APES Unit 1 Review - The Living World

Front

What is the term for a symbiotic relationship that benefits both organisms involved?

Back

Mutualism

Front

In a food chain or food web, what does the direction of the arrows indicate?

Back

The direction of energy flow (upward).

Front

What is the process called that converts nitrogen from the atmosphere into organic compounds?

Back

Nitrogen fixation.

Front

Which process in the nitrogen cycle involves plant roots absorbing ammonium and nitrate ions?

Back

Assimilation.

Front

What is the chemical formula for ammonia?

Back

NH₃.

Front

What is the role of decomposers in an ecosystem?

Back

Decomposers break down dead organic matter, recycling nutrients back into the soil.

Front

Define the term 'trophic level' in an ecosystem.

Back

A trophic level is a position in a food chain or food web, representing the flow of energy and nutrients.

Front

What is the significance of nitrogen-fixing bacteria in the nitrogen cycle?

Back

They convert atmospheric nitrogen into forms usable by plants.

Front

Explain the process of denitrification in the nitrogen cycle.

Back

Denitrification is the process by which bacteria convert nitrates back into nitrogen gas, returning it to the atmosphere.

Front

What is the difference between autotrophs and heterotrophs?

Back

Autotrophs produce their own food (e.g., plants), while heterotrophs consume other organisms for energy.