Ch. 23 Vocab Flashcards Preview

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Flashcards in Ch. 23 Vocab Deck (25):
1

the percent, on average, of a population's loci that are heterozygous in members of the population

average heterozygosity

2

a change in the nucleotide sequence of an organism's DNA, ultimately creating genetic diversity

mutation

3

differences between the gene pools of geographically separate populations or population subgroups

geographic variation

4

a graded change in a character along a geographic axis

cline

5

a localized group of individuals of the same species that can interbreed, producing fertile offspring

population

6

the aggregate of all of the alleles for all of the loci in all individuals in a population

gene pool

7

the condition describing a nonevolving population

Hardy-Weinburg equilibrium

8

the principle that frequencies of alleles and genotypes in a population remain constant from generation to generation provided that only Mendelian segregation and recombination of alleles are at work

Hardy-Weinburg principle

9

a process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next

genetic drift

10

genetic drift that occurs when the size of a population is reduced, as by a natural disaster or human actions

bottleneck effect

11

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

founder effect

12

the transfer of alleles from one population to another, resulting from the movement of fertile individuals or their gametes

gene flow

13

the contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals in the population

relative fitness

14

natural selection in which individuals at one end of the phenotypic range survive or reproduce more successfully than do other individuals

directional selection

15

natural selection in which individuals on both extremes of a phenotypic range survive or reproduce more successfully than do individuals with intermediate phenotypes

disruptive selection

16

natural selection in which intermediate phenotypes survive or reproduce more successfully than do extreme phenotypes

stabilizing selection

17

a form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates

sexual selection

18

marked differences between the secondary sex characteristics of males and females

sexual dimorphism

19

a direct competition among individuals of one sex for mates of the opposite sex

intrasexual selection

20

selection whereby individuals of one sex are choosy in selecting their mates from individuals of the other sex

intersexual selection

21

natural selection that maintains two or more phenotypic forms in a population

balancing selection

22

greater reproductive success of heterozygous individuals compared with homozygotes; tends to preserve variation in gene pool

heterozygote advantage

23

a decline in the reproductive success of individuals that have a phenotype that has become too common in a population

Frequency-dependent selection

24

genetic variation that doesn't appear to provide a selective advantage or disadvantage

neutral variation

25

evolutionary change below the species level

microevolution