Week 4- Quizzes, Animations, Clicker Questions Flashcards Preview

LS 7B- Genetics, Evolution, & Ecology > Week 4- Quizzes, Animations, Clicker Questions > Flashcards

Flashcards in Week 4- Quizzes, Animations, Clicker Questions Deck (41)
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1
Q

All the alleles present in all individuals in a species are referred to as the _____ of that species.

gene pool

genotype frequency

genotype

phenotype

allele frequency

A

gene pool

Why: A gene pool represents all alleles in a given species in any given individual.

2
Q

Genetic variation has two sources–mutation and:

recombination.

non-random mating.

genetic drift.

cell division.

natural selection.

A

recombination

Why: When mutations occur it allows new pairings of nucleotide base pairs. If a T is added instead of a G then there is recombination possible for pairs that receive the the T as it was not a possible pair before the mutation. Thus increasing genetic variation because it is different from the rest.

3
Q

What is the result of a mutation that occurs in somatic cells?

The mutation will prevent all reproduction.

The mutation will be passed along to the organism’s offspring.

The mutation may be expressed in the individual, but will not be passed along to its offspring.

There will never be any visible effect.

The mutation will be deleterious.

A

The mutation may be expressed in the individual, but will not be passed along to its offspring.

Why: Germ-line mutations affect the individual and also is passed along to the offspring. Somatic cells when there is a mutation affect the individual and is not passed to the next generation because somatic cells are nonreproductive cells.

4
Q

As a population geneticist, you find a species of snails with more genetic diversity than humans. What does this mean?

There is not enough information provided to answer this question.

There is more variety in the gene pool of snails than humans.

The snails have more genes on their chromosomes than humans.

The snails have more mutations occurring than humans.

The snails have more DNA than humans.

A

There is more variety in the gene pool of snails than humans.

Why: A Gene pool is all the alleles present in all individuals in a given population, and genetic variation is the differences in genotypes among individuals in a population. So the more variety in the gene pool the more differences in genotype hence more genetic variation.

5
Q

Consider a population of killer whales. The gene pool of this population would only contain alleles harboring beneficial or neutral mutations, as deleterious mutations are efficiently eliminated from the gene pool of a species.

False

True

A

False

Why: Deleterious mutations may take some time to leave the gene pool there is no efficient and quick way to eliminate it but eventually it will be weeded out if it decreases survival.

6
Q

In a given population, all humans have the same blood type O. If no other alleles for blood type exist in this population, this population if “fixed” for the O allele.

True

False

A

True

Why: For blood type O you need to have the genotype OO meaning the allele frequency for O is 100% because it is the only allele available in the population.

7
Q

If a gene has two alleles, and alleles A has a frequency of 83%, then allele a has a frequency of:

17%

7%

41.5%

166%

117%

A

17%

Why: If allele A is 83% then to find the allele frequency for a you take the known allele and subtract it from 100%.

100% - 83% = 17%
total - allele A% = allele a%

8
Q

Why can’t we measure genetic variation in a population using observable traits (phenotypes)? (Select all that apply.)

All traits are encoded by a single gene.

The environment can also affect the phenotype.

Many traits are encoded by multiple genes.

Phenotypes are not determined by genes.

A

The environment can also affect the phenotype.

Many traits are encoded by multiple genes.

Why: Genotype and environment make up the phenotype and trait are usually determined by more than one gene.

9
Q

In a fish species the eggs tend to be fertilized more often by the mid-sized males and less often by the largest and smallest males. This is an example of:

A., stabilizing selection.

B., directional selection.

C., disruptive selection.

D., None of the other answer options is correct.

A

A., stabilizing selection.

Why: Stabilizing selection favors the average/ intermediate of the the two extremes. So by favoring the middle trait it is stabilizing the trend of survival.

So medium sized males is better than big and small sized males.

10
Q

A cattle breeder selects the largest males for breeding with the largest females. This is an example of:

A., stabilizing selection.

B., directional selection.

C., disruptive selection.

D., None of the other answer options is correct.

A

B., directional selection.

Why: This is directional selection because one of the extremes is favored in this case the largest size of both gender for better breeding results in offspring. By choosing the largest size, over time the trait will become larger.

11
Q

Female starlings (birds) that lay clutches of four or five eggs have more surviving young than those with either larger or smaller clutches. This is an example of:

A., stabilizing selection.

B., directional selection.

C., disruptive selection.

D., None of the other answer options is correct.

A

A., stabilizing selection.

