In my world there was a sentient being who was able to witness the evolution of life on the planet for a few million years. He watched as human beings evolved from monkeys. This knowledge may not be widely known, except among a few scholars, but I wonder what implications that this knowledge might have on a magical world at a roughly medieval tech level, if any at all.
Also in my world evolution and creationism are not mutually exclusive. Throughout the world's history the gods have acted as bioengineers and probably seeded the world with life. While humans evolved naturally a number of intelligent species were created.
Obviously the impacts would be culturally relative, but my world has a very wide range of cultures so I am thinking in broad general terms. Some cultures may be completely unaware of evolution while it may be common knowledge in others.
How might knowledge of evolutionary theory impact this medieval society?