Question

What was Bateman's key insight that furthered the study of sexual selection?

1) That some species are sex-role reversed
2) That sometimes natural selection and sexual selection are opposing forces
3) That to understand sexual dimorphism we must quantify the relationship between number of mates and reproductive success for both males and females
4) That reproductive success in males is dependent upon the variation in sexually selected traits possessed by that male

Answer 1

Bateman's insight was about quantifying the correlation between the number of mates and reproductive success, providing a foundation for understanding sexual dimorphism and selection.

Step-by-step explanation:

Bateman's key insight that furthered the study of sexual selection was the quantification of the relationship between number of mates and reproductive success for both males and females. This understanding is crucial for explaining sexual dimorphism. Sexual dimorphism, such as the elaborate plumage of male birds compared to female birds, arises from different reproductive strategies and success between the sexes, where often males have greater variance in reproductive success. This variance is attributed to factors such as male-male competition and female mate choice, which lead to sexual selection pressures and promote the development of traits that enhance mating success, even if they decrease survival odds.

Sexual selection can influence evolution by developing secondary sexual characteristics through intrasexual selection—competition between the same sex—and intersexual selection—mate choice. Traits that arise from sexual selection sometimes do not improve survival but play key roles in reproductive success, such as a peacock's tail, which is both attractive to females and a potential handicap due to predator visibility.