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BISC 2 - Genetics, Ecology, Evolution > Natural Selection > Flashcards

Natural Selection Flashcards

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1
Q

One cause of genetic drift is ___, in which a small group of individuals leaves its home population and establishes a new, isolated settlement.

A

the founder effect

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2
Q

Select all of the following that can lead to evolution in a population.

A
  • mutation
  • migration
  • selection
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3
Q

A ____ is a change in an organism’s DNA sequence and is the raw material for evolution, because genes affect the phenotypes and evolution acts on phenotypes.

A

mutation

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4
Q

Reproductive success of an organism can also be referred to as

A

fitness

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5
Q

When a population size drops rapidly over a short period, causing a loss of many alleles that were present in the larger ancestral population, this is referred to as the ____ effect.

A

bottleneck

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6
Q

A change in allele frequencies hat occurs by chance and that tends to eliminate alleles in a population rather than increase diversity is called

A

genetic drift

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7
Q

A mutation can affect evolution in a species only if

A

subsequent generations inherit it

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8
Q

Rank the following from highest fitness at the top to lowest fitness at the bottom. (Assume that the numbers represent the entire lifetime of the mayfly mother.)

A
  1. A mayfly that lays 400 eggs and mothers 3 offspring that survive to reproductive age
  2. A mayfly that lays 800 eggs and mothers 2 offspring that survive to reproductive age
  3. A mayfly that lays 900 eggs and mothers 1 offspring that survive to reproductive age
  4. A mayfly that lays 1,000 eggs and mothers 0 offspring that survive to reproductive age
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9
Q

Select all the examples of nonrandom mating.

A
  • mating only within a specific group
  • choosing mates based on certain characteristics
  • mate choice based on social position
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10
Q

When the intermediate phenotype of a trait is being selected for and the extreme phenotypes are being selected against, the population is probably undergoing

A

stabilizing selection

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11
Q

A difference in the appearance between males and females of a species is called

A

sexual dimorphism

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12
Q

Fitness depends on which of the following?

A
  • number of successful reproductive efforts in lifetime
  • proportion of offspring that survive to reproduce
  • ability to survive long enough to successfully reproduce
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13
Q

Natural selection requires

A

genetic diversity

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14
Q

Select all the key properties of evolutionary adaptations

A
  • they are heritable

- they can confer reproductive success

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15
Q

When two phenotypic extremes of a trait are being selectively favored, then a natural population is undergoing ____ selection.

A

disruptive

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16
Q

The ability of an organism to camouflage with its environment is an example of a(n)

A

adaptation

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17
Q

Selection for dark-winged moths in a population of moths with pigmentation that varies from light to dark is an example of ___ selection.

A

directional

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18
Q

Sexual selection is a special form of natural selection in which individuals vary in ability to

A

obtain mates

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19
Q

Rank the following turtles from lowest fitness at the top to highest fitness at the bottom.

A
  1. A turtle that dies at 100 years and fathers 0 surviving offspring
  2. A turtle that dies at 75 years and fathers 10 surviving offspring
  3. A turtle that dies at 50 years and fathers 20 surviving offspring
  4. A turtle that dies at 20 years and fathers 30 surviving offspring
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20
Q

Select all of the following that are examples of sexual selection.

A
  • male to male combat during the mating season
  • female birds choosing mates with the best nest-building skills
  • males displaying showy plumage to females to get more opportunities to mate
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21
Q

Select all of the following that are examples of the bottleneck effect.

A
  • North American bison

- greater prairie chickens

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22
Q

What is an example of the founder effect?

A

A few birds colonizing an isolated island

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23
Q

What causes the movement of alleles between populations?

A

Migration

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24
Q

Directional, disruptive, and stabilizing are all types of ____, in which certain phenotypes are favored over others.

A

natural selection

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25
Q

Select all of the effects of migration.

A
  • introduce new alleles into a population

- decreased regional differences in genetic diversity

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26
Q

A chance change in a population’s allele frequencies, such as after a drastic reduction in population size, is the root of what force of evolution?

A

genetic drift

27
Q

If a predator is more likely to prey upon fish that are brightest in color, then natural selection in this environment will favor

A

drabber fish

28
Q

Select the true statement about mutation and natural selection.

A

Natural selection acts on existing mutation.

29
Q

What is a mechanism by which harmful alleles can be maintained in a population even though homozygous recessive individuals have greatly reduced fitness?

A

heterozygotes have greater fitness

30
Q

Select all of the following that can limit the actions of natural selection.

A
  • an organism’s evolutionary history
  • traits that affect survival but not reproduction
  • disasters such as floods and volcanoes that eliminate allele combinations
31
Q

Select all the reasons why males usually show the greatest effects of sexual selection.

A
  • Females have high investment in reproduction

- Males mush compete for access to females

32
Q

What genotype for the “sickle cell gene” causes mild symptoms of sickle cell disease but confers resistance to malaria?

