Question

what is nonrandom mating? how does sexual selection cause evolution?

Explanation:

Sub - question 1: What is nonrandom mating?

Nonrandom mating is when individuals in a population don't mate randomly. Instead, they choose mates based on certain traits (like physical appearance, behavior, or genetic relatedness). For example, in some species, individuals with similar phenotypes (e.g., body size, color) are more likely to mate, or close relatives may mate (inbreeding), or there may be assortative mating where like - mates with like. This can affect the genetic composition of the population over time as it can change the frequencies of genotypes.

Sexual selection is a type of natural selection related to mating. There are two main forms: intersexual selection (where one sex, usually females, chooses mates from the other sex) and intrasexual selection (where members of the same sex, usually males, compete for access to mates). In intersexual selection, if females prefer males with certain traits (e.g., bright plumage in birds), males with those traits are more likely to reproduce. Over time, the genes for those preferred traits become more common in the population. In intrasexual selection, males with traits that help them win competitions (e.g., larger size, better fighting abilities) are more likely to mate. This leads to the spread of genes associated with those competitive traits. As a result, the frequency of alleles (gene variants) related to these selected traits changes in the population, which is evolution.

Answer:

Nonrandom mating is a mating pattern in a population where individuals do not choose mates randomly. Mating occurs based on specific traits (such as phenotype, genetic relatedness, or behavioral characteristics), which can alter the genetic makeup of the population over generations.

Sub - question 2: How does sexual selection cause evolution?