Replaying the Tape of Life: "Are Humans Inevitable"

Dr. Larry Moran of the University of Toronto will challenge your preconceptions of evolution in this interesting discussion as a prelude to our Ancestor's Trail Hike on Sunday, June 28th.

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http://biochemistry.utoronto.ca/wp-content/uploads/2014/10/Moran-e1412390438910.jpg

==== From Dr. Moran's essay "Evolution by Accident (http://bioinfo.med.utoronto.ca/Evolution_by_Accident/Evolution_by_Accident.html)"===

Stephen Jay Gould wrote a book about the role of chance in evolution. He called it "Wonderful Life." On the surface it's a book about the Burgess Shale and the Cambrian explosion but there's a powerful message as well. Gould is interested in why some species survive while others go extinct. Are the survivors better adapted than the losers of is it a matter of luck? We could answer this question if we could carry out an experiment.

I call this experiment "replaying life's tape." You press the rewind button and, making sure you thoroughly erase everything that actually happens, go back to any time and place in the past—say, to the seas of the Burgess Shale. Then let the tape run again and see if the repetition looks at all like the original. If each replay strongly resembles life's actual pathway, then we must conclude that what really happened pretty much had to occur. But suppose that the experimental versions all yield sensible results strikingly different from the actual history of life? What could we then say about the predictability of self-conscious intelligence? or of mammals? or of vertebrates? or of life on land? or simply of multicellular persistence for 600 million years?
Stephen Jay Gould (1989) pp. 48-50