILLIONS OF YEARS AGO — and Spot the cat becomes an iguana. Apparently in Star Trek, everyone walks around with copies of not only the future evolutionary patterns of their own species but also whole swathes of species that are completely unrelated to them from their home planet. The worst offender being Barclay's devolution (and presumably re-evolution) into a spider, which would only be possible if he devolved into a pre-Cambrian lifeform first. Data devolving into a pocket calculator would have made more sense. The episode also claims that the disease was the result of cells turning into viruses. While viruses do infect cells and use them to reproduce, they don't cause cells to transform into copies of them. There's also Spot's kittens. First off, they're meowing when Data discovers them — in real life, kittens only start to meow at one month old. Secondly, some of them are calico, implying their father is calico. In real life, male calico cats are sterile.
    • Star Trek: Discovery: The mycelial network and space tardigrades integral to USS Discovery's signature "spore drive" were inspired by actual science, but as per usual for Star Trek, are mixed with hefty amounts of Applied Phlebotinum, Technobabble, and misused terminology.
  • Supernatural:
    • "The Kids Are Alright" involves changelings that replace children, then feed on the unsuspecting mothers' synovial fluid. The creatures leave big lamprey-like bite marks at the bases of the mothers' necks, which only makes anatomical sense if they feed on cerebrospinal fluid; to get synovial fluid, they ought to have bitten knees, hips, and other large diarthrotic joints. A loss of synovial fluid should not cause death, by the way: it causes severe arthritis, which none of the afflicted mothers exhibited.
    • In another episode, a charred bone from a witch's bundle is identified by the boys as that of a newborn baby. Long bones of infants don't have fused epiphyses on their ends, while this one clearly has them.
  • In Terminator: The Sarah Connor Chronicles’s first season, Derek needs a blood transfusion. Apparently, he needs his own blood type despite being AB ("Universal recipient", able to take blood from any other type)... Sarah said she was type O ("Universal donor", able to give blood to anyone), but her biological son John was AB?! Even if John's father Kyle was also AB, John must have an O from his mother, so he's either A or B, yet his not-AB-blood worked just fine...
  • Brannon Braga, of Star Trek fame, went on to create a short-lived sci-fi series also called Threshold. The premise? Alien space signals cause people's DNA to begin re-writing itself! At least this time, the characters acknowledged that this should be impossible and had trouble dealing with the idea that it was actually happening.
  • In Toby Terrier and His Video Pals, Toby helps Don by pointing out he's about to pick up the cleanser that someone left out, not the chocolate powder that he wanted in their milk. If they were real dogs, they'd have to worry about both of them being harmful - chocolate is poisonous to dogs.
  • The Tomorrow People (1973): What makes it worse in this case is the fact that the show had a scientific advisor listed in the credits!
    • Claims that evolution takes "thousands" of years. It is far more complicated than that. Populations and species are constantly evolving — they are not simply different a million years later. Microbes, bacteria and viruses especially, evolve in terms of decades and single years. Why do you need a flu vaccine every year? Why do bacteria like MRSA come along? Microevolution.
    • In "Hitler's Last Secret", John explains, straight faced, that "Genes are those body cells known as the DNA molecule." Which is like saying "voting districts are those sovereign nations known as the first-past-the-post electoral system"—each of the component phrases has a definite meaning, but they are combined into gibberish.
  • The spin-off Torchwood has a character ask if Weevils might be mutating and thus becoming immune to the Weevil spray. So far so good. Then the Battle Butler adds "or evolving".
  • In "The Fur-gitive" from Turner & Hooch (2021), Trent touches what is said to be poison oak and then touches his face. Within about a minute, he has a terrible red rash on his face. In real life, rashes caused poison oak, poison ivy or other similar plants are a delayed reaction that takes at least 4 hours to even start developing in someone who has been previously exposed.
  • In Twin Peaks, much like the Friends example above, some of the female characters (Donna and Audrey in particular) have significant hair growth after a few episodes, considering each episode is supposed to represent about a day in real time. Obviously an issue of scenes being filmed weeks or months apart. Example here.
  • Wilfred: Wilfred sees only in black and white, but this is a common misconception. Dogs can see several colors, including blue and yellow. However, given that Wilfred's whole personality is revealed to be Ryan's imagination, he apparently just believes this misconception.
  • An episode of the National Geographic Channel's series World's Deadliest claimed that the lion is the largest African predator. A large Nile crocodile can weigh five times as much. Potentially due to confusion over "Carnivore" (as in "order Carnivora", of which the lion is indeed the largest member in Africa), and "carnivore" (as in "meat-eater in general"), which is often used interchangeably with "predator" (despite scavengers also eating meat).
  • The X-Files has a bit of this with most monsters-of-the-week.
    • Human-flatworm hybrids can happen on their own with enough radioactive sludge.

      The same monster also mashes together three different and entirely unrelated flatworms: planarian (the "larva" prop animal note ), tapeworm (it has a scolex, i.e. the "head" of a tapeworm), and finally fluke (the name given).
    • In "Blood" an LSD-like substance was combining with adrenaline to produce a hallucinogenic substance... in the eyeball. They have visual hallucinations (or did they?) The eyeball could probably absorb it into the blood, but the coincidence is a bit much.

