Charles Darwin's Sexual Selection Theory

Charles Darwin, an English naturalist and geologist, created a concept known as sexual selection. A quote from NESCI describes sexual selection as “choosing traits that enable an organism to reproduce, without necessarily helping them to survive are selected for”. The animals that are picked to reproduce pass their selected traits onto their offspring and the traits that are not picked eventually die off within the population. Some examples of these selected traits include coloration, increased size, or ornaments. In an article written by Francisco Jose Ayala, it is elaborated that the preference shown by female animals for their male counterparts have an effect on whom she will mate with. And more often than not, the female species will have

One theory that researchers have toward this sexual selection is discussed in an article called How Did the Peacock Get His Tail written in National Geographic News is the Sexy Son Theory. It can also be called Fisher’s runaway process, which was created by Ronald Fisher, a mathematical geneticist. This theory is based on the assumption that once a female finds and mates with an attractive male, his sexy genes will then be passed on to her sons, which will then have the attractive genetic advantage over a less colorful peacock and thus carry on the genetic line. The article explains an experiment performed by Anders Moller, a researcher at the French national research center, and his partner Petrie to test a new theory. They took blood samples from male peacocks and recorded the amounts of B and T cells which are cells designed to help defend the body against pathogens. They also measured the tail length and counted the eye spots on the peacocks. Moller hypothesized that due to the multiple ornaments on male peacocks, such as long tails, eye spots, a crested head, and a mating call, that the different ornaments signified different aspects to why he is a dominant and worthy male. By looking at B and T cell counts, the researchers concluded that the coloration and length of the peacock’s tail, along with eye spots are directly correlated. The beautiful ornaments shown off by male peacock’s is a way for them to show their health to the females. This factor is attractive to the females because they want their young to have a greater chance at survival and