The Evolution of Cooperation insects, where the workers – which are sterile, and therefore incapable of passing on their genes – benefit the queen, who is essentially passing on copies of "their" genes. This is further elaborated in the "selfish gene" theory of Richard Dawkins, that the unit of evolution is not the individual organism, but the gene. (As stated by Wilson: "the organism is only DNA's way of making more DNA.") However, kinship selection works only where the individuals involved are closely related; it fails to explain the presence of altruism and cooperation between unrelated individuals, particularly across species. In a 1971 paper
The Genius of Charles Darwin selection. He goes on to explaining sexual selection, with peafowls as an example. To find out whether sexual selection plays a role for altruism and kindness among humans, he visits women who are looking for sperm donors, as well as a sperm bank manager. Dawkins also explains kin selection and selfish genes. In the third and final episode, Dawkins explains why Darwin's theory is one of history's most controversial ideas. Dawkins uses this episode to discuss the opposition that evolution has experienced since it was first discovered. He starts by approaching various anti-evolutionists, ranging from John Mackay from Creation Research,