Chapter 25- Evolutionary Processes Flashcards
Hardy-Weinberg Principle
A principle of population genetics stating that genotype frequencies in a large population do not change from generation to generation in the absence of evolutionary processes.
Fitness
The ability of an individual to produce viable offspring relative to others of the same species.
Null Hypothesis
A hypothesis that specifies what the results of an experiment will be if the main hypothesis being tested is wrong.
Gene Pool
All of the alleles of all of the genes in a certain population.
Genetic Variation
1) The number and relative frequency of alleles present in a particular population.
Directional Selection
A pattern of natural selection that favors one extreme phenotype with the result that the average phenotype of a population changes in one direction.
Stabilizing Selection
A pattern of natural selection that favors phenotypes near the middle of the range of phenotypic variation.
Purifying Selection
Selection that lowers the frequency or even eliminates deleterious alleles.
Disruptive Selection
A pattern of natural selection that favors extreme phenotypes at both ends of the range of phenotypic variation.
Speciation
The evolution of two or more species from a single ancestral species.
Balancing Selection
A pattern of natural selection in which no single allele is favored in all populations of a species at all times.
Frequency-Dependent Selection
A pattern of selection in which certain alleles are favored only when they are rare.
Genetic Drift
Any change in allele frequencies due to random events.
Sampling Error
The accidental selection of a nonrepresentative sample from some larger population, due to chance.
Genetic Marker
A genetic locus that can be identified and traced in populations by laboratory techniques or by a distinctive visible phenotype.
Founder Effect
A change in allele frequencies that often occurs when a new population is established from a small group of individuals.
Genetic Bottleneck
A reduction in allele diversity resulting from a sudden reduction in the size of a large population, due to a random event.
Population Bottleneck
A sudden reduction in the size of a large population.
Gene Flow
The movement of alleles between populations.
Migration
The movement of individuals from one population to another.
Mutation
Any chanhe in the hereditary material of an organism.
Deleterious allele
An allele that reduces an individual’s fitness.
Inbreeding
Mating between closely related individuals.
Inbreeding Depression
In inbred offspring, fitness declines due to deleterious recessive alleles that are homozygous.
