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J Scott Hill

Food For Thought: Meat-Based Diet Made Us Smarter : NPR - 0 views

www.npr.org/...eat-based-diet-made-us-smarter

evolution human thought food diet

shared by J Scott Hill on 29 Jan 13 - No Cached
  • Our earliest ancestors ate their food raw — fruit, leaves, maybe some nuts. When they ventured down onto land, they added things like underground tubers, roots and berries.
  • "You can't have a large brain and big guts at the same time," explains Leslie Aiello, an anthropologist and director of the Wenner-Gren Foundation in New York City, which funds research on evolution. Digestion, she says, was the energy-hog of our primate ancestor's body. The brain was the poor stepsister who got the leftovers.
  • "What we think is that this dietary change around 2.3 million years ago was one of the major significant factors in the evolution of our own species," Aiello says.
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  • cut marks on animal bones appeared
  • that could have been made only by a sharp tool.
  • But Aiello's favorite clue is somewhat ickier — it's a tapeworm. "The closest relative of human tapeworms are tapeworms that affect African hyenas and wild dogs," she says.
  • Besides better taste, cooked food had other benefits — cooking killed some pathogens on food.
  • It breaks up the long protein chains, and that makes them easier for stomach enzymes to digest. "
  • collagen is very hard to digest. But if you heat it, it turns to jelly."
  • starchy foods like turnips, cooking gelatinizes the tough starch granules and makes them easier to digest too. Even just softening food — which cooking does — makes it more digestible. In the end, you get more energy out of the food.
  • J Scott Hill on 29 Jan 13
     
    Interesting audio piece on cooked food, meat, and the evolution of our big brains.
J Scott Hill

A Family Tree in Every Gene - 0 views

raceandgenomics.ssrc.org/Leroi

race culture racism genetics adaptation evolution

shared by J Scott Hill on 26 Feb 13 - No Cached
  • Who speaks of "racial stocks" anymore? After all, to do so would be to speak of something that many scientists and scholars say does not exist. If modern anthropologists mention the concept of race, it is invariably only to warn against and dismiss it. Likewise many geneticists. "Race is social concept, not a scientific one," according to Dr. Craig Venter—and he should know, since he was first to sequence the human genome.
  • But now, perhaps, that is about to change
  • The dominance of the social construct theory can be traced to a 1972 article by Dr. Richard Lewontin, a Harvard geneticist, who wrote that most human genetic variation can be found within any given "race." If one looked at genes rather than faces, he claimed, the difference between an African and a European would be scarcely greater than the difference between any two Europeans.
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  • Three decades later, it seems that Dr. Lewontin's facts were correct, and have been abundantly confirmed by ever better techniques of detecting genetic variety. His reasoning, however, was wrong. His error was an elementary one, but such was the appeal of his argument that it was only a couple of years ago that a Cambridge University statistician, A. W. F. Edwards, put his finger on it.
  • Genetic variants that aren't written on our faces, but that can be detected only in the genome, show similar correlations. It is these correlations that Dr. Lewontin seems to have ignored. In essence, he looked at one gene at a time and failed to see races. But if many—a few hundred—variable genes are considered simultaneously, then it is very easy to do so. Indeed, a 2002 study by scientists at the University of Southern California and Stanford showed that if a sample of people from around the world are sorted by computer into five groups on the basis of genetic similarity, the groups that emerge are native to Europe, East Asia, Africa, America and Australasia—more or less the major races of traditional anthropology.
  • J Scott Hill on 26 Feb 13
     
    "A Family Tree in Every Gene By Armand Marie Leroi Published on: Jun 07, 2006 Armand Marie Leroi, an evolutionary developmental biologist at Imperial College in London, is the author of Mutants: On Genetic Variety and the Human Body." This Article is a fairly sensible, nuanced, defense of the race concept based on recent genetic analyses of hundreds of genetic variables at a time.   
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