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all of the changes that have transformed life over an immense time


an inherited characteristic that improves and organism's ability to survive and reproduce in a particular evronment

Natural Section

the process by which individuals with inherited characteristics well-suited to the environment leave more offspring on average than do other individuals


preserved remains or markings left by organisms that lived in the past

Fossil record

the collection of fossils recorded in rock layers over time


species that no longer exist

homologous Structures

similar structures found in different organisms with a common ancestor

Vestigial Structures

homologous structures that have a major function in one species but not in a related species

Descent with Modification

populations change over time


group of individuals of the same species


differences among members of the same species

Artificial Selection

selective breeding has resulted in many different types of domestic plants and animals, in a relatively short time

Population Genetics

changes in the frequency of various genes in the gene pool

Gene Pool

all of the genes of all of the individuals in a population


changes in the gene pool. Small changes over relatively short periods of time

Hardy-Weinberg Equilibrium

populations that do not undergo change to their gene pools are not presently evolving


drugs that kill or slow the growth of bacteria

Genetic Drift

changes in the frequencies of genes in a small population caused by chance

Bottleneck Effect

changes in the gene pool caused by a rapid reduction in population size. Reduces genetic variability

Founder Effect

changes that occur in a small population that populates a new environment

Gene Flow

addition of new genes to the gene pool by migration


creation of new genes by changing DNA. Increases genetic variation

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