Principles of Life, Ch. 13 Reading

Biologists

Biologists

________ regard an organism as being adapted to a particular environment when they can demonstrate that a slightly different organism reproduces and survives less well in that environment.

Hardy Weinberg

Populations in nature never meet the conditions for ________ equilibrium, which is why we can say all biological populations evolve.

mechanism of evolution

The ________ proposed by Charles Darwin.

origin of genetic variation

The ________ is mutation.

Darwin

________ realized that many more individuals of most species are born than survive to reproduce.

Darwinian evolution

Most often refers to organic or ________, which is the genetic and resulting phenotypic change in populations of organisms from generation to generation.

Genetic variation

________ within species is maintained in geographically distinct populations.

Hardy Weinberg

________ only applies to sexually reproducing organisms.

Evolution

Any gradual change

Evolutionary Theory

The understanding and application of the mechanisms of evolutionary change to biological problems

Descent with Modification

Darwins premise that all species share a common ancestor and have diverged from one another gradually over time

Natural Selection

The differential contribution of offspring to the next generation by various genetic types belonging to the same population

Artificial Selection

Selective breeding of organisms, commonly practiced by animal and plant breeders, to increase the frequency of a favored trait from one generation to the next

Population

In ecology, a group of individuals of the same species that live, interact, and reproduce together in a particular geographic area

Alleles

A specific form of a gene at a given locus on a chromosome, among multiple possible forms

Gene Pool

All of the different alleles of all of the genes existing in all individuals of a population

Allele Frequency

The proportion of each allele in a gene pool

Genotype Frequency

The proportion of each genotype among individuals in a population

Adaptation

In evolutionary biology, a particular structure, physiological process, or behavior that makes an organism better able to survive and reproduce

Gene Flow

Exchange of genes between populations through migration of individuals or movements of gametes

Genetic Drift

Changes in gene frequencies from generation to generation as a result of random (chance) processes

Population Bottleneck

A period during which only a few individuals of a normally large population survive

Founder effect

Random changes in allele frequencies resulting from establishment of a population by a very small number of individuals

Sexual Selection

Selection by one sex of characteristics in individuals of the opposite sex

Genetic Structure

The frequencies of the different alleles at each locus and the frequencies of the different genotypes in a population

Hardy-Weinberg Equilibrium

The expected frequencies of alleles and genotypes in a population under random mating, in the absence of natural selection, mutation, migration, and genetic drift

Fitness

An individuals contribution of genes to the next generation, as a consequence of its success in surviving and reproducing

Stabilizing Selection

Selection against the extreme phenotypes in a population, so that the intermediate types are favored

Directional Selection

Selection in which phenotypes at one extreme of the population distribution are favored

Disruptive Selection

Selection in which phenotypes at both extremes of the population distribution are favored

Purifying Selection

The elimination by natural selection of detrimental characters from a population

Positive Selection

Natural selection that acts to establish a trait that enhances survival in a population

Frequency-Dependent Selection

Selection that changes in intensity with the proportion of individuals in a population having the trait

Clinal Variation

Gradual change in the phenotype of a species over a geographic gradient

Genetic Drift

________: Changes in gene frequencies from generation to generation as a result of random (chance) processes.

Natural Selection

________: The differential contribution of offspring to the next generation by various genetic types belonging to the same population.

allele frequencies

Founder effect: Random changes in ________ resulting from establishment of a population by a very small number of individuals.

Population

________: In ecology, a group of individuals of the same species that live, interact, and reproduce together in a particular geographic area.

Fitness

________: An individuals contribution of genes to the next generation, as a consequence of its success in surviving and reproducing.

Genetic Structure

________: The frequencies of the different alleles at each locus and the frequencies of the different genotypes in a population.

evolutionary biology

Adaptation: In ________, a particular structure, physiological process, or behavior that makes an organism better able to survive and reproduce.

Alleles

________: A specific form of a gene at a given locus on a chromosome, among multiple possible forms.

Clinal Variation

________: Gradual change in the phenotype of a species over a geographic gradient.

Population Bottleneck

________: A period during which only a few individuals of a normally large population survive.

Genotype Frequency

________: The proportion of each genotype among individuals in a population.

Hardy Weinberg

________ Equilibrium: The expected frequencies of alleles and genotypes in a population under random mating, in the absence of natural selection, mutation, migration, and genetic drift.