Erasmus (Dec. 12, 1731 – April 18, 1802) was a prominent English physician, poet, philosopher, botanist, naturalist and the
grandfather of naturalist Charles Darwin and the biologist Francis Galton. Erasmus Darwin was one of the leading intellectuals of 18th century England.
As a naturalist, he formulated one of the first formal theories on evolution in Zoonomia, or, The Laws of Organic Life (1794-1796). Although he did not come up with natural selection, he did discuss ideas that his grandson elaborated on sixty years later, such as how life evolved from a single common ancestor, forming "one living filament".
Although some of his ideas on how evolution might occur are quite close to those of Lamarck,
Erasmus Darwin also talked about how competition and sexual selection could cause changes in species. link
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