The Biology, Agriculture, and Paleontology thread

It's probably just random luck.

They probably evolved after the toothed baleen whales went extict, filling a niche left vacant, or a similar one. Just like most modern fauna evolved after the Oligocene extinction; before that one, mammalian fauna seems to exist on a bizarro phase (hippos and rhinos are gracile runners, horses are bulky horned creatures, hyraxes are giant hippolike creatures with a pair of nose horns (but side by side), odd-toed ungulates outnumber even-toed ones...).

Stuff changes, specialists die out, the survivors diversify, until there is another big change (the plio-pleistocene turnover meant the end of most of the sperm whale diversity, as well as that of the megalodon; sea currents changed, baleen whales became dwellers of colder waters, and those specialiced macropredators lost their prey, while the dolphins generated a pack hunter of great size that thrived under those conditions).

Damn, I love cenozoic evolutive history. Shame it doesn't get the ammount of work it would merit (and that the more recent parts are a taxonomic clusterfuck).

Makes sense.

Complex cognition shaped the Stone Age hand axe: "The ability to make a Lower Paleolithic hand axe depends on complex cognitive control by the prefrontal cortex, including the 'central executive' function of working memory, a new study finds. The results knock another chip off theories that Stone Age hand axes are simple tools that don't involve higher-order executive function of the brain."

Longest mammal migration raises questions about distinct species of whales: "A team of scientists has documented the longest migration of a mammal ever recorded — a round-trip trek of nearly 14,000 miles by a whale identified as a critically endangered species that raises questions about its status as a distinct species."

Speaking of baleen whales.

Uh-the killer sperm whales went extinct before the turnover. Megalodon way outlasted them by at least five million years.

Also Orcinus Orca would not evolve for a few million years yet. (therefore the theory orcas wiped out Megalodon is inaccurate, since orcas never existed back then)

For me, the reason the shark went extinct is less climate change and more geographical change (closing off the isthmus of Panama)

edited 16th Apr '15 7:18:25 AM by Bk-notburgerking

You know, closing off the comunication between the Pacific and Atlantic oceans is prone to change the way sea currents work, therefore changing global climate to a huge degree. The world changed quite a bit with that.

And killer sperm whales are poorly known so far. We know Livyathan lived 12 million years ago because it was found in rocks of said age, but we don't know when that lineage became extinct.

As for the killer whale, its lineage seems to be one of the first to split from the common dolphin lineage (modern dolphins, like a crapload of modern clades, seem to have their LCA living 10 million years ago). Even if O.orca doesn't appear until much later, its lineage existed and was probably evolving into shapes similar to what they are today. We need more fossils tho, but I can see competition between different cetacean hypercarnivores; dolphins are very specialiced for high speed lifestyles among cetaceans AFAIK, and that may have given them a niche in that area, as well as the pack hunting.

And you never capitalice specific names. Orcinus orca, you may even disregard the italycs if informal (but don't make a habit out of that), but never capitalize the second name.

Oh, and never assume something doesn't exist because we don't have fossils. We have points of divergence with the closest living relatives, and those speak of evolutive histories we can only infer.

The giant panda diverges from the rest of bears 20 million years ago, but we only have fossils from its lineage from 5 million years ago on (and in the center of origin no less). That lineage had to be doing something those 15 million years, specially knowing stem-ursids lack the specializations the panda has. Killer whales ought to be a similar case.

But we know the ancestor of our orca (Orcinus cirtonensis) was alive back then, and it was rather small (about 13 feet long). It wasn't killing big whales. And it seems to have either become O. orca or go etxinct at about the same time as the giant ssark.

As for the climate hypothesis, the reason I don't buy it is the fact modern lamnids are endothermic, and even if Meg wasn't its huge size does help with heat retention.

BTW, the very last killer sperm whales are from 8 million years ago or so.

edited 16th Apr '15 9:16:01 AM by Bk-notburgerking

Megalodon seems to fall outside crown-Lamnidae quite often nowadays (as an Otodontid) and, in any case, Carcharodon and Isurus tend to prefer warmer waters, with Lamna being the cold water specialists. Plus, a hypercarnivore the size of megalodon will die out with almost any disruption, that thing is inadaptable. It is not it freezing out due to climate change, it is climate change disrupting its environment in ways it couldn't cope with. Temperature is a huge factor even for birds and mammals, and lamnids have a more simple system to work with.

