Georgius Agricola challanges contemporary six-day creationism with his study and release of observations on geological and fossil strata in "De Natura Fossilium"
Erasmus Darwin publishes Zoonomia. He talked about competition, sexual selection, and hypothesized all life may have arisen from "one living filement."
Georges Cuvier established extinction as a fact.
Charles Darwin publishes "On the Origin of Species by Means of Natural Selection"
Alfred Wallace travels in Malay archipelago and corresponds with Darwin on the diversity of species and explains it through natural selection-like ways.
E.D. Cope studied embryology and hypothesized differences in species to arise from changes in development