Chapter 21 Flashcards
A group of individuals that can exchange genetic material through interbreeding to produce fertile offspring.
Species
All the alleles present in all individuals in a population or species.
gene pool
All the individuals of a given species that live and reproduce in a particular place; one of several interbreeding groups of organisms of the same species living in the same geographical area.
Population
A mutation that occurs in somatic cells.
Somatic mutation
A mutation that occurs in eggs and sperm or in the cells that give rise to these reproductive cells and therefore is passed on to the next generation.
germ-line mutation
Genetic changes that have no effect or negligible effects on the organism, or whose effects are not associated with differences in survival or reproduction.
neutral mutations
Genetic changes that are harmful to an organism.
deleterious mutations
Genetic changes that improve their carriers’ chances of survival or reproduction.
Advantageous mutations
Among all the alleles of a gene in a population, the proportion that are of a specified allele.
allele frequency
Describes a population that exhibits only one allele at a particular gene.
fixed
A state in which particular allele and genotype frequencies do not change over time, implying the absence of evolutionary forces. It also specifies a mathematical relationship between allele frequencies and genotype frequencies.
Hardy-Weinberg equilibrium
The retention or elimination of mutations in a population of organisms.
selection
A change in the frequency of an allele due to the random effects of finite population size.
genetic drift
Mate selection biased by genotype or relatedness.
non-random mating
The current theory of evolution, which combines Darwin’s theory of natural selection and Mendelian genetics.
Modern Synthesis
Natural selection that increases the frequency of a favorable allele.
Positive selection
Natural selection that reduces the frequency of a deleterious allele.
Negative Selection
Natural selection that acts to maintain two or more alleles of a given gene in a population.
Balancing selection