Why: The clutches of 4-5 is the intermediate of bigger and smaller clutches. and since the intermediate is favored the trait is stabilizing.

12
Q

On Island X the plant population contains only two species. One plant species produces only very large seeds, and the other produces only small seeds. There is only one species of bird on the island, and the birds use these seeds as their only food source. Currently there is a wide range of beak sizes within the population of birds as shown in the diagram below. Small-beaked birds are better able to consume the smaller seeds, while large-beaked birds are better at consuming the larger seeds. Birds with intermediate beak size can make use of both seed sizes.

A disease is introduced to the island which kills only the plants that produce the large seeds. Consider changes in the bird population following the death of all plants that produce large seeds. Which portion(s) of the finch population will be selected against and least likely to have their genes represented in the next generations?

A., portion A only

B., portion B only

C., portion C only

D., portions A and C simultaneously

E., portions B and C simultaneously

A

C., portion C only

Why: Portion C represents the birds with large beak sizes and they only eat the plant with the large seeds. Once there are no large seeded plants left the large beaked birds will die off with out the only food source and will not likely be shown in the next generation.

13
Q

What type of selection occurs when an environmental condition, for example food source characteristics, causes selection toward one extreme of a trait’s range of variation?

A., stabilizing

B., directional

C., disruptive

A

B. directional

Why: Directional selection is when one extreme is favored so over time the trait will change in that direction of the favored extreme.

14
Q

On Island X the plant population contains only two species. One plant species produces only very large seeds, and the other produces only small seeds. A rare storm blows in a flock of birds of a species never before found on the island. Within this flock there is a wide range of beak sizes as shown in the diagram here.

As their only food source, the birds find the plant seeds quite delectable. However, while small-beaked birds do very well consuming the smaller seeds, and large-beaked birds thrive on the larger seeds, birds with intermediate beak size are not good at consuming either size seed, and they struggle to get sufficient nutrition. What type of selection might we predict over the course of multiple generations of these birds?

A. stabilizing

B. directional

C. disruptive

A

C. disruptive

Why: Disruptive selection favors the two extremes for a trait and selects against the intermediate in this case the mid-sized beaks. Over time the mid-sized beaks will decrease until only small and large sized beak birds inhabit the island.

15
Q

Prior to the publication of Darwin’s On the Origin of Species, people thought what about species?

Species evolved at one point, but no longer changed because they were not adapted to their environment.

Species were designed already perfectly adapted to their environment.

Species changed over time as guided by a divine creator.

Species changed over time because they were not adapted to their environment.

A

Species were designed already perfectly adapted to their environment.

Why: It was thought that a Divine Creator had made species perfectly adapted to their environment so there was no evolving.

16
Q

Which of the following is an example of stabilizing selection?

decrease in the number of birds with intermediate-sized beaks who are unable to eat large or small seeds

antibiotic resistance in bacteria

selection for average birth weight in humans

breeding dogs from wolves

A

selection for average birth weight in humans

Why: Average birth weight in humans represents stabilizing selection because the intermediate trait is favored and the extreme traits (large and small) are selected against.

17
Q

Malthus pointed out that populations have the potential to increase geometrically. What did this observation suggest that contributed to the idea of natural selection?

Populations may grow quickly, and then will evolve more quickly.

Populations grow quickly, but predators grow more quickly.

Populations may grow quickly and spread out over the planet.

Populations may grow faster than other competing populations.

Populations may grow faster than their resources.

A

Populations may grow faster than their resources.

Why: Malthus said that is the human race started by each couple having 4 children then in 20 generations there would be over a million people on the planet. This indicates that the population can grow faster than finding the resources to accommodate the population increase.

18
Q

Why is it thought that the majority of natural selection is stabilizing selection?

Directional selection is more common because it increases adaptations to the environment.

Mutations produce extreme phenotypes, which are selected for.

Most mutations are beneficial and produce intermediate phenotypes.

Artificial selection is the most common, which is a type of stabilizing selection.

Most mutations are deleterious and produce an extreme phenotype that is selected against.

A

Most mutations are deleterious and produce an extreme phenotype that is selected against.

Why: Mutations that are deleterious often reflect one of the extreme characteristics and these mutations do not increase the extremes chance of survival so they are selected against.

19
Q

Traits favored by sexual selection are the same traits favored by natural selection.

False

True

A

False

Why: Some traits favored by sexual selection such as (colorful or larger features) often would be selected against for natural selection as these traits would make the individual stand out more to predators.

