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| 257626977 | microevolution | evolutionary change below the species level; change in the allele frequencies in a population over generations, caused by natural selection, genetic drift, and gene flow (p 469) | 0 | |
| 257626978 | genetic variation | differences among individuals in the composition of the genes or other DNA segments; only phenotypes determined by genes can have evolutionary consequences (ex/ bodybuilders do not pass on muscles) | 1 | |
| 257626979 | distinct, quantitative | _____ characters can be classified on an either-or basis, determined by a single gene locus with different alleles that produce distinct phenotypes; _____ characters vary along a continuum within a population, resulting from the influence of two or more genes on a single phenotypic character | 2 | |
| 257626980 | average heterozygosity | the average percentage of loci that are heterozygous (heterozygous = 2 different alleles for a given locus, homozygous = 2 identical alleles) (p 470) | 3 | |
| 257626981 | gene (variability), nucleotide (variability) | _____ is variation at whole-gene level, which is greater variability than _____, genetic variation at the molecular level of DNA; | 4 | |
| 257626982 | geographic variation | differences in the genetic composition of separate populations or population subgroups | 5 | |
| 257626983 | cline | a graded change in a character along a geographic axis (p 471); ex/ frequency of a certain allele in fish decreases from Maine to Georgia | 6 | |
| 257626984 | mutation, gene duplication, rapid reproduction, sexual reproduction | sources of genetic variation (4) (p 471) | 7 | |
| 257626985 | population | a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring | 8 | |
| 257626986 | gene pool | all copies of every type of allele at every locus in all members of the population; also--the aggregate of alleles for just one or a few loci in a population (p 473) | 9 | |
| 257626987 | Hardy-Weinberg principle | the principle that states that the frequencies of alleles and genotypes in a population will remain constant from generation to generation, provided that only Mendelian segregation and recombination of alleles are at work (equilibrium) | 10 | |
| 257626988 | Hardy-Weinberg equilibrium | when genotype frequencies are p² + 2pq +q² = 1; remains constant after mating randomly over generations; only happens when: 1) no mutations 2) random mating 3) no natural selection 4) extremely large population/no genetic drift 5) no gene flow; deviation from this could cause evolution | 11 | |
| 257887692 | genetic drift | a process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next, leading to a loss of genetic variation and possibly fixed harmful alleles; effects of this are most pronounced in small populations | 12 | |
| 257887693 | founder effect | 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 | 13 | |
| 257887694 | bottleneck effect | genetic drift that occurs when the size of a population is reduced, as by a natural disaster or human actions. typically, the surviving population is no longer genetically representative of the original population. | 14 | |
| 257887695 | gene flow | the transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes, modifies population's allele frequencies in next generation (p 479) ex/ when insects pollinate plants within different gene pools | 15 | |
| 257887696 | relative fitness | the contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals in the population (p 481) | 16 | |
| 257887697 | directional selection | natural selection in which individuals at one end of the phenotypic range survive or reproduce more successfully than do other individuals, shifting a population's frequency curve for the character in one direction or the other, common when environment changes or after migration | 17 | |
| 257887698 | disruptive selection | natural selection in which individuals on both extremes of a phenotypic range survive or reproduce more successfully than do individuals with intermediate phenotypes | 18 | |
| 257887699 | stabilizing selection | natural selection in which intermediate phenotypes survive or reproduce more successfully than do extreme phenotypes | 19 | |
| 257887700 | natural selection | the only evolutionary mechanism that consistently leads to adaptive evolution | 20 | |
| 257887701 | sexual selection | a form of selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates (p482) | 21 | |
| 257887702 | sexual dimorphism | a difference between the two sexes in secondary sexual characteristics | 22 | |
| 257887703 | intrasexual selection | selection in which there is direct competition among individuals of one sex for mates of the opposite sex | 23 | |
| 257887704 | intersexual selection (mate choice) | selection whereby individuals of one sex (usually females) are choosy in selecting their mates from individuals of the other sex | 24 | |
| 257887705 | neutral variation | genetic variation that does not provide a selective advantage or disadvantage | 25 | |
| 257887706 | balancing selection | natural selection that maintains two or more phenotypic forms in a population | 26 | |
| 257887707 | heterozygote advantage | greater reproductive success of heterozygous individuals compared with homozygotes (therefore defined in terms of genotype); tends to preserve variation in a gene pool | 27 | |
| 257887708 | frequency-dependent selection | selection in which the fitness of a phenotype depends on how common the phenotype is in a population | 28 | |
| 257887709 | existing | natural selection/evolution does not lead to perfect organisms because 1) selection can only act on _____ variations 2) it is limited by historical constraints 3) adaptations are often compromises 4) chance, natural selection, and the environment interact | 29 |