  • Dem Bones song found here (warning for sound)
    • "...the toe bone's connected to the heel bone..." [Nope, there's metatarsals and other tarsals in between.]
    • "...the thigh bone's connected to the backbone..." [Also nope, there's a little thing called a pelvis between them.]
    • "...the neck bone's connected to the head bone..." [No such thing as "the" neck or head bone: both head and neck have several.]
    • Depending on how you look at it, either very few bones are actually "connected" to other bones, or all of them are connected to all the others (the various skull bones are pretty clearly connected to each other, as are the fused bones at the other end of the spine; other than that, they mostly just hang out near each other and are connected only by soft tissue without actually touching).
  • In the children's song "I'm Being Eaten By A Boa Constrictor", the snake swallows its prey feet-first. This is backwards from how snakes normally feed (granted, doing it the right way around would make for a much shorter song...) Another problem with the song is that boas kill their prey before they start to swallow it.
  • "Worlds Within The Margins" by In Flames contains the line "coded within the spinal cord of the trilobite". Trilobites were invertebrates, they did not have spinal cords.
  • The original demo of "Four of Two" by They Might Be Giants ends with the narrator being Driven to Suicide note : His method is self-strangulation with his bare hands, which isn't physically possible - at worst you'd pass out from lack of oxygen before you succeeded in strangling yourself for long enough. This may have been meant to add to the Black Comedy tone of the song.

    Pro Wrestling 
  • Back in Stampede Wrestling, the Dynamite Kid, a Heel, was feuding with Davey Boy Smith. Dynamite took a rather, to put it mildly, unique approach to generating heat for the feud. He and manager JR Foleynote  were being interviewed and Dynamite claimed that Davey Boy was a test tube baby, but that's not the unscientific part. The unscientific part was Dynamite saying that Davey being a test tube baby meant that he wasn't human and that he should "go back to Jupiter or Mars."
  • Black Tiger's mask having silver stripes is clearly for artistic purposes. Real black tigers have black stripes, with the "stripes" being thicker areas of fur. But that's not so visible to those in the cheap seats, is it?

  • In Survival of the Fittest, during V1 in particular, there were examples of writers who decided to eschew any pretence of realism in their kills. Later versions have done their best to avert this. A particularly...interesting example.

    Tabletop Games 
  • White Wolf's Aeon Trinity contains the following gem: "[Psions are] the product of natural human evolution, not genetic mutation." This was later retconned to refer to mankind's spiritual evolution.
  • Dungeons & Dragons:
    • Any character who has Planetouched ancestry (tiefings, aasimar, and genasi) has a chance to have offspring of that type. No matter how many generations removed from their Planetouched ancestry they are. Of course, this is because it's magic, not genetics. Or magical beings like demons, celestials, and genies have equally magical genetics
      • As of 4th edition, though, tieflings are back to having supernaturally tainted blood, rather than a genetic condition; the first tieflings were the result of normal humans undergoing an infernal ritual, rather than interbreeding with demons.
      • The Brimstone Angels novel series offers a further clarification for the Forgotten Realms setting; thanks to a powerful ritual, all tieflings are, spiritually, considered descendants of Asmodeus regardless of their actual lineage. Since Asmodeus is a god, his power is just that virulent and natural laws really are just guidelines as far as he's concerned. That said, tieflings with a lot of human blood are still depicted as being somewhat more human looking than those who are closer to the fiendish end of the family tree.
    • Some D&D examples of this trope don't even have A Wizard Did It as an excuse. One of the Mystara setting's supplements featured a former underground empire of gnomes, now abandoned and infested with kobolds, various dungeon vermin, and wild herds of fungus-grazing mules. The mules were supposedly the feral descendents of the gnomes' mule beasts of burden. While female mules may not be 100% sterile, fertile males are so rare that the only evidence of such creatures is anecdotal, making a wild population of mules virtually impossible even on the surface, never mind underground!
    • Fungal enemies, such as the shrieker or violet fungus, are generally listed as belonging to the Plant type. "Plant" and "fungus" are mutually exclusive — in fact, fungi are more closely related to animals than to plants. Pathfinder, being spun off from D&D, initially did the same thing, but Second Edition introduced a separate "Fungus" creature type.
    • The rules for creatures that can Swallow Whole say that if a swallowed opponent manages to cut their way out of the stomach, "muscular action" will force the hole shut behind them. Of course, muscles don't work like that, but the rule was instituted as an Obvious Rule Patch to keep the creature from becoming little more than a really macabre water slide. Fifth Edition changed things so that instead a creature will involuntarily regurgitate everything it's swallowed if it takes a certain amount of damage from creatures it's swallowed whole in one round.
    • The adventure "Icewind Dale: Rime of the Frost Maiden" has the titular effect being a magical ritual that essentially blots out the sun, leaving only indirect sunlight equivalent to pre-dawn light, and that only for four hours a day. The remaining hours of the day have no sunlight. The adventure essentially states that if this isn't stopped, all wildlife will die out before too long. However, the effect has been in place for two years. In reality, after that much time had passed most vegetation would die off, followed by the herbivores, followed by the carnivores and humanoids. At a minimum, the entire ecosystem would completely change. In addition, the adventure states that the average temperature is about -49°F, with windchill lowering that even further by up to 80°. There would be no way for humans and most wildlife to tolerate that kind of cold for more than a minute or two, not even counting the fact that the wind required to lower the temperature by that much would be over 100 mph.
  • F.A.T.A.L. allows for completely out-of-whack character biology. Would you like to have nipples the size of your head and anus with negative circumference? Equally silly is being able to hit a very specific internal organ AND NOTHING ELSE on the enemy; to quote one of the more infamous reviews:
    "The two stared at each other, then struck simultaneously. Jack's sword cleaved through the cultist's chest, cleaving through the nipple, the xiphoid process — the lowest part of the sternum — and the shoulder blade. The cultist's blade only caused damage to Jack's appendix and his adrenal gland, somehow missing everything else in front of and in back of Jack's adrenal gland and appendix."
    • Having your heart torn out kills you in two rounds, which is slower than having your testicles cut off, which with a failed save will kill you instantly. Exactly why the creators of FATAL consider the testicles more vital to life than the heart is left as an exercise for the reader, one you probably don't want to solve. Considering the sophomoric sensibilities of the creators, it's possible that they personally value their testicles more than their hearts.
  • In FGU's Space Opera, a character who has died can be injected with "TKM"; a drug that stops cell decomposition. But the drug reaches the whole body via circulation, a function that stops at the moment of death.
  • Two specific cases in Rifts, listed separately:
    • In the Atlantis Sourcebook, a parasite called a Brain Feeder is said to "...excrete a chemical that anesthetizes the area of the brain it is eating..." This would be unnecessary, as there are no pain receptors in the brain, and therefore it can't feel pain.
    • This one could well be a case of Science Marches On. There is an animal race in the books called an Ostrosaurus, which is not a dinosaur but "a large featherless bird." According to modern paleontology, birds are dinosaurs.
    • The description of dragons says that they are actually mammals, not reptiles, even though they are scaly, hairless, egg-laying creatures that don't produce milk.
  • In Warhammer 40,000 science generally takes a backseat to the Rule of Cool, but...
    • One particularly egregious example needs to be mentioned: The Eldar are stated to have TRIPLE HELIX DNAnote  and are somehow still hinted to be capable of birthing a viable human/Eldar hybrid, the sole example of which is one of the Ultramarines. This has since been retconned out of existence. The fact that female Eldar may have ample chests even though Eldar have literally not a single gramm fat in their bodies is almost tame in comparison.
    • The Kroot. Mostly blank DNA, and they evolve very rapidly by incorporating DNA from everything they eat into their genetic structure. Now answer us this: if their DNA is "blank", how do their embryos form into Kroot in the first place? Definitely a case of 'well, it sounded cool when I wrote it''.
    • Ork DNA, in past editions, contained an "algal base" that explained their resilience. This made no sense whatsoever and was dropped; now their DNA just happens to be very, very similar to algae, to the point where they can photosynthesize.
    • The Obliterator virus. Exacctly how it works is anyone's guess (the Warp is involved), but the infectee ends up bonded to his weapon, and ends up able to produce the ammo for it.

