Stages of the carbon cycle

Question 1

what are the stages of the carbon cycle

Answer 1

1. combustion
2. respiration
3. photosynthesis
4. decay
5. fossilisation
6. ingestion
7. assimilation
8. egestion

Question 2

combustion

Answer 2

stage 1 - burning
- increases CO2
- fossil fuels (coal, oil, petrol)

fuel + oxygen -> carbon dioxide + water

Question 3

respiration

Answer 3

stage 2 - increases CO2
- animal, plants, fungi

Question 4

photosynthesis

Answer 4

stage 3 - decreases CO2
- plants (+ algae)

Question 5

decay

Answer 5

stage 4 - increases CO2 due to decomposers respiring

Question 6

fossilisation

Answer 6

stage 5 - dead organic material that does not decay

dead organic material ——> fossil fuels

Question 7

ingestion

Answer 7

stage 6 - eating a starch / fat meal

Question 8

assimilation

Answer 8

stage 7 - uptake and use of glucose by body cells

Question 9

egestion

Answer 9

stage 8 - removal from the body of undigested food (fibre = cellulose)

Question 10

Summary of carbon cycle

Answer 10

• carbon is found in the atmosphere as carbon dioxide
• carbon in fixed into complex organic. compounds by plants during photosynthesis
• carbon in producers is passed onto consumers by feeding
• carbon is passed up the trophic levels of the food chain by ingestion
• when producers or consumers die or animals excrete organic waste, the complex molecules are decayed by the decomposers: fungi and bacteria
• decomposers are saprophytic feeders so they externally digest food
• producers, consumers and decomposers release co2 into the air during respiration
• if dead organisms or detritus are under extreme temp. or pressure, decay does not occur
• organic compounds converted into fossil fuels during fossilisation
• when fuels are combusted, they release methane