The Biology, Agriculture, and Paleontology thread

Apparently, the mandrill has its blue colour thanks to collagen fibers which in the right disposition colour blue.

"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman

Blue is structural most of the time anyway. Green is blue plus diet carotenoids.

So... exotic human hair/skin colors are scientifically plausible for at least some "natural" colors (e.g. blue, green, orange), provided the necessary tweaks to the genome are done? And without significant changes in dietary intake?

What do mean by "structural"? Do you mean like how blue human irises are that color because light is refracted through an iris that more or less lacks sufficient amounts of the normal pigments to render other colors?

edited 12th Jun '16 1:34:01 PM by MarqFJA

Fiat iustitia, et pereat mundus.

Blue hair would be hard due to the structure of hair, and the others would require blue. Feathers are much better at having those colors.

And "the right genetic changes" is insanely broad when speaking about eucaryotic organisms.

Can you elaborate?

edited 12th Jun '16 5:38:37 PM by MarqFJA

Fiat iustitia, et pereat mundus.

Epigenetics are a bitch, and there is a reason transgenics, while not inherently bad, have potential problems due to us having a trial and error approach without proper understanding of what we are doing.

A hair is a single strand of keratin. A feather is a net. That complex structure allows feathers to reflect light in ways that makes them look blue, while hair cannot do that.

Ah, so it's a matter of our currently still incomplete knowledge of how the human genome exactly works; just because we sequenced almost the entire genome ^note Yes, dear reader who may not be aware of this fact, there's a tiny portion that hasn't been mapped yet, with no intentions so far to do so anytime soon due to reasons that are beyond me (originally it's because the tech couldn't cope with the highly repetitive nature of the remaining sequences). doesn't mean that we know all there is about what each and every gene does alone or in concert with other genes.

That said, would the entire problem be sidestepped by the fact that I'm asking these questions for a made-up Human Subspecies that is technically not a subspecies of H. sapiens, but rather a sister species within the same genus?

OK, so... what if the individual human hair was made of a net of keratin strands? What differences beyond coloration range should we expect on the macroscopic scale? Or is that physically impossible somehow?

Fiat iustitia, et pereat mundus.

https://en.wikipedia.org/wiki/Feather#Evolutionary_stages

A hair is not a branched structure with interlocking barbules. Downy feathers are not colored.

Also, genetics are more than sequences of genes. Check out what introns and extrons are, check out overlapping genes, and remember that DNA just codes proteins.

Proteins and enzymes are what do stuff. A neurotransmisor gene duplicating itself is no big deal. Said duplicate being expressed on the salivary glands, ending up giving said saliva neurotoxic properties, is a big deal.

Check also out mutation mechanisms, not just "is it plausible?".

Not sure if it's the right place,but how do organisms develop "instinctual fear" of something?Is it something like,some of them are born with "phobias" of certain shapes,and those that manage to survive thanks to that pass it down to later generations?

Cause my roach-o-phobia gets tingly pretty often in summer,damnit,and as species we've been "together" since our dawn,sheesh.

Secret Signature

The animals more attuned to certain sights, sounds, smells, etc., of dangerous animals and things are the ones who lived and went on to breed. The animals who can better hear the frequency of a rattlesnake's rattle or any snake's hiss obviously has a better chance of living then the ones who don't, for example.

&

It's also worth point out that these things are likely to be honed to be overly sensitive. Speaking in evolutionary terms its generally more conducive to see potential threats where there are none than to not see a threat that really is there.

So,those creatures on remote islands that are rather fearless,is because they never had any serious predators?

Secret Signature

Not necessarily. They could have predators, but the human body shape is different enough from whatever they are that we don't trip even the most sensitive threat warning.

So I was doing some amateur research on insect anatomy for a made-up arthropodal chimera species, and... well, I only learned that insects actually fold their wings just a few minutes ago, and was puzzling on what exactly did Wikipedia mean by "longitudinal" and "transverse" folding (I knew what the words meant, I just had trouble visualizing how they could apply to insect wings). So I looked up "insect wings folding" on Youtube... and did this beetle just fold its wings twice?! By God in Heaven, Wikipedia wasn't kidding: The wings actually folded length-wise and cross-wise! I thought those structures were too stiff to do that!

Fiat iustitia, et pereat mundus.

So, I just learned that the insect analogue of a penis is called by entomologists an "aedeagus" (from Greek words for "genitals" and "leader").

... Why don't they just called it a penis, or even a phallus, like they do with every vertebrate animal with a penis? What's so important of a difference from the vertebrate penis that they have to invent a whole new name for the insect version?

edited 4th Aug '16 4:08:40 PM by MarqFJA

Fiat iustitia, et pereat mundus.

