Sexual Selection In Charles Darwin's The Descent Of Man

Sexual selection is a theory that Charles Darwin discussed in his book, The Descent of Man. The theory is that animals evolve certain traits over time, such as striking ornaments on a ram, to compete with other members of the same sex to be selected by the opposite sex for the purpose of mating. Some animals evolve and gain a physiological difference than the opposite sex, this phenomena is called sexual dimorphism. . Some animals have small differences such as beasts on a female human and some traits are more prominent. animal with clear sexual dimorphic differences are peacocks. Male peacocks have large colorful feathers not found on female peacocks, these feathers are vital to this species in being selected to mate. Mutual attraction is

Frogs have two inner ear organs to hear these calls, the amphibian papilla and the basilar papilla. The more sensitive of the two papillae is the basilar papilla, which has a frequency sensitivity of 2130 Hz. The male chuck that is closest to this tuning is the one that will attract females the most effectively. What scientists want to understand is: if the male chuck is a result of the ear tuning or if the tuning of the ear is a reflection of the chuck. In order to truly understand which trait is a product of evolution from the other trait; biologists first looked at tuning of ears in similar species to the tungara frogs. Biologists found that “females of related species have similar tuning of this inner ear organ. Only a few members of the Physalaemus species group, however produce call suffixes that excite this inner ear organ” (Page Bernal R979). This fact alone points in the direction that it is improbable that the tuning of the basilar papilla is a result of the male tungula mating call, but rather the call is a result of the female tungula’s ear tuning. The fibrous mass in the larynx of male tangula frogs is a sexually dimorphic evolutionary trait that is the result of tuning in female’s ear. This study suggests that the female’s inclination to that sound was prominent before the male’s chuck ever