Much has been made of our ancestors “coming down out of the trees,” and many researchers view terrestrial bipedalism as the hallmark of “humanness.” After all, most of our living primate relatives — the great apes, specifically — still spend their time in the trees. Humans are the only member of the family devoted to the ground, living terrestrial rather than arboreal lives, but that wasn’t always the case. The fossil record shows that our predecessors were arboreal habitués, that is, until Lucy arrived on the scene. About 3.5 million years ago in Africa, this new creature, Australopithecus afarensis, appeared; Lucy was the first specimen discovered. Anthropologists agree that A. afarensis was bipedal, but had Lucy and her legions totally forsaken the trees? The question is at the root of a controversy that still rages. “Australopithecus afarensis possessed a rigid ankle and an arched, nongrasping foot,” write Nathaniel Dominy and his co-authors in Proceedings of the National Academy of Sciences (PNAS). “These traits are widely interpreted as being functionally incompatible with climbing and thus definitive markers of terrestriality,” says Dominy, an associate professor of anthropology at Dartmouth.
Posts Tagged ‘Evolution’
Tags: Art, being human, Evolution, more than human, photography, sentiency
The difference in mind between man and the higher animals, great as it is, is certainly one of degree and not of kind. We have seen that the senses and intuitions, the various emotions and faculties, such as love, memory, attention, curiosity, imitation, reason, etc., of which man boasts, may be found in an incipient, or even sometimes in a well-developed condition, in the lower animals. (via More Than Human: Tim Flach’s Striking Portraits of Animals | Brain Pickings)
I have some bad news and some good news for you about the future. First, the bad news. The future is not coming at us any faster than it ever has. We will not become immortal cyborgs with superintelligent computer friends in the next twenty years. The good news is that means we have a lot more time to get our shit together, and possibly to save the world. Welcome to the slow future. Sculpture by Christopher Locke One of the big mistakes that futurists make today is suggesting that our future is accelerating because science is operating at a fever pitch. We’re churning out so many magical devices that in twenty years we’ll have transcended death, disease, and poverty. Whether they’re wild-eyed Utopians like Ray Kurzweil or pessimistic doomsayers like Bill Joy (who popularized the idea of a “gray goo” apocalypse), they’ve made the error of assuming that all aspects of our lives will change as quickly as microchips do under Moore’s Law. When you consider that our technology has advanced from the first telephones to smart phones in roughly a century, it’s easy to understand why it seems like tomorrow is arriving faster than it ever did. (via The Future Is Not Accelerating)
If you could escape the human time scale for a moment, and regard evolution from the perspective of deep time, in which the last 10,000 years are a short chapter in a long story, you’d say: Things are pretty wild right now. In the most massive study of genetic variation yet, researchers estimated the age of more than one million variants, or changes to our DNA code, found across human populations. The vast majority proved to be quite young. The chronologies tell a story of evolutionary dynamics in recent human history, a period characterized by both narrow reproductive bottlenecks and sudden, enormous population growth. The evolutionary dynamics of these features resulted in a flood of new genetic variation, accumulating so fast that natural selection hasn’t caught up yet. As a species, we are freshly bursting with the raw material of evolution. “Most of the mutations that we found arose in the last 200 generations or so. There hasn’t been much time for random change or deterministic change through natural selection,” said geneticist Joshua Akey of the University of Washington, co-author of the Nov. 28 Nature study. “We have a repository of all this new variation for humanity to use as a substrate. In a way, we’re more evolvable now than at any time in our history.” Akey specializes in what’s known as rare variation, or changes in DNA that are found in perhaps one in 100 people, or even fewer. For practical reasons, rare variants have only been studied in earnest for the last several years. Before then, it was simply too expensive. Genomics focused mostly on what are known as common variants. However, as dramatically illustrated by a landmark series of papers to appear this year — by Alon Keinan and Andrew Clark, by Matt Nelson and John Novembre, and another by Akey’s group, all appearing in Science, along with new results from the humanity-spanning 1,000 Genomes Project — common variants are just a small part of the big picture. They’re vastly outnumbered by rare variants, and tend to have weaker effects. The medical implications of this realization are profound. The previously unappreciated significance of rare variation could explain much of why scientists have struggled to identify more than a small fraction of the genetic components of common, complex disease, limiting the predictive value of genomics. (via Human Evolution Enters an Exciting New Phase | Wired Science | Wired.com)
A recently discovered class of gene may help regulate embryonic development, control the differences between body tissues and even drive animal evolution
THE old saying that where there’s muck, there’s brass has never proved more true than in genetics. Once, and not so long ago, received wisdom was that most of the human genome—perhaps as much as 99% of it—was “junk”. If this junk had a role, it was just to space out the remaining 1%, the genes in which instructions about how to make proteins are encoded, in a useful way in the cell nucleus. That, it now seems, was about as far from the truth as it is possible to be. The decade or so since the completion of the Human Genome Project has shown that lots of the junk must indeed have a function. The culmination of that demonstration was the publication, in September, of the results of the ENCODE project. This suggested that almost two-thirds of human DNA, rather than just 1% of it, is being copied into molecules of RNA, the chemical that carries protein-making instructions to the sub-cellular factories which turn those proteins out, and that as a consequence, rather than there being just 23,000 genes (namely, the bits of DNA that encode proteins), there may be millions of them. The task now is to work out what all these extra genes are up to. And a study just published in Genome Biology, by David Kelley and John Rinn of Harvard University, helps do that for one new genetic class, a type known as lincRNAs. In doing so, moreover, Dr Kelley and Dr Rinn show just how complicated the modern science of genetics has become, and hint also at how animal species split from one another. (via RNA-only genes: The origin of species? | The Economist)