Darwins grandfather wrote poems about evolution years before Darwin was even born.
Organic life beneath the shoreless waves
Was born and nurs'd in ocean's pearly caves;
First forms minute, unseen by spheric glass,
Move on the mud, or pierce the watery mass;
These, as successive generations bloom,
New powers acquire and larger limbs assume;
Whence countless groups of vegetation spring,
And breathing realms of fin and feet and wing.
Erasmus Darwin. The Temple of Nature. 1802.
http://www.ucmp.berkeley.edu/history/Edarwin.html