3.5 human impact on the environment

Question 1

What are fertilisers?

Answer 1

products that are used to add extra nitrate to the soil to help plants grow

Question 2

Give an example of biological control

Answer 2

release parasitic wasps to reduce aphids

Question 3

Explain the importance of nitrates to plant growth

Answer 3

• plants absorb nitrates through their roots
• they use this as a source of nitrogen to produce proteins
• nitrogen is also a major component of chlorophyll

Question 4

What is biological control?

Answer 4

the use of natural predators to control pests

Question 5

What are the advantages and disadvantages of biological control?

Answer 5

advantages - only needs to be applied once and is effective
disadvantages - it’s a slow process and it cannot wipe out the entire pest population. It can only be done in enclosed areas as it does not work well in open areas

Question 6

Give an example of an indicator species for fresh water pollution by organic waste

Answer 6

low freshwater invertebrates–> high freshwater pollution

Question 7

Give an example of an indicator species for sulphur dioxide pollution

Answer 7

low lichen populations–>high sulphur dioxide concentration

Question 8

What are monocultures?

Answer 8

large areas containing just one crop

Question 9

What are advantages and disadvantages of monocultures?

Answer 9

advantages - higher yields and it only requires one method of farming
disadvantages - it destroys soil nutrients and to counteract this large amounts of harmful chemicals have to be used. these can end up in the human food chain

Question 10

Why does feeding a growing population require intensive farming?

Answer 10

It makes farming more efficient by producing a larger crop yield or more meat

Question 11

What is intensive farming?

Answer 11

the use of:
-herbicides
-pesticides
-fertilisers
-battery farming animals
to produce a higher crop yield or more meat

Question 12

What are pesticides?

Answer 12

chemicals used to control the levels of unwanted plants(herbicides) or insects(pesticides)

Question 13

What are the problems with fertilisers entering freshwater?

Answer 13

it causes algal blooms

Question 14

What is an algal bloom?

Answer 14

• fertilisers run into water
• fertilisers make the algae grow
• this blocks out sunlight to the plants below
• plants at the bottom of the water die and start to rot as bacteria eat them
• bacteria grow and use the oxygen
• insects and fish that need oxygen suffocate and die

Question 15

What does aerobic mean?

Answer 15

in the presence of or involving oxygen

Question 16

What is bio accumulation?

Answer 16

the build up of toxic substances in living organisms

Question 17

what are nitrates?

Answer 17

nutrients absorbed from soil by plants to produce amino acids

Question 18

What are the problems with pesticides?

Answer 18

• some insecticides aren’t specific and kill other insects as well
• bioaccumulation happens and the toxicity level builds up in carnivores and can eventually reach levels that can be lethal or that can damage their reproduction

Question 19

What are alternatives to fertilisers?

Answer 19

• genetically modified crops (GM crops)

- plant nitrogen fixing plants such as peas and clover

Question 20

What are alternatives to pesticides?

Answer 20

• genetically modified crops (GM crops)

- biological control

Question 21

What is integrated pest management?

Answer 21

• a combination of biological control and pesticides

- it reduces the amount of pesticides that farmers need to use