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; sexual reproduction almost
always includes segregation of alleles and recombination, which increases 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 such as 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 of many species of animals 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