We control the selection and mating of domestic livestock in order to generate and exploit favorable genetic effects. This is an artificial process we disrupt what may happen naturally in order to help meet our goals and yet we can learn from the patterns of evolution of sex and mating systems that we see in natural populations.
An equal sex ratio has usually evolved, because each animal has one father and one mother. The sexes are thus, on average, equally prolific, but biology dictates that females are much more consistent. Males compete hard to generate progeny, with much more variable results. Females also compete with each other for high-quality mates to help project their genes into future generations, and the best females are more likely to attract the best males. We can observe such battles within and between the sexes throughout nature. These struggles serve the interests of genes and the animals that host them. Under domestication, the focus is shifted to agriculture and to the genes, animals, and mating systems that can best serve that purpose.
Was this article helpful?