AP Environmental Science Unit 1 Practice Test: The Living World – Ecosystems

The correct answer is (A). In a mutualistic relationship, both organisms derive a benefit. In a commensalistic relationship, one organism benefits, and one is not substantially harmed or helped. In a parasitic relationship, one organism benefits at the expense of the other’s health. Predation occurs when one animal consumes another to extend its survival.

The correct answer is (C). Detritivores obtain nutrients by consuming decomposing organic matter, or detritus. Scavengers obtain nutrients from carrion or animal waste, they do not possess the enzymes required to utilize detritus for nutrients. Parasites rely upon a living host for their nutrients. Omnivores consume both plants and animals.

The correct answer is (C). Cheetahs are secondary consumers because they eat primary consumers, such as gazelle or hare.

The correct answer is (C). Net primary productivity is highest where the temperature is warm, and where water and solar energy are most abundant.

The correct answer is (3). This diagram shows that 10% of the energy is conserved from one trophic level to the next. For example, if the amount of grass in an ecosystem represents 10,000 joules, then in that same ecosystem, the energy contained in the primary consumer level will represent 1,000 J. This is because organisms use roughly about 90% of the energy they consume for cellular activities (such as respiration and growth).

The correct answer is (A). The nitrogen cycle depends on nitrogen-fixing bacteria to convert atmospheric nitrogen into a form usable by plants.

The correct answer is (B). Boreal forests are found between 50° and 60° N in Europe, Russia, and North America. Most vegetation is made up of coniferous trees.

The correct answer is (C). Mangroves are the dominant vegetation in mangrove swamps. They are salt-tolerant and help to stabilize tropical and subtropical coastlines, as well as provide important habitat for marine organisms.

The correct answer is (B). Communities are different populations of organisms living in the same location and interacting with one another.

The correct answer is (A). Typically, producers are only able to capture 1% of the solar energy available through photosynthesis.

The correct answer is (B). Burning fossil fuels releases carbon into the atmosphere. This increases atmospheric carbon concentrations and thus promotes global warming.

The correct answer is (C). Sulfur is an important nutrient. Volcanic eruptions are natural sources of sulfur dioxide as are geothermal vents on the ocean floor. Burning fossil fuels also releases sulfur into the atmosphere, leading to acid precipitation.

The correct answer is (D). The phosphorus cycle has no atmospheric component. Phosphorous comes from the weathering of rocks and can find its way into surface waters but does not evaporate into the atmosphere in any way.

The correct answer is (A). The water cycle requires solar energy to evaporate water from the earth into the atmosphere.

The correct answer is (B). Phosphorus is only added to the environment due to the weathering of rocks. Since this process is very slow any amount of phosphorus added by humans can throw off the balance of an ecosystem and lead to eutrophication of surface waters.