By 125 million years ago the mammals had already become a diverse group of organisms. Some of them would have resembled today's (e.g. platypus and echidna), but early (a group that includes modern kangaroos and possums) were also present. Until recently it was thought that mammals (the group to which most living mammals belong) had a much later evolutionary origin. However, and DNA evidence suggest that the placental mammals are much older, perhaps evolving more than 105 million years ago. Note that the marsupial and placental mammals provide some excellent examples of , where organisms that are not particularly closely related have evolved similar body forms in response to similar environmental pressures.
Eusthenopteron had a number of that pre-adapted it to life on land: it had that allowed it to move around on the bottom of pools, lungs - which meant it could gulp air at the surface, and the beginnings of a neck. This last is important as a terrestrial predator cannot rely on water current to bring food into its mouth, but must move its head to catch prey. And the bones in Eusthenopteron's fins are almost identical to those in the limbs of the earliest amphibians, an example of .
While it was originally described as simply a feathered reptile, Archaeopteryx has long been regarded as a transitional form between birds and reptiles, making it one of the most important fossils ever discovered. Until relatively recently it was also the earliest known bird. Lately, scientists have realised that Archaeopteryx bears even more , a group of dinosaurs that includes the infamous velociraptors of "Jurassic Park", than to modern birds. Thus the provides a strong phylogenetic link between the two groups. Fossil birds have been discovered in China that are even older than Archaeopteryx, and other discoveries of feathered dinosaurs support the theory that theropods evolved feathers for insulation and thermo-regulation before birds used them for flight. This is an example of an .
The that Conway, Gibson, and their colleagues eventually wrote came out in last week’s Proceedings of the National Academies of Science. And the results are … illuminating. Gibson and Conway have a new theory about how the human brain makes color, and it is less about how people see and more about what they do.
So, like, Tsimane' speakers who also speak a lot of Spanish say "yushnus" for blue (-ish) and "shandyes" for green (-ish). But others call both the sky and grass "yushnyes," and others call all green and blue things "shandyes." Or, to take another example, different Tsimane' speakers call yellowish colors "cuchicuciyeisi," "ifuyeisi," or "chamus."
So Berlin and Kay went big. They sent teams into the field, finding people who spoke 110 different languages and showing them, one by one, the chips in the Munsell array—adding 10 “achromatic” chips, neutral colors. The field workers were supposed to ask for “short names” for the colors of the chips. And then, once they had the gamut of basic color terms, the workers would show the subjects the whole palette, a board with all the chips. And the native speakers were supposed to point to the best example of each basic term. Those findings became the World Color Survey, still one of the best databases on how people talk about color.
So the hypothesis was that maybe something about those colors, or the human brain’s perception of those colors, is more fundamental than culture—like, the human brain has a “deep grammar” for color, a hard-coded categorization of the color space.
Our brains might form memories in that same way, creating a memory structure—connections between specific cells—and then maintaining that structure even as the pieces are replaced over a lifetime. The hardware is more entangled with the software because the software changes the hardware, modifying the connections as a memory takes shape. This is just a hypothesis, but a compelling one given Ryan’s data. He that even when rodents have Alzheimer’s disease and seem to forget their memories, those memories are still physically present in the brain and can be . It’s just the way to access them that’s been lost.
New Zealand, by virtue of its isolation and its relatively recent geological development, was not the centre of any novel evolutionary development. However, many of the species that date back to Gondwanaland, or that arrived more recently as migrants, have undergone significant adaptive radiation in their new homeland. Some of the best examples of this can be related to the major ecological changes that accompanied the Pleistocene Ice Ages.
Instead of throwing out the metaphor, though, scientists like Gallistel have massaged their theories, trying to align the brain’s biological reality with computational complexity. Rather than question the assumption that the brain’s information is Shannon-like, Gallistel—a wiry emeritus professor at Rutgers—devised an alternate hypothesis for storing Shannon information as molecules inside the neurons themselves. Chemical bits, he argued, are cheaper than synapses. Problem solved.
For example, speciation patterns in the native flax snails of Northland can be related to changes in sea level. Originally 2-3 species were widespread at a time of low sea levels. Rising seas at the end of the glacial period isolated these as populations on offshore islands, where differential natural selection pressures led to the evolution of a greater number of separate species.
The reason for the disparity isn't totally clear, but Dudley has a hypothesis: If you're a doctor in Philadelphia diagnosing a patient in Albuquerque, you're not familiar with which local provider to refer them. It's the kind of problem that could be solved with some back and forth or an ongoing patient-doctor relationship. But absent both, a surprising number of clinicians wound up not connecting the dots. "So yeah, it's terrible webside manner, and terrible care" says Dudley.
As a hypothesis, this idea provides not only an explanation for the array of languages and how well they convey warm-versus-cool but also for why languages acquire new color words in a predictable order: usefulness. The colors that are more a part of daily life enter the lexicon sooner. That’s a very different way of thinking about color than Sapir-Whorf, or anthropologically, or neurophysiologically.