Question 1

Refer to the figure.

- Consider the three most dramatic mass extinctions in Earth's history. If a fourth major mass extinction occurred after the same interval as the previous ones, around how many million years from now would you predict it would occur?
A) 125 years from now
B) 200 years from now
C) 250 years from now
D) 300 years from now

Accepted Answer

The answer of Refer to the figure.

- Consider the three...

Question 2

Which of the following evolutionary innovations is least likely to have been a key feature driving adaptive radiation?
A) Insect wings
B) Platypus bill
C) Insect herbivory
D) Mammal placenta

Accepted Answer

The platypus bill is a unique adaptation but not a key feature driving adaptive radiation, unlike the other options which have led to significant diversification in their respective lineages.

Question 3

If a plant population evolves the ability to grow on soils with a chemical composition that most plants cannot tolerate, which of the following statements is false?
A) The species may expand into geographic areas where it did not previously occur.
B) Because of the competitive advantage they provide, the alleles that facilitate growing on the chemically challenging soils will almost surely spread throughout the geographic range of the species.
C) The population may have to adapt to a different suite of competitors that occur on more typical soils.
D) The population may have to adapt to a different suite of herbivores that occur on more typical soils.

Accepted Answer

The alleles that facilitate growing on chemically challenging soils may not spread throughout the entire geographic range of the species if those conditions are not present everywhere. They provide an advantage only in specific environments.

Question 4

The studies by Rieseberg and colleagues on sunflowers showed that hybrids between two species
A) are always sterile.
B) have new genetic combinations that their parental species do not have.
C) sometimes can grow in environments where their parental species cannot.
D) typically outcompete individuals of their parental species due to hybrid vigor.

Accepted Answer

The answer of The studies by Rieseberg and colleagues on...

Question 5

As a habitat becomes fragmented, the population sizes of a species in the habitat should _______, effects of genetic drift should _______, and genetic variation within populations of this species should _______.
A) increase; increase; increase
B) increase; increase; decrease
C) decrease; increase; decrease
D) decrease; decrease; increase

Accepted Answer

Fragmentation typically reduces population sizes, increases the effects of genetic drift, and decreases genetic variation within populations.

Question 6

Refer to the figure.
  
-You are studying a remote island before and after a volcanic eruption. Data at Time 1 were collected one month before the eruption, and data at Time 2 were collected one month after the eruption. All of the species on the island are endemic. The island is 100 km across. Each animal icon represents 20 individuals. Species A and B (the two snail species) generally move a distance of only 2 m a day. Species C (the bird) often covers 20 km a day in search of food. After the eruption, the lava flow hardens, and the island is divided by a 20-km strip of bare rock with few, if any, resources these animals need to survive. Would you expect to see a change in patterns of gene flow in species B and C? Why or why not?

Accepted Answer

The answer of Refer to the figure.
  
-You are...

Question 7

Refer to the figure.
 
- You are studying a remote island before and after a volcanic eruption. Data at Time 1 were collected one month before the eruption, and data at Time 2 were collected one month after the eruption. All of the species on the island are endemic. The island is 100 km across. Each animal icon represents 20 individuals. Species A and B (the two snail species) generally move a distance of only 2 m a day. Species C (the bird) often covers 20 km a day in search of food. After the eruption, the lava flow hardens, and the island is divided by a 20-km strip of bare rock with few if any resources these animals need to survive. Deaths of individuals due to the volcanic eruption could change the frequency of alleles in these very small island populations. Unfortunately, however, you do not have data on the allele frequencies before and after the eruption for any of these species. Based on your understanding of genetic change in populations, do you expect that these three species would be affected by increased genetic drift after the eruption? Why or why not?

Accepted Answer

The answer of Refer to the figure.
 
- You are...

Question 8

Refer to the figure.
  
-You are studying a remote island before and after a volcanic eruption. Data at Time 1 were collected one month before the eruption, and data at Time 2 were collected one month after the eruption. All of the species on the island are endemic. The island is 100 km across. Each animal icon represents 20 individuals. Species A and B (the two snail species) generally move a distance of only 2 m a day. Species C (the bird) often covers 20 km a day in search of food. After the eruption, the lava flow hardens, and the island is divided by a 20-km strip of bare rock with few if any resources these animals need to survive. Based on your knowledge of gene flow, genetic drift, and speciation, what do you predict will happen to these species over time? Do you predict that the current species will remain the same species or do you think they might split? How would you determine whether a species had split into two new species?

Accepted Answer

The answer of Refer to the figure.
  
-You are...

Question 9

Refer to the figure.
  
-You are studying a remote island before and after a volcanic eruption. Data at Time 1 were collected one month before the eruption, and data at Time 2 were collected one month after the eruption. All of the species on the island are endemic. The island is 100 km across. Each animal icon represents 20 individuals. Species A and B (the two snail species) generally move a distance of only 2 m a day. Species C (the bird) often covers 20 km a day in search of food. After the eruption, the lava flow hardens, and the island is divided by a 20-km strip of bare rock with few if any resources these animals need to survive. What is the most likely explanation for what happened to species A as a result of the volcanic eruption?

Accepted Answer

The answer of Refer to the figure.
  
-You are...

Question 10

Refer to the figure.
  The figure shows the mortality rate for female red deer of different ages that reproduced (blue curve) or did not reproduce (red curve). Describe the patterns you see and suggest likely explanations for the general shapes of these two curves.

Accepted Answer

The answer of Refer to the figure.
  The figure...