And, still, we do not know if we are talking about directly ancestral taxa, or just radiations (and the Mediterranean was kinda dynamic in those times, with the whole being insulated/drying out/being suddenly refilled deal going on, as well as the islands with giant rabbits and dwarf elephants). We need more fossils, but pliocene ones tend to suffer from having more names than material...

All in all, we can agree that there was turnover over those few million years.

Palaeolithic remains show cannibalistic habits of human ancestors: "Analysis of ancient cadavers recovered at a famous archaeological site confirm the existence of a sophisticated culture of butchering and carving human remains, according to a team of scientists."

Morphing octopuses have unique way to control their 'odd' forms: "The body plan of octopuses is nothing if not unique, with a sophisticated brain in a soft, bilaterally symmetrical body, encircled by eight radially symmetrical and incredibly flexible arms. Now, researchers reporting the first detailed kinematic analysis of octopus arm coordination in crawling show that the animals have a unique motor control strategy to match their 'odd' form."

How dogs stole our hearts: "If you think of your dog as your 'fur baby,' science has your back. New research shows that when our canine pals stare into our eyes, they activate the same hormonal response that bonds us to human infants. The study—the first to show this hormonal bonding effect between humans and another species—may help explain how dogs became our companions thousands of years ago."

edited 16th Apr '15 3:47:30 PM by rmctagg09

Carcharodon and Isurus are actually well-known for being most frequently seen is warm temperate waters.

If it was unadaptable, how did it survive for over 20 million years as a single species, during a time when turnover was very high? Megalodon survived so many turnovers that it had to be adaptable.

That's what I was saying about those two, I think.

As for megalodon, it appears to be a chronospecies more than anything, and, all in all, lived sandwiched between the Oligocene and the Pliocene extinctions. It adapted to a niche, but that niche remained fairly constant until it suddenly changed. Of course, it was an specialist at the end of that, relying on certain conditions for reproduction it appears, so, a change on that would prove to be catastrophic.

Flourishing faster: How to make trees grow bigger and quicker: "Scientists have discovered a way to make trees grow bigger and faster, which could increase supplies of renewable resources and help trees cope with the effects of climate change."

Discovery of new plant switch could boost crops, biofuel production: "A team of Michigan State University researchers has discovered a switch that regulates plant photosynthesis - the process that lets plants store solar energy and use it to grow and produce food.

Photosynthesis stores energy in two forms that are used to power plants' metabolism. The amount of energy flowing into each of these must be perfectly balanced to match the needs of plants' metabolism or the plant will self-destruct.

The results, featured in the current issue of Proceedings of the National Academy of Sciences, focus on what happens when photosynthetic output becomes unequal and plants begin to produce toxins that must be immediately addressed."

Cow Milk Without the Cow Is Coming to Change Food Forever: "Counter Culture Labs takes its name pretty literally. It is a bio lab, for sure, complete with pipettes, carboys, microscopes, and flasks. But it is decidedly counter to the traditional culture of laboratory science. The DIY tinkerers who hang out here—in the back of a sprawling space that used to house a heavy metal club in Oakland, California—are working beyond conventional notions of inquiry and research. Their goal is nothing less than to hack nature.

Consider one group of bio-hackers who meet in the lab each Monday night to work on a project that sounds like a contradiction in terms: They’re trying to make cow’s milk cheese without the cow. Using mail-order DNA, they’re tricking yeast cells into producing a substance that’s molecularly identical to milk. And if successful, they’ll turn this milk into cheese. Real cheese. But vegan cheese. Real vegan cheese."

Aphrodisiac for fish and frogs discovered: "A supplement simply added to water has been shown to boost reproduction in nematodes (roundworms), molluscs, fish and frogs – and researchers believe it could work for humans too."

