Animals
It is believed that the American Robin practices assortative mating on plumage color, a melanin based trait. However, in female American Robins, dark plumage indicates reproductive performance, while dark plumage in males indicates health and decreased parental investment. Nevertheless, positive assortment based on plumage color may explain the American Robin’s unique mating pattern of remaining together throughout the breeding season but never reuniting in subsequent breeding seasons. Because assortative mating based on plumage color adequately predicts reproductive success, there are higher levels of fidelity and less need for extra pair relations.
Positive assortative mating is believed to be the cause of the speciation of a daughter species from the parent species of coral-dwelling goby fish. The species live in a small area of rare coral in the ocean around Bootless Bay in southern Papua New Guinea which the parent species shun. The daughter species has become reproductively isolated from the parent species even though the parent species surrounds the daughter species so there is no geographic isolation. The speciation in the early stages would depend on assortative mating in which the evolving goby fishes would prefer to mate with other fish that preferred to spawn in the same area of rare coral.
Read more about this topic: Assortative Mating
Famous quotes containing the word animals:
“Thou almost mak’st me waver in my faith
To hold opinion with Pythagoras,
That souls of animals infuse themselves
Into the trunks of men.”
—William Shakespeare (1564–1616)
“Shall we never have done with that cliché, so stupid that it could only be human, about the sympathy of animals for man when he is unhappy? Animals love happiness almost as much as we do. A fit of crying disturbs them, they’ll sometimes imitate sobbing, and for a moment they’ll reflect our sadness. But they flee unhappiness as they flee fever, and I believe that in the long run they are capable of boycotting it.”
—Colette [Sidonie Gabrielle Colette] (1873–1954)
“There is nothing worse than an idle hour, with no occupation offering. People who have many such hours are simply animals waiting docilely for death. We all come to that state soon or late. It is the curse of senility.”
—H.L. (Henry Lewis)