Question

What is random fertilization

Answer 1

Random fertilization means that the collection of genes within one gamete (such as a sperm cell) do not give that gamete a lesser or better chance than any of the other sperm cells of fusing with an egg cell to produce a zygote. This does not really generate new variation within the species, but it does preserve the variation that is already there. It does this by giving every version of every gene a more fair shot of being passed on to the next generation. If random fertilization was not occurring, that is, if some gene versions had a better chance of fertilizing an egg than other gene versions, then that gene version would increase in frequency in the next generation, while the other gene versions would decrease in frequency, and eventually there would only be one gene version left. In other words, there would no longer be any variation left for that gene (until mutation generated new variation).