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03/23/2008: "What motivates evolution?"

There is general agreement that Homo erectus, the precursor to modern humans, evolved in Africa and gradually expanded to Eurasia beginning about 1.7 million years ago. Anatomically modern humans—humans that more or less looked like us—arose in Africa at least 130,000 years ago.

By 100,000 years ago, several species of hominids populated the Earth. H. sapiens—us—lived in Africa, H. erectus in Southeast Asia and China, and Neandertals in Europe. Around 50,000 years ago, there was a sudden explosion [sic] of human migration out of Africa [by some estimates, numbering only in the hundreds], and by about 30,000 years ago, we were the last ones standing.

One school of thought argues that Homo sapiens emerged with the abilities needed to be modern, and it simply took 70,000 years to hone the technological and social skills needed before they could successfully venture out and populate the rest of the world.

http://news.nationalgeographic.com/news/2003/02/0220_030220_humanorigins2_2.html

Researchers have found evidence which suggests that evolution drives animals to become increasingly more complex.

"If you start with the simplest possible animal body, then there's only one direction to evolve in . you have to become more complex," said Dr Matthew Wills from the Department of Biology & Biochemistry at the University of Bath who worked with colleagues Sarah Adamowicz from from the University of Waterloo (Canada) and Andy Purvis from Imperial College London.

"Sooner or later, however, you reach a level of complexity where it's possible to go backwards and become simpler again."

"What's astonishing is that hardly any crustaceans have taken this backwards route. Instead, almost all branches have evolved in the same direction, becoming more complex in parallel."

"This is the nearest thing to a pervasive evolutionary rule that's been found."

http://www.sciencedaily.com/releases/2008/03/080317171027.htm