Online Galleries
From Histories of Life: Searching for Order
_-_CQ_thumb.jpg){kind=small}
Darwin to Lyell, 23 Sept. 1860
In this diagram, like the one in the Origin of Species (previous image), Darwin showed the descent of animals from a common ancestor. However, in this letter, he drew the tree “upside down,” with time flowing from top to bottom, and he showed the evolution of actual mammals rather than hypothetical species. Writing of the mammals’ anatomical and embryological features, he wrote, “. . .this large amount of similarity I must look at as certainly due to inheritance from a common stock.”
Charles Darwin (1809–1882). Letter to Charles Lyell, September 23, 1860.
