food production

Question 1

2 ways to increase crop yield

Answer 1

fertilisers and pesticides

Question 2

fertilisers

Answer 2

substance added to soil to increase its fertility

Question 3

pesticides

Answer 3

chemicals used to kill pests that damages crops

Question 4

disadvantages of pesticides

Answer 4

pesticides on crops can accumulate in the bodies of organisms over time. as passed along the food chain the toxicity builds up

Question 5

alternatives to pesticides

Answer 5

• genetically modified crops
• biological control (reduces pests therefore reduces damage)

Question 6

alternatives to fertilisers

Answer 6

• natural fertilisers
• genetically modified crops (increase yield)

Question 7

use of nitrogen - stages

Answer 7

1. nitrates dissolved in soil water are absorbed by roots
2. nitrates produce amino acids that are synthesised into plant proteins
3. animals consume plants/organisms to obtain amino acids for protein synthesis

Question 8

why are fertilisers added to soil

Answer 8

to increase nitrate content of soil

Question 9

problems with fertilisers

Answer 9

• leach into water causing algal bloom causing reduction in oxygen levels

Question 10

why does algal blood reduce oxygen levels?

Answer 10

1. fertilisers leach into water adding unwanted nitrates
2. increases algal population causing algal bloom
3. reduces light levels causing plants to die
4. bacteria feeds on dead plants and algae causing bacteria to increase
5. bacteria uses a lot of oxygen reducing oxygen available for other organisms