Like this study set? Create a free account to save it.

Sign up for an account

Already have a Quizlet account? .

Create an account

Only 10% of the energy stored in an organism can be passed on to the next trophic level. Of the remaining energy (90%), some is used for the organisms' life processes, and the rest is:

eliminated as heat

carbon cycles through the biosphere in all of the following processes except:


what are the combined portions of Earth called in which all living things exist?


which one of the following is not a basic method used by ecologists to study the living world?


Green plants are:


an organism that cannot make its own food is called a(n)


Organisms that obtain nutrients by breaking down dead and decaying plants and animals are called:


what is an organism that feeds only on plants called?


all the interconnected feeding relationships in an ecosystem make up a food


which type of pyramid shows the amount of living tissue at each trophic level in an ecosystem?

a biomass pyramid

the repeated movement of water between Earth's surface and the atmosphere is called:

the water cycle

nitrogen denitrification is carried by:


the rate at which organic matter is created by producers in an ecosystem is called:

primary productivity

what is nitrogen fixation?

converting nitrogen to ammonia

what is the right order from the smallest to the largest part of an ecosystem?

individual, population, community, ecosystem, biome, biosphere

in the diagram below, which one is a 2-level consumer (plants to mouse to fox to water)


all the biotic and abiotic factors in a pond form a(n):


a form of symbiosis in which both organisms benefit is called:


natural disturbances, such as fires and plowing a land, can result in:

secondary succession

a relationship in which one organism is helped and another organism is neither helped nor hurt is called:


a type of symbiosis in which one organism benefits and the other is harmed is called:


all of life on earth exists in a region known as:

the biosphere

autotrophs are organisms that:

use energy they take in from the environment to convert inorganic molecules into complex organic molecules

the series of steps in which a large fish eats a small fish that has eaten algae is a:

food chain

which of the following organisms is a decomposer? bacteria, bird, plant, or dog


the total mass of living tissue at each trophic level can be shown in a(n):

biomass pyramid

Nutrients move through an ecosystem in:

biogeochemical cycles

in the nitrogen cycle, bacteria that live on the roots of plants:

change nitrogen gas into ammonia

which biogeochemical cycle does not involve a state where the chemical enters the atmosphere?

limiting nutrient

when an ecosystem is limited by a single nutrient that either is scarce or cycles very slowly, this substance is called a(n):

limiting nutrient

what is the definition of ecology?

the scientific study of interactions among organisms and between organisms and their environment, or surroundings.

name the different levels of organization within the biosphere, from smallest to largest.

individual, population, community, ecosystem, biome, biosphere

how do scientists use modeling to study ecological changes?

ecologists make models to gain insight into complex phenomena such as the effects of global warming on ecosystems.

how is sunlight important to most ecosystem?

it is the main energy source for life on earth

what is chemosynthesis?

when organism use chemical energy to produce carbohydrates.

distinguish between autotrophs and heterotrophs. give an example of each.

autotrophs are plants only, capture energy from sunlight or chemicals and use that energy to produce food. heterotrophs is organisms that rely on other organisms for their energy and food supply.

what is a decomposer? provide an example.

it is an organism that breaks down and obtains energy from the dead organic matter. fungus and bacteria are example.

which group of organisms is always found at the base of a food chain or food web? why?

producers (autotrophs) is the only group able to give food to animals/people/food.

why is the transfer of energy and matter in a food chain only about 10 percent efficient?

because organisms use the energy they obtain for their life processes, about 90 percent so they only pass on 10 percent, because they need the 90 percent to survive.

what is a biogeochemical cycle?

element, chemical compounds, and other forms of matter are passed from one organism to another. It is a cycle when one part of the biosphere is transfered to another.

Explain the process of nitrogen fixation.

bacteria, which lives in soil and roots of plants called legumes convert nitrogen gas into ammonia in a process called nitrogen fixation.

what is the denitrification?

it is when other soil bacteria convert nitrates into nitrogen gas.

briefly, explain the carbon cycle


what is meant by "nutrient limitation"?

it is when an ecosystem is limited by a single nutrient that scarce or cycles very slowly, this substance is called a limiting nutrient.

ecogologists discovered that trout were dying in a stream that ran through some farmland where nitrogen fertilizer was used on the crops. how might you explain what happened?

the nutrient spread so quickly and there was too much of nutrients. the trout couldn't get some oxygen (Algae Bloom)

classify each of the following as an herbivore, a carnivore, an omnivore, or a detritivore: earthworm, bear, cow, snail, owl, human.


native americans taught european settlers to bury pieces of fish with the seeds of corn they planted. why might this practice ensure a good harvest?

the fish would decompose, releasing the nutrients to the plants.

what is the difference between an organisms' habitat and its niche?

habitat is where it lives. Niche is how it lives.

Water Cycle: the processes happening inside the cycle

Ocean > Evaporation + Transpiration > Condensation > Precipitation > runoff > transpiration and start the cycle again or seepage > root uptake > transpiration or ocean then cycle starts again.

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

Voice Recording