  • From BIONICLE: According to the Greg Farshtey, the Makuta "evolved" into antidermis. However, if the Makuta were originally meant and specifically engineered by the Great Beings so that this would happen, this would make it simple metamorphosis.
    • Greg Farshtey has addressed his use of the term "evolution." Because natives of the Matoran Universe don't biologically reproduce, such changes are referred to as evolution. In the story's final days, it was revealed that dead beings are sent to the Red Star for healing and repairs, but a malfunction kept them from returning.
  • Bratz has "'Lil Angelz" veterinarian toys, including pets who get sick. The problem? You take their temperature orally. That's passable, for a children's toy, but the animals' temperatures are at normal human temperatures — as opposed to their actual regular temperatures.
  • Crazy Bonez plastic skeletons meant as Halloween decorations are a bit less realistic than advertised. Most non-human mammals feature bones for their external ears, birds have feather bones, and spiders are given whole vertebrate-like internal skeletons.

    Video Games 
  • Amnesia: The Dark Descent: When Daniel has to (quoting TV Tropes here), "drill a hole in the head of a corpse,[sic] insert a copper tube into the hole, and stick yourself on the needle to give yourself an injection of a vaccine." God only knows if they're the same blood type or how long the body's been dead, if he had any infectious diseases, or if the antibodies have degraded and are no longer viable. Somewhat justified since the game takes place in 1839. Blood groups weren't starting to be identified until 1901. How blood-borne pathogens work and the intricacies of vaccinations was also not as well understood at the time.
  • Borderlands 2: Mister Torgue's Campaign of Carnage: The Big Bad Piston mocks the Vault Hunter throughout the main story missions. At one point, he claims to have less than one percent body fat and thirteen pecs, which earlier laughed at the Vault Hunter.
  • Dr. Jekyll and Mr. Hyde: The birds defecate large brown poop instead of the small white pellets birds normally excrete.
  • Fable II:
    • Eating celery makes your character lose weight because, as the flavor text states, it costs more energy to digest celery than it provides. This is an urban legend. Eating celery provides calories.
    • There's something a little magical about the dog's longevity. The character gains its companionship in childhood, and it's still just as spry when the character is an adult with children who are old enough to speak. Dogs of that size rarely live more than 13 years.
  • Final Fantasy:
  • Hitman (2016): The final mission of Season One brings you to the most advanced hospital in the world, where one of 47's targets, a person who suffers the condition Situs Inversus (Mirrored organs), is about to have a heart transplant. 47 can destroy the mirrored heart that was meant for him, which, in theory, dooms him to die at the operating table because mirrored hearts are extremely rare and they would have no time to find another. In practice, however, patients suffering from Situs Inversus can receive non-mirrored organ transplants. The operation is a lot more complicated but, again, we're talking of the most advanced hospital in the world...
  • Jump Start Spelling features some cavemen mistaken Edison Firefly for fire. And yes, his abdomen gives off heat.
  • The Legend of Spyro: The main villains for most of the series are called apes, but their tails show them to be monkeys and their colorful faces specifically identify them as mandrills.
  • The Legend of Zelda:
    • In general, beehives take the form of round fans of hexagonal cells hanging from a stem, which look like wasp nests far more than anything bees make — wild beehives consist of parallel sheets of honeycomb hanging down from a support structure.
    • The Legend of Zelda: Breath of the Wild:
      • Wasteland coyotes have very little in common with the actual animals. They're a recolor of the game's other wolf varieties (real-life coyotes are much smaller than wolves), hunt in packs (coyotes are usually solitary, and at most form mated pairs), and are found in the wrong environments (coyotes can be found in rocky deserts and dry scrub, but they don't live in true sand seas like the Gerudo Desert).
      • The Hyrule Compendium describes grassland foxes as solitary animals that don't form packs, which is correct, but in this they're explicitly to be "unlike other foxes". All real-life foxes are solitary animals, and the other kind of fox in the game, snowcoat foxes, are also only found alone. Also, in-game foxes will eat fruits but won't touch meat, in contrast to the primarily carnivorous real deal.
  • Leisure Suit Larry 6: Shape Up or Slip Out!: If Larry goes to the mud bath still wearing his leisure suit, it melts and the narrator says La Costa Lotta keeps the temperature of their mud baths slightly higher than the melting point of polyester. He can survive if he takes it off before bathing, though. The melting point of polyester is somewhere around 482 degrees Farenheit or 250 degrees Celsius. No human, wearing a leisure suit or not, could survive bathing in such a temperature.
  • Little Red Hood: Cherries come out of palm trees. Needless to say, in real life, the only fruit palm trees can produce are coconuts.
  • The developer of The Sapling has admitted in the devlogs that he simplified parts of biology in order to make the game easier to understand. For example, whether an animal can breathe on land or water depends on its mouth, even though not all animals breathe through their mouths in real life.
  • Madagascar: Escape 2 Africa: Did you know that giraffes get actual butterflies flying in their stomachs? As well as fish and even whole colonies of mushrooms - not fungus, but regular, stem-and-cap mushrooms? Play this game and you’ll be delighted.
  • Mario Kart 8 makes the same mistake that The Super Mario Bros. Super Show did decades earlier: the giant beanstalk in Cloudtop Cruise is growing equally large pea pods. Same family, different genus—not to mention that pea plants don't grow anywhere near as tall as beans do.
  • Mass Effect, like most Space Opera settings, takes quite a few liberties, like most sapient alien species bearing a humanoid body plan or resembling earth reptiles, arthropods, and amphibians in biology. However, two examples stand out:
    • The presence of fish on many worlds. As in, bony fish classifiable as such.
    • A rather unfortunate misunderstanding of dextro-amino acids. See Mirror Chemistry for more information.
  • Metal Gear:
    • Metal Gear 2: Solid Snake. Four words: Deadly poisonous Zanzibar hamsters.
    • The whole business in Metal Gear Solid where the Les Enfants Terribles twins were created as double-dominant and double-recessive for absolutely no reason other than to give Liquid Snake something to obsess over. And no, you can't be a homozygous recessive individual because the term is meaningless outside a breeding population.
      • Even if he could have all of Big Boss' recessive genes, there is nothing about this that would make him inferior. Really, one learns in fifth grade that a gene being recessive simply means it will be overridden by a gene that is dominant to it, which is not the same as saying the dominant gene is better. There's also the part where Liquid grossly misapplies Asymmetry Theory. His ramblings just make it seem like the writers had at some point heard of the biology/genetic concepts mentioned, but didn't actually bother to look into them any real way.note 
