Darwin’s Tree Got Tangled. What Happened?
Within just months of returning from a 5-year voyage on the HMS Beagle, Charles Darwin was quick to start working on a new theory in what he called his “notebooks.” The year was 1837. Etched in a leathery notebook with the letter “B” on the cover, now known as Notebook B, with Darwin’s tree diagram. Starting with “1” at the tree trunk, the twigs and branches represent relationships between species, like a family tree. Species were indicated with sequential letters; simple enough.
Scientists, however, have become increasingly skeptical of Darwin’s tree metaphor to explain how biology works. “Evolution is trickier, far more intricate, than we had realized,” David Quammen explains in his new book entitled The Tangled Tree (2018). Somehow, Darwin’s tree got tangled. What happened?
