But this is a purely incidental consequence of the property of the bacteria. As an example, he takes whales that over millions of years have evolved from some form of land dwelling animal to one able to exploit the marine environment. The built-up experience of the species, in adapting to a marine environment, is expressed in the genetic makeup of the whale. In the final two chapters, Dawkins examines how we interpret the world. He explains that the brain and its senses are attuned to detect changes.
Faces play an important part for both monkeys and man.
Face recognition would play an important part in any intelligent social animals. He brings out the essential role of brain capacity in human evolution. He speculates on how this process may have taken place. He uses critical mass concept, i.e., that once it reached a certain size, positive feedback ensured even further growth. As for the mechanisms that brought this about, he cites the evolution of language as a prime candidate.