Carbon Cycle And Human Influences On The Environment

Question 1

Carbon cycle

Answer 1

Describes the movement of carbon molecules in the environment

Question 2

Respiration in carbon cycle

Answer 2

All living organisms will respire aerobically and release carbon dioxide into the atmosphere as organic compounds that are broken down to release energy

Question 3

Photosynthesis

Answer 3

Fixes carbon atoms from atmospheric carbon dioxide into organic molecules and becomes part of complex carbon compounds in plants

Question 4

Decomposition

Answer 4

Dead organisms are broken down by decomposers and carbon in their bodies are returned to the atmosphere as carbon dioxide

Question 5

Combustion

Answer 5

If decomposition is blocked, plant and animal material are available as fossil fuels after a long period of time

Question 6

Biological consequences of pollution of air by sulfur dioxide and carbon monoxide

Answer 6

Carbon monoxide is a product of incomplete combustion. When humans breathe it in, it binds with the haemoglobin in red blood cells to create carboxyhemoglobin instead of oxyhemoglobin. To much carboxyhemoglobin in the body can lead to carbon monoxide poisoning.
-Sulfur dioxide dissolves in the water vapour in the air to create sulfuric acid, which normally has a low pH. This cause acid rain which can be damaging to ecosystems and to humans when consumed

Question 7

Greenhouse gases

Answer 7

Water vapour, carbon dioxide, nitrous oxide, methane and CFC’s because they prevent heat from escaping the earth trough the atmosphere

Question 8

How human activities contribute to greenhouse gases

Answer 8

Water vapour: is produced through transpiration and evaporation
Carbon dioxide: is produced when fossil fuels are burnt and when trees are cut down
NO: Are produced when car engines get hot enough for nitrogen to chemically bond with oxygen
Methane: Is produced from rotting plants, growing rice and cow farts
CFC’s: Are manmade chemicals that were once used to make aerosol sprays and fridges, they damage the ozone layer, and CFC’s still heak from old fridges

Question 9

Increase in greenhouse gases had greenhouse effect

Answer 9

When additional greenhouses gases are added to the atmosphere, the greenhouse effect is enhanced. These gases reflect the heat back to the earth’s surface, which increases the general temperature as well as melting polar ice caps. This results in an increase in sea level which, along with the increased temperature, causes more evaporation. More evaporation means more rain, which leads to natural disasters such as typhoons and hurricanes

Question 10

Biological consequences of pollution of water by sewage

Answer 10

-sewage contains phosphates from detergents
-urine and faeces contain nitrates.
When sewage, urine, and faeces are released into bodies of water, eutrophication occurs.

Question 11

Biological consequences of eutrophication caused by leached minerals from fertiliser

Answer 11

1. Nitrates and phosphates from fertilizers leech into water when it rains, they speed up the growth of algae on the pond surface
2. More algae on the pond surface prevents plants in the deep from getting sunlight for photosynthesis-they die.
3. Decomposers break down the dead plants and this releases carbon.
4. Decomposers increase in number because of increased food supply and they use up all the oxygen in the water for respiration
5. Fish die from lack of oxygen- tertiary consumers are also affected by lack of food