LE5

Question 1

What does an increase in human population require?

Answer 1

increasing human population requires an increased food yield

Question 2

How is an increased food yield partly brought about?

Answer 2

Increased food yield is partly brought about by the use of pesticides and fertilisers

Question 3

What is a pest?

Answer 3

A pest is a destructive insect/animal that attacks crops and livestock

Question 4

What is a pesticide?

Answer 4

a pesticide is a chemical used to kill unwanted organisms

Question 5

What is bioaccumulation?

Answer 5

bioaccumulation is the buildup of pesticides in an animals body fat

Question 6

What is biomagnification?

Answer 6

biomagnification is when pesticides are passed along food chains and toxicity increases

Question 7

What are two alternatives to the use of pesticides?

Answer 7

-biological control
-genetically modified (GM) crops

Question 8

What is biological control?

Answer 8

biological control is a way of controlling pest species with the use of other living organisms, which often relies on predation/parasitism

Question 9

Why are fertilisers used?

Answer 9

fertilisers are used to increase the nitrate content of the soil and to increase crop yield

Question 10

What are nitrates used to produce?

Answer 10

nitrates are used to produce amino acids, which are synthesised into plant proteins

Question 11

Explain the algal bloom/eutrophication process:

Answer 11

-fertilisers can leach into freshwater, adding unwanted nitrates
-algae increases in number
-algae blocks/reduces light, killing aquatic plants
-dead plants and algae feed the bacteria, meaning bacteria increases in number
-oxygen levels decrease
-fish and other species die