      • It's also later revealed that it was actually Liquid who got all the dominant genes, and Solid got the recessive ones. One problem - Liquid Snake is blond. The gene for blonde hair is recessive. Similarly, Snake has brown hair, when the "brown hair" gene is the dominant one. If Liquid really got all the dominant genes and Solid got all the recessive ones, then Solid should be blond and Liquid should be brunet. This is possibly partially averted, as the briefing footage depicts Solid's hair as fair-colored or blonde, implying that he had dyed his hair brown before the mission. This is not the case in The Twin Snakes, where the footage was recreated with the character models. That being said, the remake's detail differences conflict with later references to the Shadow Moses Incident, so its canon status is questionable.
    • Metal Gear Solid 3: Snake Eater goes with this as part of its attempt to be more camp and silly than the noticeably-more-serious Metal Gear Solid 2, with bosses that do things that make no biological sense without any sort of long-winded explanation for why. There's the guy whose body carries a charge of ten million volts, the guy who controls bees (and can't make up his mind whether they're bees or hornets) to do things with them including shooting them out of his mouth or forming them into a fully-functional Tommy gun, and the hundred-year-old guy who can actually recover his stamina through photosynthesis.
  • In Metal Slug 3D, there's a scene when Rumi tells Marco that carbon dating estimated that an alien ruin Marco was exploring was 8 billion years old. Even bypassing Ragnarök Proofing, carbon dating will only work on artifacts less than 60,000 years (or so) old. Other methods of testing radioactive decay are necessary for something far older. The alien ruins are well on their way to being twice as old as the Earth (4.6 billion years old).
  • Apples in Minecraft are harvested from oak trees. This is, admittedly, because they started as plain oak trees that didn't have any fruit, and the apple drop was added later, but you'd think Mojang could have at least renamed them — it's easy enough to do it yourself with a resource pack, after all.
  • Mortal Kombat is very guilty of this, especially in the 3D games: Rip out a brain, the body is still standing AND feeling pain; rip out a skull, and the head still has shape; rip out your own tibias, and you're still standing; sever someone's head, and the body is still standing; the list goes on. In Mortal Kombat 3, certain Fatalities can cause several of the same thing to get ripped out, including multiple hearts, rib cages, and skulls. Also, most often these are ripped out through the chest. Yes, even the skulls.
  • In Moshi Monsters, the chimpanzees have tails.
  • NetHack variant Slash'EM Extended has goats and other mammals that lay eggs.
  • Deliberately invoked for horror in Outlast: Whistleblower. Eddie Gluskin, a psychotic Serial Killer even before his Mind Rape in the illegal underground lab below the Asylum, is fixated on finding himself a perfect bride. In response to being surrounded only by men, he's come to the conclusion that as the only major difference between genders is that men have a penis and testicles whilst women have a vagina, and as the vagina looks a lot like a cut, brutally castrating men and using the resultant wound as a vagina will make them fully functional as women, complete with bearing his much-wanted children. Needless to say, it does not work that way, but he's so demented that he refuses to accept that he's doomed to fail.
  • New Super Mario Bros. 2 Introduces the bone piranha plant, which is a plant skeleton. Since when do plants have bones? Not to mention it has lip bones as well!
  • Planet Zoo:
    • The gharials use the same animations as the crocodiles, including "high walking" like them in order to move around on land. In real life, adult gharials are incapable of walking, instead pushing themselves around with their limbs like seals.
    • The patterns of the Nile monitors are much simpler and brighter in color than those of the real animals.
    • Giant tiger land snails can be male or female in the game just like any other animal, but in real life they're simultaneous hermaphrodites, i.e. all individuals have functioning male and female genitalia.
    • Birds, reptiles, amphibians & invertebrates don't lay eggs in the game, babies are just spawned. Though this may be just simplicity for the sake of gameplay. In real zoos, visitors don't see eggs in enclosures since they're taken away for incubation. This mechanic could have been included in the game, vets already can take away sick & injured animals for treatment.
    • The titan beetle is present in the game even though it cannot yet be bred in captivity.
    • Some snakes are modeled with scale textures on their heads instead of scutes.
    • Reptile and bird poop looks unrealistic (with exception of penguins): it's brown, while the real thing has white portion (urates), and bird poop is modeled as round mammal-like droppings.
  • Plague Inc.:
    • Whenever you mutate your pathogen, the mutation appears simultaneously in all of the pathogens at once. The game's creator likened this to if a six-fingered baby were born and every human on Earth suddenly sprouted an additional digit too. Rule of Fun is clearly in effect here because it would drag the game out very tediously if you had to start over with every new strain.
    • All acquirable mutations are purchased using a "currency" known as DNA Points. However, it is possible to play as a prion, which are non-living entities that do not have DNA. They're also incurable in reality, but to keep the game balanced it can still be cured in-game (however, it still takes longer for the population to find a cure versus other types of pathogens as a nod).
  • Pokémon:
    • Several of Cubone's Pokédex entries state that it wears the skull of its mother. Every Cubone encountered has a skull on its face, which means that EVERY SINGLE Cubone commits matricide (or its mother just dies) shortly after birth and each female Marowak/Cubone can only have one child. The species should have either died out or have rapidly dwindling numbers at this point. However, worth noting is that when breeding Cubones, you can get as many of them as you want from one mother, and they will all already have skull helmets. Additionally, in Pokémon Origins a Cubone is seen with its alive mother Marowak, and yet it has a helmet. These suggest that this Pokedex "fact" is either not true or has since been retconned.
    • The Pokédex also states that Vaporeon's "cell composition is similar to water molecules. As a result, it can melt away into water." A cell is a lot more complex than a three-atom molecule. Even if we assume this to be a mistranslation that should read something like 'its cells are composed mostly of water', then we (and everything else alive) could too.
    • All Pokémon capable of breeding lay eggs, even those based on mammals. In real life, most mammals bear live young, except for the monotremes. This is likely done to avoid teaching children the truth about mammalian reproduction before they are ready. Nevertheless, many fan works depict these Pokémon bearing live young like most of their real-life counterparts.
  • Red Dead Redemption: Pumas don't sound like jaguars. In fact, they don't roar at all, but growl, hiss and make snarly near-human screams.
