AP Biology Unit 8 Practice Test & Exam | 26 Questions

Questions 1-3 refer to the following scenario.

1. Which of the following best explains the role of the environmental cue in initiating the courtship behavior?

(A)The increased photoperiod acts as a stimulus, triggering a physiological response that leads to the dive display behavior.(B)The male hummingbirds learn the dive display from their parents, which is a behavior passed down through generations.(C)The presence of a female hummingbird is the primary stimulus that causes the male to begin practicing his dive.(D)The increase in temperature in the spring provides the male with more metabolic energy to perform the dive.

2. The observation that males with more vigorous displays are more likely to mate is an example of which of the following concepts?

(A)Kin selection, because the male's behavior benefits his relatives.(B)Habituation, because the female becomes accustomed to the male's presence.(C)A fixed action pattern, because the dive display is an unchangeable sequence of behaviors.(D)Natural selection, because the behavior is linked to differential reproductive success.

3. The male's aerial dive is a form of communication. Which of the following best describes the function of this signal?

(A)It is a tactile signal used to establish dominance over other males.(B)It is a chemical signal (pheromone) used to mark territory.(C)It is a visual signal used to convey information about the male's fitness to the female.(D)It is an audible signal used to warn other species of a potential threat.

Questions 4-7 refer to the diagram below, which represents the flow of energy through a terrestrial ecosystem.

4. Which of the following statements best describes the pattern of energy flow shown in the diagram?

(A)Energy is cycled from the producers to the consumers and then back to the producers.(B)The amount of energy available increases at each successive trophic level.(C)Approximately 90% of the energy is lost as heat at each trophic level transfer.(D)Tertiary consumers are the most energy-efficient organisms in the ecosystem.

5. Which of the following best explains why the biomass of the producer level is greater than the biomass of the primary consumer level?

(A)Producers are physically larger than primary consumers.(B)The transfer of energy between trophic levels is inefficient, requiring a large base of producers to support the next level.(C)Primary consumers have a faster metabolic rate than producers.(D)Matter is lost at each trophic level, while energy is conserved.

6. A prolonged period of drought significantly reduces the biomass of the producers in this ecosystem. Which of the following describes the most likely immediate effect on the ecosystem?

(A)The biomass of tertiary consumers will increase as they find new food sources.(B)The carrying capacity for the primary consumer population will decrease due to reduced energy availability.(C)The energy transferred to secondary consumers will increase as primary consumers become easier to hunt.(D)The ecosystem will become more stable due to the reduction in competition at the producer level.

7. The nitrogen cycle is essential for this ecosystem because nitrogen is a primary component of which two molecules required by producers and consumers?

(A)Glucose and starch(B)Water and carbon dioxide(C)Proteins and nucleic acids(D)Lipids and phospholipids

Questions 8-10 refer to the graph below, which shows the growth of a yeast population in a nutrient-rich broth over time.

8. Which of the following best describes the population growth pattern between hours 0 and 40 (the initial steep part of the curve)?

(A)Logistic growth, where the population is approaching its carrying capacity.(B)Exponential growth, where the rate of growth is proportional to the population size.(C)Linear growth, where the population increases by a fixed number of cells each hour.(D)Population decline, where the death rate exceeds the birth rate.

9. The leveling off of the population size around the line labeled "K" is most likely due to which of the following?

(A)A density-independent factor, such as a sudden change in temperature.(B)The yeast cells adapting to the new environment and ceasing reproduction.(C)The population reaching the carrying capacity of the environment due to density-dependent factors like nutrient limitation.(D)The intrinsic rate of increase ($r$) becoming negative.

10. If the initial population size ($N_0$) is 20 cells and the intrinsic rate of increase ($r$) is 0.5 cells/hour, which of the following is the correct calculation for the population size after one hour, assuming exponential growth?

(A)$dN/dt = (0.5)(20) = 10$ cells(B)Population size = $20 + (0.5 \times 20) = 30$ cells(C)Population size = $20 / 0.5 = 40$ cells(D)Population size = $20 - (0.5 \times 20) = 10$ cells

Questions 11-13 refer to the data from an experiment investigating competition between two species of protists, Paramecium aurelia and Paramecium caudatum.

11. Which of the following statements correctly describes a trend observed in the data?

(A)When grown alone, P. caudatum reaches a higher carrying capacity than P. aurelia.(B)When grown together, both species experience a decrease in their population growth compared to when grown alone.(C)P. aurelia is negatively affected by the presence of P. caudatum, while P. caudatum is unaffected.(D)P. caudatum is driven to extinction when grown in the presence of P. aurelia.

12. The results of this experiment best illustrate which of the following ecological principles?

(A)Mutualism, where both species benefit from the interaction.(B)The competitive exclusion principle, where one species outcompetes another for the same limited resources.(C)Niche partitioning, where both species coexist by using different resources.(D)Predation, where P. aurelia consumes P. caudatum.

13. Based on the data, which of the following best explains the interaction between the two species?

(A)The interaction is commensal (+/0), as P. aurelia benefits and P. caudatum is unharmed.(B)The interaction is a form of competition (-/-), as both species show reduced growth when together, but P. aurelia is a stronger competitor.(C)The interaction is amensalism (-/0), as P. caudatum is harmed and P. aurelia is unaffected.(D)The interaction is parasitism (+/-), as P. aurelia acts as a parasite on P. caudatum.

14. A community is composed of populations of snails, algae, and small fish. The snails eat the algae, and the fish eat the snails. This set of interactions is an example of a:

(A)Food web(B)Trophic cascade(C)Food chain(D)Symbiotic relationship

Questions 15-17 refer to the following information.

15. Based on their role in the ecosystem, sea otters are best described as:

(A)A producer species(B)A keystone species(C)An invasive species(D)A decomposer species

16. Which of the following claims is best supported by the information provided?

(A)The removal of a single species can cause a cascade of effects that alter the structure of an entire ecosystem.(B)Ecosystems with low biodiversity are more resilient to the removal of a predator.(C)Sea urchin populations are limited primarily by the availability of kelp, not by predation.(D)The diversity of fish and invertebrates is independent of the health of the kelp forests.

17. The decline in kelp forests following the removal of sea otters demonstrates that:

(A)Highly diverse ecosystems are inherently unstable.(B)The loss of a key biotic factor can lead to a decrease in ecosystem resilience.(C)Abiotic factors, such as water temperature, are the primary drivers of ecosystem structure.(D)Herbivores always have a positive impact on producer populations.

Questions 18-20 refer to the diagram below, which shows the concentration of a pesticide, DDT, in the tissues of organisms in a food web.

18. Which of the following statements best describes the data presented in the diagram?

(A)DDT concentration is highest in the water and decreases at higher trophic levels.(B)All organisms in the food web have approximately the same concentration of DDT.(C)The concentration of DDT increases at successively higher trophic levels.(D)Zooplankton are more resistant to the effects of DDT than fish-eating birds are.

19. The phenomenon illustrated in the diagram, where certain substances become more concentrated in organisms at higher trophic levels, is known as:

(A)Eutrophication(B)Decomposition(C)Biomagnification(D)Nitrogen fixation

20. Which claim about human impact on ecosystems is best supported by the information?

(A)Human-introduced pollutants can be transferred through food webs and have disproportionately large effects on top predators.(B)The use of pesticides has no long-term effects on aquatic ecosystems.(C)Humans can easily remove pollutants like DDT from ecosystems through cleanup efforts.(D)Only organisms at the bottom of the food web are negatively affected by chemical pollution.

21. Some bacteria are capable of nitrogen fixation. This process is critical for ecosystems because it:

(A)Converts atmospheric nitrogen gas into forms, such as ammonia, that can be used by plants.(B)Releases nitrogen gas back into the atmosphere, completing the nitrogen cycle.(C)Breaks down nitrogen-containing organic molecules into inorganic components.(D)Synthesizes complex organic molecules from nitrogen and carbon dioxide.

22. A species of mouse lives in a stable forest environment. The mice produce a small number of offspring and provide a high degree of parental care. This reproductive strategy is characteristic of:

(A)An r-selected species(B)A K-selected species(C)A pioneer species(D)A density-independent species

23. Zebra mussels are an invasive species in the Great Lakes of North America. They filter large quantities of water, removing phytoplankton that native species depend on. This introduction has led to a decline in several native fish populations. This is an example of a disruption caused by:

(A)The exploitation of a new niche by an introduced species, leading to increased competition.(B)A geological event that altered the habitat structure.(C)A mutualistic relationship forming between the zebra mussels and native species.(D)An increase in the overall biodiversity and resilience of the ecosystem.

24. A researcher is comparing the biodiversity of two forest communities. Community A has 5 tree species with 20 individuals each. Community B has 5 tree species, but one species has 84 individuals while the other four species have 4 individuals each. Which of the following statements is true?

(A)Community A and Community B have the same species richness and the same species diversity.(B)Community A and Community B have the same species richness, but Community A has greater species diversity (evenness).(C)Community B has greater species richness and greater species diversity than Community A.(D)Community A has greater species richness but lower species diversity than Community B.

AP Biology Unit 8: Ecology Practice Exam

Exam Details

A. Multiple-Choice Questions (24 Questions)

B. Short Answer Questions (2 Questions)

AP Biology Unit 8: Ecology Practice Exam

Exam Details

A. Multiple-Choice Questions (24 Questions)

B. Short Answer Questions (2 Questions)