Chapter 10: Population & Evolutionary Genetics Flashcards

1
Q

Evolution

A

Change in allele frequency of a population

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2
Q

Charles Darwin

A

Origin of Species (1859)

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3
Q

Take a population (5,000 fruit flies)

A

Average survival without food (20 hours)

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4
Q

Starve until 80% of flies

A

Dies

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5
Q

Feed survivors, allow them to

A

Breed

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6
Q

Starve offspring until

A

80% dies, takes longer than parent generation (average survival without food: 23 hours)

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7
Q

Repeat for many generations, selecting for

A

Starvation survival, generation 60: average survival: 160 hours

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8
Q

How does evolution occur? How do allele frequencies change in population?

A
  1. Mutation
  2. Genetic drift
  3. Migration
  4. Natural selection
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9
Q

Mutation

A

Change to genome

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10
Q

Mutation are randome events, although they can be

A

Encouraged (mutagens)

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11
Q

Mutations are the root of all

A

Genetic variation

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12
Q

Most mutation have negative effect by the two following:

A

1) Generally create non-functioning genes
2) If mutation creates functional gene, may or may not make the organism more fit

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13
Q

Genetic drift

A

Random changes in allele frequency

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14
Q

Unlike natural selection, the change does not impact

A

Fitness directly; it is just which allele combination are inherited from parents

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15
Q

Genetic drift can cause traits to

A

Increase or decrease in a population and acts more strongly on small population

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16
Q

Genetic drift can lead to

A

Allele fixation: frequency of an allele = 100%
1) No variability
2) Genetic drift can lower variation

17
Q

Genetic drift examples:

A

1) Founder effect
2) Bottlenecks

18
Q

Founder effect

A

New, isolated populations exhibit different allele frequencies than original population

19
Q

Bottlenecks

A

After large die off, survivors may have different allele frequencies than original population

20
Q

Gene flow

A

Movement of individuals into other populations

21
Q

Gene flow can introduce (or reintroduce) alleles to

A

Separated populations

22
Q

Natural selection

A

Selection of traits (alleles) improving an organism chance of surviving and producing offspring (fitness)

23
Q

Natural selection not directly removing

A

Unwanted genes

24
Q

Natural selection origin of

A

Survival of the fittest

25
Q

Natural selection requires 3 conditions

A

1) Variation in the trait
2) Heritability
3) Differential reproductive success

26
Q

Three types of natural selection:

A

1) Stabilizing
2) Directional
3) Disruptive

27
Q

Stabilizing

A

Favors the average/most common phenotype

28
Q

Directional

A

Favors an extreme phenotype

29
Q

Disruptive

A

Favors more than one phenotype

30
Q

Sexual selection

A

Form of natural selection specifically acting on traits that increase the ability to gain mating opportunities

31
Q

Sexual selection may

A

Decrease lifespan, but increase reproductive output

32
Q

Sexual selection leads to

A

Sexual dimorphism

33
Q

How do we get adaptations?

A

Populations typically have some variation in traits; all possible alleles form the gene fool

34
Q

Adaptation key point:

A

The variation in phenotypes (dependent on the gene tool) is what natural selection acts upon

35
Q

Different alleles:

A

Variation in phenotypes = adaptations

36
Q

Genetic variation

A

1) Most populations exhibit genetic variability
2) No variation = no evolution