Why so many sexual species, and why with males and females ? Why do we age ?

This lecture will focus on the evolution of modes of reproduction (sexual reproduction versus clonal reproduction, self-fertilization), the evolution of different sexes (males versus females, or sexual types), and the evolution of the sex chromosomes that determine these traits. In particular, we'll see that the fact that so many species (but not all) reproduce sexually, and with male or female individuals, remains an active field of research in evolutionary biology. This lecture will also look at the evolution of sex chromosomes, the evolutionary mechanisms of which are still under debate.