Fundamentals exam 3 Pt3

Anisogamy

Dimorphism in gamete (egg and sperm) size.

Sexual dimorphism

Condition in which females and males are phenotypically distinct.

Hermaphroditism

Each individual has both female and male gonads.

Sex

Union of two gametes, each carrying a separate genome; sexually reproducing almost always includes segregation of alleles and recombination, increasing phenotypic variation in the population.

Cost of sex

Cost of producing males; all the offspring from an asexual female are female, yet only half of most sexual female offspring are female.

Parthenogenesis

Reproduction from an egg without fertilization.

Selective interference

Reduction in the spread of an advantageous allele that results from selection acting on other loci.

Muller’s rachet

Genomes of asexual populations accumulate deleterious mutations in an irreversible manner.

Sexual selection

Differential reproduction as a result of variation in the ability to obtain mates.

Intrasexual selection

Also called male-male competition; males often compete for mating opportunities through visual displays of bright colors or ornaments.

Secondary sexual characteristics

Characters selected for by sexual selection, such as visual displays of bright colors or ornaments and weapons like horns or antlers.

Alternative mating strategies

A strategy used by male or female animals, often with distinct phenotypes, that differs from the prevailing mating strategy of their sex.

Intersexual selection

Also known as female choice; females prefer to mate with males that have exaggerated characters, such as color patterns, vocalizations, or display behaviors.

Lek

Communal area in which two or more males of a species perform courtship displays.

Good genes model

Preferred male traits indicate higher viability, which is inherited by the offspring of the females who choose good males.

Runaway sexual selection

Sons of females that choose a certain male trait have improved mating success because they inherit the trait that made their fathers appealing to their mothers; also called the sexy son hypothesis.