Source: Malcom Schofield, "The Presocratics," The Cambridge Companion to Greek and Roman Philosophy, ed. David Sedley (Cambridge: Cambridge University Press, 2003) 71-72.
Empedocles was a fifth century B.C.E., pre-Socratic philosopher. And he believed in some form of evolution:
"Empedocles' most memorable contribution to speculation about nature was his theory of the origin of species. He posited a sequence of stages (much debated by scholars) in the emergence of animal forms, starting at a point when Strife was even more dominant than it is now. First came a phase when 'many faces sprung up without necks, arms wandered without shoulders, unattached, and eyes strayed alone, in need of foreheads'...This was followed by a generation of monsters, such as bulls with human faces and 'ox-headed offspring of man'. After that the picture is less clear. What is well attested is Empedocles' frequent appeal to chance in spelling this theory out; and Aristotle suggests that he proposed an idea of the survival of the fittest: from amongst the monsters of the second generation, only those who happened to be biologically viable survived and reproduced in kind. Aristotle had greater admiration for Empedocles' perception of homologous functions in the living beings of our present zoological phase..."
Odd transitional forms? Survival of the fittest? Commonalities among different living things? Sounds like the theory of evolution! I wonder if Henry Morris mentions Empedocles in his The Long War Against God: The History and Impact of the Creation/Evolution Conflict, in which he claims to examine evolution in ancient religions.