NCEA Level 3 Biology – Speciation (AS91605) Practice Exam

The main premise of sexual selection is that mates are chosen based on specific traits. This concept is rooted in the idea that certain characteristics can enhance an individual's chances of attracting a mate, thereby influencing reproductive success.

In many species, individuals exhibit distinct traits—such as elaborate plumage in birds or impressive antlers in deer—that signal fitness and genetic quality to potential mates. These traits can serve to attract mates, leading to a preference for individuals that display them. This selective pressure results in the evolution of pronounced traits that may not necessarily contribute to survival but significantly affect reproductive success.

Mating occurring at random would negate the selective pressures that shape the evolution of these traits. Similarly, the notion that only the strongest males mate simplifies the complex dynamics of sexual selection, which can involve various factors beyond physical strength, including behaviors and displays of fitness. Lastly, the idea that all traits are considered equally overlooks how specific traits can become advantageous during mate selection, illustrating the selective nature of mating preferences in species.