Unit 1 MCQ Review - AP Classroom

Which of the following trophic levels represents a primary producer in an aquatic food chain?

Phytoplankton - Phytoplankton uses solar energy to produce food; it is a producer.

Marine Food Web: Based on the second law of thermodynamics, how much biomass of phytoplankton would be needed to produce 1 kilogram (kg) of large fish in this food web?

1,000 kg-Assuming only approximately 10% of biomass is available to be transferred to the next trophic level, 1,000kg1 of phytoplankton would be needed because of the four different energy transfers in this food web. [1,000kg phytoplankton ×0.10=100kg available to herbivorous zooplankton; 100kg zooplankton ×0.10=10kg available to small fish; 10kg small fish ×0.10=1kg of large fish biomass]

Based on the food web shown above, which of the following correctly describes the flow of energy through the trophic levels from producers to quaternary consumers?

Brittlebrush, grasshopper, grasshopper mouse, rattlesnake, red-tailed hawk - The energy flows up the food web through trophic levels based on feeding relationships.

Which of the boxes represents a carbon source?

D. Burning of Fossil Fuels - Burning fossil fuels is a source because it releases carbon that has been stored in coal, oil, or natural gas, which are carbon sinks.

A temperate grassland biome has a gross primary productivity of 3,480kilocalories/meter2/year and a net primary productivity of 2,000kilocalories/meter2/year. Which of the following is the approximate number of kilocalories/meter2/year available to herbivores in that biome?

10% of the kilocalories from net primary productivity would be available (2,000kilocalories/meter2/year×0.10=200kilocalories/meter2/year)

Nitrogen Cycle: Which of the following processes is illustrated by the downward arrows from the atmosphere that show the conversion of nitrogen gas into usable forms available to producers?

Nitrogen Fixation-Nitrifying bacteria or lighting converts atmospheric nitrogen N2 to ammonia.

Marine Food Web: Which of the following best describes what is represented by the arrows in the food web?

The flow of energy-Arrows in a food web depict the flow of energy between trophic levels.

Which of the following terrestrial biomes has the highest net primary productivity?

Tropical rain forest - Net primary productivity (NPP) is higher in biomes that are warm year-round and receive abundant rainfall and sunlight to encourage the growth of producers, which are all characteristics of tropical rain forests.

Which of the following best describes an example of resource partitioning in an ecosystem?

Two different bird species feed from the same oak tree; one eats acorns, and the other eats insects in the bark-The two bird species are using the same resource in slightly different ways to reduce the negative impact of competition on the two species.

Which box represents a carbon sink that holds carbon compounds for the shortest period of time?

A. Vegetation - Carbon dioxide can move into plants to be stored as glucose much more quickly than sedimentary rocks and fossil fuels can be stored. Carbon compounds are held for the shortest amount of time in vegetation.

Nitrogen Cycle: The majority of the nitrogen on Earth can be found in which of the following reservoirs?

Atmosphere-The largest reservoir of nitrogen is the atmosphere, which is about 80% free nitrogen (N2) and contains 3,870,000,000 tetragrams of nitrogen.

Nitrogen Cycle: Which of the following types of organisms are required to complete the nitrogen cycle, including the process of denitrification?

Bacteria-Certain bacteria are specialized in fixing nitrogen, in association with plants such as soybeans and other legumes. Other types of bacteria perform nitrification: converting ammonium ions into nitrite ions, and then into nitrate ions. Finally, other bacteria perform denitrification, the reduction of nitrates back into nitrogen gas.

This rate of reaction can be measured in the dark by determining the amount of oxygen gas consumed in a period of time.

Cellular respiration - Cellular respiration does not require sunlight, so it can be measured in the dark.

This biome is found in shallow waters off the coastline and is Earth's most biologically diverse marine biome.

Coral Reefs - Corals live in vast colonies off the coast and create a reef that provides habitat for a variety of organisms, including algae, tropical fish, and birds.

This biome contains a nutrient-rich environment created by falling leaves and trapped organic materials from the large trees, and it provides the ecosystem service of filtering pollutants from water.

Freshwater Wetlands - Freshwater wetlands have trees with roots that are submerged in water. The trees drop their leaves, and the water traps organic materials released from decomposition. The wetlands also trap pollutants.

The total rate of photosynthesis in a given area.

Gross Primary Productivity - Gross primary productivity is defined as the total rate of photosynthesis in a given area.

Hydrologic Cycle: Which of the following smaller reservoirs of freshwater are missing from the diagram?

Ice Caps-Ice caps (and glaciers) store almost 70% of the Earth's total freshwater.

Energy is transferred along food chains from one stage to the next. Which statement best explains how the energy is transferred?

If a primary producer stores 10,000kcal of energy, then a tertiary consumer will have 10kcal of energy available - Energy lost is 90% per trophic level so 10% is transferred. If level 1 (primary producer) stores 10,000kcal of energy, than level 2 (primary consumer) would have 1,000kcal of energy available, level 3 (secondary consumer) would have 100kcal of energy available, and level 4 (tertiary consumer) would have 10kcal of energy available. (10,000kcal×0.10×0.10×0.10=10kcal)

Marine Food Web: Which trophic level has the least available energy in kilojoules in this food web?

Killer Whale-The amount of energy available decreases up the food chain, so the organisms at the highest trophic level would have the fewest kilojoules of energy available. The killer whale is a top predator (quaternary consumer).

In reef ecosystems, corals often have microalgae living inside them. The algae supply the corals with nutrients, and the coral give shelter to the algae. Which of the following interactions best describes the relationship between the corals and the algae?

Mutualism-The two organisms both benefit from the relationship.

The energy available to consumers determined by subtracting the energy used by plants from the total energy transformed by the process of photosynthesis.

Net Primary Productivity - Net primary productivity is the rate of energy storage by photosynthesizers after subtracting energy used for cellular respiration in plants.

Which of the following best describes the flow of energy in most terrestrial and near-surface marine ecosystems?

Producers use energy from the sun to make organic matter, such as sugars, from carbon dioxide and water and are then consumed by organisms higher in the food chain - Through the process of photosynthesis, plants convert solar energy into chemical energy, which moves through the food chain when one organism feeds on another.

This freshwater biome is characterized by fast-flowing water that can originate from underground springs or runoff, which carries sediment and organic material.

Rivers - Rivers carry runoff from rain or snow. Turbulent water, known as rapids, form from the fast-moving water flow.

Hydrologic Cycle: Which of the following best identifies a key component of the hydrologic cycle that powers the movement of water and is missing from the diagram?

The Sun-The Sun powers the movement of water through evaporation and transpiration.

Which of the following biogeochemical cycles includes the processes of buffering ocean pH and photosynthesis, as shown in the diagram?

The carbon cycle - Carbon is converted from atmospheric CO2 to organic carbon compounds via photosynthesis, and carbon sequestered by the ocean buffers ocean pH.

Which of the following describes the most likely change to terrestrial biomes resulting from warmer average global temperatures?

The global distribution of midlatitude biomes, such as grasslands and temperate rain forests, would increase - Warmer average global temperatures would expand the range of biomes currently found at midlatitudes.

Which of the following statements is best supported by the diagram of the phosphorus cycle?

The phosphates absorbed by animal tissue through consumption eventually return to the soil - The phosphates absorbed by animal tissue through consumption eventually return to the soil through the excretion of plants and animals and their decomposition after death.

The diagram above best illustrates major processes in which of the following biogeochemical cycles?

The phosphorus cycle - The phosphorus cycle does not have an atmospheric sink and is driven by weathering and uplift.

Six white-tailed deer and six sika deer were enclosed in a pasture for observation during an eight-year study in central Texas. White-tailed deer are a native species to central Texas, while sika deer are a nonnative species to central Texas. White-tailed deer feed on flowering plants and the tips of trees and shrubs but do not eat grass. Sika deer feed on flowering plants, the tips of trees and shrubs, and grass. All other grazing animals were kept out of the pasture during the study. The number of sika deer more than doubled after the eight years, while the population of white-tailed deer decreased by 50 percent.

The sika deer out competed the white-tailed deer in consuming flowering plants and shrubs-Since both species eat the same food, there is competition for a limited resource in the confined space.

Farmers in a suburban coastal town started using no-till agriculture, a practice that reduces soil erosion from their farmland. Use the image above to determine which of the following long-term effects no-till agriculture will have on the ecosystem surrounding the farmland.

There will be less algal growth in the nearby ocean - Phosphorous is a limiting factor in biological systems. By decreasing the amount of erosion, less phosphorous will run off into waterways and be available to algae to use for growth.

Which of the following terrestrial biomes has the highest primary productivity per unit area?

Tropical Rain Forest - Tropical rain forests have a yearlong growing season and more than 60 inches of rain per year. The warm climate and the rainfall leads to high levels of photosynthesis in the numerous plant species that inhabit the biome.

Which of the following best describes a terrestrial ecosystem that will have the highest net primary productivity?

Warm temperatures, high rainfall, and consistent sunlight - Net primary productivity is highest in areas where temperatures are warm and water and solar energy are abundant and encourage the growth of producers.

Based on the diagram, which of the following statements about the hydrologic cycle is true?

Water from the ocean evaporates and condenses in the atmosphere - The ocean is the largest reservoir and over 70% of the Earth's surface of water and therefore the greatest source for evaporation.