  • Red Dead Redemption II:
    • Tuberculosis doesn't quite work in real life the way it works in this game, presumably for the sake of time compression. First of all, only about 10% of people who get infected ever develop the disease and generally speaking if you make it two years without showing symptoms, you're in the clear. Although people who smoke like Arthur Morgan do have a higher probability of it becoming active. Even today about 80% of people who live in the developing world carry the disease even though it can now be treated with a course of antibiotics. Second of all, even pre-antibiotics you had about 1/3 chance of being able to survive it so it wasn't an automatic death sentence. It varies how long it takes to start showing symptoms but presuming the game takes place over the course of a few months, the time it takes for Arthur to start getting sick is accurate. What's not accurate is how quickly it takes him to die. It usually takes several years for this to happen,note  not several months. Had it taken that long for Arthur to die, it likely would have dragged the story out, especially given that they were already working with a pre-existing timeline. Of course, he does die after receiving a hard beating and sharp blow to the head, so the TB may have simply left him too weak to survive that.
    • Dutch's horse, The Count, is said to be an Albino Arabian Stallion. In real life, horses cannot carry true albinism due to Lethal White Syndrome. Albino horses are born with non-functioning colons and die within a few days of birth. (Then again, this might be an intentional clue to highlight Dutch's tendency to lie and exaggerate, and thus simply be a white horse.)
  • Resident Evil:
    • Viruses that jump species like they're on a trampoline, a single strain that triggers all kinds of mutations depending on the host, people that explode into building-sized masses of limbs and tentacles in seconds, giant arthropods who somehow don't suffocate to death, a modified gene that kills weaker cells "through natural selection" to somehow empower the carrier, mind-controlling parasites with a caste system, monsters with biological machine guns and chainsaws... and all of this is tied back to a rare flower that produces a gene-altering virus, but only if it's in a very specific location in Africa.
    • For example, the T-Virus is able to infect humans, mammals, reptiles, birds, even invertebrates; real-life viruses are usually limited to a few, closely-related species due to messing with DNA. The third game (and the movie that takes cues from it) even had it affect coffin bound dead bodies in a cemetery, all of which were six feet under and conveniently popped out of the ground. As you might imagine, RE viruses tend to discard the rule of biology whenever it interferes with the Rule of Cool.
    • Resident Evil 6 has its zombie-making virus transmissible via gas.
  • In Ripper, the killer is revealed as hacking people's minds/brains to program their bodies to self destruct. While there are ways to theoretically kill someone if you interface with their brain, the Ripper somehow increases the internal body pressure to cause them to explode from the inside. Somehow the forensics investigators keep thinking the killer is killing by slicing people up with a knife, which would look nothing like exploding from within, even assuming programming your body to explode was possible.
  • In Sly 2: Band Of Thieves, one of Bentley's plans works on the assumption that tigers dislike water. In real life, tigers are one of the few known types of cat who like to get wet. Also in the Sly Cooper games, Bentley (a turtle) and Murray (a hippopotamus), both aquatic creatures, instantly drown upon contact with a body of water.
  • Sonic the Hedgehog:
    • Knuckles the echidna does not really have the beak of an echidna.
    • Charmy does not have the 6 limbs of a bee.
  • StarCraft: For a series that goes to great length to explain how everything works, the powered marine armour really shouldn't require multiple shoulder dislocations... Arguably explained and justified by the opening cinematic for StarCraft II, though that depends on whether you believe Tychus Findley's build is at all realistic.
  • Star Ocean: The Last Hope features a number of baffling evolutionary presumptions. For instance, there are apparently "right" and "wrong" ways to evolve, and we should "make our hearts worthy" of evolution. Edge Maverick must not hold protozoa in very high regard. Edge, sweetie, that's "cultural development" and "reaching a specific level of technological advancement (specifically interstellar travel) within that culture" you're thinking of, not evolution, the two are almost entirely unrelated.
  • Wario: Master of Disguise has a dolphin boss who breathes water instead of air, and the way to beat it involves trapping it above water so it gasps like a fish. Because dolphins are obviously fish.
  • In Webbed, the main character is a jumping spider whose abilities are weaving webs... and shooting laser beams from her eyes.
  • The Witness: Out of all the rooms inside the greenhouse, the one with green light is probably the most prominent: it provides the main difficulty for the elevator puzzle, it's harder to reach compared to the other rooms, it contains an audio log and an environmental puzzle, and it's the only one which can be seen from the outside. It's ironic that the green room was chosen to be this way, considering it's also the most unrealistic. Chlorophyll absorbs light throughout the visible spectrum, but mostly in the blue and red regions and very little in the green region (in fact, of all the many pigments that plants use to absorb light, none of them absorb much green light).note  Plants look green because they reflect green rather than use it.
  • Wildlife Park 2:
    • Bear models have 3 claws instead of 5.
    • Baby mammals don't nurse from their mothers, unlike in Zoo Tycoon 2.
  • Wildlife Park 3:
    • Female gorilla model is identical to male.
    • Baby King penguin modeled after Emperor penguin.
  • World of Warcraft:
    • The devs don't know how horses run (the game animates them the same way as a cheetah, with legs outstretched in the suspension phase instead of collected). But is it a big enough deal for the devs to correct it? Not really.
    • Elekk (a pseudo elephant mount) freakin' gallop. Come to think of it, so do the mammoths. Knee joints of adamantium!
    • The wolf mounts, and by extension, all wolf mobs using the worg model run nothing like an actual wolf would run. Wolf mobs using the alternative wolf model run properly.
    • Orcas apparently produce humpback whale song. When fighting, no less.
  • Splatoon 2: Played for Laughs. Within the game's lore, whatever wins a Splatfest competition is legally the "correct" choice. Most are simple things like "Which is better: ketchup or mayonnaise?", however one was "Which came first: the chicken or the egg?". Pearl believes it was the chicken and Marina believes it was the egg. Chicken ended up winning. After losing, Marina notes that most scientists believe that the egg came first, but Pearl won't listen and says that the law is the law note .
  • The videogame Trauma Center seemed determined to use every medical term possible to describe the main evil disease causing thing. The official name is the GUILT Virus, in which the T stands for "Toxin", but when you actually operate on it it tends to look like a tumor or parasite.

