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46 terms

Biology 112 Evolution

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natural selection
Differential success in the reproduction of different phenotypes resulting from the interaction of organisms with their environment. Evolution occurs when natural selection causes changes in relative frequencies of alleles in the gene pool.
evolutionary adaptation
result of natural selection, a prevalence of inherited characteristics that enhance organism's survival and reproduction in specific environments
evolution
All the changes that have transformed life on Earth from its earliest beginnings to the diversity that characterizes it today.
natural theology
A philosophy dedicated to discovering the Creator's plan by studying nature. Adaptations of organisms are viewed as evidence that the Creator had designed each and every species for a particular purpose.
taxonomy
The branch of biology concerned with naming and classifying the diverse forms of life. <Linnaeus>
fossils
A preserved remnant or impression of an organism that lived in the past.
sedimentary rocks
Rock formed from sand and mud that once settled in layers on the bottom of seas, lakes, and marshes. Sedimentary rocks are often rich in fossils.
paleontology
The scientific study of fossils.
catastrophism
The hypothesis by Georges Cuvier that each boundary between strata corresponded in time to a catastrophe, such as a flood or drought, that had destroyed many of the species living there at that time.
gradualism
A view of Earth's history that attributes profound change to the cumulative product of slow but continuous processes. <Hutton>
uniformitarianism
Charles Lyell's idea that geologic processes have not changed throughout Earth's history.
descent with modification
Darwin's initial phrase for the general process of evolution.
artificial selection
The selective breeding of domesticated plants and animals to encourage the occurrence of desirable traits.
homology
Similarity in characteristics resulting from a shared ancestry.
homologous structures
Structures in different species that are similar because of common ancestry.
vestigial organs
Structures of marginal, if any, importance to an organism. They are historical remnants of structures that had important functions in ancestors.
biogeography
The study of the past and present distribution of species.
population genetics
The study of genetic changes in populations; the science of microevolutionary changes in populations.
modern synthesis
A comprehensive theory of evolution emphasizing natural selection, gradualism, and populations as the fundamental units of evolutionary change; also called neo-Darwinism.
population
A group of individuals of one species that live in a particular geographic area.
species
A group whose members possess similar anatomical characteristics and have the ability to interbreed.
gene pool
The total aggregate of genes in a population at any one time.
hardy weinberg equilibrium
The condition describing a non-evolving population (one that is in genetic equilibrium).
hardy weinberg theorem
An axiom maintaining that the sexual shuffling of genes alone cannot alter the overall genetic makeup of a population.
hardy weinberg equation
A formula for calculating the frequencies of genotypes in a gene pool from the frequencies of alleles, and vice versa.
microevolution
A change in the gene pool of a population from generation to generation.
genetic drift
Changes in the gene pool of a small population due to chance.
bottleneck effect
Genetic drift resulting from the reduction of a population, typically by a natural disaster, such that the surviving population is no longer genetically representative of the original population.
founder effect
Genetic drift attributable to colonization by a limited number of individuals from a parent population.
gene flow
The loss or gain of alleles in a population due to the migration of fertile individuals or gametes between populations.
polymorphic
Referring to a population in which two or more physical forms are present in readily noticeable frequencies.
gene diversity
measures the average percentage of gene loci that are heterozygous
geographic variation
Differences in genetic structure between populations.
cline
Graded variation in some traits of individuals that parallels a gradient in the environment.
balanced polymorphism
The ability of natural selection to maintain diversity in a population.
heterozygote advantage
Greater reproductive success of heterozygous individuals compared to homozygotes; tends to preserve variation in gene pools.
frequency dependent scale
A decline in the reproductive success of a morph resulting from the morph's phenotype becoming too common in a population; a cause of balanced polymorphism in populations.
neutral variation
Genetic diversity that confers no apparent selective advantage.
darwinian fitness
The contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals.
relative fitness
The contribution of one genotype to the next generation compared to that of alternative genotypes for the same locus.
directional selection
Natural selection that favors individuals at one end of the phenotypic range.
stabilizing selection
Natural selection that favors intermediate variants by acting against extreme phenotypes.
sexual dimorphism
A special case of polymorphism based on the distinction between the secondary sex characteristics of males and females.
intrasexual selection
A direct competition among individuals of one sex (usually the males in vertebrates) for mates of the opposite sex.
intersexual selection
Individuals of one sex (usually females) are choosy in selecting their mates from individuals of the other sex, also called mate choice.
diversifying selection
Natural selection that favors opposite extreme over intermediate phenotypes.