4.4 Human influences on the environment

Question 1

deforestation

Answer 1

removal of trees to use the resources on the tree for fuel or for space that the trees occupy

Question 2

eutrophication

Answer 2

pollution of water by fertilisers being added in nearby land and nutrients leaching into the water causing excessive growth of algae on the surface of the water
which prevents light reaching photosynthetic plants at the bottom of the water
causing them to die
reducing the oxygen levels in the water and eventually resulting in the death of all aerobic organisms in the water

Question 3

global warming

Answer 3

rise in average temperatures on the earth due to increased levels of greenhouse gases like carbon dioxide
causing the enhanced greenhouse effect where more heat is trapped in the atmosphere and once reflected of the surface is reflected back into the surface rather than escaping

Question 4

greenhouse gases

Answer 4

gases in the earth’s atmosphere that trap heat and cause the greenhouse effect, examples being water vapour, carbon dioxide, methane, nitrous oxide and CFCs

Question 5

leaching

Answer 5

movement of nutrients
e.g. nitrates in the soil into lakes and rivers due to rain and can lead to eutrophication

Question 6

pollution

Answer 6

contamination or destruction of the environment due to human impacts