04 genetic variation, allele frequencies and hardy weinberg, 05 microevolution genetic drift, 06 microevolution natural selection

Question 1

all new alleles are the result of mutation in what?

Answer 1

in genetic variation

Question 2

analysis of fruit fly genomes indicates that about 85% of their genes are fixed, meaning what

Answer 2

meaning that they only come in one version with no allelic variation

Question 3

in a hypothetical population, there are two alleles B and b, where B is completely dominant over b. their allele frequencies are 0.85 and 0.15 respectively. based on this information alone, can we make any predictions about how allele frequencies are likely to change in this population?

Answer 3

not enough information is provided

Question 4

image illustrating the range of possible eye colors shows a continuum of grey-green-brown iris colour, ranging from small pupil ring to almost complete brown with peripheral green flecks. eye colour in humans is determined by 2 main genes, while another 14 genes contribute but to a lesser extent.

Answer 4

eye color in humans is heritable and quantitative

Question 5

in a hardy-weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2 and it is recessive. what is the frequency of individuals that are heterozygous for this allele?

Answer 5

0.32

Question 6

in a hardy-weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2 and it is recessive. what is the frequency of individuals that are homozygous for this allele?

Answer 6

0.04

Question 7

in a hardy-weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2 and it is recessive. what is the frequency of allele A?

Answer 7

0.8

Question 8

t/f in a different population with the same two alleles, A and a, the frequency of allele a is still 0.2. you note that the frequency of the dominant phenotype in this population is 0.62. that number matches what you would expect if this population was in hardy weinberg equilibrium

Answer 8

false

Question 9

the previous question addressed a population with the two alleles, A and a, the frequency of allele a is still 0.2. you noted that the frequency of the dominant phenotype in this population is 0.62. which of the following statements are most correct about this population?

Answer 9

there are fewer of the dominant phenotype than expected.

Question 10

the ability to taste phenylthiocarbamide (PTC) is a heritable dominant trait in humans. suppose 64% of a remote mountain village can taste PTC and therefore must have at least one copy of the dominant PTC taster allele. If this population conforms to hardy-weinberg equilibrium for this gene, what percentage of the population must be heterozygous for this trait?

Answer 10

0.48

Question 11

microevolution occurs in a population when

Answer 11

allele frequencies change over time in that population

Question 12

what if I told you the above plot was generated from a very small population (say, fewer than 50 individuals). what would you conclude?

Answer 12

it seemsl likely that A1 was eliminated via genetic drift

Question 13

what if I now told you that the above plot was generated using an infinitely large population? what does this suggest?

Answer 13

it suggests A1 was eliminated via natural selection

Question 14

transfer of alleles in and out of a population due to movement of fertile individuals

Answer 14

gene flow

Question 15

alleles transferred to the next generation in proportions that differ from previous generation

Answer 15

microevolution

Question 16

chance events that change allele frequencies in a population over time

Answer 16

genetic drift

Question 17

reduction in population size that alters gene frequencies of that population

Answer 17

genetic bottleneck

Question 18

allele frequency in a species differs between populations near the “core” of the species’ range and populations expanding into new habitats

Answer 18

founder effect

Question 19

which of the following microevolutionary processes causes populations of organisms to become better suited to their environments?

Answer 19

natural selection

Question 20

why are french canadians from the saguenay-lac st jean area so genetically distinct from other north americans?

Answer 20

• their population was founded by a small number of individuals who settled the area in the 17th and 18th centuries
• historically, this population had a high birthrate
• members of this population tend to have children with partners from their own cultural group

Question 21

given a population that contains genetic variation, what is the correct sequence of the following events under the influence of natural selection?

Answer 21

a change occurs in the environment -> poorly adapted individuals have decreased survivorship -> well-adapted individuals leave more offspring than do poorly adapted individuals -> genetic frequencies within the population change

Question 22

the dunkers are a religious group that moved from germany to pennsylvania in the mid-1700s. since their arrival they have almost never married with members outside their own immediate community. today, the dunkers are genetically unique and differ in gene frequencies, at many loci, from all other USA populations, as well as those in their original homeland. which of the following mechanisms likely explains the genetic uniqueness of this population?

Answer 22

founder effect and genetic drift

Question 23

this is a robin’s nest (robin= a species of bird). female robins almost always lay exactly 4 eggs per breeding season. this suggests that

Answer 23

the number of eggs produced in any one breeding event has undergone strong stabalizing selection

Question 24

kale was produced by

Answer 24

selective breeding of wild mustard plants that produced large leaves, making it a great example of artifical selection

Question 25

what aspect of the peacock’s tail made darwin sick?

Answer 25

the showiness of the tail seems to violate the laws of natural selection