AP Biology Chapter 21 Flashcards

4924436076	Macroevolution	Evolutionary change above species level.	0
4924436077	Microevolution.	Evolutionary change within allele frequencies in species.	1
4924436078	Hardy-Weinberg Equations	Used to calculate allele frequencies to determine if evolution is occuring.	2
4924436079	Allele Frequency Equation	p + q = 1	3
4924436080	p	Frequency of dominant allele.	4
4924436081	q	Frequency of recessive allele.	5
4924436082	Genotype Frequency Equation	p^2 + 2pq + q^2 = 1	6
4924436083	p^2	Frequency of homozygous dominant individuals.	7
4924436084	2pq	Frequency of heterozygote individuals.	8
4924436085	q^2	Frequency of homozygous recessive individuals.	9
4924436086	Hardy-Weinberg Equilibrium	Large population size, no gene flow (immigration/ emigration), no mutations, random mating, and no natural selection.	10
4924436087	Factors that Lead to a Change in Allele Frequency	Small population size (genetic drift), bottleneck, founder effect.	11
4924436088	Genetic Drift	A process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next; effects are most pronounced in small populations.	12
4924436089	Bottleneck	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	13
4924436090	Founder Effect	Genetic drift that occurs when a few individuals become isolated from a larger population whose gene pool composition is not reflective of that of the original population.	14
4924436091	Sexual Selection	Adaptive changes that lead to an increased ability to secure a mate.	15
4924436092	Sexual Dimorphism	A difference in secondary sexual characteristics between males and females of the same species (size, color, ornamentation, behavior).	16
4924436093	Natural Selection	Only mechanism of evolution that leads to adaptation to environment.	17
4924436094	Directional Selection	A mode of natural selection in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype.	18
4924436095	Disruptive Selection	Describes changes in population genetics in which extreme values for a trait are favored over intermediate values. In this case, the variance of the trait increases and the population is divided into two distinct groups.	19
4924436096	Stabilizing Selection	Instead of favoring individuals with extreme phenotypes, it favors the intermediate variants. It reduces phenotypic variation and maintains the status quo.	20
4924436097	Diploidy	Unfavorable recessive alleles can "hide" in the population as heterozygotes. Only expressed when two heterozygotes have offspring.	21
4924436098	Balanced Polymorphism	Natural selection maintains stable frequencies of two or more phenotypes in a population (heterozygote advantage).	22
4924436099	Genetic Variation	Differences among individuals in the composition of their genes or other DNA sequences.	23
4924436100	Gene Flow	The transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes.	24
4924436101	Neutral Variation	Differences in DNA sequence that do not confer a selective advantage or disadvantage.	25