Evolution is not a genetically controlled distortion of one adult form into another; it is a genetically controlled alteration in a developmental program.
Richard DawkinsSuppose that there's a gene that makes you gay if you were bottle-fed but that has some completely different effect if you were breast-fed. So in the days before bottles were invented that gene would not have manifested itself as gay behavior, but now that bottles are common it can do so.
Richard DawkinsThe messages that DNA molecules contain are all but eternal when seen against the time scale of individual lifetimes. The lifetimes of DNA messages give or take a few mutations are measured in units ranging from millions of years to hundreds of millions of years; or, in other words, ranging from 10,000 individual lifetimes to a trillion individual lifetimes. Each individual organism should be seen as a temporary vehicle, in which DNA messages spend a tiny fraction of their geological lifetimes.
Richard Dawkins