24 terms

Chapter 15 - The Theory of Evolution

analogous structure
structures that do not have a common evolutionary origin but are similar in function
artificial selection
process of breeding organisms with specific traits in order to produce offspring with identical traits
structural adaptation that enables species to blend with their surroundings; allows a species to avoid detection by predators
earliest stage of growth and development of both plants and animal
homologous structure
structures with common evolutionary origins
structural adaptation that enables one species to resemble another species; may provide protection from predators or other advantages
natural selection
process by which individuals that are better suited to their environment survive and reproduce most successfully, also called survival of the fittest
vestigial structure
structure in a present-day organism that no longer serves its natural purpose, but was probably useful to an ancestor
adaptive radiation
divergent evolution in which ancestral species evolve into an array of species to fit a number of diverse habitats
allelic frequency
percentage of any specific allele in a population's gene pool
convergent evolution
evolution in which distantly related organisms evolve similar traits
directional selection
natural selection that favors one of the extreme variations of a trait
disruptive selection
natural selection that favors individuals with either extreme of a trait
divergent evolution
evolution in which species that once were similar to an ancestral species diverge
gene pool
all of the alleles in a population's genes
genetic drift
alteration of allelic frequencies in a population by chance events
genetic equilibrium
condition in which the frequency of alleles in a population remains the same over generations
geographic isolation
occurs whenever a physical barrier divides a population, which results in individuals no longer being able to mate; can lead to the formation of a new species
idea that species originate through a gradual change of adaptations
any species with multiple sets of the normal set of chromosomes; results from errors during mitosis or meiosis
punctuated equilibrium
idea that periods of speciation occur relatively quickly with long periods of genetic equilibrium in between
reproductive isolation
occurs when formerly interbreeding organisms can no longer mate and produce fertile offspring
process of evolution of new species that occurs when members of similar populations no longer interbreed to produce fertile offspring within their natural environment
stabilizing selection
natural selection that favors average individuals in a population