Paper 1 - Human Influences

Question 1

What is the biological consequence of water pollution by sewage?

Answer 1

• Faeces and urine contain high levels of nitrates which cause algae to bloom
• Algae blocks out sunlight causing other plants to die because they cannot photosynthesize
• Dead plants are broken down by decomposing bacteria which aerobically respirate and take up all O2 in the water
• Fish cannot aerobically respire
• Causing fish to die

Question 2

What are the biological consequences of habitat destruction?

Answer 2

• Increase in extinction rate
• Decrease in biodiversity

Question 3

What are water vapour, CO2, NOx, Methane and CFC’s all examples of?

Answer 3

Greenhouse gases

Question 4

How do human activities contribute to greenhouse gases?

Answer 4

• Burning fossil fuels creates acid rain
• Burning petrol/diesel creates carbon monoxide
• Overfarminmg of cow produces methane
• Deforestation reduced the earth’s ability to take in CO2

Question 5

How can an increase in greenhouse gases result in an enhanced greenhouse effect?

Answer 5

• Heat radiation strikes the planet’s surface and is reflected
• Radiation hits layer of greenhouse gases
• Heat is trapped by greenhouse gases and is reflected back into earth

Question 6

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

Answer 6

Sulphur Dioxide
- Sulphur dioxide reacts with water in the air to make acid rain
- Acid rain falls and kills trees, increases the pH of lakes, rivers and soil which kills fish and plants, damages buildings

Carbon Monoxide
- Binds irreversible with haemoglobin in red blood cells so red blood cells cannot carry any oxygen for respiration
- Causes fainting, comas or even death