Chapter 16 Flashcards
relative frequency
number of times an allele occurs in a gene pool compared with the number of times other alleles for the same gene occur
a percent number
gene pool
all genes, including all different alleles, present in a population
single-gene trait
controlled by a single gene with two alleles
polygenic traits
traits controlled by two or more genes
directional selection
when individuals on a scale gradually have higher fitness, reach a point, and gradually have lower fitness
stabilizing selection
when the more median individuals on a scale have higher fitness than individuals on either end
disruptive selection
when the individuals centered have lower than those around them, and the edges have even less
genetic drift
random changes in allele frequency
founder effect
when allele frequencies change as a result of migration of a small subgroup of a population
Hardy-Weinberg principle
allele frequencies in a population will remain constant unless one or more factors cause those frequencies to change
genetic equilibrium
the situation in which allele frequencies remain constant
speciation
formation of new species
reproductive isolation
when members of two populations cannot interbreed or produce fertile offspring
behavioral isolation
when two populations are capable of interbreeding but have differences in courtship rituals or other reproductive strategies that involve behavior
geographic isolation
two populations are separated by geographical barriers such as rivers, mountains, or bodies of water