A

heterozygous

33
Q

The goal of natural selection is to produce perfect organisms.

A

False

34
Q

Genetic drift has a greater effect on

A

small populations

35
Q

The diagram illustrates change in a bacteria population due to the presence of an antibiotic over many generations. This is an example of

A

natural selection

36
Q

If the environment changes, a trait that was adaptive may become nonadaptive or costly, demonstrating that

A

evolution continuously shapes populations

37
Q

A population of snails is separated when an eight-lane highway is built. After 50 years, the two separate populations can no longer interbreed. This describes the process of

A

new species forming

38
Q

The model that proposes that speciation occurs in brief bursts interrupted by long periods of little change is ____ equilibrium.

A

punctuated

39
Q

Select all of the following that are prevented by postzygotic reproductive barriers.

A
  • production of fertile offspring

- survival of offspring to maturity

40
Q

Match the postzygotic reproductive barrier on the left with its example on the right.

A
  • Hybrid inviability - Hybrid eucalyptus seeds do not germinate; seedlings die very early.
  • Hybrid infertility - The offspring of a lion-tiger mating (liger) is infertile.
  • Hybrid breakdown - Offspring of hybrid mosquitoes have abnormal genitalia.
41
Q

If a zygote cannot form between two organisms, then a type of ____ reproductive barrier is present.

A

prezygotic

42
Q

Organisms have changed over time; new species have appeared while other species have gone extinct. This is a description of ____.

A

macroevolution

43
Q

The ____ model of speciation proposes that evolution proceeds in small, incremental changes over many generations.

A

gradualism

44
Q

According to the biological species concept, a species is a population

A

whose members can interbreed and produce fertile offspring.

45
Q

What type of reproductive isolating barrier occurs after the formation of a zygote and reduces the fitness of a hybrid?

A

postzygotic

46
Q

Select all the examples of organisms from the fossil record that offer evidence of punctuated equilibrium.

A
  • mammals
  • bryozoans
  • mollusks
47
Q

Match the type of prezygotic reproductive barrier on the left with its example on the right.

A
  • Habitat isolation - Herbivores ladybird beetles feed on different types of plants.
  • Temporal isolation - Field crickets mature at different times.
  • Behavioral isolation - Frog mating calls differ.
48
Q

The formation of a new species is called

A

speciation

49
Q

Select all of the reasons why the biological species concept is not a perfect definition of a species.

A
  • It doesn’t apply to asexually reproducing organisms
  • It only accounts for absolute reproductive isolation
  • It is impossible to apply to extinct organisms known only from fossils
50
Q

Select the two models of speciation.

A
  • gradualism

- punctuated equilibrium

51
Q

Match the name of the type of prezygotic reproductive barrier on the left with its description or an example on the right.

A
  • Habitat isolation - populations live in different places
  • Behavioral isolation - a variation in a courtship ritual
  • Mechanical isolation - reproductive structures that do no fit together
  • Gametic isolation - sperm that does not fertilize the egg
  • Temporal isolation - active at different times of day
52
Q

Select all the postzygotic reproductive barriers.

A
  • hybrid infertility
  • hybrid inviability
  • hybrid breakdown
53
Q

Over many hundreds of years, the definition of ____ has changed several times as scientists have refined ideas.

A

a species

54
Q

The figure labeled A represents ____, and the figure labeled B represents ____.

A

gradualism; punctuated equilibrium

55
Q

The speciation and extinction of the dinosaurs are examples of ____, and the increased frequency of a particular genotype that specifies a color patter in fish is an example of ____.

A

macroevolution; microevolution

56
Q

When two populations no longer share the same gene pool, then ____ has occurred.

A

speciation

57
Q

The accumulation of small changes in a population by microevolution can eventually lead to large-scale

A

macroevolution

58
Q

Mechanisms of ____ prevent successful reproduction and include prezygotic barriers and postzygotic barriers.

A

reproductive isolation

59
Q

Carolus Linnaeus classified species based upon ____ but not upon ____.

A

body structure; evolutionary relationships

60
Q

Select all the criteria biologists can use to define species.

A
  • reproductive isolation

- DNA sequence analysis

61
Q

Select three ways that genetic divergence can occur between two separated populations.

A
  • natural selection
  • genetic drift
  • mutation
62
Q

Select the most accurate statement about gradualism and the fossil record.

A

For organisms such as diatoms that existed in large, connected populations, the fossil record shows a slow pace of gradual changes.

63
Q

When might speciation occur rapidly? Select all that apply.

A
  • After a key adaptation arises

- After a major environmental change wipes out many species

64
Q

What type of organisms appear to have evolved by gradualism, as suggested by the fossil record?

A

microscopic protists

BISC 2 - Genetics, Ecology, Evolution (5 decks)

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