Exam 42: Ecosystems and Energy

Please use the following information to answer the question(s) below. The tundra biome is rapidly changing as a result of global warming. Studying the energy budget of the tundra can help scientists to evaluate the magnitude of these changes. In a randomly selected square meter of tundra, the amount of plant biomass is 200 g. The amount of new plant biomass added in a year is 100 g. In the same square meter, the total biomass added in a year is 15 g. A grasshopper that eats 1 g of plant biomass is able to use 0.15 g of that biomass for growth. The grasshopper cannot assimilate 50% of the plant's biomass. -What is the production efficiency of the grasshopper?

Figure 42.1 Food web for a particular terrestrial ecosystem (arrows represent energy flow and numbers represent species) -Examine the food web for a particular terrestrial ecosystem in Figure 42.1. Species C is toxic to predators. Which species is most likely to benefit from being a mimic of C?

Which of the following has the greatest effect on the rate of chemical cycling in an ecosystem?

Which of the following is primarily responsible for limiting the number of trophic levels in most ecosystems?

Which of the following statements is true?

Which of the following locations is the largest reservoir for carbon in the carbon cycle?

Which of the following is true of detritivores?

Please use the following information to answer the question(s) below. Starting with the European settlers, humans have introduced earthworms from Europe and Asia into North American forests. These introductions continue through the transport of soil that contains non-native earthworms, such as during construction, and through the release of non-native earthworms used for fishing. The effects of non-native earthworms are especially large in forests that did not have any native earthworms. For example, forests of the Great Lakes region did not previously have earthworms until humans introduced them. When non-native earthworms are introduced, the thick layer of leaf litter disappears quickly, thereby altering biogeochemical cycles. -Which of the following correctly traces a carbon molecule in a Great Lakes forest that is invaded with non-native earthworms?

Which of the following organisms is incorrectly paired with its trophic level?

Approximately how many kilograms of secondary consumer biomass can be supported by a field plot containing 1,000 kg of plant material?

Which of the following is an example of bioremediation?

Figure 42.3 -In the diagram of the nitrogen cycle in Figure 42.3, which number represents nitrifying bacteria?

The amount of chemical energy in a consumer's food that is converted to its own new biomass during a given time period is known as which of the following?

If the flow of energy in an arctic ecosystem goes through a simple food chain, perhaps involving humans, moving from phytoplankton to zooplankton to fish to seals to polar bears, then which of the following could be true?

To recycle nutrients, an ecosystem must have, at a minimum,

What is the first step in the restoration of an extremely degraded ecosystem?

The Hubbard Brook watershed deforestation experiment yielded all of the following results except:

Please use the following information to answer the question(s) below. The tundra biome is rapidly changing as a result of global warming. Studying the energy budget of the tundra can help scientists to evaluate the magnitude of these changes. In a randomly selected square meter of tundra, the amount of plant biomass is 200 g. The amount of new plant biomass added in a year is 100 g. In the same square meter, the total biomass added in a year is 15 g. A grasshopper that eats 1 g of plant biomass is able to use 0.15 g of that biomass for growth. The grasshopper cannot assimilate 50% of the plant's biomass. -What is the maximum biomass of grasshoppers that could be supported by this square meter of tundra (i.e., if grasshoppers ate all of the existing vegetation)?

In ecosystems, why is the term cycling used to describe the transfer of chemical elements, whereas the term flow is used for energy exchange?

If the sun were to suddenly stop providing energy to Earth, most ecosystems would vanish. Which of the following ecosystems would likely survive the longest after this hypothetical disaster?