Who was Erasmus Darwin?

Erasmus Darwin (1731-1802) 

was Charles Darwin's grandfather. He was a deist, not an atheist. He was one of the leading intellectuals of eighteenth-century England. Erasmus Darwin was a respected physician, a well-known poet, philosopher, botanist, and naturalist. As a naturalist, he formulated one of the first formal theories on evolution in Zoonomia, or, The Laws of Organic Life (1794-1796). He also presented his evolutionary ideas in verse, in particular in the posthumously published poem The Temple of Nature. 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." Erasmus Darwin wrestled with the question of how one species could evolve into another.