Late, but... were I arguing against those findings of cannibalism, I'd point at Tibetan sky burial and kindly remind the idiots who jump on other people always doing the eating... That it's a little hard to bury people who die in the middle of winter in an ice age. You might have to prepare the body quite extensively for the local clean-up crew to make quick work of most of it before it turns into a corpsicle, or face a very slowly rotting corpse hanging around your digs for months while being a disease hazard. -_-

edited 19th Apr '15 1:54:34 PM by Euodiachloris

Human incisor marks in bones are quite easy to tell apart from those of carnivorans, however.

Yeah: I also snip thread with my teeth when I don't have scissors handy.

Look, I'm not suggesting "no cannibalism, evah" (heck, ritual cannibalism is as old as the hills, let alone Leatherface deals), but... sometimes teeth will beat what flint you have to hand in precision. (Gags thinking about it.)

Sixth extinction, rivaling that of the dinosaurs, should join the big five, scientists say: "Earth has seen its share of catastrophes, the worst being the 'big five' mass extinctions scientists traditionally talk about. Now, paleontologists are arguing that a sixth extinction, 260 million years ago, at the end of a geological age called the Capitanian, deserves to be a member of the exclusive club. In a new study, they offer evidence for a massive die-off in shallow, cool waters in what is now Norway. That finding, combined with previous evidence of extinctions in tropical waters, means that the Capitanian was a global catastrophe."

Getting a better grasp of primate grip: "Scientists are coming to grips with the superior grasping ability of humans and other primates throughout history. In a new study, a research team found that even the oldest known human ancestors may have had precision grip capabilities comparable to modern humans. This includes Australopithecus afarensis, which appears in the fossil record a million years before the first evidence of stone tools."

Vampire squid discovery shows how little we know of the deep sea: "Among soft-bodied cephalopods, vampire squid live life at a slower pace. At ocean depths from 500 to 3,000 meters, they don't swim so much as float, and they get by with little oxygen while consuming a low-calorie diet of zooplankton and detritus. Now, researchers have found that vampire squid differ from all other living coleoid cephalopods in their reproductive strategy as well."

Horizonal gene transfer: Sweet potato naturally 'genetically modified': "Sweet potatoes from all over the world naturally contain genes from the bacterium Agrobacterium, researchers report. Sweet potato is one of the most important food crops for human consumption in the world. Because of the presence of this 'foreign' DNA, sweet potato can be seen as a 'natural GMO,' the researchers say."

3.46-billion-year-old 'fossils' were not created by life forms: "What are the oldest fossils on Earth? For a long time, a 3.46-billion-year-old rock from Western Australia seemed to hold the record. A 1993 Science paper suggested that the Apex chert contained tiny, wormy structures (pictured) that could have been fossilized cell walls of some of the world’s first cyanobacteria. But now there is more evidence that these structures have nothing to do with life. The elongated filaments were instead created by minerals forming in hydrothermal systems, researchers report online today in a new study in the Proceedings of the National Academy of Sciences."

Interstellar-like blight could ravage Earth's wheat: "In the 2014 sci-fi movie Interstellar (pictured above), a cataclysmic blight has wiped out the world’s wheat, forcing astronauts to hunt for another habitable planet. A new study on barley yellow dwarf virus (BYDV), a wheat and cereal crop disease, shows that this fictional dystopia carries more than a few grains of truth."

The puns, they BURN!

Stegosaurus plates may have differed between male, female: "The first convincing evidence for sexual differences in a species of dinosaur has been described in a study of the iconic dinosaur Stegosaurus."

Myth of tolerant dogs and aggressive wolves refuted: "Dogs are regarded as more tolerant and less aggressive compared to their ancestors, the wolves. Researchers from the Messerli Research Institute at the Vetmeduni Vienna question this image. They show in a recent study that wolves interact with conspecifics in an even more tolerant way than dogs, suggesting that dogs have a steeper dominance hierarchy than wolves. The results will be published in the journal Proceedings of the Royal Society B."

DNA of bacteria crucial to ecosystem defies explanation: "Scientists have found something they can't quite explain in one of the most barren environments on Earth: a bacterium whose DNA sequence contains elements usually only found in a much higher organism.

