Chapter 19 Flashcards
The fitness of a particular phenotype depends on how frequently it appears in the population
Frequency-Dependent Selection
The genetic drift that results when a small number of individuals from a large population found a new colony
Founder Effect
What is it when individuals select mates by their phenotypes
Assortative mating
When the heterozygote Aa has a higher degree of fitness than either homozygote AA or aa
Heterozygote Advantage
The migration of breeding individuals between populations
Gene Flow
Alleles that differ by only one nucleotide
Single Nucleotide Polymorphisms
Favors phenotypes at one of the extremes of the normal distribution
Directional Selection
The proportion of a particular phenotype in the population
Phenotype Frequency
The production of random evolutionary changes in small breeding populations
Genetic Drift
A special type of genetic polymorphism in which two or more alleles persist in a population over many generations
Balanced Polymorphism
What enables populations to change?
Natural Selection
Type of selection with a trend in several directions rather than just one
Disruptive Selection
The proportion of a specific allele in a particular population
Allele frequency
Variation that does not alter the ability of an individual to survive and reproduce
Neutral Variation
The mechanism of evolution first proposed by Darwin in which members of a population that are more successfully adapted to the environment have greater fitness
Natural Selection
The phenomenon that genetic differences often exist among different populations within the same species
Geographic Variation
What are the 3 things that cause mutations?
- A change in the nucleotide base pairs of a gene
- A rearrangement of genes within chromosomes so that their interactions produce different effects
- A change in chromosome structure
Genetic variation among individuals in a population
Genetic Polymorphism
The proportion of a particular genotype in the population
Genotype Frequency
A gradual change in a species’s phenotype and genotype frequencies through a series of geographically separate populations as a result of an environmental gradient
Cline
Inbred individuals have lower fitness than not inbred
Inbreeding Depression
Selection of mates with the opposite phenotype
Negative Assortative Mating
Includes all the alleles for all the loci present in the population
Gene Pool
An unpredictable change in deoxyribonucleic acid
Mutation
The process of natural selection associated with a population well adapted to its environment
Stabilizing Selection
When a population whose allele and genotype frequencies do not change from generation to generation
Genetic Equilibrium
It shows that if the population is large, the process of inheritance does not by itself causes changes in allele frequencies
Hardy-Weinburg Principle
Selection of mates with the same phenotype
Positive Assortative Mating
What are the 5 conditions that must be met for genetic equilibrium?
- Random Mating
- No Net Mutations
- Large Population Size
- No Migration
- No Natural Selection
The study of genetic variability within a population and of the evolutionary forces that act on it
Population Genetics
The mating of genetically similar individuals who are more closely related than if they had been chosen at random from the entire population.
Inbreeding
Generation-to-generation changes in allele or genotype frequencies within a population
Microevolution
One of two or more alternate forms of a gene
Allele