I would assume for the same reason they don't call cloacas penises – it's not one.

edited 4th Aug '16 4:13:37 PM by majoraoftime

... Cloacas are orifices that combine both the excretory and the genital orifices into a single one. They're more comparable in males to the orifice at the tip of the penis from which the sperm is ejaculated... well, unless you're a reptile with a penis, then you have said organ using the cloaca as its sheath.

And one major flaw with the Wikipedia article is that it doesn't properly explain what it meant by "the matter is actually quite more complex". No comparisons between the aedeagus and the mammal penis have ever been made clearly anywhere in the subsequent description.

edited 4th Aug '16 4:20:08 PM by MarqFJA

Fiat iustitia, et pereat mundus.

The last common ancestor of insects and vertebrates didn't have a penis. Or a liver. Hell, it didn't have a digestive tract, only a sac with a single opening.

Homologous organs. Because internal fecundation is great, and optimized insemination is good enough to have evolved plenty of times. Just like accessory digestive glands becoming large organs happened several times.

For the record, most entomologists I know of call it penis. But, come on, you are complaining about jargon existing? Get away from comparative anatomy FAST. At least those are unrelated organs doing the same stuff; mammals tend to have different names for their skull bones than the rest of tetrapods.

Convergent evolution is a thing, you know.

Fiat iustitia, et pereat mundus.

My mother's complaint about anatomy, comparative and human: "Bad Latin, worse Greek and I don't remember being asked to learn various brands of German, too!"

Taking the coined names very seriously is a telltale sign of biologists, so consensus is hard.

Doesn't help that anatomy is taught by memorization of clade after clade, and that, like taxonomy, it is a tool, and having several names for tbe same thing is overcomplicating stuff.

And yeah, convergent evolution is a thing, but for that you'd also want a bit of analogy and not just homology.

And, of course, you don't say a dolphin is a tuna.

A cloaca is also not solely an orifice, it's also a chamber.

Secondhandly, I am not sure if aedeagus is the same organ as penis is. There is a difference between function and sameness, the pineal gland is the same organ as the eyes - sort of - but their function in humans are very different.

"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman

In the course of writing down notes and doing personal research for a fictional race of Cute Monster Girl-style Insectoid Aliens with Bizarre Alien Sexes (including Bizarre Sexual Dimorphism) going on for them, I've been shocked to discover that two elements which I had believed I had invented turned out to be Truth in Television.

Exhibit A: The dung beetle species Oxysternon festivum...

1. has its males split into two distinct morphotypes. To quote, "Major males are horned and substantially bigger than the hornless female, while minor males are hornless and often smaller than females. Females and small males differ in the form of the transverse carina."
2. Each male morphotype has its own starkly different reproductive behavior. Again, to quote, "major males fight for females and guard and defend burrows actively, while minor males evade fights and try to sneak to the burrows to mate with females."

Exhibit B: The barklice genus Neotrogla has the roles and organs of its sexes reversed. To quote, "Female Neotrogla possess a penis-like organ, properly termed a "gynosome", but interchangeably called a penis. They aggressively seek out mates, while males are more selective. During mating, the female mounts the male and penetrates his small genital opening from behind. Her gynosome swells and tiny barbs on the organ lock the individuals tightly together; when a researcher tried to separate mating individuals the male was torn in two, leaving his reproductive organs attached to the female. During mating, the female uses her gynosome to extract sperm and nutrient-filled seminal fluid from the male. A single mating session can last from 40 to 70 hours."

... The more I learn about Mother Nature's more bizarre aspects, the more I realize that there's a lot about Creation that I have no knowledge of... and that's while humanity still keeps making new discoveries, both big and small, each and every day!

EDIT: Alright, this is just getting silly!

edited 17th Aug '16 5:07:50 AM by MarqFJA

Fiat iustitia, et pereat mundus.

Well, sexual intercourse in bedbugs involves tearing up the belly of the female ("traumatic insemination"), not sure why you'd be surprised at something as prosaic as a flip in (anatomic) gender roles.

"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman

The much more widely-known bees do the traumatic insemination thing too. The surprise factor is to know that intersexuality (that is, mixing the two sexes' characteristics so as to blur the boundaries between them) and anatomical reversal of sex roles can and is normal for some species in real life; physiological intersexuality and anatomical sex role reversal is a whole different level from physiological assured lethality of copulation for males, since the latter doesn't change the actual process of copulation (i.e. male's genitals penetrate female's genitals and ejaculates sperm inside her).

On a different note, I've searched far and wide, but could not find a proper etymology for the myrmecological term "dichthadiiform". Does anyone know?

edited 23rd Aug '16 3:32:35 AM by MarqFJA

Fiat iustitia, et pereat mundus.