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AP®BiologyCollege BoardExam QuestionsUnit 8: EcologyEcosystems

Ecosystems (College Board AP® Biology)

Exam Questions

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Ecosystems

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Ecosystems

1
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Animals may use visual, auditory, and chemical signals which lead to changes in behavior. These signals can affect reproductive success. Which of the following best explains how an animal uses signaling behavior to enhance reproductive fitness?

  • Animals may use random movement to determine the location of suitable environmental conditions, ensuring access to a food source.

  • The fight-or-flight response increases blood flow to the muscles, allowing prey organisms to run quickly.

  • Colorful flowers attract insect pollinators, increasing the transfer of pollen between flowers.

  • Animals may use scent marking to indicate the extent of a territory and deter other members of the same species.

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The life history strategy of a species includes factors such as age of reproduction, frequency of reproduction and number of offspring. One example of a life history strategy sometimes found in insect species is a period of suspended development known as diapause. One study looked at the relationship between mean daily temperature during larval development and entry into prolonged diapause (a period of diapause that lasts for a year or longer) in a species of moth. The results are shown in Figure 1 below.

Scatter plot showing individuals in prolonged diapause (%) versus mean larval development temperature (°C), with a downward curve peaking at 0°C and 12°C.
Figure 1. The effect of mean temperature during larval development on entry into prolonged diapause in moths

Which of the following provides the most likely explanation for the relationship between mean temperature and entry into prolonged diapause?

  • Increasing average global temperatures, due to climate change, are causing more moths to enter prolonged diapause.

  • Moth larvae enter prolonged diapause to reduce competition between surviving moths in future years.

  • Moth larvae enter prolonged diapause to save energy over multiple cold or warm seasons.

  • Moth larvae are less likely to enter diapause when mean temperatures are in between extremes of cold and warm.

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Metabolic rate is the energy expended over time by an organism or cell. Researchers measured the metabolic rate of cells within a series of organisms of different body mass. They recorded metabolic rate of the cells within the body of the organism (in vivo) and in a petri dish in the laboratory (in vitro). Their results are shown in Figure 1.

Scatter plot showing cellular metabolic rate vs body mass. Solid line indicates in vivo data; dashed line shows in vitro data. Key provided below graph.
Figure 1. The metabolic rate of cells for organisms of differing body mass, both in vivo and in vitro.

Which of the following claims is most likely to be correct for the data shown in Figure 1?

  • The cells of each species have a fixed metabolic rate that is determined by body mass.

  • Cellular metabolic rate is affected by external conditions as well as body mass.

  • Cellular metabolic rate is determined by nutrient availability.

  • Metabolic rate is determined by environmental conditions and is not affected by body mass.

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Plankton are small organisms that live in aquatic environments. Plankton can be photosynthetic (phytoplankton) or heterotrophic (zooplankton). A study measured the biomass of phytoplankton and zooplankton between July and May of a single year. The results of the study are shown in Figure 1.

Line graph showing monthly biomass (mg/l) of phytoplankton and zooplankton from July to May. Phytoplankton peaks in February, zooplankton in July.
Figure 1. Biomass of phytoplankton and zooplankton between July and May.

Which of the following are correct descriptions of the data in Figure 1?

  • Zooplankton biomass decreases by around 120 % between July and May.

  • Between July and December the zooplankton population experiences a net loss of energy.

  • The average rate of biomass growth in zooplankton between January and April is 11.7 mg l-1 month-1.

  • The average rate of biomass growth in zooplankton between January and April is -0.7 mg l-1 month-1.

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All living organisms need energy to maintain their tissues, grow and reproduce. Different groups of organisms rely on different modes of nutrition in order to gain energy. Which of the following correctly describes mechanisms by which living organisms capture energy in ecosystems?

  • Heterotrophic and chemosynthetic organisms both gain their energy from the carbon compounds in other living organisms.

  • Photosynthetic organisms gain their energy from carbon compounds gained from the soil.

  • Chemosynthetic and photosynthetic organisms are examples of autotrophs.

  • Heterotrophic organisms produce their own organic molecules using inorganic substances.

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