14-5 What is the nitrogen cycle?
Aim: What is the nitrogen cycle?
OBJECTIVE: Explain the nitrogen cycle.
Key Terms
nitrogen fixation: process of combining nitrogen with other elements to make usable compounds
nitrogen cycle: repeated movement of nitrogen compounds between the atmosphere, the soil, and
living organisms
Lesson Summary
• The process of combining nitrogen with other elements in order to make usable compounds is called
nitrogen fixation.
• When decomposers break down animal wastes, ammonia is released. The ammonia is turned into
nitrates again and returned to the soil for reuse.
• The nitrogen cycle is the using and reusing of nitrogen in an ecosystem.
OBJECTIVE: Explain the nitrogen cycle.
Key Terms
nitrogen fixation: process of combining nitrogen with other elements to make usable compounds
nitrogen cycle: repeated movement of nitrogen compounds between the atmosphere, the soil, and
living organisms
Lesson Summary
• The process of combining nitrogen with other elements in order to make usable compounds is called
nitrogen fixation.
• When decomposers break down animal wastes, ammonia is released. The ammonia is turned into
nitrates again and returned to the soil for reuse.
• The nitrogen cycle is the using and reusing of nitrogen in an ecosystem.