BIOL 355 B0: Ecology - Dr. Larson Exam #3 Practice Version A KEY Spring 2026
Follow these DIRECTIONS for full credit:
1. Fill out the Gradescope Bubble Sheet with:
a. Your full name
b. Your B-Number next to ID
c. Version A or B. You can find your version at the top of this page.
d. Your Discussion Section # next to Section
2. Write your full name and B-Number on the exam packet.
3. Fill in the appropriate answer on the Bubble Sheet for all multiple choice questions, and answer the short answer
questions completely.
4. After the exam, read and sign the following statement and turn in both the answer sheet and exam booklet.
By signing below, I acknowledge that I have followed academic honesty expectations while using this original practice
packet. This study version is not an official university exam.
NAME________________________________________ Section: __________________
B#_____________________________
Signature________________________________
Exam directions:
There are 50 questions on the exam (100 points total). Always read all answer choices carefully before choosing the best
answer based on BIOL 355 B0 course material.
Practice note: correct answers are marked with an asterisk (*) to match a key-style review packet.
1. A bird predator repeatedly feeds on a brown insect found on tree bark. This insect remains relatively still when a bird is
near. Over time, the bird becomes more efficient at spotting and capturing this brown insect, but overlooks other brown
insect species that fly away when a bird is near. This predator adaptation is best explained by:
a. The prey developing behavioral defenses
*b. The predator forming a search image for a specific prey type
c. The prey mimicking another insect species
d. The predator engaging in mutualism with the other brown insects
Answer Questions 2-3 based on the following scenario:
Oak trees produce tannins, compounds found in leaves, bark, acorns, and seeds. Tannins can reduce digestibility
for herbivores and may limit consumption by insects and mammals. Squirrels have behaviors that allow them to
use acorns despite these defenses, such as selective feeding and caching acorns while tannins leach from the food
over time.
2. The tannins represent a:
a. physical defense against herbivory
*b. chemical defense against herbivory
c. facilitative mechanism for seed dispersal
d. competitive relationship between the seeds and mature trees
3. The interaction between oak trees producing tannins and squirrels adapting to tolerate or avoid tannins is an example
of:
a. Batesian mimicry
b. mutualism
*c. coevolutionary arms race
d. parasitism
1
, 4. In the evolutionary arms race between bats and moths, which of the following was NOT a moth response to evolving
bat predation?
a. large ears to detect bat sonar
b. sounds emitted as warnings to bats that the moths are unpalatable
c. remaining still when bat sonar was detected
*d. bright orange and yellow warning patterns on their wings
5. In the evolutionary arms race between bats and moths, some moths were "cheaters" because they emitted warning
signals to bats that they were distasteful, but they did not actually contain any distasteful chemicals. These cheater moths
are an example of:
a. aposematism
*b. Batesian mimicry
c. Mullerian mimicry
d. A and B
6. Which statement best describes coevolution?
a. A single species changes because of random mutation only
*b. Two or more interacting species exert reciprocal selective pressures on one another
c. All species in a community evolve toward the same body size
d. A population changes only because climate changes
7. A plant produces nectar that attracts pollinating insects. The insects gain food, and the plant gains pollen transfer. This
relationship is best classified as:
a. commensalism
b. parasitism
*c. mutualism
d. amensalism
8. A tick feeds on the blood of a deer and may reduce the deer's fitness. This interaction is best described as:
*a. parasitism
b. commensalism
c. facilitation
d. resource partitioning
9. Two bird species use the same insect prey, but one feeds mainly in the canopy and the other feeds on lower branches.
This pattern is most consistent with:
a. competitive exclusion
*b. resource partitioning
c. aposematism
d. density-independent growth
10. The competitive exclusion principle predicts that:
*a. two species with identical niches cannot coexist indefinitely in the same place
b. predators always eliminate prey populations
c. species richness is highest when no species interact
d. mutualists eventually become parasites
11. A species whose presence has a disproportionately large effect on community structure relative to its abundance is
called a:
a. pioneer species
*b. keystone species
c. fundamental species
d. cryptic species
2
Follow these DIRECTIONS for full credit:
1. Fill out the Gradescope Bubble Sheet with:
a. Your full name
b. Your B-Number next to ID
c. Version A or B. You can find your version at the top of this page.
d. Your Discussion Section # next to Section
2. Write your full name and B-Number on the exam packet.
3. Fill in the appropriate answer on the Bubble Sheet for all multiple choice questions, and answer the short answer
questions completely.
