This Week in Human Evolution

Posted on by Lori Jia

I’ve been in low-blogging mode for a few days as I try to fire off a few dead-tree articles. But I wanted to write up a quick post to draw your attention to threetwo very interesting pieces of human evolution in the news.

1. Modern evolution. A new paper presents the results of a systematic scan for human genes that have experienced natural selection in the past few thousand years. An impressive 700 regions turned up. The fact that humans have been evolving during recorded history is not new. The ability to digest lactose in milk as an adult, resistance to malaria, and other traits have long been recognized as having experienced strong natural selection after the dawn of agriculture.

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Tree of Life, c. 2006

Posted on by Lori Jia

Scientists are probably centuries away from drawing the full tree of life. For one thing, they have only discovered a small fraction of the species on Earth–perhaps only ten percent. They are also grappling with the relationships between the species they have discovered. Systematists (scientists who study the tree of life) rely mainly on DNA these days to figure out how species are related to one another. They compare the similarities and differences in a given gene in several different species to figure out which ones share the closest kinship. But they have actually sequenced DNA from relatively few species. And in many cases, that DNA may come from a single gene.

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Chimps Display a Hallmark of Human Behavior: Cooperation

Posted on by Lori Jia

The New York Times, March 3, 2006

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One of the hallmarks of being human is cooperation. No other primate exhibits the same kind of helpfulness to others. Humans have made even violence a highly cooperative effort, and scientists have wondered how far back in evolution this trait goes.

New studies on chimpanzees suggest that this part of human nature may have already existed millions of years ago, perhaps before the human and ape lineages divided.

Scientists had observed chimpanzees in the wild apparently cooperating in the past. “They work together to chase monkeys, and they’re quite effective when they chase them together,” said Brian Hare of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

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Darwin’s Passion and Fear

Posted on by Lori Jia

Discover, February 28, 2006

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Mounted on a carrot and a plum, two soldiers armed with swords and trumpets make war on one another. The Battle of the Fruit and Vegetable Soldiers is no ordinary child’s sketch. The artist was a young Francis Darwin, son of the celebrated Charles, and the drawing appears on the back of a manuscript page of his father’s most famous work, On the Origin of Species. Tucked away in a glass case in a corner of the American Museum of Natural History’s new Darwin exhibit, the page is one of only 28 to survive from the original manuscript of what many called “the book that shook the world.”

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Set Your Watch

Posted on by Lori Jia

This image came out a couple months ago in Nature, but I just came across it today. I quite like the way it sums up the history of life–something that’s maddening hard to do, since the time scales are so vast. It shows how life’s diversity has been accumulating for billions of years. This chart shows the timing of the earliest paeolontological evidence for different kinds of life, ranging from fossils to chemical markers. A few definitions may help.

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