Trichodesmium is a type of bacteria known as an oligotroph, meaning that it can survive in incredibly nutrient-poor regions of the ocean. In fact, it thrives there—to the point that great blooms of the microorganism can be seen both with the naked eye and from satellites in space, earning it the name "sea sawdust" from ancient mariners.

This is because Trichodesmium is a 'nitrogen fixer'—it makes harsh environments more habitable by turning nitrogen gas from the air into ammonium, a nutrient that other organisms can use. It's foundational to the entire food web of the ocean and therefore an important organism for scientists to understand.

By sequencing multiple Trichodesmium genomes—and using a wide variety of samples to ensure that there was no error—researchers found that only about 63 percent of the bacteria's genome is expressed as protein. That's an incredibly low amount for a bacterium and unheard of for a free-living oligotroph."

Entire genomes of woolly mammoths mapped: Clues to extinction, possibility of bringing mammoths back: "An international team of researchers has sequenced the nearly complete genome of two Siberian woolly mammoths — revealing the most complete picture to date — including new information about the species' evolutionary history and the conditions that led to its mass extinction at the end of the Ice Age."

Marmoset 'conversations' may give clues to evolution of human language: "Baby common marmosets, small primates found in the forests of northeastern Brazil, must learn to take turns when calling, just as human infants learn not to interrupt. Even though the marmosets (Callithrix jacchus) don’t have language, they do exchange calls. And the discovery that a young marmoset (as in the photo above) learns to wait for another marmoset to finish its call before uttering its own sound may help us better understand the origins of human language, say scientists online today in the Proceedings of the Royal Society B."

Are bees 'hooked' on nectar containing pesticides?: "Bees are attracted to nectar containing common pesticides, scientists have discovered. This could increase their chances of exposure to high levels of pesticides.

Previous studies have suggested that exposure of this kind can affect bees' fitness. The research, published in Nature, discovered that buff-tailed bumblebees and honeybees could not taste the three most commonly used neonicotinoid pesticides and so did not avoid them. In fact, the bees showed a preference for food which contained pesticides: when the bees were given a choice between sugar solution, and sugar solution containing neonicotinoids, they chose the neonicotinoid-laced food."

A focus on flight: Birds use just two postures to avoid obstacles during flight: "A new study shows birds use two highly stereotyped postures to avoid obstacles in flight. The study could open the door to new ways to program drones and other unmanned aerial vehicles to avoid similar obstacles."

Photosynthesis has unique isotopic signature: "Photosynthesis leaves behind a unique calling card, a chemical signature that is spelled out with stable oxygen isotopes, according to a new study in Science. The findings suggest that similar isotopic signatures could exist for many biological processes, including some that are difficult to observe with current tools."

Sophisticated tools may have spelled doom for Neandertals: "Nearly 42,000 years ago, ancient humans began wielding a new kind of Stone Age toolkit in southern Europe—one that included perforated shell ornaments and long, pointed stone bladelets that were thrown long distances atop spears. Now, after decades of speculation about who made the tools, scientists have finally shown that they were crafted by modern humans, rather than Neandertals. The technological breakthrough may have helped our species outcompete Neandertals, who went extinct shortly after the new tools appeared in Europe."

Bizarre 'platypus' dinosaur: Vegetarian relative of T. rex: "Although closely related to the notorious carnivore Tyrannosaurus rex, a new lineage of dinosaur discovered in Chile is proving to be an evolutionary jigsaw puzzle, as it preferred to graze upon plants. Chilesaurus boasted a proportionally small skull, hands with two fingers like Tyrannosaurus rex and feet more akin to primitive long-neck dinosaurs."

Origin of life: Chemistry of seabed's hot vents could explain emergence of life: "Hot vents on the seabed could have spontaneously produced the organic molecules necessary for life, according to new research. The study shows how the surfaces of mineral particles inside hydrothermal vents have similar chemical properties to enzymes, the biological molecules that govern chemical reactions in living organisms. This means that vents are able to create simple carbon-based molecules, such as methanol and formic acid, out of the dissolved CO₂ in the water."