4. After the exam, read and sign the following statement and turn in both the answer sheet and exam booklet.
By signing below, I acknowledge that I have followed academic honesty expectations while using this original practice
packet. This study version is not an official university exam.
NAME________________________________________ Section: __________________
B#_____________________________
Signature________________________________
Exam directions:
There are 50 questions on the exam (100 points total). Always read all answer choices carefully before choosing the best
answer based on BIOL 355 B0 course material.
Practice note: correct answers are marked with an asterisk (*) to match a key-style review packet.
1. A bird predator repeatedly feeds on a brown insect found on tree bark. This insect remains relatively still when a bird is
near. Over time, the bird becomes more efficient at spotting and capturing this brown insect, but overlooks other brown
insect species that fly away when a bird is near. This predator adaptation is best explained by:
a. The prey developing behavioral defenses
*b. The predator forming a search image for a specific prey type
c. The prey mimicking another insect species
d. The predator engaging in mutualism with the other brown insects
Answer Questions 2-3 based on the following scenario:
Oak trees produce tannins, compounds found in leaves, bark, acorns, and seeds. Tannins can reduce digestibility
for herbivores and may limit consumption by insects and mammals. Squirrels have behaviors that allow them to
use acorns despite these defenses, such as selective feeding and caching acorns while tannins leach from the food
over time.
2. The tannins represent a:
a. physical defense against herbivory
*b. chemical defense against herbivory
c. facilitative mechanism for seed dispersal
d. competitive relationship between the seeds and mature trees
3. The interaction between oak trees producing tannins and squirrels adapting to tolerate or avoid tannins is an example
of:
a. Batesian mimicry
b. mutualism
*c. coevolutionary arms race
d. parasitism
1
, 4. In the evolutionary arms race between bats and moths, which of the following was NOT a moth response to evolving
bat predation?
a. large ears to detect bat sonar
b. sounds emitted as warnings to bats that the moths are unpalatable
c. remaining still when bat sonar was detected
*d. bright orange and yellow warning patterns on their wings
5. In the evolutionary arms race between bats and moths, some moths were "cheaters" because they emitted warning
signals to bats that they were distasteful, but they did not actually contain any distasteful chemicals. These cheater moths
are an example of:
a. aposematism
*b. Batesian mimicry
c. Mullerian mimicry
d. A and B
6. Which statement best describes coevolution?
a. A single species changes because of random mutation only
*b. Two or more interacting species exert reciprocal selective pressures on one another
c. All species in a community evolve toward the same body size
d. A population changes only because climate changes
7. A plant produces nectar that attracts pollinating insects. The insects gain food, and the plant gains pollen transfer. This
relationship is best classified as:
a. commensalism
b. parasitism
*c. mutualism
d. amensalism
8. A tick feeds on the blood of a deer and may reduce the deer's fitness. This interaction is best described as:
*a. parasitism
b. commensalism
c. facilitation
d. resource partitioning
9. Two bird species use the same insect prey, but one feeds mainly in the canopy and the other feeds on lower branches.
This pattern is most consistent with:
a. competitive exclusion
*b. resource partitioning
c. aposematism
d. density-independent growth
10. The competitive exclusion principle predicts that:
*a. two species with identical niches cannot coexist indefinitely in the same place
b. predators always eliminate prey populations
c. species richness is highest when no species interact
d. mutualists eventually become parasites
11. A species whose presence has a disproportionately large effect on community structure relative to its abundance is
called a:
a. pioneer species
*b. keystone species
c. fundamental species
d. cryptic species
2
