A lot of interesting games suggested in this thread like 'sacrifice' :)
I'll just add one that didnt sell, it's probably the most detailed and accurate sim of evolution, but with some really fascinating strategy gameplay
Evolution: The Game of Intelligent Life (1997) is a life simulation and real-time strategy game that allows players to experience, guide, and control evolution from an isometric view on either historical earth or on randomly generated worlds while racing against computer opponents to reach the top of the evolution chain, and gradually evolving the player's animals to reach the "grand goal of intelligent life"