What a biologist wrote about natural selection and genetic drift.

Natural selection is NOT random. It is directional. For example, there is nothing random about the evolution of walking on 2 legs. When the ancestors of humans needed to walk on 2 legs, any mutations that arise that help them walk better on 2 legs would be adaptive, and any mutation that makes them worse would be deleterious. Deleterious mutations are eliminated but adaptive ones are retained and may even spread. Natural selection allows an adaptive trait to evolve fairly quickly because they give an individual and its descendants a big advantage in survival or reproduction.

Selectively neutral traits (traits that do not affect survival) evolve randomly and their evolution is called genetic drift. Genetic drift is random and depends entirely on chance. For example, serum albumin is selectively neutral, and that is why it can evolve randomly through genetic drift. Genetically neutral mutations are most often found in the 3rd nucleotide of a codon, since a change in that nucleotide usually does not change the amino acid that is being encoded. Because neutral mutations are random, they can be used as molecular clocks. Adaptive traits however are poor candidates for the molecular clock.

If you have some special talents and you inherited it, then it is probably because the genes you have allowed your ancestors to survive better than the average person. And that is why those genes passed down through to you over many generations.

-- Anonymous