17 terms

Chapter 16 Evolution of Populations

Prentice Hall Biology, Chapter 16 Evolution of Populations. 16-1 Genes and Variation 16-2 Evolution as Genetic Change 16-3 The Process of Speciation
gene pool
the combined genetic information of all the members of a particular population
relative frequencies
the number of times a certain allele occurs in a gene pool compared with the number of times the other alleles occur
single-gene trait
trait controlled by a single gene
polygenic trait
trait controlled by two or more genes
directional selection
individuals at one end of the curve have higher fitness than individuals in the middle or at the other end
stabilizing selection
individuals near the center of the curve have higher fitness than individuals at the end
disruptive selection
individuals at the upper and lower end of the curve have higher fitness than individuals near the middle
genetic drift
random changes in allele frequencies in small populations
founder effect
a situation in which allele frequencies change as a result of the 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
5 conditions required to maintain genetic equilibrium
random mating, large population, no movement in/out of population, no mutations, no natural selection
species in a genetically isolated organism capable of reproducing
reproductive isolation
the members of two populations cannot interbreed and produce fertile offspring
behavioral isolation
two population are capable of interbreeding but have differences in courtship rituals or other types of behavior
geographical isolation
two populations are separated by geographic barriers such as rivers, mountains, or bodies of water
temporal isolation
two or more species reproduce at different times