Mastering Biology Chapter 22 Exam
2025 With 100% Correct Answers
(Pre test: Q.3) Charles Darwin _____. - correct answers ✔✔proposed natural selection as the mechanism
of evolution
(Pre test: Q. 4)From his observations of organisms in the Galapagos islands, Darwin reasoned that _____.
- correct answers ✔✔organisms had adapted to new environments, giving rise to new species
(HHMI) Why did dark-colored rock pocket mice first appear in a population of light-colored rock pocket
mice?They have a genetic mutation that affects their fur color. - correct answers ✔✔They have a genetic
mutation that affects their fur color.
(HHMI) Why do dark-colored rock pocket mice on dark lava flows have white bellies? - correct answers
✔✔There is no selection for dark bellies by visual predators.
(HHMI) Mutations are always __________ - correct answers ✔✔a change in an individual's DNA
(HHMI) When dark-colored fur gives mice a 1% competitive advantage and 1% of the population begins
with dark fur, in about 1000 years, 95% of the population will have dark fur. Which of the following
statements is true? - correct answers ✔✔If dark-colored rock pocket mice had a competitive advantage
of 0.1%, it would take longer for 95% of the population to have dark fur.
(HHMI) What does Dr. Carroll mean when he says, "while mutation is random, natural selection is not"? -
correct answers ✔✔-Mutations for advantageous traits are more likely to be passed on to the next
generation.
-Natural selection acts on traits.
-Natural selection favors some mutations.
(HHMI) In the lab, Nachman examined dark mice from two different populations living hundreds of miles
apart. The mice looked nearly identical. Their dark color was caused by two different genes. What does
,this tell you? - correct answers ✔✔-Two completely different mutations in two separate genes can
generate the same phenotype.
-Dark fur color evolved independently on each lava flow.
-Under very similar conditions, natural selection can favor very similar adaptations.
-There are at least two genes involved in creating dark mouse fur.
(Scientific Skills) This experiment is an example of hypothesis-based science. What question did the
researchers ask? - correct answers ✔✔Can predation result in selection for color patterns in guppies?
(Scientific Skills) What was the researchers' main hypothesis? - correct answers ✔✔Predation results in
selection for more drab color patterns in guppies.
(Scientific Skills) Researchers further hypothesized that if predation pressure is reduced, drab coloration
would become less beneficial (since females prefer brightly colored mates). Based on this hypothesis,
what prediction did the researchers test in this experiment? - correct answers ✔✔When guppies with
drab colors are transferred to a pool with only killifish, the transplanted population will evolve brighter
colors than the original source population.
(Scientific Skills) What was the control group in this study? - correct answers ✔✔the source population
in the pike-cichlid pools
(Scientific Skills) What was the experimental group in this study? - correct answers ✔✔the transplanted
population in the killifish pools
(Scientific Skills) How did the types of data the researchers collected enable them to test their
prediction? - correct answers ✔✔Tracking the number and area of colored spots provided a quantitative
way to compare the brightness of different populations.
(Scientific Skills) What conclusion would you draw from the data presented? - correct answers
✔✔Predation results in selection for more drab coloration in pike-cichlid pools.
(Scientific Skills) Which of the following would help strengthen the researchers' conclusion? - correct
answers ✔✔if no other characteristics differed significantly between the source and transplanted
populations
, (Scientific Skills) Suppose that after 22 months, guppies from the transplanted population were returned
to the source pool. What would most likely happen to those guppies? - correct answers ✔✔They would
experience a higher rate of predation than the native population, and over time they would evolve and
resemble the original source population.
(Scientific Skills) What data should you collect in order to test your prediction? - correct answers
✔✔predation rate on transplanted versus original source guppies, and color patterns of the population
over time
(Evidence for Evolution) Scientific evidence documents the pattern of evolution. The evidence exists in a
variety of categories, including direct observation of evolutionary change, the fossil record, homology,
and biogeography. Sort the following examples into the correct categories. - correct answers ✔✔Direct
observation of evolutionary change: Development of drug resistant bacteria
Fossil record: Discovery of transitional forms of horses, Discovery of shells of extinct species
Homology: Similarities in mammalian forelimbs, Same genetic code in fireflies and tobacco plants,
Vestigial pelvis in right whales
Biogeography: Similarity of endemic island species to nearby mainland species, The high concentration
of marsupial species in Australia
(Evidence for evolution) The island fox shares a common ancestor with the gray fox, Urocyon
cinereoargenteus, which is found on the mainland. Both species have similar coloration and a diploid
chromosome number of 66. One structural difference between the two species is the reduced size of the
island fox, a feature known as dwarfism. The various island subspecies also differ from each other in size,
number of tail vertebrae, and other characteristics.The phylogenetic tree below shows the evolutionary
relationships between the island fox subspecies and the gray fox. Drag the labels to their appropriate
locations on the tree. - correct answers ✔✔a. ancestor of gray foxes and island foxes
b. ancestor of Santa Rosa and San Miguel foxes
c. Dwarfism
d. ancestor of northern channel island foxes
e. most closely related
2025 With 100% Correct Answers
(Pre test: Q.3) Charles Darwin _____. - correct answers ✔✔proposed natural selection as the mechanism
of evolution
(Pre test: Q. 4)From his observations of organisms in the Galapagos islands, Darwin reasoned that _____.
