In 1970, the natural history illustrator Rudolph Zallingerpainted a picture of human evolution called “The March of Progress” in which a parade of hominids walked along from left to right, evolving from knuckle-walking ape to tall, spear-carrying Cro-Magnon. The picture is etched in our collective consciousness, making it possible for cartoonists to draw pictures like the one here safe in the knowledge that we’ll all get the joke. I had actually wanted to show Zallinger’s own picture, but, like others before me, I failed to find it on the web. I was inspired to hunt down the picture by the news today of the discovery of a strange new fossil of a hominid–an extinct relative of humans–that lived 900,000 years ago.
Author: admin
Our brains are huge, particularly if you take into consideration the relative size of our bodies. Generally, the proportion of brain to body is pretty tight among mammals. But the human brain is seven times bigger than what you’d predict from the size of our body. Six million years ago, hominid brains were about a third the size they are today, comparable to a chimp’s. So what accounts for the big boom? It would be flattering ourselves to say that the cause was something we are proud of–our ability to talk, or our gifts with tools. Certainly, our brains show signs of being adapted for these sorts of things (consider the language gene FOXP2). But those adaptations probably were little more than tinkerings with a brain that was already expanding thanks to other factors. And one of those factors may have been tricking our fellow hominid.
Discover, June 26, 2004
The question took me by surprise. I was sitting in a noisy Boston cafe with two biochemists who were having a straight-faced conversation about putting together a budget to create synthetic life-forms. Next to me was Jack Szostak of Harvard Medical School, and across the table was Steven Benner, who had flown up from the University of Florida to pay Szostak a visit. The conversation was thrumming along, touching on the efficiencies of chemical reactions and the like, when Benner abruptly turned to me and asked, “How much do you think it would cost to create a self-replicating organism capable of Darwinian evolution?”
A press release turned up in the comments for a couple of my posts. While that’s not as bad as Viagra-ad spam, it’s not in the spirit of blogosphere. If you post a press release, it will be deleted. Post a comment in your own words, and it will stay.
We like to think of boundaries as being clear-cut borders, but at least in the biological world they generally turn out to be fuzzy zones of change. The line between land and sea is my own favorite example. Last summer my wife and I would sometimes take our oldest daughter Charlotte to the beach. At the time she was a year old and refused to put her toe in the water. This summer she heads straight in, but only about up to her knees. She runs back out and goes back in, repeating the circuit a few dozen times. Next year, I still expect to see her chin above the water line. In her own tadpoling way, Charlotte is reenacting an evolutionary journey taken many times by her fellow mammals–the evolutionary transition back to the water.