1641, "to unfold, open out, expand," from L. evolvere "unroll," from ex- "out" + volvere "to roll" (see vulva). Evolution (1622), originally meant "unrolling of a book;" it first was used in the modern scientific sense 1832 by Scot. geologist Charles Lyell. Charles Darwin used the word only once, in the closing paragraph of "The Origin of Species" (1859), and preferred descent with modification, in part because evolution already had been used in the 18c. homunculus theory of embryological development (first proposed under this name by Bonnet, 1762), in part because it carried a sense of "progress" not found in Darwin's idea. But Victorian belief in progress prevailed (along with brevity), and Herbert Spencer and other biologists popularized evolution.
Argh. I hate it when this happens. Somehow I picked up the apparently false-factoid that "evolution" was a botanical term before Darwin used it which meant "the unfurling of pedals." And so up to this moment there has always been a particular grace about the image that the word inspires, namely that of a flower opening up, its pedals radiating outward like innumerable species evolving from a common ancestral beginning.
Oh well. On the positive side, I've learned something new that makes Darwin seem even more impressive. Did you read the bold lines? Darwin totally anticipated and rebuked the imbecilic interpretation of his theory as necessarily progressive!
I try to curb the impulse for hero worship, but Chuckie D makes it so difficult!