Question

Variation is the raw material of natural selection. List some of the ways in which variations arise in a population

Answer 1

The ultimate cause of all variation is mutation. If there was zero mutation than there would be no variation between individuals of a species so things like sexual recombination and/or transponsons would only have the exact same material to work with so it would not matter. Note that we are ignoring horizontal gene transfer, but even with that if the first life could not have any mutations than even HGT wouldn't matter.