How Ecosystems Work

_______________ uses carbon dioxide, water, and energy to produce sugars and oxygen.

• trophic level

• carbon cycle

• photosynthesis

• decomposers

Each step through which energy is transferred in a food chain is known as a ________________________.

• trophic level

• carbon cycle

• decomposers

• nitrogen-fixing bacteria

Organisms add carbon to the _________________ during cellular respiration.

• photosynthesis

• trophic level

• carbon cycle

• water cycle

______________________ can fix atmospheric nitrogen into a useful form called ammonia.

• Trophic level

• Photosynthesis

• Nitrogen Cycle

• Nitrogen-fixing bacteria

_____________________ break down dead organic matter.

• Photosynthesis

• Decomposers

• Primary Consumers

• Producers

A _________________ is an organism that makes its own food.

• Producer

• Consumer

• Primary Consumer

• Tertiary Consumer

A _____________________ is an organism that gets its energy by eating other organisms.

• Producer

• Consumer

• Primary Consumer

• Tertiary Consumer

_____________________ is a type of succession that occurs on a surface where no ecosystem existed before. _____________________ occurs on a surface where an ecosystem has previously existed.

• Primary succession, Secondary succession

• Secondary succession, Primary Succession

A______________ is a sequence in which energy is transferred from one organism to another. A _____________ is made up of many food chains and shows the possible feeding relationships in an ecosystem.

• food web, food chain

• food chain, food web

Which of the following statements is not true of consumers?

• They get energy indirectly from the sun

• They are also called heterotrophs.

• They make their own food.

• They sometimes eat other consumers.