Using nitrogen and returning it
Assimilation and ammonification.
From soil to plate and back
A plant takes nitrogen compounds from the soil. A goat eats the plant. Later, the goat's waste goes back to the soil.
What happens to the nitrogen in the waste?
What this lesson covers
The idea
Plants assimilate nitrogen compounds from the soil and animals obtain nitrogen by eating plants or other animals; decomposers break down dead organisms and wastes, returning ammonia to the soil (ammonification).
From soil to plate and back
A plant takes nitrogen compounds from the soil. A goat eats the plant. Later, the goat's waste goes back to the soil.
What happens to the nitrogen in the waste?
- Decomposers return it to the soil as ammonia
- It disappears
- It becomes oxygen
Plants, animals, decomposers
Press Next step.
Taken up, handed on, returned
Plants take in nitrogen compounds, animals get nitrogen from food, and decomposers give nitrogen compounds back to the soil. Then the soil can supply plants again.
Plants assimilate nitrogen compounds from the soil and animals obtain nitrogen by eating plants or other animals. Decomposers break down dead organisms and wastes, returning ammonia to the soil (ammonification).
Notes
Plants assimilate nitrogen compounds from soil; animals eat plants or animals; decomposers break down dead matter and wastes, returning ammonia to the soil (ammonification).
Check yourself
How do plants get nitrogen?
How do animals obtain nitrogen?
Which organisms break down dead organisms and wastes, returning nitrogen compounds to the soil?
What is the return of ammonia to the soil by decomposers called?
- They take in nitrogen gas, N₂, from the air directly. N₂ is non-reactive and cannot be used directly by plants and animals.
- They assimilate nitrogen compounds from the soil — correct. Yes!
- They eat animals. Plants assimilate nitrogen compounds from the soil.
- By absorbing nitrogen compounds from the soil. Plants assimilate compounds from the soil. Animals obtain nitrogen by eating plants or other animals.
- By breathing in N₂. N₂ is non-reactive and cannot be used directly by animals.
- By eating plants or other animals — correct. Yes!
- Decomposers such as bacteria and fungi — correct. Yes!
- Nitrogen-fixing legumes. Rhizobium bacteria in legumes fix nitrogen. Decomposers return nitrogen compounds from dead organisms and wastes.
- Plants. Plants assimilate nitrogen compounds from the soil.
- Nitrification. Nitrification is the conversion of ammonia to nitrite and then nitrate.
- Ammonification — correct. Yes!
- Denitrification. Denitrification converts some nitrates back into nitrogen gas.