The Tangled Tree Review: Evolution Was Never Just a Tree
Cover image: The Tangled Tree by David Quammen. Used here for purposes of review and commentary. David Quammen begins with a diagram most readers think they understand: Darwin’s tree of life. Molecular biology did not merely add new branches to it. The discovery of Archaea, horizontal gene transfer and the composite origin of complex cells revealed histories that cross between branches, fuse separate lineages and resist any single diagram. The Tangled Tree: A Radical New History of Life is also about a second kind of disorder. Its microorganisms exchange genes and acquire new identities; its scientists compete for recognition, defend inherited classifications and sometimes resist evidence that threatens the structure of their fields. Quammen’s history is tangled in both senses. Evolution is less orderly than the familiar picture suggests, and the people reconstructing it are no more detached from pride, rivalry and institutional habit than anyone else. Quammen make...