Cycles within the Ecosystems Flashcards
What are the four main processes of the carbon cycle?
- Respiration
- Photosynthesis
- Decomposition
- Combustion
Explain the role of respiration in the carbon cycle (2)
- Plants and animals aerobically respire, releasing CO2 into the air
- Decomposers respire while they break down compounds
Explain the role of photosynthesis in the carbon cycle
- Plants remove CO2 from the air through photosynthesis
Explain the role of decomposition in the carbon cycle (2)
- Dead plants and animals are broken down by decomposers
- The carbon is then returned into the atmosphere
Explain the role of combustion in the carbon cycle
- When plants and fossil fuels are burnt, the CO2 is released into the atmosphere
Why is nitrogen (found in the atmosphere) hard to break? (2)
- Has a triple covalent bond (unreactive)
- Needs a lot of energy to convert it into something useful
What are the four main components of the nitrogen cycle?
- Nitrogen-fixing bacteria
- Denitrifying bacteria
- Lightning
- Nitrifying bacteria
Where can nitrogen-fixing bacteria be found? (2)
- Root nodules
- Free living
What does nitrogen-fixing bacteria do?
It converts nitrogen gas into nitrates
What does lightning do?
It converts nitrogen gas in the atmosphere to different oxides of nitrogen
What does nitrifying bacteria do?
It converts ammonia into nitrites then nitrates
What are nitrates used for? (3)
- Proteins in plants, animals and dead matter
- They are absorbed by plants through active transport
- They are assimilated into DNA and amino acids
What does denitrifying bacteria do?
It converts nitrates back into nitrogen gas (completes the cycle - keeps things balanced)
What do decomposers do?
They break down the protein in dead matter into ammonia
