front 1 Natural Selection | back 1 A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits. |
front 2 Adaptation | back 2 inherited characteristic that increases an organism's chance of survival |
front 3 Descent with modification | back 3 principle that each living species has descended, with changes, from other species over time |
front 4 Homology | back 4 Similarity in characteristics resulting from a shared ancestry. |
front 5 Analogy | back 5 similarities among unrelated species that result from convergent evolution |
front 6 Vestigial Structures | back 6 remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species. |
front 7 Convergent Evolution | back 7 Process by which unrelated organisms independently evolve similarities when adapting to similar environments |
front 8 Divergent Evolution | back 8 when two or more species sharing a common ancestor become more different over time |
front 9 Adaptive Radiation(Divergent Evolution) | back 9 An evolutionary pattern in which many species evolve from a single ancestral species |
front 10 Biogeography | back 10 Study of past and present distribution of organisms |
front 11 Endemic Species | back 11 species that are native to and found only within a limited area |
front 12 Phylogeny | back 12 Evolutionary history of a species or group of species. |
front 13 Genus | back 13 group of closely related species; the first part of the scientific name in binomial nomenclature |
front 14 Microevolution | back 14 Evolutionary change below the species level; change in the allele frequencies in a population over generations. |
front 15 Macroevolution | back 15 large-scale evolutionary changes that take place over long periods of time |
front 16 Species | back 16 A group of similar organisms that can breed and produce fertile offspring. |
front 17 Speciation | back 17 the formation of new and distinct species in the course of evolution. |
front 18 Reproductive Isolation | back 18 Separation of species or populations so that they cannot interbreed and produce fertile offspring |
front 19 Prezygotic Barriers | back 19 A reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted |
front 20 Habitat Isolation | back 20 Two species encounter each other rarely, or not at all, because they occupy different habitats, even though not isolated by physical barriers |
front 21 Temporal Isolation | back 21 form of reproductive isolation in which two populations reproduce at different times |
front 22 Behavioral Isolation | back 22 isolation between populations due to differences in courtship or mating behavior |
front 23 Mechanical Isolation | back 23 mating is attempted, but morphological differences prevent its successful completion |
front 24 Gametic Isolation | back 24 Sperm of one species may not be able to fertilize eggs of another species |
front 25 Postzygotic Barriers | back 25 Barriers that prevent the hybrid zygote from becoming a fertile adult. |
front 26 Allopatric Speciation | back 26 The formation of a new species as a result of an ancestral population's becoming isolated by a geographic barrier. |
front 27 Sympatric Speciation | back 27 The formation of a new species as a result of a genetic change that produces a reproductive barrier between the changed population (mutants) and the parent population. No geographic barrier is present. |
front 28 Genetic Variation | back 28 Differences among individuals in the composition of their genes or other DNA segments |
front 29 Population | back 29 A group of individuals that belong to the same species and live in the same area |
front 30 Gene Pool | back 30 All the genes, including all the different alleles for each gene, that are present in a population at any one time |
front 31 Genetic Drift | back 31 A change in the allele frequency of a population as a result of chance events rather than natural selection. |
front 32 Bottleneck Effect | back 32 A change in allele frequency following a dramatic reduction in the size of a population |
front 33 Founder Effect | back 33 Genetic drift that occurs when a few individuals become isolated from a larger population and form a new population whose gene pool composition is not reflective of that of the original population. |
front 34 Gene Flow | back 34 Movement of alleles into or out of a population due to the migration of individuals to or from the population |
front 35 Fitness | back 35 how well an organism can survive and reproduce in its environment |
front 36 Stabilizing Selection | back 36 Natural selection that favors intermediate variants by acting against extreme phenotypes |
front 37 Directional Selection | back 37 Form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve |
front 38 Disruptive Selection | back 38 natural selection in which individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle of the curve |
front 39 Sexual Selection | back 39 A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates. |
front 40 Artificial Selection | back 40 Selection by humans for breeding of useful traits from the natural variation among different organisms |
front 41 Extinction | back 41 A term that typically describes a species that no longer has any known living individuals. |
front 42 Punctuated Equilibrium | back 42 Pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change |
front 43 Phylogenetic Tree | back 43 A family tree that shows the evolutionary relationships thought to exist among groups of organisms |
front 44 Gradualism | back 44 The theory that evolution occurs slowly but steadily |
front 45 Alleles | back 45 Different forms of a gene |
front 46 Hardy-Weinberg Equilibrium | back 46 condition that occurs when the frequency of alleles in a particular gene pool remain constant over time |
front 47 Conditions for Hardy-Weinberg Equilibrium | back 47 1. No mutations |
front 48 Hardy-Weinberg Equation | back 48 p^2 + 2pq + q^2 = 1, where p is the frequency of the dominant allele and q is the frequency of the recessive allele. It predicts the frequency of homozygous dominants, homozygous recessives, and heterozygotes. |
front 49 p | back 49 frequency of dominant allele |
front 50 q | back 50 frequency of recessive allele |
front 51 p^2 | back 51 frequency of homozygous dominant genotype |
front 52 2pq | back 52 frequency of heterozygous genotype |
front 53 q^2 | back 53 frequency of homozygous recessive genotype |