the amount of energy is much greater than the amount of nutrients
	energy is recycled, but nutrients are not
	organisms always need nutrients, but they don't always need energy
	nutrients are recycled, but energy is not
	organisms always need energy, but they don't always need nutrients

	transferred from one trophic level to the next
	transferred to the decomposers
	dissipated into space as heat
	used in photosynthesis
	none of the above

	detritivores
	shrimp
	poison ivy
	lions
	humans

	autotrophs
	heterotrophs
	herbivores
	carnivores
	consumers

	primary consumer
	carnivore
	primary producer
	secondary consumer
	tertiary consumer

	plants and animals
	prokaryotes and animals
	fungi and prokaryotes
	prokaryotes and plants
	plants and fungi

	is used by plants for photosynthesis
	is not captured for use by living things
	is continually recycled by ecosystems
	is trapped by greenhouse gases
	is used by algae for photosynthesis

	biomass
	standing crop
	biomagnification
	net productivity
	gross primary productivity

	Community biomass is increasing.
	Community biomass is decreasing.
	A climax community has been reached.
	The first law of thermodynamics (energy is conserved) in not in effect.
	The second law of thermodynamics (in a closed system, there is a general tendency toward disorder) is not in effect.

	Overall, terrestrial ecosystems contribute two-thirds of global net primary production, and marine ecosystems contribute about one-third.
	Overall, marine ecosystems contribute about two-thirds of global net primary production, and terrestrial ecosystems contribute about one-third.
	Satellite images reveal how unproductive tropical rain forests are on a per-unit-area basis.
	The primary production per unit area of the open ocean is greater than that of any other single ecosystem.
	A forest with large trees is apt to have more primary production than most grassland, which tends to lack large vegetation.

	Without iron, eukaryotic phytoplankton populations fall because they cannot convert atmospheric N2 to nitrogenous minerals.
	In the presence of too much iron, eukaryotic phytoplankton populations fall because they cannot convert atmospheric N2 to nitrogenous minerals.
	Iron stimulates the growth of cyanobacteria, which convert atmospheric N2 to nitrogenous minerals, stimulating the growth of phytoplankton.
	Iron halts the growth of cyanobacteria, which convert atmospheric N2 to nitrogenous minerals; therefore, phytoplankton populations are limited.
	Nitrogen and phosphorus are the only known limiting nutrients in marine ecosystems.

	a diminished supply of nitrates and phosphates
	industrial poisons
	nutrient enrichment such as nitrate and phosphate runoffs from land
	an increase in predators
	none of the above

	primary production
	secondary production
	production efficiency
	assimilation of primary production
	This question cannot be answered without knowing at which trophic level the organism feeds.

	80% gain of energy
	2% gain of energy
	80% loss of energy
	2% loss of energy
	5% loss of energy

	Its size depends on the energy available from detritivores.
	It contains the energy left after the producers have died.
	It represents the energy available to secondary consumers.
	It contains the energy captured by photosynthesis.
	It receives energy from the primary, secondary, and tertiary consumers.

	producers
	herbivores
	primary consumers
	tertiary consumers
	secondary consumers

	organisms are inefficient at converting the energy they consume into biomass
	biomass shrinks as it rises
	top-level predators use so much energy to catch their food
	producers (for example, plants) tend to be heavier than consumers (for example, birds)
	most of the solar energy hitting Earth is reflected or re-radiated into space

	Plants have defenses against herbivores.
	Intraspecific competition can limit herbivore numbers.
	Abiotic factors limit herbivores.
	Energy supply, not nutrients, usually limits herbivores.
	Interspecific interactions check herbivore densities.

	oceans
	rivers
	soil
	wind
	the atmosphere

	Over land, evaporation exceeds transpiration and precipitation.
	Over land, evaporation and transpiration exceed precipitation.
	Over oceans, transpiration exceeds precipitation.
	Over oceans, evaporation exceeds precipitation.
	Most of Earth's water can be found in living systems.

	from the oceans to land
	from land to the oceans
	from polar to tropical regions
	from tropical to polar regions
	from unforested to forested biomes

	Organisms do not need very much carbon.
	Plants can make their own carbon using water and sunlight.
	Plants are much better at absorbing carbon from the soil.
	Many nutrients come from the soil, but carbon comes from the air.
	Symbiotic bacteria help plants capture carbon.

	return of CO2 to the atmosphere by microbial respiration in soils
	assimilation of atmospheric CO2 by plant photosynthesis
	return of CO2 to the atmosphere by animal and plant respiration
	breakdown by decomposers of carbon-containing dead plants and animals
	All of the above processes are key parts of the carbon cycle.

	photosynthesis
	respiration
	ammonification
	phosphorylation
	evaporation

	water
	nitrogen
	carbon
	phosphorus
	energy

	NH4+
	NO2-
	NO3-
	NH3
	N2

	It requires different types of bacteria.
	Plants can take in and use atmospheric nitrogen through their leaves.
	Nitrogen needs to be cycled through living organisms.
	When plants and animals die, the nitrogen within their bodies is recycled.
	Nitrite is converted to nitrate (NO3-) by nitrifying bacteria.

	atmospheric
	organic
	mineral
	aquatic
	organic and gaseous

	the mineral levels were unaffected as long as the tree remains were not removed
	primary production was not affected as long as Ca2+ was added to the soil
	the forest was able to grow back before mineral levels changed significantly
	the amount of nutrients leaving an intact forest ecosystem is controlled by the plants
	none of the above

	use of nitrogen fertilizers
	increased cultivation of legumes
	deliberate burning of fields
	The first and third answers are correct.
	The first, second, and third answers are correct.

	The water in these areas is acidic to begin with.
	The lakes tend to have relatively poor buffering capacity.
	The wildlife in these areas tends to be more sensitive to change in pH.
	Other types of industrial pollution tend to magnify the effects of acid rain.
	Environmental regulations have not reduced the levels of sulfur dioxide emissions in these areas.

	Cyanobacteria ... many of these compounds prevent nitrogen fixation
	Phytoplankton ... many of these compounds halt photosynthesis
	Primary consumers ... they consume primary producers containing the compounds
	Top-level carnivores ... the biomass at any given trophic level is produced from a larger biomass ingested at the level below
	Herbivores ... plants tend to store these toxic compounds in large quantities.

	C4 crops, such as corn, being replaced by more C3 plants such as wheat and soybeans
	rising global temperature
	increased breakdown of atmospheric ozone
	increased vegetative productivity
	coastal flooding

	harmful in the upper atmosphere
	beneficial in the upper atmosphere
	beneficial in the lower atmosphere
	harmful in the upper atmosphere and beneficial in the lower atmosphere
	beneficial in both the upper atmosphere and the lower atmosphere

	increasing levels of CO2 in the atmosphere
	destruction of tropical rain forests
	release of chlorofluorocarbons (CFCs) into the atmosphere
	decrease in the production of ozone precursors by chemical production plants
	global warming