Chapter 23: The Evolution of Populations Flashcards

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1
Q

Microevolution

A

Evolution on its smallest scale

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2
Q

Genetic Variation

A

Differences among individuals in the composition of their genes or other DNA sequences

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3
Q

Neutral Variation

A

Differences in DNA sequence that do not confer a selective advantage or disadvantage

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4
Q

Population

A

Group of individuals of the same species that live in the same area and interbreed, producing fertile offspring

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5
Q

Gene Pool

A

Consists of copies of every allele at every locus in all members of a population

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6
Q

Hardy-Weinberg Equilibrium

A
  • Allele and genotype frequencies are constant
  • Population is not evolving
  • p + q = 1
  • p^2 + 2pq + q^2 = 1
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7
Q

Adaptive Evolution

A

Evolution that results in a better match between organisms and their environment

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8
Q

Genetic Drift

A

Chance events cause allele frequencies to unpredictably fluctuate from one generation to the next (especially in smaller populations)

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9
Q

Founder Effect

A
  • Few individuals become isolated from a larger population

- This smaller group may establish a population whose gene pools differ from the original population

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10
Q

Bottleneck Effect

A

Sudden change in the environment reduces the size of a population drastically
-Certain alleles are over-represented, under-represented, and absent

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11
Q

Gene Flow

A

Transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes

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12
Q

Relative Fitness

A

The contribution of an individual makes to the gene pool of the next generation relative to the contributions of other individuals

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13
Q

Directional Selection

A
  • Conditions favor individuals exhibiting one extreme of a phenotypic range
  • Shifts a population’s frequency curve for the phenotypic character in one direction or the other
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14
Q

Disruptive Selection

A

Conditions favor individuals at both extremes of a phenotypic range over individuals with intermediate phenotypes

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15
Q

Stabilizing Selection

A

Acts against both extreme phenotypes and favors intermediate variants

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16
Q

Sexual Selection

A

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

17
Q

Intersexual Selection (Mate Choice)

A

Individuals of one sex (usually females) are choosy in selecting their mates from the other sex

18
Q

Intrasexual Selection

A

Individuals of one sex compete directly for mates of the opposite sex

19
Q

Balancing Selection

A
  • Preserves variation through heterozygote

- Includes heterozygote advantage and frequency dependent selection

20
Q

Heterozygote Advantange

A

Individuals who are heterozygous at a particular locus have greater fitness than do both kinds of homozygotes

21
Q

Frequency Dependent Advantage

A

The fitness of a phenotype depends on how common it is in a population

22
Q

Diploidy

A

Maintains genetic variation in the form of hidden recessive alleles