    Visual Novels 
  • The Cure Virus in Ever17. Willing suspension of disbelief can take you a pretty long way... but a natural retrovirus that not only rewrites the host to be immortal and has a Healing Factor? Maybe that one can slide. But with no apparent benefit to itself and also apparently adapting itself to give infrared vision to cover the inability to cope with UV rays and therefore be unable to go out when it's not dark? Don't think so! Retroviruses are not magical, intelligent and they do not change DNA for the benefit of their host. Odds are, however, that the Cure virus isn't natural. Leiblich was researching virus engineering, after all. It would explain how and why they knew Tsugumi had been infected at all. They infected her. Then, they studied her to try and find out what was about her that made the virus work. Never 7 reveals that the Cure Virus was created as a result of a Cure Syndrome delusion, so the "magical" part of the virus can be explained that the virus adapted itself to work in a human's body that way.
  • In Steins;Gate, Lukako's sex is changed by making the mother eat a lot of vegetables instead of meat. This is lampshaded as being an old wives' tale, and none of the characters really think it will work... so they are extremely surprised when it apparently does.
  • The Fruit of Grisaia: While cell memory similar to Michiru's does exist, and the heart is certainly the most reliable organ to donate for it to happen, it doesn't actually transmit an entire personality as a living consciousness with memories and all. Even if it did, it would absolutely not co-exist with Michiru in the separate-but-equal state shown in the novell.

