Just wanted to post an excerpt from a Newsweek article from 2 or 3 weeks ago. I have a subscription, but I was waiting until I could get the online article to post here. The part I'm posting deals with the evolution of the brain, and how scientists believe that different structural changes in the brain were the cause of several major leaps in human cognitive and social abilities.
Newsweek is not a reputable scientific source by any means, and is in fact pretty well known for shoddy science. I dont claim anything here is true, only that it is purported to be so.
Quote:
A curious thing about early Homo species is that they looked quite human early on. "By 600,000 years ago everyone had a big brain, and by 200,000 years ago people in Africa looked like modern humans," says archeologist Richard Klein of Stanford. "But there was no representational art, no figurines, no jewelry until 50,000 years ago. Some kind of cognitive advance was required, probably in language or working memory. But since size hardly changed, the brain change that produced behaviorally modern humans must have been in structure."
The source of such structural changes must come, like every aspect of our physiology, from genes. Combing the genome for genes that emerged just when language, art, culture and other products of higher intelligence did, researchers have found three with the right timing.
The first, called FOXP2, plays a role in human speech and language, but it must do something else in other species, because the decidedly nonverbal mouse has a version of it. Using the standard molecular-clock tactic, Svante Paabo and colleagues at the Max Planck Institute estimate that the human version of FOXP2 appeared less than 200,000 years ago—about when anatomically modern humans stepped onto the world stage—and maybe as recently as 50,000. If so, then it is only humans as modern as those in the last diaspora out of Africa who developed advanced, spoken language. Another gene with interesting timing is microcephalin, which affects brain size. It carries a time stamp of 37,000 years ago, again when symbolic thinking was taking hold in our most recent ancestors. The third, called ASPM and also involved in brain size, clocks in at 5,800 years. That was just before people established the first cities in the Near East and is well after Homo sapiens attained their modern form. It therefore suggests that we are still evolving.
The fossils have not finished speaking, of course. These countless postcards from the past surely still lie en-cased in the rocks of the Old World. But now, as ancient DNA and gray matter give up their secrets, they are adding life to the age-old quest to understand where humankind came from and how we got here.
This is a very short excerpt from a very long article that can be found here...
http://www.msnbc.msn.com/id/17542627/site/newsweek/
Just kind of makes you think. If tiny structural or chemical changes in the brain actually caused such great advances, which I do not yet believe but do find plausible, it leads you wonder what the next major evolutionary step might bring....
-------------------- After one comes, through contact with it's administrators, no longer to cherish greatly the law as a remedy in abuses, then the bottle becomes a sovereign means of direct action. If you cannot throw it at least you can always drink out of it. - Ernest Hemingway If it is life that you feel you are missing I can tell you where to find it. In the law courts, in business, in government. There is nothing occurring in the streets. Nothing but a dumbshow composed of the helpless and the impotent. -Cormac MacCarthy He who learns must suffer. And even in our sleep pain that cannot forget falls drop by drop upon the heart, and in our own despair, against our will, comes wisdom to us by the awful grace of God. - Aeschylus
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