20
Q

The intricate plumage of male birds of paradise has become increasingly elaborate throughout their evolution due to females mating preferentially with males that display the most impressive feathers. This is an example of _____ selection.

artificial

stabilizing

disruptive

sexual

A

sexual

Why: Males have more color of ruffles on their feathers to attract a female to mate with.

21
Q

The goldenrod gall fly lays its eggs on the terminal buds of goldenrod plants. Larvae chew through the buds and into the stems, where their saliva induces the plant to generate a gall, or outgrowth of tissue that then provides food and shelter for the developing larva. The larvae are prey to both parasitoid wasps and to birds; wasps selectively prey on larvae inside the smallest galls while birds selectively prey on larvae inside the largest galls. Goldenrod gall flies are therefore subject to _____ selection.

stabilizing

heterozygote

disruptional

directional

balancing

A

stabilizing

Why: Due to predators eating both the extremes this means the intermediate is favored and stabilizing selection will occur because both alleles/traits are not being eliminated.

22
Q

Meerkats are small desert mammals that live in groups of 20–50 individuals. You observe one meerkat standing upright on a stump, looking around, while other meerkats forage for food. You hypothesize that this is an example of kin selection. What additional information would you need to know to evaluate your hypothesis?

the gender of this meerkat as well as that of all other members of the group

the degree of genetic relatedness of this meerkat to all members of the group

the body size of this meerkat relative to other members of the group

the foraging success of this meerkat as well as that of all other members of the group

all other activities of this meerkat as well as those of all other members of the group

A

the degree of genetic relatedness of this meerkat to all members of the group

Why: the relatedness of the meerkat with the rest of his group can explain the role the meerkat plays in the group.

23
Q

According to William Hamilton’s formulation of kin selection, in which scenario would you have the greatest fitness? Use Figure 45.17 below for help.

Sacrificing yourself for the benefit of one child.

Sacrificing yourself for the benefit of three nieces and/or nephews.

Sacrificing yourself for the benefit of one sibling.

Sacrificing yourself for the benefit of two nieces and/or nephews.

A

Sacrificing yourself for the benefit of three nieces and/or nephews.

Why: Each niece/nephew represents 0.25 probability that the fitness gene will be in the next generation. So if you (being a 0.5 probability to pass the fitness down) sacrifice yourself for the birth of 3 nieces/nephews it would be 0.25 x 3 = 0.75 which would be greater fitness.

24
Q

If B = the benefit of a behavior to a recipient, C = the cost of the behavior of the donor, and r = the degree of relatedness between the recipient and donor, then if rB > C, altruism can evolve.

True

False

A

True

Why: If the degree of relatedness multiplied by the benefit to a recipient it greater than the cost to the donor than altruism can evolve because the cost is not greater than the benefit so it is favored.

25
Q

Group selection is not typically seen as an evolutionarily stable strategy because:

None of the answer options is correct.

it cannot explain behaviors for species with solitary individuals.

average relatedness is very low between individuals in a population, therefore individual fitness cannot increase.

selfish behaviors are more likely to increase individual fitness.

A

selfish behaviors are more likely to increase individual fitness.

Why: Fitness will increase if the selfish individuals reproduce since the self-sacrificial individuals will not reproduce. The selfish individual will pass there genes to the next generation. Group selection allows for a species/population to be eliminated.

26
Q

You are given the following information about a population:
• There are two alleles: C and c.
• C codes for green hair and c codes for white hair.
• C is dominant over c.
• The frequency of the c allele is 0.3.
• The population is comprised of 100 individuals.

Assuming the population is in Hardy-Weinberg equilibrium, how many individuals have green hair?

9% of the population will have green hair.

49% of the population will have green hair.

51% of the population will have green hair.

91% of the population will have green hair.

A

91% of the population will have green hair.

Why: Since C is dominant the green hair phenotype corresponds to CC and Cc/cC. We know that c is 0.3 and p+q=1, so 1-q(0.3) = p. This gives us 0.7 for the C allele. So for CC we multiply 0.7 x 0.7 and get O.49, next we do 2pq which is 2( 0.7 x 0.3) = 0.42. Then you add 0.49 + 0.42= 0.91 or 91% of the population with green hair.

27
Q

What term CORRECTLY describes change in allele frequency due to random effect of a small population?

selection

immigration

mutation

nonrandom mating

genetic drift

A

genetic drift

Why: Genetic drift is the variation in the relative frequency of different genotypes in a small population.

