Human influences on the environment

explain the biological consequences of carbon monoxide in the air

• binds to haemoglobin in the blood.

• prevents blood from transporting oxygen around the body.

how is carbon monoxide produced?

• when fossil fuels are burnt without enough air supply, carbon monoxide gas is formed.

• comes from exhaust fumes, caused by burning petrol.

how is sulfur dioxide/acid rain produced?

• produced from burning fossil fuels.

• sulfur dioxide dissolves in water in the atmosphere and forms sulfuric acid.

• falls as acid rain

explain the consequences of sulfur dioxide on freshwater lakes

• lakes very acidic

• affects successful reproduction of fish.

• fish produce sticky mucus on their gills, making gas exchange difficult.

• lack of microscopic algae and plants.

explain the consequences of sulfur dioxide on plant life

• acidity in soil interferes with roots ability to uptake mineral ions from the soil.

explain the consequences of sulfur dioxide on buildings

• acid reacts with calcium carbonate in the stone.

• dissolves the surface layers.

pollution

introduction of harmful of poisonous substances into the environment.

name 5 greenhouse gases

1. water vapour

2. carbon dioxide

3. nitrous oxide

4. methane

5. CFCs (chlorofluorocarbons)

explain how human activities have caused an increase in carbon dioxide

1. burning fossil fuels in cars, factories

2. deforestation - removal of trees upsets balance between respiration and photosynthesis. carbon dioxide increases.

explain how human activities have caused an increase in methane

1. farming cattle - digestion in ruminants produces methane as a waste product.

2. rice paddy fields - methane produced by bacterial activity in wet anaerobic conditions.

3. decay of waste materials - anaerobic decay of waste produces methane, which leak from landfill sites.

explain how human activities have caused an increase in CFCs

1. aerosol cans

2. refrigerators

3. air conditioning

explain how human activities have caused an increase in nitrous oxide

1. burning fossil fuels - exhaust from car contains nitrous oxide. (catalytical converters converts nitrous oxide to nitrogen dioxide)

2. nitrogen fertilizers - nitrates in soil/fertilizers converted by denitrifying bacteria to nitrous oxide.

what is the effect of an increase in greenhouse gases?

1. melting of ice in glaciers/polar regions

2. increased volume of water in oceans

3. changes in distribution of plants/animals

4. more extreme weather patterns

The Greenhouse Effect

1. Gases in Earth’s atmosphere absorb heat from sun that would otherwise be radiated into space. (This stops the earth getting too cold)

2. however, increase in carbon dioxide has enhanced the greenhouse effect.

3. earth is heating up (global warming).

4. causes extreme weather, rising sea levels, habitat loss etc.

explain the biological consequences of the pollution of water caused by sewage

1. sewage = metal ions, nitrates and phosphates.

2. sewage released into freshwater.

3. microorganisms in sewage breakdown organic matter found in sewage.

4. releases more nutrients.

5. causes rapid growth of algae

6. lack of oxygen = fish die

Eutrophication

the enrichment of minerals in water

explain the biological consequences of leached minerals from fertilizer

1. added minerals in water causes mass algal bloom - eutrophication

2. algae respires and there’s a lack of oxygen

3. fish kill occurs

explain the effects of deforestation

forests take up CO2 by photosynthesis, store it in wood, and slowly release the CO2 when they decompose…

1. trees cut down and burnt = stored CO2 released at once.

2. fewer trees = less photosynthesis and less oxygen.

explain the effects of leaching

1. trees take up nutrients from soil before they are leached (washed away) by rain.

2. when trees are cut down, nutrients get washed away, leaving infertile soil.

explain the effects of soil erosion

1. tree roots hold soil together.

2. lack of trees = soil washed away

3. infertile soil

explain the effects of disturbing evapotranspiration

evapotranspiration is the process of water evaporating from the earth’s surface, and plant transpiration…

1. water falls back to earth as rain

2. when trees are cut down, evapotranspiration is reduced.

3. makes climate drier.