BIO 182 EXAM 2 QUESTIONS &
ANSWERS (RATED A+)
Which of these individuals has the highest biological fitness in an evolutionary
sense? - ANSWERan organism that dies after 5 days of life but leaves 10 offspring,
all of whom survive to reproduce
True or False: The genotype of an organism describes the physical traits that one
can observe. - ANSWERFalse
A populationʹs carrying capacity... - ANSWERmay change as environmental
conditions change
An ecologist recorded 12 white-tailed deer, Odocoileus virginianus, per square mile
in one woodlot and 20 per square mile on another woodlot. What was the ecologist
comparing? - ANSWERdensity
Which of the following statement(s) regarding evolutionary adaptation is/are true?
Select ALL that apply. - ANSWER- A trait that is adaptive in one environment may
not be adaptive in a different environment.
- The adaptive value of a trait can change over time as the environment changes.
What are the core principles necessary for natural selection to occur in a population?
Select ALL that apply. - ANSWER- Traits need to be passed on from parents to
offspring
- There needs to be variation in a population
- Some organisms have a higher reproductive success than others
Evolution of a new trait typically takes many generations. Yet a dramatic shift in the
extent of armor plating in the Lake Washington stickleback population occurred in
the 50 years following the cleanup of the lake. Which of the following best describes
the mechanism of the rapid evolution of the armor phenotype in the Lake
Washington sticklebacks? - ANSWERNew selective pressures favored individuals
with the plated phenotype, causing the plated allele frequency in the population to
quickly increase.
True or False: Sexual selection is a case of natural selection that describes evolution
due not to variable survival rates, but rather due to variable reproductive rates
stemming from characteristics that allow an individual to successfully attract a mate.
- ANSWERTrue
In the northeastern United States and adjacent Canada, there has been intense
industrial fishing for large predatory fishes, such as Atlantic Cod. Prior to industrial
fishing, the relationship between the size of a fish at maturity and its fitness is shown
by the graph on the left (below). Fishing is size-selective, with fishers generally
, taking the largest fish. The fitness function during industrial fishing is reflected in the
graph on the right (below).
Based on this information, which of the following is true about the selection for size
at maturity? - ANSWERCod experienced balancing selection before industrial
fishing, but now experience directional selection.
A new plant population develops the ability to grow on high-zinc-soil and can do so
at concentrations which are otherwise lethal to plants of the same species. This is an
example of ___________ selection: - ANSWERDirectional
A farmer sprays insecticides on her crops to successfully get rid of weevils, a beetle
pest. After a few years of spraying the insecticide, she finds that weevils are
becoming more and more common again. What is the most likely explanation for
this? Select only ONE answer choice. - ANSWERWeevils that are resistant to the
insecticide are favoured by natural selection over weevils that are susceptible to the
insecticide.
According to the biological species concept, the main criterion for identifying a
species is: - ANSWERreproductive isolation
Which of the following statements is/are correct? - ANSWERA population is a local
subset of a species.
Which of the following is/are a criticism(s) of the usefulness of the biological species
concept? - ANSWERB & C only
- It is difficult to tell whether two individuals are actually or potentially capable of
producing fertile offspring in the field.
- Some species only reproduce asexually.
You collect individuals from different allopatric populations of a leaf-eating beetle. In
the laboratory, you conduct mate-choice experiments to assess levels of
reproductive isolation among beetles from different populations.
