Chapter 20: Evolution Flashcards
species
a group of individuals capable, through reproduction, of sharing alleles with one another
Gene pool
consists of all the alleles present in all the individuals in the species
populations
interbreeding groups of organisms of the same species living in the same geographical area
What are the two sources of genetic variation?
Mutation and recombination
Recombination
a process by which pieces of DNA are broken and recombined to produce new combinations of alleles
Neutral mutation
a mutation that has little to no effect (most of the genome consists of noncoding DNA so most mutations are neutral)
deleterious mutation
when a large population of mutations occurs in protein-coding regions of the genome
advantageous mutation
a mutation occurs that has a beneficial effect to the carriers’ chances of survival or reproduction
evolution
a change in the frequency of alleles or genotype in a population over time
What are the conditions of the Hardy-Weinberg Equilibrium model?
no migration, no mutation, large population, no mate choice, and no differential survival or reproductive success of individuals (natural selection)
what is p^2 +2pq +q^2 = 1 used for?
to find the predicted genotype frequencies for a population
Stabilizing selection
selects against the extremes
directional selection
selects against one of the two extremes
disruptive selection
selects against the mean
natural selection
the change in an allele’s frequency over time base on that particular allele’s impact on survival and reproduction
fitness
a measure of the extent to which the individual’s genotype is represented in the next generation
the modern synthesis
a synthesis between Darwin’s theory of natural selection and Mendelian genetics
intrasexual selection
members of one sex compete with one another for access to the other sex
intersexual selection
a form of sexual selection involving interaction between males and females as when females choose form among males
artificial selection
selection by a breeder rather than by natural selection
What are the nonadaptive mechanisms of evolution?
migration, mutation, genetic drift, and non-random mating
molecular evolution
a change in DNA or amino acid sequences over time
What evolutionary factor leads to adaptations?
natural selection
How do we measure evolutionary change?
gel electrophoresis, observable physical traits, and DNA sequencing
