Mechanisms of Population Evolution. The History of Evolutionary Biology. When Darwin developed his theory of evolution, he did not understand how heredity worked! He didn’t know how traits were passed onto the next generation. He didn’t know how variation in populations appeared.
1. Mating must be random. (No sexual selection.)
2. There is a very large population size. (No bottlenecks.)
3. There is no movement into or out of the population. (No immigration or emigration.)
4. No mutations. (No changes in the DNA.)
5. No natural selection. (No changes in the environment or presence of predators.)