3.6 Human impact on the environment

Question 1

What is meant by the term extinction?

Answer 1

The complete loss of species due to a number of reasons.

Question 2

Why may a species become endangered and possibly extinct?

Answer 2

• Natural selection
• Non continguous populations
• Loss of habitat
• Overhunting by humans
• Competition
• Pollution.

Question 3

What is meant by the term conservation?

Answer 3

The protection, preservation, management and restoration of natural habitats and their communities.

Question 4

Name some examples of conservation efforts.

Answer 4

• Protecting habitats e.g., Nature Reserves
• Gene and sperm banks
• Seed banks
• Species re introduction

Question 5

Why is it important to conserve endangered species?

Answer 5

• Every individual is unique and ethically it is Important we look after them.
• Can be used for medical use.
• Agricultural and horicutlura use can be useful if rarer helpful alleles are restored into a stable environment.

Question 6

What is agricultural exploitation?

Answer 6

When farmers use the land for agricultural use that jeopardise the natural area of that environment, often killing many habitats.

Question 7

Provide some examples of agricultural exploitation and how this has affected biodiversity.

Answer 7

• Use of land for monoculture, producing the same crop which destroys habitats and reduces biodiversity.
• Hedgerows are sometimes removed for agricultural use
• Overgrazing of cattle which causes the soil to become dehydrated and unable to grow.

Question 8

What are the complications of Mono culturing land?

Answer 8

The same crop is grown therefore the roots only reach the same point so minerals are depleting meaning the same fertalisers etc are used at a high rate. Same pesticides are also used.

Question 9

What is deforestation and why do people do it?

Answer 9

The cutting down of trees for resources or clearing for land for agricultural use.

Question 10

What are the effects of deforestation?

Answer 10

• Soil erosion, the trees roots hold the soil together but without them wind and rain can easily erode the soil and therefore crops can no longer grow efficiently.
• Can cause low land flooding
• The trees can no longer transpire so water is lost from the soil through evaporation which is slower meaning the soil is wetter.
• Due to lack of transpiration and water returns to the atmosphere much slower therefore there is less rainfall. Accelerating desertification.
• Habitat loss
• Removal of CO 2 from the atmosphere is reduced, more is released from burned trees.

Question 11

Why should we manage forests?

Answer 11

Forests provide great resources so they need to be managed properly in order to be able to use these resources sustainably.

Question 12

What is meant by the term coppicing?

Answer 12

When a tree trunk is cut to a stub is left for new shoots to emerge from. These can then be cut to provide resources humans need. They can regenerate over long periods of time so this method is sustainable.

Question 13

What is meant by the term selective cutting?

Answer 13

Only cutting certain trees within an area to mitigate the effects e.g., only cutting a small amount of trees on a slope to avoid maximum soil erosion.

Question 14

Why is it important to cut trees a suitable distance apart?

Answer 14

Because if they are to close together then they can not grow properly due to intra specific competition and poor timber is produced

Question 15

What is over-fishing and why is it bad?

Answer 15

Overfishing is when excessive fishing occurs within a given area, it depletes fish stock and populations become very low. This impacts the food chain al together.

Question 16

What are the commercial fishing methods?

Answer 16

• Drift netting
• Trawling

Question 17

What is Drift Netting and why is it bad?

Answer 17

When a long net covers a large are to catch fish however, it catches species that are non targeted and they become trapped.

Question 18

What is Trawling? Why is it bad?

Answer 18

Weighted nets are dragged across the ocean floor which damages the floor and picks up everything with it. Destroys habitats etc.

Question 19

Methods to preserve fish stock?

Answer 19

• Regulating mesh size
• Quotas
• Exclusion zones
• Legislation

Question 20

How can mesh size help fish populations?

Answer 20

If they are larger it allows the younger smaller fish to swim, through meaning that they can reproduce to restore the population.

Question 21

What is a Quota?

Answer 21

It’s a maximum amount of fish that fisherman can bring back onto land, it aims to maintain the population and avoid over fishing.

Question 22

What are exclusion zones?

Answer 22

Certain areas of the sea are prohibited from being fished at certain times of the year, allowing the fish within that area to reproduce.

Question 23

What is fish farming?

Answer 23

When fish are monitored within a controlled area, they are given the right amount of food etc until they are ready to be harvested.

Question 24

What are the benefits of fish farming?

Answer 24

• Fish convert their food into protein more efficiently.
• More of the fish are edible
• Has a lower carbon footprint

Question 25

What are the disadvantages of fish farming?

Answer 25

- Disease can spread quickly due to high density, antibiotics can be used but then these may enter the food chain. - Decreased water quality e.g., eutrophication - Any escaped fish may contain disease and spread to wild populations.

Question 26

How can we monitor the sustainability of the Earth?

Answer 26

- Air quality monitoring - Soil monitoring - Water quality monitoring e.g., chemical, biological and microbiological aspect.

Question 27

What is an environmental impact assessment and what does it include?

Answer 27

A document which uses data to predict the environmental effects of a proposed project, it should include description of the site and proposed project. Description of abiotic and biotic factors and mitigation (ways of limiting environmental damage and maintaining biodiversity)