AP Biology Chapter 21 Flashcards

6385704531	Macroevolution	Evolutionary change above species level.	0
6385704532	Microevolution.	Evolutionary change within allele frequencies in species.	1
6385704533	Hardy-Weinberg Equations	Used to calculate allele frequencies to determine if evolution is occuring.	2
6385704534	Allele Frequency Equation	p + q = 1	3
6385704535	p	Frequency of dominant allele.	4
6385704536	q	Frequency of recessive allele.	5
6385704537	Genotype Frequency Equation	p^2 + 2pq + q^2 = 1	6
6385704538	p^2	Frequency of homozygous dominant individuals.	7
6385704539	2pq	Frequency of heterozygote individuals.	8
6385704540	q^2	Frequency of homozygous recessive individuals.	9
6385704541	Hardy-Weinberg Equilibrium	Large population size, no gene flow (immigration/ emigration), no mutations, random mating, and no natural selection.	10
6385704542	Factors that Lead to a Change in Allele Frequency	Small population size (genetic drift), bottleneck, founder effect.	11
6385704543	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
6385704544	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
6385704545	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
6385704546	Sexual Selection	Adaptive changes that lead to an increased ability to secure a mate.	15
6385704547	Sexual Dimorphism	A difference in secondary sexual characteristics between males and females of the same species (size, color, ornamentation, behavior).	16
6385704548	Natural Selection	Only mechanism of evolution that leads to adaptation to environment.	17
6385704549	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
6385704550	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
6385704551	Stabilizing Selection	Instead of favoring individuals with extreme phenotypes, it favors the intermediate variants. It reduces phenotypic variation and maintains the status quo.	20
6385704552	Diploidy	Unfavorable recessive alleles can "hide" in the population as heterozygotes. Only expressed when two heterozygotes have offspring.	21
6385704553	Balanced Polymorphism	Natural selection maintains stable frequencies of two or more phenotypes in a population (heterozygote advantage).	22
6385704554	Genetic Variation	Differences among individuals in the composition of their genes or other DNA sequences.	23
6385704555	Gene Flow	The transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes.	24
6385704556	Neutral Variation	Differences in DNA sequence that do not confer a selective advantage or disadvantage.	25