Answer :

Over the year of evolution, only the strongest survived and reproduced. So, having this happen over millions of years, species got stronger and stronger. For example, if there were two species of monkey's, one with fangs, one without fangs. The species with fangs would survive, and soon all monkeys would develop fangs because all the monkeys without them would die and not reproduce. That's how the evolved into what animals are today.


It does not support his hypothesis but it gave him a clue about selecting desired characteristics. Replace the breeder by the opportunities that are in the environment and you have it.  Breeders depend on variations to deliver new characteristics. If reproduction did not vary between generations, breeders will not get any new characteristics

according to David Chan,