APES Unit 1 Progress Check MCQ

The diagram below shows a particular 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. Correct. Assuming only approximately 10% of biomass is available to be transferred to the next trophic level, 1,000kg 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]

The diagram below shows a simplified nitrogen cycle. Which of the following types of organisms are required to complete the nitrogen cycle, including the process of denitrification?

Bacteria. "Correct. 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."

The diagram below shows the hydrologic cycle. Which of the following smaller reservoirs of freshwater are missing from the diagram?

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

The diagram below shows a particular marine food web. Which trophic level has the least available energy in kilojoules in this food web?

Killer whale. "Correct. 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. "Correct. The two organisms both benefit from the relationship."

The diagram below shows a simplified 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. "Correct. Nitrifying bacteria or lighting converts atmospheric nitrogen N2 to ammonia."

The diagram below shows the 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. "Correct. The Sun powers the movement of water through evaporation and transpiration."

The diagram below shows a particular marine food web. Which of the following best describes what is represented by the arrows in the food web?

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

The diagram below shows a simplified nitrogen cycle. The majority of the nitrogen on Earth can be found in which of the following reservoirs?

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

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. Which of the following statements best supports the results from the study?

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