Chapter 14 How Populations Evolve Flashcards
Adaptation
A trait that increases the ability of an individual to survive and reproduce compared to individuals without the trait.
Adaptive Radiation
The rise of many new species in a relatively short time as a result of a single species that invades different habitats and evolves under different enviromental pressures in those habitats.
Allele Frequency
For any given gene, the relative proportion of each allele of that gene in a population.
Coevolution
The evolution of adaptations in two species due to their extensive interactions with one another, in which each species is a source of natural selection on the other.
Competition
Interaction among individuals who attempt to use a resource (for example, food or space) that is limited relative to the demand for it.
Equilibrium Population
A population in which allele frequencies and the distribution of genotypes do not change from generation to generation.
Extinction
The death of all members of a species.
Fitness
The reproductive success of an oganism, usually expressed in relation to the average reproductive success of all individuals in the same population.
Founder Effect
The result of an event in which an isolated population is founded by a small number of individuals; may result in genetic drift if allele frequencies in the founder population are by chance different from those parent population.
Gene Flow
The movement of alleles from one poluation to another owing to the movement of individual oganisms of their gametes.
Gene Pool
The total of all alleles of all genes in a population; for a single gene, the total of all the alleles of that gene that occur in a population.
Genetic Drift
A change in the allele frequencies of a population hat occurs purely by chance.
Hardy-Weinberg principle
A mathematical model proposing that, under certain conditions, the allele frequencies and genotype frequencies in a sexually reproducing population will remain constant over generations.
Isolating Mechanism
A morphological, physiological, behavioral, or ecological difference that prevents members of two species from interbreeding.
Mutation
A change in the base sequence of DNA in a gene; normally refers to genetic change significant enough to alter the appearance or functions of the organism.
Natural Selection
The process in which unequal survival and reproduction of organisms, favoring individuals with particular traits, causes those traits to become increasingly common in a population.
Population
All the members of a species that occupy a particular area at the same time.
Population Bottleneck
The result of an event that causes a population to become extremely small; may cause genetic drift that results in changd allele frequencies and loss of genetic variability.
Postmating Isolating Mechanism
Any structure, physiological function, or developmental abnormality that prevents organisms of two different populations, once mting has occured, from producing vigorous, ferile offspring.
Predation
The act of eating another living organism.
Premating Isolating Mechanism
Any structure, physiological function, or behavior that prevents organisms of two different populations from interbreeding.
Reproductive Isolation
The failure of organisms of one poluation to breed successfully with members of another; may be due to premating or postmating isolating mechanisms.
Sexual Selection
A form of reproduction in which genetic material from two parent organisms is combined in the offspring; normally, two haploid gametes fuse to form a diploid zygote.
Speciation
The process of species formation, in which a single species splits into two or more species.
Species
The basic unit of taxonomic classification, consisting of a group of poluations that evolves independently. In sexually reproducing organisms, a species can be defined as a population or series of populations of organisms that interbreed freely with one another under natural conditions but that do not interbreed with members of other species.
