ECOLOGY AND ENVIRONMENT - Carbon cycle

Question 1

DESCRIBE THE STAGES IN THE CARBON CYCLE

Answer 1

1. carbon taken out of atmosphere as (CO2) by plants through photosynthesis
2. passed on to animals by feeding
3. returned to atmosphere as (CO2) by plants, animals + microorganisms as a result of RESPIRATION.
4. Animals feed on plants, passing carbon along food chain.
5. Most of carbon they consume is exhaled as CO2 during anaerobic respiration.
6. Animals + plants eventually die
7. Decomposers break down dead organisms + return carbon in their bodies to atmosphere as CO2 by respiration.

Question 2

What happens if animals + plants die in conditions where there are NO decomposers?

Answer 2

carbon in their body is converted over million of years + pressure into FOSSIL FUELS

Question 3

What happens when fossil fuels are burned?

Answer 3

COMBUSTION
carbon combines with oxygen
CO2 RELEASED INTO ATMOSPHERE

Question 4

Consequences of pollution by water sewage

Answer 4

untreated sewage in water provides SOURCE OF FOOD FOR DECOMPOSING BACTERIA.

• quickly increase in number + use up O2 in water for aerobic respiration
• therefore there´s less O2 in water so aquatic organisms die

Question 5

What happens if sewage IS treated before entering water?

Answer 5

lots of O2 is provided by stirring waste or injecting compressed air
- (allows microorganisms to break down waste COMPLETELY before treated water discharged into river or sea)

Question 6

Describe the process of eutrophication

Answer 6

1. fertilisers + liquid nutrients get washed into water
2. ALGAE BLOOM - algae grows rapidly (blocks sunlight)
3. plants below water surface die
4. O2 levels drop as microbes feed on dead plants
5. fish + invertebrates die from lack of O2

Question 7

How can eutrophication be reduced?

Answer 7

• less fertiliser
• use organic fertiliser
• no fertiliser in rainy seasons
• reduced fertilisers near bodies of water

Question 8

biological consequences of pollution of air by sulphur dioxide

Answer 8

Sulphur dioxide combines with O2 from combustion of fossil fuels forming SULFUR TRIOXIDE
- sulphur trioxide dissolves in water droplets in clouds + forms ACID RAIN

Question 9

What are the consequences of acid rain?

Answer 9

1. leaches minerals + nutrients out of soil (causing plants and trees to die)
2. damages waxy cuticle of leaves
3. makes river too acidic (death of aquatic organisms)

Question 10

biological consequences of pollution of air by carbon monoxide

Answer 10

CO produced when fossil fuels burn in limited amount of air

Question 11

What are the consequences of production of CO?

Answer 11

1. binds to haemoglobin in red blood cells (reduces amount of O2 able to be carried in blood)
2. Exposure leads to tiredness
3. Long exposure leads to unconciousness or death
4. Exposure when pregnant causes disruption of growth + development of foetus (lesss O2 available in blood for respiration)