Question 1

Which of the following best explains why energy transfer between trophic levels in an ecosystem is inefficient?

Accepted Answer

Energy is lost as heat and molecular waste during metabolic processes, according to the laws of thermodynamics.

Question 2

A forest ecosystem has a gross primary productivity (GPP) of $$12,000\ \mathrm{$$kcal/m^2$$/year}$$ and the energy used for respiration (R) is $$7,000\ \mathrm{$$kcal/m^2$$/year}. $$What is the net primary productivity (NPP) of this ecosystem?

Accepted Answer

$$NPP = GPP - R = 5,000\ \mathrm{$$kcal/m^2$$/year}$$

Question 3

Which process is primarily responsible for moving carbon from the atmosphere into the biotic reservoir of an ecosystem?

Accepted Answer

Photosynthesis

Question 4

Why are decomposers considered essential for ecosystem functioning?

Accepted Answer

They recycle nutrients from dead organic matter, making them available to primary producers.

Question 5

Which of the following best describes biomagnification in food webs?

Accepted Answer

The accumulation and magnification of harmful chemicals at higher trophic levels.

Question 6

A grassland ecosystem supports a population of herbivores with a biomass of $$2,000\ \mathrm{kg}. If $$only 10% of the energy is transferred to the next trophic level, what is the maximum biomass of carnivores that can be supported?

Accepted Answer

$$200\ \mathrm{kg}$$

Question 7

Which human activity has most directly increased the amount of atmospheric carbon dioxide, contributing to global warming?

Accepted Answer

Burning fossil fuels and deforestation

Question 8

In the nitrogen cycle, which process converts atmospheric nitrogen ($$N_2) $$into a biologically usable form for plants?

Accepted Answer

Nitrogen fixation by microorganisms

Question 9

Which of the following is a direct consequence of eutrophication caused by excess nitrogen and phosphorus in aquatic ecosystems?

Accepted Answer

Algal blooms and aquatic dead zones

Question 10

Which equation correctly represents the relationship between gross primary productivity (GPP), respiration (R), and net primary productivity (NPP)?

Accepted Answer

$$NPP = GPP - R$$

Question 11

How does the alteration of surface permeability by urban development affect the water cycle in ecosystems?

Accepted Answer

It decreases percolation, increases water runoff, and carries nutrients away.

Question 12

Which of the following statements about the cycling of nutrients and energy in ecosystems is correct?

Accepted Answer

Nutrients are recycled, but energy flows one-way and is eventually lost as heat.

Question 13

Which major reservoir contains the largest amount of phosphorus available to ecosystems?

Accepted Answer

Rock formations and earth's crust

Question 14

A scientist observes that decomposition rates are very slow in a northern forest with cool temperatures and high moisture. What is the most likely consequence for nutrient cycling in this ecosystem?

Accepted Answer

Accumulation of organic matter (detritus) in the soil

Question 15

Which of the following is a predicted effect of global climate change on biodiversity?

Accepted Answer

Shifts in geographic ranges, phenology, and increased risk of extinction

Question 16

Which of the following best distinguishes weather from climate?

Accepted Answer

Weather refers to short-term, variable atmospheric conditions; climate is the long-term average pattern.

Question 17

Which of the following is NOT a natural process that moves elements between reservoirs in biogeochemical cycles?

Accepted Answer

Application of synthetic fertilizers

Question 18

If humans shift from a diet based on secondary consumers (meat) to one based on primary producers (plants), what is the most likely ecological consequence?

Accepted Answer

More humans can be supported by the same amount of primary producer biomass.

Question 19

Which greenhouse gas is most directly linked to the greenhouse effect and global warming due to human activities?

Accepted Answer

Carbon dioxide ($$CO_2)$$

Question 20

Which of the following is a direct result of the law of thermodynamics in ecosystem energy flow?

Accepted Answer

Some energy is lost as heat and cannot be transferred to higher trophic levels.

Energy Flow, Nutrient Cycling, and Ecosystem Ecology

Guida di studio - Domande di pratica

Study guide - Flashcard