food production

Question 1

how can food yield be increased?

Answer 1

• fertilisers: provide nutrients to help crops grow
• pesticides: to kill pests that eat crops

Question 2

what are fertilisers and pesticides used for?

Answer 2

intensive farming

Question 3

what is intensive farming?

Answer 3

large-scale farming to produce more food for our population

Question 4

why do we use fertilisers?

Answer 4

farmers use fertilisers to increase crop yield by increasing the available nutrient levels (nitrates) of the soil

Question 5

what does increasing the nutrient levels (nitrates) of the soil allow?

Answer 5

allows plants to produce amino acids for protein synthesis and growth
animals eat plants/animals to obtain aminio acids for protein synthesis

Question 6

what happens to the nitrates?

Answer 6

• plants absorb nitrates dissolved in the soil through their roots
• plants convert the nitrates into plant protein which they need to grow
• animals eat the plants, they convert the plant protein into animal protein

Question 7

what happens when fertilisers leach into fresh water?

Answer 7

adds extra nitrates which will increase algal populations which can cause algal blooms

Question 8

what do algal blooms do?

Answer 8

reduce light levels , killing aquatic plants

Question 9

what is a solution to algal bloom?

Answer 9

genetically modified crops can be used to reduce the use of fertilisers

Question 10

what are the stages of algal bloom?

Answer 10

1. nitrates in fertilisers leached into waterways
2. increased growth of algae forming algal bloom on surface of water
3. algal bloom blocks sunlight from entering water
4. dead plants (cant photosynthesise) means more bacteria
5. bacteria use up large quantites of oxygen when decomposing dead plants

Question 11

what are pesticides?

Answer 11

chemicals which are used to kill plants and animals that destroy/eat crops and therefore increase crop yield

Question 12

bioaccumulation

Answer 12

pesticides sprayed onto crops can accumulate in the bodies of organisms over time
chemicals pass along food chains, increasing in concentration and reach toxic levels

Question 13

what are the solutions to bioaccumulation?

Answer 13

1. genetically modified plants that are resistant to pests
2. biological control: use a predator or virus to kill pests

Question 14

what are examples of biological controls?

Answer 14

• ladybirds are used to kill alphids
• virus are used to kill rabits

Question 15

what is bioaccumulation?

Answer 15

the build-up of toxic substances in living organisms