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Biology 106 2015 > Evolutionary mechanisms part 1 > Flashcards

Evolutionary mechanisms part 1 Flashcards

1
Q

evolution

A

change in allele frequencies over time

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2
Q

evidence of evolutionary change

A

geology, biogeography, comparative studies of morphology, embryology, and genetics

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3
Q

geology

A

-fossil records documents continuity in morphological characteristics- evidence of ongoing change in biological lineages

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4
Q

biogeography

A

-distribution of plants and animals in relation to history of landforms, mountain ranges, and oceans is consistent with evolutionary processes

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5
Q

comparative emrbyology

A
  • early embryos of related species are similar
  • reflect common ancestry
  • morphological differences appear as embryos develop
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6
Q

comparative morphology

A
  • homologous structures
  • reflects common ancestry
  • similar embryonic origins, but may have different functions
    • human forearm, bat wing
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7
Q

comparative genetics

A

-comparison of DNA sequences of extant and extinct organisms to address questions about evolutionary relationships

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8
Q

are african or asian elephants more closely related to the extinct wooly mammoth?

A

asian elephants

-mammoth DNA more similar to asian elephants

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9
Q

mutation

A

-production of new alleles

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10
Q

rearrangement of existing alleles into new combination via:

A

sexual reproduction

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11
Q

true or false: more generations= more mutations

A

true

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12
Q

deleterious mutations

A
  • alter an individual’s structure, function, or behavior in harmful ways
  • some are lethal
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13
Q

advantageous mutations

A

-confer a beneit on individuals that carry it- may increase in frequency

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14
Q

neutral mutations

A

neither harmful nor helpful

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15
Q

do mutations happen because an individual/ species/ population “needs” them to deal with some specific problem?

A

no! mutations arise randomly with respects to needs

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16
Q

does sexual selection generate new alleles?

A

no! but it generates new combos of alleles through crossing over and random fertilization

17
Q

quantitative variation

A

traits that vary along a continuum

-height

18
Q

qualitative variation

A

either you have the trait or you dont

19
Q

hardy weinberg principle

A
  • model that specifies conditions in which allele frequencies would NOT change and a population would be at genetic equilibrium
  • it specifies the conditions in which evolution would not occur
20
Q

genetic equilibrium is possible only if all of the following conditions are met in a population

A
  • no mutations are occurring
  • the population is closed to migration
  • the population is infinite in size
  • all genotypes survive and reproduce equally well
  • individuals mate randomly with respect to genotype
  • natural populations never meet all 5 requirements
21
Q

relative fitness

A

number of surviving offspring that an individual produces compared with others in the population

22
Q

examples of evolution by natural selection

A
  • pesticide (mosquitoes and DDT)

- coat coloration in oldfield mice

23
Q

gene pool

A

all the genes, or genetic information in any population

24
Q

product

A

an adaptive trait is any product of natural selection that increases the relative fitness of an organism in its environment

25
Q

process

A

adaptation is the accumulation of adaptive traits over time

26
Q

adaptation s come in 2 general forms

A

physical and behavioral

27
Q

physical adaptation

A

camouflage, hair, large ears, flashy plumage

28
Q

behavior adaptation

A

group living, migration, hibernation, brood parasitism, defensive posture

29
Q

directional selection

A

occurs when individuals near one end of phenotypic distribution are favored
-shifts mean value for the trait away from the existing mean and toward the favored extreme

30
Q

stabilizing selection

A

occurs when individuals expressing intermediate phenotypes are favored- it eliminates phenotypic extremes
-reduces variation, but does not change the mean value of a trait

31
Q

disruptive selection

A

favors extreme phenotypes over intermediate phenotypes

- ex. small and large beak size in black bellied seed crackers - alleles producing extreme phenotypes become more common, promoting discrete traits
32
Q

why doesn’t natural selection produce perfect organisms?

A
  • can only act on existing variation in a population
  • has to work within the bounds of universal physical and chemical constraints
  • any adaptations usually require compromises (tradeoffs) among different traits
33
Q

natural selection acts on ____ of _____, but ______ is change in allele frequencies (______)in a _______ over time

A

phenotypes, individuals, evolution, genotypes, population

Biology 106 2015 (9 decks)

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