Question 11

Refer to the figure.
  You are studying the evolution of a group of tree species that all share a common ancestor. 
-Referring to the figure, which two species are most closely related? What evidence do you have to support this?

Accepted Answer

The answer of Refer to the figure.
  You are...

Question 12

Refer to the figure.
  You are studying the evolution of a group of tree species that all share a common ancestor. 
-Referring to the figure, when might an adaptive radiation have occurred? Explain.

Accepted Answer

The answer of Refer to the figure.
  You are...

Question 13

Refer to the figure.
  You are studying the evolution of a group of tree species that all share a common ancestor. 
-Suppose that species B, C, E, and F all share characteristics that are very different from those of species D, but there are currently no living species that "fill the gap" between the B/C/E/F group and species D. Now suppose you could team up with a paleontologist to look for fossils to better understand how B/C/E/F became so different from species D. What age of rocks would you look for to target your search?

Accepted Answer

The answer of Refer to the figure.
  You are...

Question 14

If a population of Silene (a plant) has 400 members with 180 of genotype DD, 180 of genotype Dd, and 40 of genotype dd, the frequency of the D allele is
A) 0.125.
B) 0.36.
C) 0.54.
D) 0.675.

Accepted Answer

The answer of If a population of Silene (a plant)...

Question 15

Two tree species live in different environments yet share many similar characteristics. The most likely reason for these similarities is
A) natural selection.
B) shared ancestry.
C) genetic drift.
D) adaptive radiations.

Accepted Answer

Shared ancestry is the most likely reason for the similarities between the two tree species, as it suggests that they have evolved from a common ancestor and inherited similar characteristics.

Question 16

The mutation rate of a gene involved in lactose metabolism is two mutations per million copies of the gene per generation. Suppose there are 15 million individuals in a population of a yeast, each with two copies of this gene (i.e., they are diploid). In this yeast population, how many new mutations would we expect at this gene each generation?
A) Fewer than 1
B) 15
C) 30
D) 60

Accepted Answer

Each individual has two copies of the gene, so there are 30 million copies in the population. With a mutation rate of two mutations per million copies, we expect 60 mutations per generation (30 million copies * 2 mutations/million copies).

Question 17

In the 1890s, the biologist Hermon Bumpus found that sparrows that had survived a Rhode Island storm were more likely to be of intermediate size than sparrows that had perished from the storm. This is most likely an example of
A) genetic drift.
B) disruptive selection.
C) stabilizing selection.
D) gene flow.

Accepted Answer

Stabilizing selection is a type of natural selection that favors intermediate variants and acts against extreme phenotypes, which is consistent with the observation that sparrows of intermediate size were more likely to survive.

Question 18

Genetic drift tends to _______ genetic variation within small populations, and _______ genetic differences among populations.
A) increase; increase
B) increase; have no effect on
C) increase; decrease
D) decrease; increase

Accepted Answer

Genetic drift decreases genetic variation within small populations due to random allele frequency changes and increases genetic differences among populations as different alleles become fixed or lost in different populations.

Question 19

Refer to the figure.
 Simulations, in which it was assumed that the populations were subject to only genetic drift (no selection), were performed using three different starting population sizes, and they were scored for the frequency of the B allele. All populations started with the frequency of 50% of the B allele. Each line represents a different replicate of the conditions. The three panels differ only in the population size. Which graph is of populations with the largest population size?
A) A
B) B
C) C
D) A and B had roughly equal population sizes, which were larger than those in panel C.

Accepted Answer

The answer of Refer to the figure.
 Simulations, in which...

Question 20

Which evolutionary process is most likely to inhibit speciation?
A) Gene flow
B) Directional selection
C) Disruptive selection
D) Genetic drift

Accepted Answer

Gene flow involves the transfer of genetic material between populations, which can homogenize genetic differences and inhibit the divergence necessary for speciation.

Quiz 6: Evolution and Ecology

Refer to the figure. - Consider the three most dramatic mass extinctions in Earth's history. If a fourth major mass extinction occurred after the same interval as the previous ones, around how many million years from now would you predict it would occur?

Which of the following evolutionary innovations is least likely to have been a key feature driving adaptive radiation?

If a plant population evolves the ability to grow on soils with a chemical composition that most plants cannot tolerate, which of the following statements is false?

The studies by Rieseberg and colleagues on sunflowers showed that hybrids between two species

As a habitat becomes fragmented, the population sizes of a species in the habitat should ___, effects of genetic drift should _, and genetic variation within populations of this species should _____.

Refer to the figure. The figure shows the mortality rate for female red deer of different ages that reproduced (blue curve) or did not reproduce (red curve). Describe the patterns you see and suggest likely explanations for the general shapes of these two curves.

Refer to the figure. You are studying the evolution of a group of tree species that all share a common ancestor. -Referring to the figure, which two species are most closely related? What evidence do you have to support this?

Refer to the figure. You are studying the evolution of a group of tree species that all share a common ancestor. -Referring to the figure, when might an adaptive radiation have occurred? Explain.

If a population of Silene (a plant) has 400 members with 180 of genotype DD, 180 of genotype Dd, and 40 of genotype dd, the frequency of the D allele is

Two tree species live in different environments yet share many similar characteristics. The most likely reason for these similarities is

In the 1890s, the biologist Hermon Bumpus found that sparrows that had survived a Rhode Island storm were more likely to be of intermediate size than sparrows that had perished from the storm. This is most likely an example of

Genetic drift tends to _ genetic variation within small populations, and _ genetic differences among populations.

Which evolutionary process is most likely to inhibit speciation?