The Carbon Cycle Flashcards
Describe the movement of carbon through the carbon cycle.
Carbon is absorbed by plants when they carry out photosynthesis- it becomes carbon compounds in plant tissues.
Carbon is passed on through the food chain by feeding.
All living organisms die and are broken down by microorganisms called decomposers.
Decomposers secrete enzymes onto dead organic materials to digest the carbon compounds in them.
They then absorb the products of digestion.
Carbon is returned to the air and water as all living organisms carry out respiration.
Some dead organic matter is fossilised- produces fossil fuels eventually.
What is the process of feeding dead organic matter called?
Saprobiontic nutrition.
Explain why carbon dioxide concentration is greater at night during the day?
Respiration occurs during the day and night whereas photosynthesis only occurs during the day.
What is global warming?
An increase in average global temperature over the last century.
Explain the link between an increase in carbon dioxide concentration in the atmosphere and global warming.
Carbon dioxide is a greenhouse gas, which absorbs outgoing energy from the earth so less is lost to space.
An increase in carbon dioxide conc. in the atmosphere means more energy is absorbed and re-radiated back to earth.
Describe one human activity that is:
a) increasing atmospheric carbon dioxide concentration.
b) increasing atmospheric methane concentration.
a) Burning fossil fuels/deforestation
b) Fossil fuel extraction/ cattle farming
The concentrations of carbon dioxide in the air at different heights above ground in a forest changes over a period of 24 hours. Use your knowledge of photosynthesis to describe these changes and explain why they occur.
High concentration of carbon dioxide is linked with darkness;
Because photosynthesis cannot occur in darkness;
In light plants use more carbon dioxide than they produce - rate of photosynthesis greater than rate of respiration;
There is a decrease in carbon dioxide concentration with height;
At ground level there is less light and so less photosynthesis (so more CO2)
