Stephanie Okolo
BIO 119-001
18 April 2016
How female choice governs sexual selection.
Sexual selection is perhaps one of the most intriguing phenomena in the mammalian kingdom. It is the functional relationship between phenotypes and fitness that enables successful genes of parents to be passed down to their progeny. One important mechanism of sexual selection is how we have evolved to have complete autonomy with whom we reproduce with, especially how that choice relies heavily with females. The captious nature of females makes sense in a system where males are indiscriminate and eager to spread their genes. The cost of reproduction weighs more heavily on the female as she invests the most time during the development of the offspring. She …show more content…
From this he noted that we have many elaborate and non-adaptive sexual traits that evolve but that do not necessarily contribute to our survival. He suggested that such traits might have evolved due to being sexually selected, that is they increase an individual's reproductive success, even if it is at the expense of their survival. He recognized two major modes of sexual selection: intrasexual selection, or competition between members of the same sex, usually between males for access to mates, and intersexual selection, where members of one sex, usually females who choose members of the opposite sex. These mechanisms don't typically work in favor of males and suggest that males undergo stronger selection as they struggle to obtain females to mate with. There is a simple biological explanation for this, in that females and males differ in the amount of gametes we have. Females produce just a set few of healthy non-motile gametes, whereas males are consistently producing an abundance of smaller and motile gametes. Since only a single gamete from each parent is required to produce an offspring, there is an excess of male gametes that will not fertilize any eggs. This imbalance is known as Bateman’s Principle, which suggests that in most species, reproductive variance, or the variability in reproductive success is greater in males than in females. This is due to the fact that “female reproduction is primarily limited by their access to resources to nourish and produce these large gametes, whereas male reproduction is mainly limited by access to females. Therefore males typically compete among themselves for access to females, whereas females tend to be choosy and mate only with preferred males” (Brennan 2010). From this it’s logical for females to be finicky in their selection because they are limited in their
BIO 119-001
18 April 2016
How female choice governs sexual selection.
Sexual selection is perhaps one of the most intriguing phenomena in the mammalian kingdom. It is the functional relationship between phenotypes and fitness that enables successful genes of parents to be passed down to their progeny. One important mechanism of sexual selection is how we have evolved to have complete autonomy with whom we reproduce with, especially how that choice relies heavily with females. The captious nature of females makes sense in a system where males are indiscriminate and eager to spread their genes. The cost of reproduction weighs more heavily on the female as she invests the most time during the development of the offspring. She …show more content…
From this he noted that we have many elaborate and non-adaptive sexual traits that evolve but that do not necessarily contribute to our survival. He suggested that such traits might have evolved due to being sexually selected, that is they increase an individual's reproductive success, even if it is at the expense of their survival. He recognized two major modes of sexual selection: intrasexual selection, or competition between members of the same sex, usually between males for access to mates, and intersexual selection, where members of one sex, usually females who choose members of the opposite sex. These mechanisms don't typically work in favor of males and suggest that males undergo stronger selection as they struggle to obtain females to mate with. There is a simple biological explanation for this, in that females and males differ in the amount of gametes we have. Females produce just a set few of healthy non-motile gametes, whereas males are consistently producing an abundance of smaller and motile gametes. Since only a single gamete from each parent is required to produce an offspring, there is an excess of male gametes that will not fertilize any eggs. This imbalance is known as Bateman’s Principle, which suggests that in most species, reproductive variance, or the variability in reproductive success is greater in males than in females. This is due to the fact that “female reproduction is primarily limited by their access to resources to nourish and produce these large gametes, whereas male reproduction is mainly limited by access to females. Therefore males typically compete among themselves for access to females, whereas females tend to be choosy and mate only with preferred males” (Brennan 2010). From this it’s logical for females to be finicky in their selection because they are limited in their