C1: Human impact on the environment

Question 1

Define extinction

Answer 1

The total loss of a species

Question 2

Define endangered

Answer 2

A species at serious risk of extinction

Question 3

Name five reasons for extinction

Answer 3

Natural selection
Habitat destruction (deforestation )
Pollution (Higher CO2 in ocean means mollusc shells become softer)
Poaching
Competition from domestic animals

Question 4

Define conservation

Answer 4

Is the planned management of ecosystems to enhance and protect gene pools

Question 5

Name six conservation methods

Answer 5

Nature reserves and SSSI’s (sites of special scientific interest)are protected by law

Banned trades of endangered species and products

Captive breeding programmes in zoos and botanic gardens enhance species numbers

Sperm and seed banks preserve gene pools for the future

Reintroduction programmes

Fishing quotas

Question 6

why conserve gene pools ?

three reasons

Answer 6

Plants may provide medicines for the future

it is the ethical thing to do

reduced gene pools make species more vulnerable to extinction

Question 7

Define agricultural exploitation

Answer 7

Describes the need to increase the efficiency and intensity of food production to meet the increasing demands of a rapidly increasing human population.

Question 8

What is the conflict of agricultural exploitation

Answer 8

there is a conflict between the need for the conservation of species and the demand for increased food production. as methods of agricultural exploitation decrease biodiversity

Question 9

Why does agricultural exploitation decrease biodiversity

4 points

Answer 9

Removal of hedgerows - destroys habitats

Monocultures - reduce available niches

Use of insecticides, herbicides and fertilisers cause death of beneficial insects, niches and habitats and causes eutrophication

Ecosystem destruction to provide additional agricultural land

Question 10

define deforestation

Answer 10

The removal of trees to use as timber or fuel or to repurpose the land use for agriculture or building

Question 11

What are the consequences of deforestation

5 points

Answer 11

Soil erosion - It is not protected from rain by the canopy, as roots decompose they no longer hold the soil together so it is eroded by wind and rain.

Flooding - evaporation from soil removes less water than transpiration, waterlogging encourages denitrification and soil loses nitrates.

Habitat loss reduces biodiversity

Less photosynthesis means that less CO2 is removed from the atmosphere. CO2 is a ‘greenhouse gas’, increased CO2 leads to global warming and climate change.

Burning of cut down trees releases CO2 into the athmosphere, CO2 is a ‘greenhouse gas’, increased CO2 leads to global warming and climate change.

Question 12

What are some solutions to deforestation

3 points

Answer 12

Selective felling.

Replanting the correct mix of species, the correct distance apart, and allowing them to regenerate.

Protecting areas.

Question 13

Define overfishing

Answer 13

Is where fish are caught at a higher rate than they can reproduce and grow ( fished at a biological unsustainable level) to the point where increased fishing efforts lead to declining catches.

Question 14

What are the consequences of overfishing on fish stocks

3 points

Answer 14

Fish populations may be reduced in size to the extent that they lose genetic diversity.

Size of fish caught is reduced as they don’t have time to grow.

Fish population has fewer individuals and cannot replace harvested fish.

Question 15

Name five solutions to overfishing

Answer 15

Quotas - max amount of fish that can be harvested

Restricted fishing seasons - to allow fish to reproduce

Exclusion zones - prevents fish in selected areas

Legislation - limits size of fishing fleets and mesh size to allow small fish to escape and grow to breeding size

Fish farming

Question 16

Define fish farming

Answer 16

Is where fish are intensively reared in ponds/tanks or nets; sea-fish are usually reared in large netted areas of the sea. This is one solution to over-fishing

Question 17

Two Positives of fish farming

Answer 17

Less fish need to be harvested from the Wild, allowing fish stocks to replenish

Fish have been selected for high growth rates and therefore have large sizes and therefore there is an increased yield

Question 18

Five negatives of fish farming

Answer 18

Toxic waste can cause eutrophication

Parasites and diseases spread quickly through the overcrowded fish

Antibiotic use may lead to antibiotic resistance and using pesticides to control parasites will harm marine invertebrates

If farmed fish escape they could outcompete wild fish or interbreed with them, passing on the alleles for fast growth, which could increase the rate of extinction of wild fish- triploid farmed fish can prevent this

The feed is often made from harvested wild fish

Question 19

How might conservation methods be monitored

Answer 19

Biological monitoring may involve field techniques like random sampling and transects.

Question 20

Why should conservation methods be monitored

3 points

Answer 20

Monitoring enables prediction of possible effects of human activities to inform planning of conservation methods.

To determine the effect of these methods and if Alternative methods need to be considered and implemented to reduce harmful effects.

To inform political decisions as they should be based on the latest scientific data

Question 21

Define planetary boundries

Answer 21

A safe operating level for humanity/ a threshold value for a global process that is affected by human activity. Above this value, the global process will not be stable and exceeding boundary leads to irreversible damage globally.

Question 22

Name all 9 planetary boundries

Name the two core boundries

Answer 22

Biodiversity
Climate change
Nitrogen boundary
Land use
Fresh water
Chemical pollution
Aerosol
Ocean acidification
Ozone

Bold = Core boundary

Question 23

Describe the Biodiversity / biosphere integrity boundary

has it been crossed?

Answer 23

It has been crossed:
Extinction in relation to natural selection; the change of habitats such as marine, tundra; coral reefs and coastal plains and its effect on indigenous species; Biodiversity monitoring; the use of gene banks; public awareness

Question 24

Describe the climate change boundary

has it been crossed?

Answer 24

The climate change boundary has been crossed:
Greenhouse gases and their sources; the production and use of biofuels; the effect on human populations; the effect on plant and animal populations.

Question 25

Describe the nitrogen boundary

has it been crossed?

Answer 25

The nitrogen boundary has been crossed:
The nitrogen cycle and the effects of eutrophication

Question 26

Describe the land use boundary

has it been crossed?

Answer 26

The land use boundary has been crossed:
The conflict over land use and food production; changes to farming practice; political considerations.

Question 27

Describe the fresh water boundary

has it been crossed?

Answer 27

The fresh water boundary has not been crossed and it is avoidable:
The need for fresh water; sources of fresh water; desalination

Question 28

Describe the chemical pollution boundary

has it been crossed?

Answer 28

The chemical pollution boundary is unquantified:
air pollution including the effects of SO2 and N oxides.

Question 29

Describe the aerosol boundary

has it been crossed?

Answer 29

The aerosol boundary is unquantified:
air pollution by particulates

Question 30

Describe the ocean acidification boundary

has it been crossed?

Answer 30

The ocean acidification boundary as not been crossed and is avoidable: the effect of fossil fuel burning on oceans; fish farming.

Question 31

Describe the ozone boundary

has it been crossed?

Answer 31

The ozone boundary has been avoided:
CFCs and the chemistry of ozone destruction; the effect of the Montreal protocols.