Human Impact on the Environment

Question 1

Describe eutrophication and how it is caused

Answer 1

Caused by algae blooms from fertilisers. These algae blooms block sunlight from reaching the aquatic plants lower down, which then die and are broken down by microorganisms. These microorganisms then use up all the oxygen in the water, causing the larger animals to suffocate.

Question 2

What is leaching and how is it made worse by inorganic fertilisers

Answer 2

Excess fertilisers are washed into the water systems and into lakes and rivers causing eutrophication. Inorganic fertilisers tend to be more soluble and so wash away more easily

Question 3

What is a biological oxygen demand and how is it measured

Answer 3

A measure of the amount of dissolved oxygen microorganisms used to break down decaying matter. The higher the BOD, the more polluted the water. It is measured in the dark to prevent photosynthesis from countering the correct figure

Question 4

What steps must farmers take to reduce leaching

Answer 4

Restricting the use of fertilisers
Only applying fertilisers while plants are growing
Dig drainage ditches
Leave a strip unfertilised near any water sources

Question 5

Name some effects of climate change

Answer 5

Rising sea levels
Glacier retreating
Mass species extinctions
Increased range of diseases
Extreme weather

Question 6

Name natural causes of global warming

Answer 6

Deforestation and combustion

Question 7

Name domestic causes of global warming

Answer 7

Use of fuel for transport and electricity for cooking/heating

Question 8

Name industrial causes of global warming

Answer 8

CO2 is widely released from factories as a by-product, and methane is released from farming

Question 9

Issues with monoculture farming

Answer 9

Growing a single crop on a large scale means shrubbery and hedges must be removed to make way for crops thereby reducing biodiversity

Question 10

Factors increasing the number of endangered species

Answer 10

loss of habitat
over hunting
deforestation
pollution
competition from alien species

Question 11

Steps taken to conserve species

Answer 11

Nature reserves
Captive Breeding programmes
Hunting bans
Global charities, WWF
Seed Banks

Question 12

Why does deforestation occur

Answer 12

Fuel
Farming
Houses
Paper and Packaging
Palm Oil

Question 13

Actions taken to reduce deforestation

Answer 13

Coppicing
Selective Cutting
Ecotourism
Long rotation time

Question 14

Solutions to overfishing

Answer 14

Exclusion Zones
Catch Quotas
Fishing Efforts limits

Question 15

Problems with fish farming

Answer 15

Relies on the use of pesticides
Disease spreads quickly
Food and biological waste causes eutrophication

Question 16

Advantages and disadvantages of biofuel

Answer 16

Advantages - Renewable, cheaper than petrol, can be manufactured from a wide range of sources

Disadvantages - Lower energy output, uses up agricultural land, uses up large amounts of freshwater

Question 17

Name the planetary boundaries

Answer 17

Climate Change
Biosphere Integrity
Land system change
Biogeochemical flows
Stratospheric ozone
Ocean Acidification
Fresh water use
Atmospheric aerosol loading
Novel Entities

Question 18

Climate change boundary

Answer 18

This boundary has been crossed because of the levels of greenhouse gases emitted in recent years

Question 19

Biosphere integrity (biodiversity) boundary

Answer 19

Core boundary that has been crossed because of high levels of habitat destruction, pollution, poaching and climate change

Question 20

Land system change boundary

Answer 20

(The way land is used) Deforestation for agriculture and housing

Question 21

Biogeochemical flow boundary

Answer 21

(Nitrogen/carbon cycle) Overuse of fertilisers as well as deforestation and combustion

Question 22

Stratospheric ozone boundary

Answer 22

We reversed crossing this boundary by banning CFCs which are responsible for causing the erosion of the ozone layer

Question 23

Ocean acidification boundary

Answer 23

pH has fallen by 0.1 causing issues for sensitive aquatic organisms, particularly those with calcium based shells

Question 24

Fresh water boundary

Answer 24

Overuse of fresh water causing diminished stocks in reservoirs. Caused by population increase, deforestation, climate change and water pollution

Question 25

Atmospheric aerosol loading boundary

Answer 25

Increased pollution of the air from fossil fuels and dust from quarries, worsening conditions like asthma and emphysema

Question 26

Novel entities boundary

Answer 26

Pollution from radioactive and nano materials. Some chemicals have been banned due to their toxicity such as DDT, and it can cause bioaccumulation

Question 27

What is bioaccumulation

Answer 27

Increase in concentration of pollutant in a single organism from the organisms it ingests

Question 28

What is biomagnification

Answer 28

Increase in concentration of a pollutant in an entire food chain

Question 29

What bacteria carry out decay

Answer 29

Saprophytes

Question 30

What are denitrifying bacteria called

Answer 30

pseudomonas

Question 31

What are nitrifying bacteria called ammonium -> nitrite

Answer 31

nitrosomonas

Question 32

What are nitrifying bacteria called nitrite -> nitrate

Answer 32

nitrobacter

Question 33

What are nitrogen fixing bacteria called

Answer 33

rhizobium