28
Q

If a population is not in Hardy-Weinberg equilibrium, we can conclude that:

one of the assumptions of the Hardy-Weinberg equilibrium has been violated.

All of these choices are correct.

natural selection has occurred.

nonrandom mating has occurred.

evolution has occurred because one or more of the assumptions of the Hardy-Weinberg equilibrium has been violated.

A

evolution has occurred because one or more of the assumptions of the Hardy-Weinberg equilibrium has been violated.

Why: When there is no Hardy-Weinberg equilibrium that means evolution occurred due to any of the 5 condition not being met.

29
Q

What does the term 2pq represent in the Hardy-Weinberg relation?

the frequency of homozygous dominant individuals

the frequency of homozygous recessive individuals

the frequency of deleterious mutations

the frequency of heterozygotes

A

the frequency of heterozygotes

Why: p^2 +2pq + q^2

p^2- frequency of the homozygous dominant allele

2pq- frequency of the heterozygous allele

q^2- frequency of the homozygous recessive allele

30
Q

Which of the following is NOT a condition of the Hardy-Weinberg equilibrium?

Individuals of any genotype must have the same reproductive success as individuals of any other genotype.

The size of a population must be large.

Individuals can migrate in and out of a population, as long as the population size remains constant.

Mutations cannot occur in a population.

Mating within a population must be random.

A

Individuals can migrate in and out of a population, as long as the population size remains constant.

Why:
Conditions:
No mutations

No non-random mating

No small populations(genetic drift)

No selection

No migration

31
Q

Endangered species with very small populations are especially at risk of loss of genetic diversity due to:

natural selection.

mutation.

genetic drift.

immigration.

A

genetic drift.

Why: Genetic drift is the variation in the relative frequency of different genotypes in a small population.

32
Q

Imagine the following genotype frequencies in a population: p2 = 0.49, 2pq = 0.42, q2 = 0.09. Now assume that there is nonrandom mating where individuals with one genotype will only mate with individuals that also have their genotype. Assume this pattern of mating goes on until the frequency of heterozygotes is effectively zero. What will the frequency of allele p be in the population?

  1. 49
  2. 7
  3. 91
  4. 0
  5. 3
A

0.7

Why:
p + q = 1
and p^2=0.49 so the square root of 0.49 will give us 0.7 which is our allele frequency for p and q would be 0.3 when you take the square root of 0.09 given as the q^2 value.

33
Q

Migration reduces genetic differences between populations by allowing gene _____ between the two.

augmentation

repression

deletion

flow

drift

A

flow

Why: Allows the two populations to mate and incorporate the alleles into one another’s gene pool.

34
Q

Why does genetic drift have more of an impact on the evolution of small populations than large ones?

Small populations are affected more by stabilizing selection.

Small populations are less affected by mutations.

Small populations have greater rates of mutation.

Small populations are more prone to migration.

Sampling from generation to generation is more variable in small populations than large.

A

Sampling from generation to generation is more variable in small populations than large.

Why:

35
Q

Mutation increases genetic variation.

False

True

A

True

Why: Can introduce new alleles into a gene pool

36
Q

You are researching a population of moles. In the course of your research, you identify a nearby population that occasionally comes into contact with your study population. What BEST describes the evolutionary process at work?

genetic drift

artificial selection

mutation

natural selection

gene flow

A

gene flow

Why: The two population are connected but not fully

37
Q

Some proteins have a slower molecular clock due to _____ selection, which eliminates harmful alleles.

beneficial

neutral

negative

positive

disruptive

A

negative

Why:

38
Q

If two populations are thought to be diverging from one another, what would you expect to observe?

more shared mutations in different populations

an accumulation of different mutations in different populations

the same genotypes, but different phenotypes

an increase in similarity of alleles coding for proteins

A

an accumulation of different mutations in different populations

Why:

39
Q

Two populations that have been separated from each other for a long period of time will have:

no similar genetic sequences.

limited differences between their genetic sequences.

no differences between their genetic sequences.

small differences in phenotype but identical genotypes.

substantial differences between their genetic sequences.

A

substantial differences between their genetic sequences.

Why:

40
Q

The correlation between the time two species have been evolutionarily separated and the amount of genetic divergence between them is known as the:

Hardy-Weinberg equilibrium.

Modern Synthesis.

molecular clock.

natural selection.

artificial selection.

A

molecular clock.

Why:

41
Q

A gene that no longer retains function is called:

a gene with a stopped molecular clock.

a terminal gene.

broken.

negatively selected.

a pseudogene.

A

a pseudogene.

Why: