Human Influences on the Environment

Question 1

What are the biological consequences of the release of sulfur dioxide and nitrous oxides?

Answer 1

• Acid rain is caused
• It damages the leaves, buds, flowers and roots of trees and other plants
• It acidifies lakes and rivers, making them inhabitable for certain marine organisms
• It causes minerals to be leached out of the soil into lakes which are toxic such as aluminium causing the death of fish, or which are fertilisers causing eutrophication

Question 2

What are the biological consequences of the release of carbon monoxide?

Answer 2

• While it does not damage plant-life, it binds readily to the haemoglobin in animals (including humans), meaning the blood oxygen carrying capacity is reduced potentially causing suffocation or organ failure
• It also contributes to climate change

Question 3

What are the most important greenhouse gases?

Answer 3

• Water vapour
• Carbon dioxide
• Methane
• Nitrous oxides
• CFCs

Question 4

What are the consequences of global warming?

Answer 4

• Glacial melt - Increased sea levels and flooding
• Ocean acidification - Coral bleaching
• Extreme weather events - More frequent drouts and super storms
• Loss of biodiversity as habitats are lost, conditions become unsuitable for certain species and food chains are disrupted
• Increase in migration of species to new places causing the spread of pests and diseases

Question 5

What are the biological consequences of the pollution of water by toxic chemicals?

Answer 5

• Agricultural runoff can cause toxic chemicals to go into the water
• These chemicals, which cannot be easily broken down by organisms are absorbed by plants and invertebrates building up in their tissues overtime
• This is called bioaccumulation, and any predators who eat them will also ingest these compounds and levels of the chemicals will build up over time - eventually humans may eat the marine organisms and ingest the chemicals
• Eventually, the toxins will build up to dangerous levels within organisms, causing their death of failure to breed and disrupting food chains

Question 6

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

Answer 6

• Sewage provides a good food source and minerals for decomposing bacteria, which rapidly multiply and deplete the levels of oxygen dissolved in the water
• This lack of oxygen eventually results in the death of aquatic organisms - this is a form of eutrophication

Question 7

What are the biological consequences of eutrophication caused by leached minerals from fertilisers running into bodies of water?

Answer 7

• Excessive nutrients and minerals from fertilisers run in to the water
• Aquatic plants and algae flourish and bloom
• Algae blooms on the surface prevent light from reaching aquatic plants, causing the rate of photosynthesis to decrease and the oxygen levels to reduce
• The increase in dead plant matter causes an increase in aerobic respiration in decomposers, further causing levels of oxygen to fall
• As a resut of low oxygen levels, marine organisms will die

Question 8

What are the consequences of deforestation?

Answer 8

• Habitats are destroyed and biodiversity is decreased
• Soil is eroded due to the loss of stabilising roots, and all the nutrients that would otherwise have been used by trees are washed away by rain and leached into lakes and rivers causing eutrophication
• The loss of nutrients also makes it very hard for plant life to regrow in the area
• Less trees means less transpiration which causes lower levels of rainfall and drouts
• Finally, the carbon cycle is disrupted as less carbon dioxide is being taken out of the atmosphere by trees, causing increased levels of atmospheric carbon dioxide
• This, coupled with the burning of trees which also increases levels of carbon dioxide, contributes to climate change