I think the difference between plants/animals and humans might be tied to mortality rates. I would imagine that urbanization has a very adverse effect on most p

I think the difference between plants/animals and humans might be tied to mortality rates. I would imagine that urbanization has a very adverse effect on most plant and animal species and that only a small minority of individuals survive the initial shock of urbanization. Those that do survive will pass on the traits that allowed them to flourish in their new environment and such traits will quickly dominate the post-urbanization populations of these plants and animals since they are necessary for their survival. Humans are different in that urbanization appears to make survival (and mating?) easier for a majority of the population and thus there are not such strong selective effects. Note: I am not a genetic biologist, this is just conjecture