Biology Human influences on the environment

What are the biological consequences of pollution of air by sulphur dioxide and by carbon monoxide?

Acid raid forms in sky and damages environment by:

• Acidification of lakes - kills bacteria, algae and fish

• Disrupts food webs in ecosystems

• Kills conifer trees

• Acidifies the soil - leaches out important minerals and damages root hairs of plants, stunting their growth

What is a greenhouse gas?

A green house gas is a gas that traps the sun’s infrared radiation in the earth’s atmosphere

Name 5 green house gases

CO2, Methane, CFC’s, Water vapour, nitrous oxide

How do humans contribute to greenhouse gases?

Humans burn fossil fuels which release CO2 into the atmosphere and sulphur and nitrous oxides

How does an increase of greenhouse gases lead to global warming?

If there are more green house gases in the atmosphere, more of the Sun’s infrared radiation will be trapped inside the Earth’s atmosphere and in consequence heats up the Earth’s temperature

Global warming consequences

• Melts the ice caps, rises sea levels

• more frequent natural disasters

• disrupt ecosystems

• alter weather patterns

• impact biodiversity

What are the biological consequences of pollution of water by sewage?

• provides a good source of food for bacteria

• as they respire aerobically, the oxygen depletes

• leads to death of many aquatic life as there is an insufficient supply of oxygen

What are the biological consequences of eutrophication?

• caused by leached minerals from fertiliser

• excessive nutrients from fertilser cause the aquatic plants to grow rapidly

• Algae however also grows rapidly on the surface of the water, and blocks the sunlight and oxygen from entering the water

• Death of organisms that require oxygen dissolved in water

What are the biological effects of deforestation?

• soil erosion occurs as no roots to anchor the soil

• disturbance of evapotranspiration - too much water in soil

• More CO2 in atmosphere, less O2

• Contributes to global warming