True or False: In order to determine if these different populations are different
species based in the biological species concept, you would need to find information
indicating complete reproductive isolation among all of the populations. -
ANSWERtrue
A defining characteristic of allopatric speciation is: - ANSWERgeographic isolation
Continuous desert tortoise populations across the Sonoran desert have adapted to
different climates, where the climate near the northern edge of the Sonoran desert is
extremely hot and dry, while the climate near the southern edge has more scrub,
shade, and access to water. Evidence suggests that there are now two species of
desert tortoises. True or False: This is an example of Allopatric speciation. -
ANSWERfalse
ANSWERS (RATED A+)
Which of these individuals has the highest biological fitness in an evolutionary
sense? - ANSWERan organism that dies after 5 days of life but leaves 10 offspring,
all of whom survive to reproduce
True or False: The genotype of an organism describes the physical traits that one
can observe. - ANSWERFalse
A populationʹs carrying capacity... - ANSWERmay change as environmental
conditions change
An ecologist recorded 12 white-tailed deer, Odocoileus virginianus, per square mile
in one woodlot and 20 per square mile on another woodlot. What was the ecologist
comparing? - ANSWERdensity
Which of the following statement(s) regarding evolutionary adaptation is/are true?
Select ALL that apply. - ANSWER- A trait that is adaptive in one environment may
not be adaptive in a different environment.
- The adaptive value of a trait can change over time as the environment changes.
What are the core principles necessary for natural selection to occur in a population?
Select ALL that apply. - ANSWER- Traits need to be passed on from parents to
offspring
- There needs to be variation in a population
- Some organisms have a higher reproductive success than others
Evolution of a new trait typically takes many generations. Yet a dramatic shift in the
extent of armor plating in the Lake Washington stickleback population occurred in
the 50 years following the cleanup of the lake. Which of the following best describes
the mechanism of the rapid evolution of the armor phenotype in the Lake
Washington sticklebacks? - ANSWERNew selective pressures favored individuals
with the plated phenotype, causing the plated allele frequency in the population to
quickly increase.
True or False: Sexual selection is a case of natural selection that describes evolution
due not to variable survival rates, but rather due to variable reproductive rates
stemming from characteristics that allow an individual to successfully attract a mate.
- ANSWERTrue
In the northeastern United States and adjacent Canada, there has been intense
industrial fishing for large predatory fishes, such as Atlantic Cod. Prior to industrial
fishing, the relationship between the size of a fish at maturity and its fitness is shown
by the graph on the left (below). Fishing is size-selective, with fishers generally
, taking the largest fish. The fitness function during industrial fishing is reflected in the
graph on the right (below).
Based on this information, which of the following is true about the selection for size
at maturity? - ANSWERCod experienced balancing selection before industrial
fishing, but now experience directional selection.
A new plant population develops the ability to grow on high-zinc-soil and can do so
at concentrations which are otherwise lethal to plants of the same species. This is an
example of ___________ selection: - ANSWERDirectional
A farmer sprays insecticides on her crops to successfully get rid of weevils, a beetle
pest. After a few years of spraying the insecticide, she finds that weevils are
becoming more and more common again. What is the most likely explanation for
this? Select only ONE answer choice. - ANSWERWeevils that are resistant to the
insecticide are favoured by natural selection over weevils that are susceptible to the
insecticide.
According to the biological species concept, the main criterion for identifying a
species is: - ANSWERreproductive isolation
Which of the following statements is/are correct? - ANSWERA population is a local
subset of a species.
Which of the following is/are a criticism(s) of the usefulness of the biological species
concept? - ANSWERB & C only
- It is difficult to tell whether two individuals are actually or potentially capable of
producing fertile offspring in the field.
- Some species only reproduce asexually.
You collect individuals from different allopatric populations of a leaf-eating beetle. In
the laboratory, you conduct mate-choice experiments to assess levels of
reproductive isolation among beetles from different populations.
True or False: In order to determine if these different populations are different
species based in the biological species concept, you would need to find information
indicating complete reproductive isolation among all of the populations. -
ANSWERtrue
A defining characteristic of allopatric speciation is: - ANSWERgeographic isolation
Continuous desert tortoise populations across the Sonoran desert have adapted to
different climates, where the climate near the northern edge of the Sonoran desert is
extremely hot and dry, while the climate near the southern edge has more scrub,
shade, and access to water. Evidence suggests that there are now two species of
desert tortoises. True or False: This is an example of Allopatric speciation. -
ANSWERfalse
