ABSTRACT
At the beginning of Part II we posed three big questions regarding the gene as a unit of inheritance. We have dealt with the fi rst two of these questions, concerning the inheritance of genes during cell division and during sexual reproduction. The third question, which we will explore in the next two chapters, concerns the link between the inheritance of genes and the evolution of species. The fact that evolution occurs tells us that the biological characteristics of a species are able to change over time. We must therefore ask how the passage of genes from generation to generation enables a species to acquire genetic diversity and eventually to evolve into a new species.
