ulates that mistakes in copying would have led to a diversity of replicator types and competition for building blocks. This may have led to superior and inferior replicators, and the superior ones may have been able to cannibalize the inferior ones to survive (1:19), similar to Darwin's idea of survival of the fittest. Now, he believes, these engines of self-preservation "survive in huge colonies, safe inside gigantic lumbering robots, sealed off from the outside world, communicating with it by tortuous indirect routes, manipulating it by remote control. They are in you and me; they created us, body and mind; and their preservation is the ultimate rationale for our existence. They have come a long way, those replicators. Now they go by the name of genes, and we are their survival machines" (1:20). Looking at the role of replicators (genes), Dawkins points out that though modern genes, made of DNA, are much the same as the first replicators, the original replicators may have been a related kind of DNA molecule or even something very different (1:21). Dawkins includes all forms of animals, plants, bacteria, and viruses as survival machines. Although the different survival machines appear varied both on the outside and in their internal organs, in their fundamental biochemistry they are quite uniform.
Dawkins asserts that the evolutionary importance of the fact that genes control embryonic development is that genes are at least partially responsible for their own survival in the future because their survival depends on the efficiency of the bodies in which they live and which they help build. He points out that individuals come and go, chromosomes are shuffled around, but the genes themselves survive the shuffling. Genes are not destroyed by crossing over from one chromosome to another. Genes are essentially immortal (1:34).
Genes compete directly with their alleles for survival, since their alleles ...