    Web Animation 
  • Cow of the Wild: Rune's distinctive scar supposedly resulted from the pupil of his eye being ripped out. The pupil is a hole in the iris. Just think about that for a minute.
  • Mongolian Erectile Dysfunction: The title refers to a fictional condition where faulty wiring in the brain results in someone vomiting or soiling themselves when they are sexually aroused.

  • Demonseed Redux: Pregnant characters sans Dee are shown with large Balloon Belly.
  • George the Dragon has a sword fighting scene where the duelists have an improbable Darth Vader/Luke Skywalker moment. "Lobster, I am your Fish"
  • Gods World: Arby dumps a Bag of Holding full of sleeping potions inside the Creator's mouth, but the path they go down ... is questionably realistic.
  • Homestuck: The salamander skeletons seen in Act 6 have solid skulls of the kind present in amniote vertebrates instead of the kind seen in real-life salamanders, which are flattened and consist mostly of thin areas of bone around large, open spaces.
  • Ménage à 3: DiDi's breasts defy the laws of both biology and physics — despite having enormous natural boobs, they not only fail to sag at all, but are completely spherical, with the nipple appearing on the upper-third of the breast. A Rule of Sexy here, as Gisele almost never draws breasts as anything but round and perky.
  • The Last Days of Foxhound: Liquid Snake's appalling grasp of biology is repeatedly referenced and mocked. It actually explains that the entire dominant/recessive genes thing was complete rubbish and that Liquid was told he was the inferior one as a part of installing a massive inferiority complex in him, so he'd constantly keep on pushing himself to do better. And then it turns out to be a Double Subversion because Big Boss explains that it was actually Solid that got all the "recessive genes." It isn't just Liquid's grasp of genetics; it's Hideo Kojima's that's so hilariously wrong. Subsequently lampshaded when Liquid consults the American Journal of Inaccurate Genetics.
  • Off-White: In the setting, humans normally can't have blue eyes at all. This is necessary for the plot to work because White Spirits are indicated by their blue eyes. If humans could have blue eyes in this comic, they would have no way of knowing that the human White Spirit is gone, something that drives much of the plot.
  • The Petri Dish:
    • iBall the Cyborg is made from a whale's eyeball that's the size of a housecat, while in reality, whale eyeballs are about the size of cow eyeballs. Then again, his creator is a goofy genetic engineer.
    • Bacteria, viruses, cells, and amoebas are treated as being nearly equal and all sapient.
  • In Teahouse the brother-sister twins Remy and Rory are said to be identical even though that's impossible for a brother and sister pair. Word of God claims they did this on purpose.
  • Downplayed in Contest Jitters. Janet is very buff for a natural bodybuilder, but her trainer did comment that she had the genes for it. It is also shown that she works very hard at weights.
  • In general, it's missing the point to complain about biological inaccuracy in Funny Animal media, but Kevin & Kell's take on Dolly the Sheep gets deep into some real life misconceptions about Dolly and cloning in general. At one point, Dolly begins aging at an accelerated rate, going from a teenager to middle-aged overnight. While there was some speculation that this was the reason for the real Dolly becoming sick and needing put down at half the typical lifespan of a sheep, it was eventually concluded that there was no evidence to support this. Also, the thinking behind this speculation was that Dolly's cells might have started out at the "same age" as her donor-mother, but in Kevin and Kell, Dolly (like most fictional clones) is already the same age as the donor (Corrie Dale), and the increased aging makes her noticeably older than Corrie.
  • Mountain Time plays it in-universe, with two characters arguing nonsense biology.
  • Litterbox Comics is a Slice of Life webcomic about a family of humanoid cats in a World of Funny Animals. The comic delves into real animal facts—such as the gazelle mom mentioning that her baby could walk minutes after being born, and the hyena mom having a horrifying delivery—but then you have the main character eating a salad and trying to get her son to eat his vegetables, even though cats can't digest plant matter. This was handwaved by the artist, who said that whatever traits don't line up with real animals are due to the characters being humanoid.
  • Chainmail Bikini: In-Universe, Josh is called on the fact his character can't in fact be half ogre, half dark elf and half human at the same time, unless he had three parents. He claims the character does-we cut to an image of a human male in bed with an ogre female and dark elf female. Funnily enough, while that itself is impossible, if the sex ratios were reversed it actually could happen, though it's rare-two fertilized ova can fuse to become what's called a chimera (women can become pregnant by different men if it's within three days). Of course, since this is fantasy, they could just say it's caused by magic too.
  • In this early El Goonish Shive strip, when Tedd genderbends back into a male, he is depicted as more aggressive. Two strips later, he explains that it was likely because he has more testosterone than he did when he was female. Contrary to popular belief, men with more testosterone tend to be less irritable than men with less testosterone. This would later be retconned as a result of magical emotional manipulation and admitting this made way more sense than any explination they had come up with for the original cause.
  • One-Punch Man: Saitama's famous training regimen consists of 100 squats, 100 push-ups, 100 sit-ups, and 10km of running every single day. While it's made clear that it's not normal for such a workout to make you the World's Strongest Man, Genos treats it as if it was nothing more than basic strength training. The push-ups, sit-ups, and squats may be quite easy to achieve (especially if you do them over multiple sets), but 10km of running is actually a lot (it's almost a quarter of a marathon). Additionally, doing this literally every single day would be extremely harmful to your health, as strength gains come from the body repairing microscopic tears that muscles receive during exercise, making them bigger in the process. For this reason, even the most dedicated athletes and bodybuilders have regularly-scheduled days off to give their body time to recover. Since Saitama did this workout daily without fail, he would have simply destroyed his muscles without giving them any time to regenerate and grow.

    Web Original 
  • Cake Wrecks often features things that are supposed to be cake-and-frosting representations of people. Most of them are anatomically implausible at best, often involving boneless limbs, off-centre faces, and oddly contorted positions.
    "Last time I checked, turtles don't walk around facing the sky."
  • Played for laughs by Cracked: " It's like every single AC/DC album cover came to life and punched your eyeballs right in the dick." Read more: 7 Images Too Badass To Be Real (That Totally Are)
  • Keith Thompson's Ghoul seems to depict Kuru as the complete opposite of what it really is: rather than slowly turning destroying the physical and mental capabilities of its victims as it does in Real Life, Keith Thompson's Kuru zombifies them. However, he has Shown His Work in that both versions of the disease are transmitted by eating infected corpses.
  • The flash clip Dugong begins with words 'Dugong, dugong it's a cow of the se-e-e-a. Dugong, dugong, also known as the manatee'. The problem is that dugong (Dugong dugong) and manatees (genus Trichechidae) are different animals. One may also argue that "sea cow" (a common name for dugong) is yet another, now extinct animal also known as Steller's Sea Cow (Hydrodamalis gigas). Furthermore, the song contains the phrase 'Compared to dolphin, its very close cousin...'. Dugong and dolphins are water mammals, but they belong to different orders (dugong to Sirenia, dolphins to Cetacea). Hardly 'very close cousins'.
  • An online quiz by the UK Guardian newspaper claims that "colubrine" means "of or relating to snakes". It doesn't; it means "of or relating to one particular type of snake". The word they were looking for is "ophidian".
  • Tortoisenapper Quince the tortoise (or possibly turtle) from Hector's World, blushes twice.
  • Jeff the Killer has a severely burned face, a Glasgow Grin, and severed eyelids, the last two of which are self-inflicted. This does not impede him in any way, even though such injuries would lead to blindness and death by sepsis in Real Life. Not only that, but after being covered in bleach and alcohol, then set on fire, all that happened was Jeff's face was bleached white. The actual results would have been far, far more gruesome.
  • "As far as I know I wasn't an egg. I don't believe human beings lay eggs do they?"

    Web Videos 
  • Lampshaded by the Angry Video Game Nerd in his review of Little Red Hood.
    Nerd: The only thing the kick can be used for is kicking palm trees to make cherries appear. But please God, tell me one thing: Why are there cherries coming out of a fucking palm tree?!'
  • Truthpoint Darkweb Rising has several in-universe examples. dril has some interesting ideas about food. He claims that, among other things, that menstrual blood is a key to immortality, that anything you can eat without vomiting is good for you, that viruses are harmless because they're animals and thus edible, and that semen is edible in part because the slang term for it is "nut".


Video Example(s):

Alternative Title(s): Artistic Licence Biology, Art Major Biology, Virus Misnomer


RRR Pitch Meeting

The video points out that (a) Raju shouldn't be getting that buff in prison if he's on a shoestring diet (b) carrying someone on your shoulders should make you bigger and slower (c) healing a busted leg doesn't work like that. But Rule of Cool perseveres.

How well does it match the trope?

5 (4 votes)

Example of:

Main / ArtisticLicenseBiology

Media sources: