Unit 8: Ecology

Topic Learning Objective(s)

ENE-3.D Explain how the behavioral and/or physiological response of an
8.1
organism is related to changes in internal or external environment.
Responses to the
IST-5.A Explain how the behavioral responses of organisms affect their
Environment
overall fitness and may contribute to the success of the population.
ENE-1.M Describe the strategies organisms use to acquire and use energy
8.2 ENE-1.N Explain how changes in energy availability affect populations and
Energy Flow Through ecosystems
Ecosystems ENE-1.O Explain how the activities of autotrophs and heterotrophs enable
the flow of energy within an ecosystem.
8.3 SYI-1.G Describe factors that influence growth dynamics of populations.
Population Ecology
8.4 SYI-1.H Explain how the density of a population affects and is determined
Effect of Density of by resource availability in the environment.
Populations
ENE-4.A Describe the structure of a community according to its species
composition and diversity
8.5 ENE-4.B Explain how interactions within and among populations influence
Community Ecology community structure.
ENE-4.C Explain how community structure is related to energy availability in
the environment.
SYI-3.F Describe the relationship between ecosystem diversity and its
8.6 resilience to changes in the environment.
Biodiversity SYI-3.G Explain how the addition or removal of any component of an
ecosystem will affect its overall short-term and long-term structure.
EVO-1.O Explain the interaction between the environment and random or
preexisting variations in populations.
SYI-2.A Explain how invasive species affect ecosystem dynamics.
8.7
SYI-2.B Describe human activities that lead to changes in ecosystem
Disruptions to Ecosystems
structure and/ or dynamics.
SYI-2.C Explain how geological and meteorological activity leads to
changes in ecosystem structure and/or dynamics
 AP Biology Exam Review
Topic 8.1: Responses to the Environment
Learning ENE-3.D Explain how the behavioral and/or physiological response of an organism is
Objective related to changes in internal or external environment.
◻ I can explain ways the behavioral response of an organisms is related to changes
in internal or external environment.
◻ I can explain ways the physiological response of an organism is related to changes
in internal or external environment.
◻ I can explain ways organisms exchange information with one another in response
I can… to internal changes.
◻ I can explain ways organisms exchange information with one another in response
to external cues.
◻ I can explain ways organism’s behaviors changes due to internal cues.
◻ I can explain ways organism’s behaviors changes due to external cues.

1. Identify two behavioral changes in an organism due to an internal cue.

2. Identify two behavioral changes in an organism due to an external cue.
3. Identify two physiological changes in an organism due to an internal cue.
4. Identify two physiological changes in an organism due to an external cue.
5. How does an organism’s responses to internal changes or external cues change their behavior?

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Learning IST-5.A Explain how the behavioral responses of organisms affect their overall fitness and
Objective may contribute to the success of the population.
◻ I can explain ways the behavioral responses of organisms affect their overall
fitness
◻ I can explain ways the behavioral responses of organisms affects the success of
the population
◻ I can describe that individuals act on information
◻ I can describe that individuals communicate with others.
I can… ◻ I can describe signaling behavior that result in differential reproductive success
◻ I can describe ways animals communicate
◻ I can describe functions of animal communication
◻ I can describe innate behaviors
◻ I can describe learned behaviors
◻ I can describe ways cooperative behaviors increase the fitness of the individual
◻ I can describe ways cooperative behaviors increase the fitness of the population

6. What is differential reproductive success?

7. How does communication result in differential reproductive success?
8. What are the five types of signals individuals use to communicate with others?
a. Describe the environment where each type is favorable.
9. What is the function of animal communication?
10. What is an innate behavior?
11. What is a learned behavior?
12. What type of behaviors does natural selection favor?
13. What is cooperative behavior?
14. How does cooperative behavior increase the fitness of an individual and the survival of the population?
15. What is altruism?
16. How does altruism increase the population’s reproductive fitness?

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Topic 8.2: Energy Flow Through Ecosystems
Learning ENE-1.M Describe the strategies organisms use to acquire and use energy
Objective
◻ I can describe the strategies organisms use to acquire and use energy.
◻ I can describe ways organisms use energy to regulate body temperature.
◻ I can describe endothermic.
◻ I can describe ways endotherms regulate their body temperature.
◻ I can describe ectothermic.
◻ I can describe ways ectotherms regulate their body temperature.
I can… ◻ I can describe ways organisms use energy for reproductive strategies.
◻ I can describe the relationship between metabolic rate per unit body mass and size
of multicellular organisms.
◻ I can describe the result of a net gain in energy on growth of an organism.
◻ I can describe the result of a net gain in energy on energy storage.
◻ I can describe the result of a net loss of energy on mass of organisms.
◻ I can describe the result of a net loss of energy on survival of an organism.

1. What is an endotherm?
2. How do endotherms regulate their body temperature?
3. What is an ectotherm?
4. How do ectotherms regulate their body temperature?
5. Which organism requires more food consumption in a cooler environment? ENDOTHERM or
ECTOTHERM
6. How would temperature effect oxygen consumption in an endotherm?
7. What is the relationship between metabolic rate per unit body mass and the size of multicellular
organisms?
8. What does a net gain in energy result in for an organism?
9. What does a net loss in energy result in for an organism?

Learning ENE-1.N Explain how changes in energy availability affect populations and ecosystems
Objective
◻ I can explain ways changes in energy availability affect populations and
ecosystems.
◻ I can explain the result of a change in energy availability on population size.
◻ I can explain the result of a change in energy availability on ecosystem.
I can… ◻ I can explain the effect of a change in sunlight on number and size of trophic
levels.
◻ I can explain the effect of a change in the producer level on number and size of
other trophic levels.

10. How does a change in energy available affect population size?

11. How does a decrease in sunlight affect the number and sizes of each trophic level?
12. How does an increase in sunlight affect the number and sizes of each trophic level?
13. How does a decrease in producers affect the number and size of other trophic levels?

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14. How does an increase in producers affect the number and size of other trophic levels?

Learning ENE-1.O Explain how the activities of autotrophs and heterotrophs enable the flow of
Objective energy within an ecosystem.
◻ I can explain ways the activities of autotroph and heterotroph enable the flow of
energy within an ecosystem.
◻ I can describe the function of autotrophs in capturing energy.
I can… ◻ I can describe ways photosynthetic organisms capture energy.
◻ I can describe ways chemosynthetic organisms capture energy.
◻ I can describe the function of heterotrophs in capturing energy.
◻ I can identify a heterotrophs sources of energy by hydrolysis.

15. What is an autotroph?

16. What is the function of an autotroph in capturing energy?
17. How do photosynthetic organisms capture energy?
a. Identify one example of a photosynthetic organism.
18. How do chemosynthetic organisms capture energy?
a. Identify one example of a photosynthetic organism.
19. True or False: Oxygen is required for the photosynthetic and chemosynthetic organism to capture
energy.
20. What is a heterotroph?
21. What macromolecules can a heterotroph use for sources of energy?

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Topic 8.3: Population Ecology
Learning SYI-1.G Describe factors that influence growth dynamics of populations.
Objective
◻ I can describe factors that influence growth dynamics of populations.
◻ I can describe ways populations interact with one another.
◻ I can describe ways populations interact with the environment.
◻ I can describe adaptations for obtaining energy and matter in the environment.
◻ I can describe adaptations for using energy and matter in the environment.
◻ I can describe factors that population growth dynamics depend on.
I can… ◻ I can calculate population growth.
◻ I can calculate birth rate (per capita).
◻ I can calculate death rate (per capita).
◻ I can describe exponential growth of a population.
◻ I can describe factors that allow for exponential growth of a population.
◻ I can calculate exponential growth rate.
◻ I can calculate per capita growth rate of a population.

Formula Sheet

1. What makes up a population?

2. How do populations interact with one another?
3. How do populations interact with the environment?
4. Identify two adaptations for obtaining energy and matter in the environment.
5. Identify two adaptations for using energy and matter in the environment.
6. Identify two factors that population growth dynamics depend on.
7. What is population growth?
8. How do you solve for B?
9. How do you solve for D?
10. If a population has 300 individuals, then 20 new individuals are born and 40 individuals die. What is the
population growth of this population?
a. Solve for B b. Solve for D c. Solve for dN/dt.
11. What is exponential growth?
12. What allows for a population to undergo exponential growth?
13. How do you solve for r?
14. If a population has 300 individuals, then 40 new individuals are born and 20 individuals die. What is the
population size after 3 generations?
a. Solve for r
b. Solve for dN/dt

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Topic 8.4: Effect of Density of Populations
Learning SYI-1.H Explain how the density of a population affects and is determined by resource
Objective availability in the environment.
◻ I can explain ways the density of a population affects resource availability in the
environment.
◻ I can explain ways the density of a population is determined by resource
availability in the environment.
◻ I can identify density-dependent factors.
◻ I can identify density-independent factors.
I can… ◻ I can describe the effect of density-dependent factors on a population’s growth.
◻ I can describe the effect of density-independent factors on a population’s growth.
◻ I can calculate logistic growth rate of a population.
◻ I can describe carrying capacity.
◻ I can describe population growth rate as the population size approaches the
carrying capacity.

Formula Sheet

1. What is density?
2. What is carrying capacity?
3. What are density-dependent factors?
a. Identify three density-dependent factors.
b. How do density-dependent factors affect a population’s growth?
4. What are density-independent factors?
a. Identify three density-independent factors.
b. How do density-independent factors affect a population’s growth?
5. If a population has 300 individuals and the environment can support 400 individuals, then 50 new
individuals are born and 10 individuals die. What is the logistic growth rate of this population?
6. What happens to the growth rate as the population size approaches the carrying capacity?

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Topic 8.5: Community Ecology
Learning ENE-4.A Describe the structure of a community according to its species composition
Objective and diversity
◻ I can describe the structure of a community according to its species composition
and diversity.
◻ I can describe ways the structure of a community is measured.
I can… ◻ I can describe ways the structure of a communication is described in terms of
species composition and species diversity.
◻ I can apply Simpson’s Diversity Index to a population.
◻ I can describe properties of a diverse population.

Formula Sheet

1. How is the structure of a community measured?

2. What is a species?
3. What is species composition?
4. What is species diversity?
5. Identify two properties of a diverse population.
6. Complete the Practice Problem for Simpson’s Index (from
http://www.countrysideinfo.co.uk/simpsons.htm):
Calculate the Simpson’s Index of a sample from the woods:

Species Number (n)

Woodrush 2

Holly (seedlings) 8

Bramble 1

Yorkshire Fog 1

Sedge 3

Total (N) 15

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Learning ENE-4.B Explain how interactions within and among populations influence community
Objective structure.
◻ I can explain ways interactions within and among populations influence community
structure.
◻ I can explain ways communities change over time depending on interactions
between populations.
◻ I can explain ways interactions among populations determine how they access
energy and matter within a community.
◻ I can describe positive interactions between populations.
◻ I can describe negative interactions between populations.
I can… ◻ I can describe predator/prey interactions.
◻ I can describe trophic cascades.
◻ I can describe niche partitioning.
◻ I can explain ways competition drives population dynamics.
◻ I can explain ways predation drives population dynamics.
◻ I can explain ways symbioses drives population dynamics.
◻ I can explain ways parasitism drives population dynamics.
◻ I can explain ways mutualism drives population dynamics.
◻ I can explain ways commensalism drives population dynamics.

7. How do interactions among populations affect their ability to access energy and matter within a
community?
8. What are positive interactions between populations?
9. What are negative interactions between populations?
10. What are trophic cascades?
11. What is niche partitioning?
12. Identify the following as positive or negative interactions?
a. Predation/prey interactions
b. Trophic cascades
c. Niche partitioning
13. What is competition?
a. How does competition drive population dynamics?
14. What is predation?
a. How does predation drive population dynamics?
15. Identify the three types of symbiosis.
16. What is parasitism?
a. How does parasitism drive population dynamics?
17. What is mutualism?

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a. How does mutualism drive population dynamics?
18. What is commensalism?
a. How does commensalism drive population dynamics?

Learning ENE-4.C Explain how community structure is related to energy availability in

Objective the environment.
◻ I can explain ways communication structure is related to energy availability in the
environment.
◻ I can explain ways cooperation between organisms can result in enhanced
movement of/access to matter and energy.
I can… ◻ I can explain ways cooperation between populations can result in enhanced
movement of/access to matter and energy.
◻ I can explain ways cooperation between species can result in enhanced movement
of/access to matter and energy.

19. What is cooperation?

20. How does cooperation affect access to matter and energy?

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Topic 8.6: Biodiversity
Learning SYI-3.F Describe the relationship between ecosystem diversity and its resilience to
Objective changes in the environment.
◻ I can describe the relationship between ecosystem diversity and its resilience to
changes in the environment.
◻ I can describe the effect of fewer components and little diversity among the parts.
◻ I can describe keystone species.
I can… ◻ I can describe producers.
◻ I can describe essential abiotic factors.
◻ I can describe essential biotic factors.
◻ I can describe ways keystone species, producers, and essential abiotic/biotic
factors maintain diversity of an ecosystem.

1. In terms of component parts and diversity, what type of ecosystem is more resilient to changes in the
environment?
2. What are keystone species?
a. How do they maintain diversity in an ecosystem?
3. What are producers?
a. How do they maintain diversity in an ecosystem?
4. What are abiotic factors?
a. What abiotic factors are essential in maintaining the diversity in an ecosystem?
5. What are biotic factors?
a. What biotic factors are essential in maintaining the diversity in an ecosystem?

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Learning SYI-3.G Explain how the addition or removal of any component of an ecosystem will affect
Objective its overall short-term and long-term structure.
◻ I can explain ways the addition of any component of an ecosystem will affect its
overall short term structures.
◻ I can explain ways the removal of any component of an ecosystem will affect its
overall short term structures.
◻ I can explain ways the addition of any component of an ecosystem will affects its
I can… long-term structure.
◻ I can explain ways the removal of any component of an ecosystem will affect its
long-term structure.
◻ I can describe ways the diversity can influence the organization of ecosystem.
◻ I can describe the effects of keystone species on the ecosystem.

6. How does the diversity of a species within an ecosystem influence the organization of the ecosystem?
7. Identify an example of an addition to an ecosystem and its effect…
a. Short-term structure
b. Long-term structure
8. Identify an example of a removal from an ecosystem and its effect on…
a. Short-term structure
b. Long-term structure
9. Identify a keystone species.
a. What would occur if this keystone species was removed from the ecosystem?

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Topic 8.7: Disruptions to Ecosystems
Learning EVO-1.O Explain the interaction between the environment and random or preexisting
Objective variations in populations.
◻ I can explain the interaction between the environment and random variation in the
populations.
◻ I can explain the interaction between the environment and preexisting variations in
populations.
I can… ◻ I can explain adaptations.
◻ I can explain ways that adaptations are selected in a population.
◻ I can explain where mutations come from.
◻ I can explain that mutations are random with no direction for selective pressures.

1. What is an adaptation?
2. How do adaptations get introduced?
3. How are adaptations selected for in a population?
4. What is a mutation?
5. Where do mutations come from?

Learning SYI-2.A Explain how invasive species affect ecosystem dynamics.

Objective
◻ I can explain ways invasive species affect ecosystem dynamics.
◻ I can describe ways invasive species enter an area.
I can… ◻ I can describe ways invasive species are able to exploit an area.
◻ I can describe the population growth rate of an invasive species.

6. What is an invasive species?

7. How are invasive species able to exploit an area?
8. What does the population growth rate curve look like?
9. How do invasive species affect ecosystem dynamics?

Learning SYI-2.B Describe human activities that lead to changes in ecosystem structure and/
Objective or dynamics.
◻ I can describe human activities that lead to changes in ecosystem structure.
◻ I can describe human activities that lead to changes in ecosystem dynamics.
I can… ◻ I can describe the distribution of global ecosystems.
◻ I can describe the effect of disease introduction.
◻ I can describe the effect of human activities on habitats.

10. What is a local ecosystem?

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11. What is a global ecosystem?
12. How does the distribution of an ecosystem change over time?
13. What happens to an ecosystem when a new disease is introduced?
14. What happens to an ecosystem due to human activity?

Learning SYI-2.C Explain how geological and meteorological activity leads to changes in ecosystem
Objective structure and/or dynamics
◻ I can explain ways geological activity leads to changes in ecosystem structure.
◻ I can explain ways meteorological activity leads to changes in ecosystem structure.
I can… ◻ I can explain ways geological activity leads to changes in ecosystem dynamics.
◻ I can explain ways meteorological activity leads to changes in ecosystem
dynamics.

15. How do geological events affect habitat change and ecosystem distribution?
16. What is biogeography?
17. How did the habitats and ecosystems change when Pangaea split apart?

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Multiple Choice Practice
1. Testosterone oxido-reductase is a liver enzyme that regulates testosterone levels in alligators. One
study compared testosterone oxido-reductase activity between male and female alligators from Lake
Woodruff, a relatively pristine environment, and from Lake Apopka, an area that has suffered severe
contamination. The graph above depicts the findings of that study.

The data in the graph best support which of the following claims?
a. Environmental contamination elevates total testosterone oxido-reductase activity in females.
b. Environmental contamination reduces total testosterone oxido-reductase activity in females.
c. Environmental contamination elevates total testosterone oxido-reductase activity in males.
d. Environmental contamination reduces total testosterone oxido-reductase activity in males.

Use the following information to answer question 2.

A student placed 20 tobacco seeds of the same species on moist paper towels in each of two petri
dishes. Dish A was wrapped completely in an opaque cover to exclude all light. Dish B was not
wrapped. The dishes were placed equidistant from a light source set to a cycle of 14 hours of light and
10 hours of dark. All other conditions were the same for both dishes. The dishes were examined after 7
days and the opaque cover was permanently removed from dish A. Both dishes were returned to the
light and examined again at 14 days. The following data were obtained.

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2. The most probable cause for the difference in mean stem length between plants in dish A and plants in
dish B is which of the following?
a. Shortening of cells in the stem in response to the lack of light
b. Elongation of seedlings in response to the lack of light
c. Enhancement of stem elongation by light
d. Genetic differences between the seeds

3. Which of the following statements most directly supports the claim that different species of organisms
use different metabolic strategies to meet their energy requirements for growth, reproduction, and
homeostasis?
a. During cold periods pond-dwelling animals can increase the number of unsaturated fatty acids
in their cell membranes while some plants make antifreeze proteins to prevent ice crystal
formation in tissues.
b. Bacteria lack introns while many eukaryotic genes contain many of these intervening
sequences.
c. Carnivores have more teeth that are specialized for ripping food while herbivores have more
teeth that are specialized for grinding food.
d. Plants generally use starch molecules for storage while animals use glycogen and fats for
storage.

4. Figure I shows the growth of an algal species in a flask of sterilized pond water. If phosphate is added
as indicated, the growth curve changes as shown in Figure II.

Which of the following is the best prediction of the algal growth if nitrate is added instead of phosphate?

a. b.

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c.
d.

5. In the Arctic Ocean, the predominant primary producers are

phytoplankton. Phytoplankton are consumed by zooplankton,
which in turn are eaten by codfish. In years when there is more
open water (less ice coverage), there are more zooplankton and
fish than in years with less open water (more ice coverage). Based
on the graph above, the difference is most likely because

a. when there is less open water, light is blocked from the

zooplankton, so they cannot produce as much food for the
fish
b. when there is more open water, the temperature is warmer, so the zooplankton and fish
populations increase in size
c. the ice blocks the light, so in years with more ice coverage, there is less photosynthesis by the
phytoplankton
d. the ice increases the light available for photosynthesis, so primary production increases and
zooplankton populations increase in size

Use the following information to answer question 6.

An experiment to measure the rate of respiration in crickets and mice at 10°C and 25°C was performed
using a respirometer, an apparatus that measures changes in gas volume. Respiration was measured
in mL of O 2 consumed per gram of organism over several five-minute trials and the following data were
obtained.

Organism Temperature (°C) Average respiration

(mL O2/g/min)
Mouse 10 0.0518
Mouse 25 0.0321
Cricket 10 0.0013
Cricket 25 0.0038

6. According to the data, the crickets at 25°C have greater oxygen consumption per gram of tissue than
do the crickets at 10°C. This trend in oxygen consumption is the opposite of that in the mice. The
difference in trends in oxygen consumption among crickets and mice is due to their
a. relative size b. mode of nutrition

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c. mode of internal temperature d. mode of ATP production
regulation

7. Beaked whales feed at various depths, but they defecate at the ocean’s surface. Nitrogen-rich whale
feces deposited in surface waters supply nutrients for algae that are eaten by surface dwelling fish.
Which of the following best predicts what would happen if the whale population decreased?
a. There would be a reduction in surface nitrogen concentration, which would cause an algal
bloom.
b. The surface fish populations would decline due to reduced populations of algae.
c. The remaining whales would accumulate mutations at a faster rate.
d. The remaining whales would be forced to forage in the deepest parts of the ocean.
8. The following is a food web for a meadow habitat that occupies 25.6 km2. The primary producers’
biomass is uniformly distributed throughout the habitat and totals 1,500 kg/km2.

Developers have approved a project that will permanently reduce the primary producers’ biomass by 50
percent and remove all rabbits and deer.

Which of the following is the most likely result at the completion of the project?
a. The biomass of coyotes will be 6 kg, and the biomass of hawks will be 0.5 kg.
b. The biomass of coyotes will be dramatically reduced.
c. The coyotes will switch prey preferences and outcompete the hawks.
d. There will be 50 percent fewer voles and 90 percent fewer hawks.

Use the following information to answer questions 9-12.

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In the early 1970s, researchers hypothesized that carbon was the limiting nutrient in many aquatic
ecosystems. To test this hypothesis, the researchers divided a small lake in two roughly equal halves
with an impermeable curtain that was fastened and sealed to the bedrock of the lake. Beginning in
1971 the researchers treated one side of the lake with sucrose and the other side with both sucrose
and phosphate. From 1971 to 1983 the researchers monitored the phytoplankton biomass in both parts
of the lake. The results are shown in Figure 1.

9. Which of the following claims is best supported by the data?

a. Carbon was a limiting factor for phytoplankton in the lake.
b. Phosphate was a limiting factor for phytoplankton in the lake.
c. Both carbon and phosphate were limiting factors for phytoplankton in the lake.
d. Neither carbon nor phosphate was a limiting factor for phytoplankton in the lake

10. The average growth rate of the phytoplankton population from 1971 to 1975 in the side of the lake
treated with sucrose and phosphate is closest to which of the following?
a. 125 (mg/m3)/year c. 1,500 (mg/m3)/year
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b. 1,000 (mg/m )/year d. 6,000 (mg/m3)/year

11. Which of the following treatments would have been the best control treatment for the experiment?
a. An untreated section of the lake
b. A section of the lake that was treated with phosphate but not sucrose
c. A different lake that was treated with sucrose and phosphate
d. A small pool of the lake water maintained in a controlled laboratory environment

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12. Which of the following was most likely a direct consequence of the addition of phosphate to the lake?
a. The amount of biomass in the first trophic level decreased.
b. The amount of biomass in the second trophic level decreased.
c. The amount of energy available to producers in the lake increased.
d. The amount of energy available to consumers in the lake increased

13. Thrips are insects that feed on rose pollen. Scientists noted that the thrips population increased in the
spring and decreased dramatically during the summer. The researchers hypothesized that food
abundance was the limiting factor for the population. Which of the following types of data would be
most useful for the scientists to collect at regular intervals on a designated test plot of rose plants?
a. Amount of sunlight (hours/day)
b. Mean temperature (°C)
c. Density of rose pollen produced (g/m2)
d. Amount of pollen produced by each flower (g/flower)

14. The diagram below shows the progression of ecological events after a fire in a particular ecosystem.
Based on the diagram, which of the following best explains why the oak trees are later replaced by
other trees?

a. Eventually the other trees grow taller than the oak trees and form a dense canopy that shades
the understory.
b. Oak trees alter the pH of the soil, making the forest better suited for shrubs and other trees.
c. Roots of shrubs proliferate in the soil of the forest and prevent the oak trees from obtaining
water.
d. Oak trees succumb to environmental pollutants more readily than do either the shrubs or the
other trees.

Use the following information to answer questions 15-17.

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The figures below show the changes in populations of two species of flour beetles, Tribolium confusum
(Figure I) and Tribolium castaneum (Figure II), in cultures without parasites (o) and in cultures infected
with a parasite (•). Each data point represents the mean population size from ten culture dishes of
equal size and food content.

15. Under which of the following conditions is the observed number of beetles per culture dish the
greatest?
a. T. confusum with parasite at 500 days
b. T. confusum without parasite at 300 days
c. T. castaneum with parasite at 100 days
d. T. castaneum with parasite at 600 days

16. The data over the duration of the experiment provide the strongest support for which of the following
conclusions regarding the effect of the parasite on Tribolium populations?
a. T. confusum is adversely affected by the parasite, while T. castaneum is not.
b. T. castaneum is adversely affected by the parasite, while T. confusum is not.
c. Both T. confusum and T. castaneum are adversely affected by the parasite.
d. Both T. confusum and T. castaneum show increased fitness in the presence of the parasite.

17. In Figure I, the difference between the two curves can best be attributed to which of the following?
a. The difference between controlled laboratory conditions and the natural environment
b. The effect of the host on its parasite
c. The influence of competition for limited resources
d. The natural variation among populations
18. If the experiment was continued for an additional 500 days, the population density of T. castaneum with
the parasite would most likely stabilize at a value closest to which of the following?
a. 5 beetles/culture dish

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b. 10 beetles/culture dish
c. 20 beetles/culture dish
d. 25 beetles/culture dish

19. A researcher is investigating the relationship between the existing species diversity in a community and
the ability of an introduced nonnative species to destabilize the community.

Which of the following graphs is most consistent with the claim that communities with high diversity are
more resistant to change than are communities with low diversity?

a. c.

b. d.

20. Scientists have found that the existing populations of a certain species of amphibian are small in
number, lacking in genetic diversity, and separated from each other by wide areas of dry land. Which of
the following human actions is most likely to improve the long-term survival of the amphibians?
a. Cloning the largest individuals to counteract the effects of aggressive predation
b. Reducing the population size by one-fifth to decrease competition for limited resources
c. Constructing a dam and irrigation system to control flooding
d. Building ponds in the areas of dry land to promote interbreeding between the separated
populations

21. Which of the following best describes altruistic behaviors?

a. a defensive behavior in which organisms huddle all together
b. a selfless behavior to save the population but risk yourself
c. a protective behavior describing how organisms migrate
d. a reproductive behavior for attracting a mate through a ritual

22. A fruit fly vibrates its wings to serenade a potential mate. Which of the following describes the type of
behavior?
a. audible
b. tactile
c. electrical
d. chemical

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 AP Biology Exam Review

23. A cheetah urinates on a tree. Which of the following types of signals is the cheetah using?
a. visual
b. audible
c. tactile
d. chemical

24. A cheetah urinates on a tree. Which of the following describes the purpose of this signal?
a. indicate dominance
b. establish territory
c. find food
d. ensure reproductive success

25. Which of the following best describes the body temperature regulation for an alligator?
a. ectotherm that maintains body temperature through metabolism
b. ectotherm that maintains body temperature through behaviors
c. endotherm that maintains body temperature through metabolism
d. endotherm that maintains body temperature through behaviors

26. Which of the following best describes the relationship between metabolic rate per unit body mass and
the size of multicellular organisms?
a. the smaller the organism, the higher the metabolic rate
b. the larger the organism, the higher the metabolic rate
c. the higher the surface area to volume ratio of the cells, the higher the metabolic rate
d. the lower the surface area to volume ratio of the cells, the higher the metabolic rate

27. Which of the following best describes the changes to the trophic structure with a decrease in plant
population?
a. increase in primary and secondary consumers
b. decrease in primary and secondary consumers
c. decrease in secondary consumer, increase in primary consumer
d. increase in secondary consumer, decrease in primary consumer

28. Which of the following describes the energy resource used by chemosynthetic organisms?
a. small inorganic molecules preset in their environment
b. organic molecules broken down by the mitochondria
c. photons absorbed by chlorophyll in the chloroplast
d. air movement turns hairs on organismal surface

29. Which of the following is a material that heterotrophs are unable to metabolize?
a. carbohydrates
b. nucleic acids
c. lipids
d. proteins

30. In a population of 100 individuals, 20 individuals are born and there are 5 deaths. What is the r value?

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 AP Biology Exam Review
Recall: r = per capita growth rate of population
a. .05 c. .20
b. .15 d. .25

31. If the population size is 100 individuals and there is a r value of 0.3, what is dN/dt?
Recall: dN/dt = rN
a. 10 c. 30
b. 15 d. 60

32. As the population size approaches carrying capacity, dN/dt...

a. increases steadily c. decreases slowly
b. increases slowly d. decreases steadily

33. Which of the following describes the relationship of the mistletoe that gains resources and harms the
mesquite tree that it grows on?
a. parasitism c. mutualism
b. commensalism d. predator/prey

34. Which of the following describes the disadvantage of little species diversity in a community?
a. less likely to have immigration
b. more likely to be consumed by predators
c. more likely to have mutations
d. less resilient to changes in the environment

35. Which of the following is an organism that is disproportionate relative to their abundance and when
removed from the ecosystem causes it to collapse?
a. dominant species c. keystone species
b. invasive species d. primary consumer

36. A group of bacteria are resistant to antibiotics. Which of the following describes HOW the bacteria
became resistant?
a. the bacterial population got changed by the antibiotic in the environment
b. the bacterial population had random mutations making them favorable in the presence of the
antibiotic
c. the bacterial population consumed the antibiotic providing a food source
d. the bacterial population uses the antibiotic for reproduction

37. Which of the following is NOT a reason for exponential growth of an invasive species?
a. outcompete other organisms
b. free of predators
c. free of competition
d. free of prey

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 AP Biology Exam Review
Multiple Choice Key
Question Correct Answer Unit/Topic Source
1 B. Environmental contamination reduces total testosterone 8.1 2012
oxido-reductase activity in females. CED #22
2 B. Elongation of seedlings in response to the lack of light 8.1 2012
CED #14
3 D. Plants generally use starch molecules for storage while animals 8.1 2012
use glycogen and fats for storage. CED #11
4 8.1 2012
CED #40

C.
5 C. the ice blocks the light, so in years with more ice coverage, there is 8.2 2013 #37
less photosynthesis by the phytoplankton
6 C. mode of internal temperature regulation 8.2 2012
CED #10
7 B. The surface fish populations would decline due to reduced 8.2 2013 #14
populations of algae.
8 B. The biomass of coyotes will be dramatically reduced. 8.2 2012
CED #4
9 B. Phosphate was a limiting factor for phytoplankton in the lake. 8.3 2020
CED #4
10 C. 1,500 (mg/m3)/year 8.3 2020
CED #5
11 A. An untreated section of the lake 8.3 2020
CED #6
12 D. The amount of energy available to consumers in the lake 8.2 2020
increased CED #7
13 C. Density of rose pollen produced (g/m2) 8.5 2012 #2
14 A. Eventually the other trees grow taller than the oak trees and form a 8.5 2012
dense canopy that shades the understory. CED #6
15 C. T. castaneum with parasite at 100 days 8.5 2013 #10
16 B. T. castaneum is adversely affected by the parasite, while T. 8.5 2013 #11
confusum is not.
17 D. The natural variation among populations 8.5 2013 #12
18 B. 10 beetles/culture dish 8.3 2013 #13
19 8.6 2013 #8

D.

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 AP Biology Exam Review
20 D. Building ponds in the areas of dry land to promote interbreeding 8.7 2013 #24
between the separated populations
21 B. a selfless behavior to save the population but risk yourself 8.1 Self
22 A. audible 8.1 Self
23 D. chemical 8.1 Self
24 B. establish territory 8.1 Self
25 B. ectotherm that maintains body temperature through behaviors 8.2 Self
26 A. the smaller the organism, the higher the metabolic rate 8.2 Self
27 B. decrease in primary and secondary consumers 8.2 Self
28 A. small inorganic molecules preset in their environment 8.2 Self
29 B. nucleic acids 8.2 Self
30 B. 0.15 8.3 Self
31 C. 30 8.3 Self
32 B. increases slowly 8.4 Self
33 A. parasitism 8.5 Self
34 D. less resilient to changes in the environment 8.6 Self
35 C. keystone species 8.6 Self
36 B. the bacterial population had random mutations making them 8.7 Self
favorable in the presence of the antibiotic
37 D. free of prey 8.7 Self

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 AP Biology Exam Review
Free Response Practice
2019 #1

Auxins are plant hormones that coordinate several aspects of root growth and development.
Indole-3-acetic acid (IAA) is an auxin that is usually synthesized from the amino acid tryptophan (Figure
1). Gene Trp-T encodes an enzyme that converts tryptophan to indole-3-pyruvic acid (I3PA), which is
then converted to IAA by an enzyme encoded by the gene YUC.

(a) Circle ONE arrow that represents transcription on the template pathway. Identify the molecule that
would be absent if enzyme YUC is nonfunctional.

(b) Predict how the deletion of one base pair in the fourth codon of the coding region of gene Trp-T would
most likely affect the production of IAA. Justify your prediction.

(c) Explain one feedback mechanism by which a cell could prevent production of too much IAA without
limiting I3PA production.

(d) Rhizobacteria are a group of bacteria that live in nodules on plant roots. Rhizobacteria can produce
IAA and convert atmospheric nitrogen into forms that can be used by plants. Plants release
carbon-containing molecules into the nodules. Based on this information, identify the most likely
ecological relationship between plants and rhizobacteria. Describe ONE advantage to the bacteria of
producing IAA.

(e) A researcher removed a plant nodule and identified several “cheater” rhizobacteria that do not
produce IAA or fix nitrogen. Describe the evolutionary advantage of being a bacterial cheater in a
population composed predominantly of non-cheater bacteria. Plants can adjust the amount of
carbon-containing molecules released into nodules in response to the amount of nitrogen fixed in the
nodule. Predict the change in the bacterial population that would cause the plant to reduce the amount of
carbon-containing molecules provided to the nodule.

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 AP Biology Exam Review

2019 #2
A student studying two different aquatic, plant-eating, unicellular protist species (species A and B)
designed an experiment to investigate the ecological relationship between the two species (Table 1).

In treatment group I, the student placed 10 individuals of species A into a container with liquid growth
medium and 10 individuals of species B into a separate container with an equal amount of the same
liquid growth medium. In treatment group II, the student placed 5 individuals of each species into a single
container with the liquid growth medium. The student then maintained the containers under the same
environmental conditions and recorded the number of individuals in each population at various time
points. The results are shown in Table 2.

(a) The growth curves for species B in group I and for species A in group II (shaded columns) have been
plotted on the template. Use the template to complete an appropriately labeled line graph to illustrate
the growth of species A in treatment group I and species B in treatment group II (unshaded columns).

(b) As shown in the table, the student established treatment group II with 5 individuals of each species.
Provide reasoning for the reduced initial population sizes.

(c) The student claims that species A and B compete for the same food source. Provide TWO pieces of
evidence from the data that support the student’s claim.

(d) Predict TWO factors that will most likely limit the population growth of species A in treatment group I.

(e) Many protists contain an organelle called a contractile vacuole that pumps water out of the cell. The
student repeated the experiment using a growth medium with a lower solute concentration. Predict how
the activity of the contractile vacuole will change under the new experimental conditions. Justify your
prediction.

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 AP Biology Exam Review

2018 #3
Seagrasses are aquatic plants that reproduce sexually. Male seagrass flowers produce sticky pollen that
is carried by circulating water to female flowers, resulting in fertilization. A researcher claims that mobile
aquatic invertebrates can also transfer pollen from male to female flowers in the absence of circulating
water. To investigate this claim, the researcher set up aquariums to model the possible interaction
between the invertebrates and seagrasses.

(a) Use the symbols below and the template aquariums to demonstrate the experimental design for
testing the researcher’s claim that mobile aquatic invertebrates can pollinate seagrass in the absence of
circulating water. Draw the appropriate symbols in the negative control aquarium AND the experimental
aquarium. Do not use an symbol more than once in the same aquarium.

(b) Identify the dependent variable in the experiment. Predict the experimental results that would
support the researcher’s claim that mobile aquatic invertebrates can also transfer pollen from male to
female flowers in the absence of circulating water.

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 AP Biology Exam Review

2018 #5
Some birds, including great spotted cuckoos, lay their eggs in the nests of other birds, such as reed
warblers. The warbler parents raise the unrelated chicks and provide them with food that would
otherwise be given to their biological offspring. A researcher conducted an investigation to determine the
type of relationship between warblers and cuckoos in an environment without predators. The researcher
found that nests containing only warblers were more likely to be successful than nests containing
warblers and cuckoos (data not shown). A successful
nest is defined as a nest where at least one chick
becomes an adult warbler.

In some geographic areas, several species of nest

predators are present. Researchers have found that
cuckoo chicks, while in the nest, produce a smelly
substance that deters nest predators. The substance
does not remain in the nest if cuckoo chicks are
removed. Figure 1 shows the probability that nest
containing only warblers or containing both warblers
and cuckoos will be successful in an environment with
predators. In a follow-up experiment, the researchers
added cuckoos to a nest that contained only warblers
(group 1) and removed from a nest containing warblers
and cuckoos (group 2).

(a) Describe the symbiotic relationship that exists between the cuckoo and warbler in an environment
predators.

(b) On the template provided, draw bars in the appropriate locations to predict the relative probability of
success for the nest in the presence of predators where:
* the cuckoos were added to the nest containing only warblers (group 1)
* the cuckoos were removed from the nest containing warblers and cuckoos (group 2)

(c) Identify the symbiotic relationship that exists between the cuckoo and the warbler in the presence of
predators.

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 AP Biology Exam Review

2018 #7
In the tongue sole fish (Cynoglossis semilaevis), sex is determined by a combination of genetics and
environmental temperature. Genetically male fish have two Z chromosomes (ZZ), and genetically female
fish have one Z chromosome and one W chromosome (ZW). When fish are raised at 22ºC, ZZ fish
develop into phenotypic males and ZW fish develop into phenotypic females. However, when fish are
raised at 28ºC, the Z chromosome is modified (denoted as Z*). Z*W individuals develop as phenotypic
males that are fertile and can pass on the Z* chromosome to their offspring even when the offspring are
raised at 22ºC. A cross between a ZW female and a Z*Z male is shown in the Punnett square below.

(a) Predict the percent of phenotypic males among the F1 offspring of the cross shown in the Punnett
square if the offspring are raised at 22ºC.

(b) At least one Z or Z* chromosome is necessary for survival of the fish. A researcher crossed two fish
and observed a 2:1 ratio of males to females among the offspring. Based on the information, identify the
genotype of the male parent in the cross. Describe ONE fitness cost to the female of mating with this
particular male.

2017 #1
In flowering plants, pollination is a process that leads to the fertilization of an egg and the production of
seeds. Some flowers attract pollinators, such as bees, using visual and chemical cues. When a bee visits
a flower, in addition to transferring pollen, the bee can take nectar from the flower and use it to make
honey for the colony.

Nectar contains sugar, but certain plants also produce caffeine in the nectar. Caffeine is a bitter-tasting
compound that can be toxic to insects at high concentrations. To investigate the role of caffeine in nectar,

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 AP Biology Exam Review
a group of researchers studied the effect of 0.1 mM caffeine on bee behavior. The results of an
experiment to test the effect of caffeine on bees’ memory of a nectar source are shown in Table 1.

(a) On the axes provided, construct an appropriately labeled graph to illustrate the effect of caffeine on
the probability of bees revisiting a nectar source (memory).

(b) Based on the results, describe the effect of caffeine on each of the following:
(i) Short-term (10 minute) memory of a nectar source
(ii) Long-term (24 hour) memory of a nectar source

(c) Design an experiment using artificial flowers to investigate potential negative effects of increasing
caffeine concentrations in nectar on the number of floral visits by bees. Identify the null hypothesis, an
appropriate control treatment, and the predicted results that could be used to reject the null hypothesis.

(d) Researchers found that nectar with caffeine tends to have a lower sugar content than nectar without
caffeine. Plants use less energy to produce the caffeine in nectar than they do to produce the sugar in
nectar. Propose ONE benefit to plants that produce nectar with caffeine and a lower sugar content.
Propose ONE cost to bees that visit the flowers of plants that produce nectar with caffeine and a lower
sugar content.

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 AP Biology Exam Review

2017 #2
Fires frequently occur in some ecosystems and can destroy all above-ground vegetation. Many species
of plants in these ecosystems respond to compounds in smoke that regulate seed germination after a
major fire. Karrikins (KAR) and trimethylbutenolides (TMB) are water-soluble compounds found in smoke
that are deposited in the soil as a result of a fire. KAR and TMB bind to receptor proteins in a seed. In a
study on the effects of smoke on seeds, researchers recorded the timing and percent of seed
germination in the presence of various combinations of KAR and TMB. The results are shown in Figure
1.
‘

In a second investigation into the effect of available water on seed germination after a fire, researchers
treated seeds with KAR or TMB. The treated seeds were then divided into two treatment groups. One

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 AP Biology Exam Review
group received a water rinse and the other group received no water rinse. The seeds were then
incubated along with a group of control seeds that were not treated. The results are shown in the table.

(a) The researchers made the following claims about the effect of KAR and the effect of TMB on seed
germination relative to the control treatment.
• KAR alone affects the timing of seed germination
• KAR alone affects the percentage of seeds that germinate
• TMB alone affects the timing of seed germination
• TMB alone affects the percentage of seeds that germinate
Provide support using data from Figure 1 for each of the researchers’ claims.

(b) Make a claim about the effect of rinsing on the binding of KAR to the receptor in the seed and about
the effect of rinsing on the binding of TMB to the receptor in the seed. Identify the appropriate treatment
groups and results from the table that, when compared with the controls, provide support for each
claim.

(c) There is intense competition by plants to successfully colonize areas that have been recently cleared
by a fire. Describe ONE advantage of KAR regulation and ONE advantage of TMB regulation to plants
that live in an ecosystem with regular fires.

2017 #4
The table below shows how much each organism in an aquatic ecosystem relies on various food
sources. The rows represent the organisms in the ecosystem, and the columns represent the food
source. The percentages indicate the proportional dietary composition of each organism. High
percentages indicate strong dependence of an organism on a food source.

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 AP Biology Exam Review

(a) Based on the food sources indicated in the data table, construct a food web in the template below.
Write the organism names on the appropriate lines AND draw the arrows necessary to indicate the
energy flow between organisms in the ecosystem.

(b) In an effort to control the number of midges, an area within the ecosystem was sprayed with the
fungus Metarhizium anisopliae, which significantly decreased the midge population. Based on the data in
the table, predict whether the spraying of fungus will have the greatest short-term impact on the
population of the stoneflies, the caddisflies, or the hellgrammites. Justify your prediction.

2016 #2

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 AP Biology Exam Review

Bacteria can be cultured in media with a carefully controlled nutrient composition. The graph above
shows the growth of a bacterial population in a medium with limiting amounts of two nutrients, I and II.

(a) Estimate the maximum population density in for the culture. Using the data, describe what
prevents further growth of the bacterial population in the culture.

(b) Using the data, calculate the growth rate in of the bacterial population between hours 2 and
4.

(c) Identify the preferred nutrient source of the bacteria in the culture over the course of the experiment.
Use the graph to justify your response. Propose ONE advantage of the nutrient preference for an
individual bacterium.
(d) Describe how nutrient I most likely regulates the genes for metabolism of nutrient I and the genes for
metabolism of nutrient II. Provide TWO reasons that the population does not grow between hours 5 and
6.

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 AP Biology Exam Review
2016 #3

The graph above illustrates the percent dry weight of different parts of a particular annual plant (plants
that live less than one year) from early May to late August. The percent dry weight can be used to
estimate the amount of energy a plant uses to produce its leaves, vegetative buds, stems, roots, and
reproductive parts (seeds, receptacles, and flowers).

(a) Identify the direct source of energy used for plant growth during the first week of May, and identify
the part of the plant that grew the most during the same period.

(b) Based on the data on the graph, estimate the percent of the total energy that the plant has allocated
to the growth of leaves on the first day of July.

(c) Compared with perennials (plants that live more than two years), annual plants often allocate a much
greater percentage of their total energy to growth of their reproductive parts in any given year. Propose
ONE evolutionary advantage of the energy allocation strategy in annual plants compared with that in
perennial plants.

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 AP Biology Exam Review
2016 #5
The graph below shows the mass of plants from two different species over time. The plants grew while
attached to each other. The plants were separated at the time indicated by the vertical line in the graph.

Using template 1, graph the predicted shape of the plant-mass lines after separation of the two plants if
the plants were in an obligate mutualistic relationship. On template 2, graph the predicted shape of the
plant-mass lines if the species 2 plant was a parasite of the species 1 plant. Justify each of your
predictions.

2016 #8
Researchers conducted a study to investigate the effect of
exercise on the release of prolactin into the blood. The
researchers measured the concentration of prolactin in the
blood of eight adult males before (T = 0 hour) and after
one hour (T = 1 hour) of vigorous exercise. As a control,
the researchers measured the concentration of blood
prolactin in the same group of individuals at the same
times of day one week later, but without having them
exercise. The results are shown in Figure 1.

(a) Justify the use of the without-exercise treatment as

the control in the study design.

(b) Using evidence from the specific treatments, describe

whether prolactin release changes after exercise. Justify
your answer.

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 AP Biology Exam Review

2015 #1
Many species have circadian rhythms that exhibit an approximately 24-hour cycle. Circadian rhythms are
controlled by both genetics and environmental conditions, including light. Researchers investigated the
effect of light on mouse behavior by using a running wheel with a motion sensor to record activity on
actograms, as shown in Figure 1.

Figure 1. Strategy for recording mouse activity data. When a mouse is active on the running wheel, the
activity is recorded as a dark horizontal line on an actogram. When the mouse is inactive, no dark line is
recorded.

For the investigation, adult male mice were individually housed in cages in a soundproof room at 25°C.
Each mouse was provided with adequate food, water, bedding material, and a running wheel. The mice
were exposed to daily periods of 12 hours of light (L) and 12 hours of dark (D) (L12:D12) for 14 days,
and their activity was continuously monitored. The activity data are shown in Figure 2.

After 14 days in L12:D12, the mice were placed in continuous darkness (DD), and their activity on the
running wheel was recorded as before. The activity data under DD conditions are shown in Figure 3.

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 AP Biology Exam Review

*NOTE: Part (a) IS OUT OF SCOPE FOR THE EXAM*

(a) The nervous system plays a role in coordinating the observed activity pattern of the mice in response
to light-dark stimuli. Describe ONE role of each of the following anatomical structures in responding to
light-dark stimuli.
• A photoreceptor in the retina of the eye
• The brain
• A motor neuron

(b) Based on an analysis of the data in Figure 2, describe the activity pattern of the mice during the light
and dark periods of the L12:D12 cycle.

(c) The researchers claim that the genetically controlled circadian rhythm in the mice does not follow a
24-hour cycle. Describe ONE difference between the daily pattern of activity under L12:D12 conditions
(Figure 2) and under DD conditions (Figure 3), and use the data to support the researchers’ claim.

(d) To investigate the claim that exposure to light overrides the genetically controlled circadian rhythm,
the researchers plan to repeat the experiment with mutant mice lacking a gene that controls the circadian
rhythm. Predict the observed activity pattern of the mutant mice under L12:D12 conditions and under
DD conditions that would support the claim that light overrides the genetically controlled circadian
rhythm.

(e) In nature, mice are potential prey for some predatory birds that hunt during the day. Describe TWO
features of a model that represents how the predator-prey relationship between the birds and the mice
may have resulted in the evolution of the observed activity pattern of the mice.

2015 #5
Phototropism in plants is a response in which a plant shoot grows toward a light source. The results of
five different experimental treatments from classic investigations of phototropism are shown below.

(a) Give support for the claim that the cells located in the tip of the plant shoot detect the light by
comparing the results from treatment group I with the results from treatment group II and treatment group
III.

(b) In treatment groups IV and V, the tips of the plants are removed and placed back onto the shoot on
either a permeable or impermeable barrier. Using the results from treatment groups IV and V, describe
TWO additional characteristics of the phototropism response.

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 AP Biology Exam Review

2015 #6
In an attempt to rescue a small isolated population of snakes from decline, a few male snakes from
several larger populations of the same species were introduced into the population in 1992. The snakes
reproduce sexually, and there are abundant resources in the environment.

The figure below shows the results of a study of the snake population both before and after the
introduction of the outside males. In the study, the numbers of captured snakes indicate the overall
population size.

(a) Describe ONE characteristic of the original population that may have led to the population’s decline
in size between 1989 and 1993.

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 AP Biology Exam Review
(b) Propose ONE reason that the introduction of the outside males rescued the snake population from
decline.

(c) Describe how the data support the statement that there are abundant resources in the environment.

2014 #3
As part of a new suburban development, a sports complex consisting of athletic fields and buildings is
constructed in a formerly wooded area.

(a) Predict ONE ecological consequence on the local plant community that is likely to result during the
site preparation and construction of the sports complex. Justify your predication.

(b) To maintain the playing fields, large quantities of water and chemicals are applied regularly to the
grass-covered areas. Predict ONE effect on the local animal community that might result from regular
use and maintenance of the playing fields. Justify your prediction.

2014 #4
Adult male guppies (Poecilia reticulata) exhibit genetically determined spots, while juvenile and adult
female guppies lack spots. In a study of selection, male and female guppies from genetically diverse
population were collected from different mountain streams and placed together in an isolated
environment containing no predators.

The study population was maintained for several generations in the isolated area before being separated
into two groups. One group was moved to an artificial pond containing a fish predator, while a second
group was moved to an artifical pond containing no predators. The two groups went through several
generations in their new environments. At different times during the experiment, the mean number of
spots per adult male guppy was determined as shown in the figure below. Vertical bars in the figure
represent two standard errors of the mean (SEM).

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 AP Biology Exam Review
(a) Describe the change in genetic variation in the population between 0 and 6 months and provide
reasoning for your description based on the means and SEM.

(b) Propose ONE type of mating behavior that could have resulted in the observed change in the
number of spots per adult male guppy between 6 and 20 months in the absence of the predator.

(c) Propose an evolutionary mechanism that explains the change in average number of spots between 6
and 20 months in the presence of the predator.

2014 #5
Genetically modifed crops have been developed that produce a protein that makes the plants resistant to
insect pests. Other genetic modification make the crops more resistace to chemicals that kill plants
(herbicides).

(a) Describe TWO potential biological risks of large-scale cultivation and use of such genetically
modified plants.

(b) For each of the risks you described in part (a), propose a practical approach for reducing the risk.

2014 #7

(a) Based on the graph, describe a specific method of thermoregulation used by the species of animal.
Provide support for your answer using the data.

(b) On the labeled axis provided below, draw a line to indicate the most likely relationship between body
temperature and environmental temperature in the species.

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 AP Biology Exam Review

2013 #1

In an investigation of fruit-fly behavior, a covered choice chamber is used to test whether the spatial
distribution of flies is affected by the presence of a substance placed at one end of the chamber. To test
the flies’ preference for glucose, 60 flies are introduced into the middle of the choice chamber at the
insertion point indicated by the arrow in the figure above. A cotton ball soaked with a 10% glucose
solution is placed at one end of the chamber, and a dry cotton ball with no solution is placed at the other
end. The positions of flies are observed and recorded every minute for 10 minutes.

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 AP Biology Exam Review
(a) Predict the distribution of flies in the chamber after 10 minutes and justify your prediction.

(b) Propose ONE specific improvement to each of the following parts of the experimental design and
explain how the modification will affect the experiment.
• Experimental control
• Environmental factors

(c) The experiment described above is repeated with ripe bananas at one end and unripe bananas at the
other end. Once again the positions of the flies are observed and recorded every minute for 10 minutes.
The positions of flies after 1 minute and after 10 minutes are shown in the table below.

DISTRIBUTION OF FLIES IN CHOICE CHAMBER

Time Position in Chamber
(minutes) End with Ripe Banana Middle End with Unripe
Banana
1 21 18 21
10 45 3 12

Perform a chi-square test on the data for the 10-minute time point in the banana experiment. Specify the
null hypothesis that you are testing and enter the values from your calculations in the table below.

(d) Explain whether your hypothesis is supported by the chi-square test and justify your explanation.

(e) Briefly propose a model that describes how environmental cues affect the behavior of the flies in the
choice
chamber.

PART (C): CHI-SQUARE CALCULATIONS

Null Hypothesis:

Observed (o) Expected (e) (o-e)2/e

End with ripe banana

Middle

End with unripe

banana
Total

2013 #4
Matter continuously cycles through an ecosystem. A simplified carbon cycle is depicted below.

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 AP Biology Exam Review

(a) Identify the key metabolic process for step I and the key metabolic process for step II, and briefly
explain how each process promotes movement of carbon through the cycle. For each process, your
explanation should focus on the role of energy in the movement of carbon.

(b) Identify an organism that carries out both processes.

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 AP Biology Exam Review
Free Response Scoring Guidelines
2019 #1
Part Scoring Guidelines Topi
c
(a) 6.3

(b) 6.3

(c) 6.3

(d) 8.5

(e) 7.2

2019 #2
Part Scoring Guidelines Topi
c
(a)

(b) 8.3

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 AP Biology Exam Review
(c) 8.4

(d) 8.5

(e) 2.8

2018 #3
Part Scoring Guidelines Topi
c
(a) 8.6

(b) 8.6

2018 #5
Part Scoring Guidelines Topi
c

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 AP Biology Exam Review
(a) 8.5

(b) 8.5

(c) 8.5

2018 #7
Part Scoring Guidelines Topi
c
(a) 5.4

(b) 8.1

2017 #1
Part Scoring Guidelines Topi
c
(a) 8.1

(b) 8.1

(c) 8.1

49
 AP Biology Exam Review
(d) 8.1

2017 #2
Part Scoring Guidelines Topi
c
(a) 3.7

(b) OOS

(c) 8.5

2017 #4
Part Scoring Guidelines Topi
c

50
 AP Biology Exam Review
(a) 8.2
8.5

(b) 8.6

2016 #2
Part Scoring Guidelines Topi
c
(a) 8.3

(b) 8.3

(c) 8.3

51
 AP Biology Exam Review
(d) 8.1

2016 #3
Part Scoring Guidelines Topi
c
(a) 3.7

(b) 3.7

(c) 7.1
8.2

2016 #5
Part Scoring Guidelines Topi
c
8.5

2016 #8
Part Scoring Guidelines Topi
c
(a) 8.1

52
 AP Biology Exam Review
(b) 8.1

2015 #1
Part Scoring Guidelines Topi
c
(a) OOS

(b) 8.1

(c)

(d)

(e) 7.1

2015 #5
Part Scoring Guidelines Topi
c

53
 AP Biology Exam Review
(a) 8.1

(b) 8.1

2015 #6
Part Scoring Guidelines Topi
c
(a) 8.3

(b) 8.3
8.7

(c) 8.4

2014 #3
Part Scoring Guidelines Topi
c

54
 AP Biology Exam Review
(a) 8.6
8.7

(b) 8.6
8.7

2014 #4
Part Scoring Guidelines Topi
c
(a) 7.1

(b) 8.1

(c) 7.5

55
 AP Biology Exam Review
2014 #5
Part Scoring Guidelines Topi
c
6.8
7.3
8.7

2014 #7
Part Scoring Guidelines Topi
c
(a) 8.1

56
 AP Biology Exam Review
(b) 8.1

2013 #1
Part Scoring Guidelines Topi
c
(a) 8.1

(b) 8.1

(c) 8.1

(d) 8.1

57
 AP Biology Exam Review
(e) 8.1

2013 #4
Part Scoring Guidelines Topi
c
(a) 3.5
3.6

(b) 8.2

58