- correct answers ✔✔organisms had adapted to new environments, giving rise to new species
(HHMI) Why did dark-colored rock pocket mice first appear in a population of light-colored rock pocket
mice?They have a genetic mutation that affects their fur color. - correct answers ✔✔They have a genetic
mutation that affects their fur color.
(HHMI) Why do dark-colored rock pocket mice on dark lava flows have white bellies? - correct answers
✔✔There is no selection for dark bellies by visual predators.
(HHMI) Mutations are always __________ - correct answers ✔✔a change in an individual's DNA
(HHMI) When dark-colored fur gives mice a 1% competitive advantage and 1% of the population begins
with dark fur, in about 1000 years, 95% of the population will have dark fur. Which of the following
statements is true? - correct answers ✔✔If dark-colored rock pocket mice had a competitive advantage
of 0.1%, it would take longer for 95% of the population to have dark fur.
(HHMI) What does Dr. Carroll mean when he says, "while mutation is random, natural selection is not"? -
correct answers ✔✔-Mutations for advantageous traits are more likely to be passed on to the next
generation.
-Natural selection acts on traits.
-Natural selection favors some mutations.
(HHMI) In the lab, Nachman examined dark mice from two different populations living hundreds of miles
apart. The mice looked nearly identical. Their dark color was caused by two different genes. What does
,this tell you? - correct answers ✔✔-Two completely different mutations in two separate genes can
generate the same phenotype.
-Dark fur color evolved independently on each lava flow.
-Under very similar conditions, natural selection can favor very similar adaptations.
-There are at least two genes involved in creating dark mouse fur.
(Scientific Skills) This experiment is an example of hypothesis-based science. What question did the
researchers ask? - correct answers ✔✔Can predation result in selection for color patterns in guppies?
(Scientific Skills) What was the researchers' main hypothesis? - correct answers ✔✔Predation results in
selection for more drab color patterns in guppies.
(Scientific Skills) Researchers further hypothesized that if predation pressure is reduced, drab coloration
would become less beneficial (since females prefer brightly colored mates). Based on this hypothesis,
what prediction did the researchers test in this experiment? - correct answers ✔✔When guppies with
drab colors are transferred to a pool with only killifish, the transplanted population will evolve brighter
colors than the original source population.
(Scientific Skills) What was the control group in this study? - correct answers ✔✔the source population
in the pike-cichlid pools
(Scientific Skills) What was the experimental group in this study? - correct answers ✔✔the transplanted
population in the killifish pools
(Scientific Skills) How did the types of data the researchers collected enable them to test their
prediction? - correct answers ✔✔Tracking the number and area of colored spots provided a quantitative
way to compare the brightness of different populations.
(Scientific Skills) What conclusion would you draw from the data presented? - correct answers
✔✔Predation results in selection for more drab coloration in pike-cichlid pools.
(Scientific Skills) Which of the following would help strengthen the researchers' conclusion? - correct
answers ✔✔if no other characteristics differed significantly between the source and transplanted
populations
, (Scientific Skills) Suppose that after 22 months, guppies from the transplanted population were returned
to the source pool. What would most likely happen to those guppies? - correct answers ✔✔They would
experience a higher rate of predation than the native population, and over time they would evolve and
resemble the original source population.
(Scientific Skills) What data should you collect in order to test your prediction? - correct answers
✔✔predation rate on transplanted versus original source guppies, and color patterns of the population
over time
(Evidence for Evolution) Scientific evidence documents the pattern of evolution. The evidence exists in a
variety of categories, including direct observation of evolutionary change, the fossil record, homology,
and biogeography. Sort the following examples into the correct categories. - correct answers ✔✔Direct
observation of evolutionary change: Development of drug resistant bacteria
Fossil record: Discovery of transitional forms of horses, Discovery of shells of extinct species
Homology: Similarities in mammalian forelimbs, Same genetic code in fireflies and tobacco plants,
Vestigial pelvis in right whales
Biogeography: Similarity of endemic island species to nearby mainland species, The high concentration
of marsupial species in Australia
(Evidence for evolution) The island fox shares a common ancestor with the gray fox, Urocyon
cinereoargenteus, which is found on the mainland. Both species have similar coloration and a diploid
chromosome number of 66. One structural difference between the two species is the reduced size of the
island fox, a feature known as dwarfism. The various island subspecies also differ from each other in size,
number of tail vertebrae, and other characteristics.The phylogenetic tree below shows the evolutionary
relationships between the island fox subspecies and the gray fox. Drag the labels to their appropriate
locations on the tree. - correct answers ✔✔a. ancestor of gray foxes and island foxes
b. ancestor of Santa Rosa and San Miguel foxes
c. Dwarfism
d. ancestor of northern channel island foxes
e. most closely related
