Sexual selection - Then and Now - Essay Example

highest number of young ones to inherit their superiority while those that protect or nourish their young and will leave their young ones to inherit weak powers (Darwin 1882, p209). The males’ modifications are generally more than the female. The male is more modified and the female almost retains a close similarity to the young of her species and the other adult members of similar group. The male is usually more eager than the female and in most cases it is the male that pursues the female and displays plumage characteristics (Darwin 1882, p221).

The male’s great vigour during the love season tends to frequently intensify the individual’s colours that are entirely different from those of the female (Darwin 1882, p224). For example, most of the birds that inhabit the northern and the southern United States, the bird specimens that come from the south are dark in colour in comparison to the ones from the north. This is attributed to the direct differences in the light, temperature and other factors of the two geographical regions. The males of Ageloeus phoeniceus have their colours more intensified while in the south and the females of Cardinalis virginianus are the ones affected.

In the species of Quiscalus major, the colour of the male remains uniform while the female have variations in the tint (Darwin 1882, p225). There are isolated cases where the females have pronounced sexual characters such as great size, brighter colours, pugnacity and strength. In the birds, there can be a complete transposition of the normal characters that are proper to each of the sex. In such a case, the females become more fervent in courtship and the males remain passive. Although the males are passive, they perform the role of selecting the most attractive females.

There are certain hen birds that are highly ornamented and more pugnacious and powerful than the cocks; these types of characters are transmitted to the female progeny alone (Darwin 1882, p225). Double process