THE SOCIAL CONQUEST OF EARTH

Never shy about tackling big questions, veteran evolutionary biologist Wilson (The Creation: An Appeal to Save Life on Earth, 2006, etc.) delivers his thoughtful if contentious explanation of why humans rule the Earth.

After a respectful nod to the old favorites (big brains, tools, language, fire), the author maintains that these merely provide the background to our overpowering “eusociality”; we are the world’s most intensely social creatures, living in complex societies of mutually dependent individuals. Wilson adds that another eusocial organism, the ant, dominated terrestrial life for 50 million years before humans appeared; it remains a close second. The author provides a provocative comparison of how this powerful but rare evolutionary strategy vaulted two wildly different species to the top of the heap. Both originated with individuals cooperating and behaving altruistically, often sacrificing themselves, to protect a defensible nest. For humans, this crucial step began when extended families of our Homo erectus ancestors gathered around campfires over 1 million years ago. Gradually, members of multiple generations divided labor and specialized. Natural selection worked to expand this eusociality, and Wilson emphasizes that it was the group that evolved. Whether they were genetically related or not mattered little. Group selection—as opposed to kin selection, i.e., the “selfish gene” à la Richard Dawkins—is the author’s big idea. Few lay readers will disagree, but Wilson’s fellow biologists are not so sure; kin versus group selection remains a subject of fierce debate. Wilson succeeds in explaining his complex ideas, so attentive readers will receive a deeply satisfying exposure to a major scientific controversy.