Food production

Question 1

What does increasing human population require?

Answer 1

An increased food yield

Question 2

What do fertilisers include that increases crop yield?

Answer 2

Chemicals such as nitrates

Question 3

Has the human population increased or decreased?

Answer 3

Increased exponentially

Question 4

Why has the human population grown?

Answer 4

A decrease in deaths from illnesses or child birth due to medical developments

An increase in ability to feed ourselves due to developments in agriculture

Question 5

How has farming changed since the Victorian times?

Answer 5

Mechanisation and increased field size increases efficiency

Monocultures - growing one crop over a large area is more efficient

Use of chemicals such as fertilisers, herbicides and pesticides

Improved crop varieties due to crop breeding and GM crops

Intensive farming practices, such as rearing animals in sheds

Question 6

What are the advantages of monocultures?

Answer 6

Farmland produces more food as only the best variety of crops is grown

It simplifies the sowing and harvesting of the crop as machinery can be used, reducing labour costs

Question 7

What are the disadvantages of monocultures?

Answer 7

As similar plants are grown close together, pests and diseases spread rapidly, and more pesticides are needed to control them

Because only one plant species is wanted, weeds are killed using herbicides

Important wildlife habitats such as hedgerows, ditches, marshes, ponds and small woodlands are removed to create larger fields
This decreases biodiversity and removes the natural predation of pests that feed on the crop

Question 8

How can we produce more food from the same area of land?

Answer 8

Increase crop yields
Prevent pests damaging crops

Question 9

How can we increase food yields?

Answer 9

Use fertilisers
Use GM crops

Question 10

How can we prevent pests damaging crops?

Answer 10

Use pesticides
Use GM crops
Use biological control

Question 11

What do plants need to build protein molecules?

Answer 11

Nitrogen, phosphorus and potassium

Question 12

Why do we need to add fertilisers in a field?

Answer 12

Harvesting crops remove essential nutrients, as they are not returned to the soil via the nitrogen cycle.
Fertilisers are added to replace these nutrients, making the crops grow better and increasing yields.

Question 13

what do plants need minerals from the soil for?

Answer 13

Build other molecules, such as proteins which they can’t do from photosynthesis

Question 14

Why are nitrates so important?

Answer 14

Nitrates are used to produce amino acids which are synthesised into plant proteins. Animals consume plants or other animals to obtain amino acids for protein

Question 15

How are nitrates taken in by plants?

Answer 15

Nitrates dissolved in soil water are then absorbed into plants

Question 16

What form does nitrogen take?

Answer 16

The form of ammonium (NH4-) and nitrate (NO3-) ions

Question 17

What form does phosphorus take?

Answer 17

Phosphate ions (PO4 3-)

Question 18

What form does potassium take?

Answer 18

Potassium ions (K+)

Question 19

What mineral helps with leaves?

Answer 19

Nitrogen

Question 20

What mineral helps with roots?

Answer 20

Phosphorus

Question 21

What mineral helps with flower and fruit growth?

Answer 21

Potassium

Question 22

How can we solve the problem of eutrophication?

Answer 22

Use less fertilisers especially on land near waterways

Use natural fertilisers like manure and compost, which do not dissolve easily in rainwater

Check the weather forecast before adding fertiliser

Only apply chemical fertiliser when plants are actively growing in the spring

Farmers could use crop rotation or grow legumes to replenish nutrients in the soil

Grow GM crops that need less fertiliser

Question 23

What is eutrophication?

Answer 23

Excessive richness of nutrients in a lake or other body of water, frequently due to run-off from the land, which causes a dense growth of plant life.

Question 24

What can pesticides do?

Answer 24

Kill plants and animals which reduce crop yield

Question 25

How is algal bloom caused?

Answer 25

Fertilisers leaching into freshwater, adding extra and unwanted nutrients.
This increases algal population which causes algal bloom.

Question 26

What does algal bloom do?

Answer 26

Reduces light levels, killing aquatic plants. These dead plants as well as dead algae, become food for bacteria which increase greatly in number. The bacteria use up large quantities of oxygen, reducing oxygen availability for other organisms.

Question 27

What is bioaccumulation?

Answer 27

The build up of toxic substances in living organisms

Question 28

What can happen to pesticides sprayed onto crops?

Answer 28

They can accumulate in the bodies of organisms over time. As they are passed along the food chain, toxicity increases and can reach lethal levels.

Question 29

What are some alternative to pesticides?

Answer 29

Biological control and GM crops

Question 30

What are pests?

Answer 30

Pests feeding on crops reduce crop yield

Question 31

What happens if a plant can’t photosynthesise?

Answer 31

If a plant can’t photosynthesise due to damaged leaves, it will not grow properly, and crop yield will be reduced

Question 32

Where does -cide come from?

Answer 32

Latin ‘cida’ meaning killer

Question 33

What is the problem with pesticides?

Answer 33

They kill a wide variety of non-pests species and can reduce biodiversity

Question 34

Where does 90% of the world’s nutrition come from?

Answer 34

Crops pollinated by bees

Question 35

What is biomagnification?

Answer 35

The build up of toxic substances along a food chain

Question 36

Why was DDT called a miracle?

Answer 36

It killed mosquitos, fleas and other insects. Mosquitos are responsible for malaria, and DDT helped reduce the spread of this disease

Question 37

What was the problem with DDT?

Answer 37

It is not metabolised in organisms. It is resistant to degradation, it bioaccumulates, and is toxic.
It also spreads easily in the environment, reaching places where it was not used (like Arctica)

Question 38

POPs are toxic - what does this mean?

Answer 38

Genotoxicity: they can damage DNA and cause mutations

Carcinogenicity: they can cause cancer

Teratogenicity: they can cause birth defects

Immunotoxicity: they can damage your immune system

Question 39

What does “genetically modified” mean?

Answer 39

Means to add a gene from one organism into another organism

Question 40

What are the advantages of GM crops?

Answer 40

GM crops grow better, and the resulting crop yield increase can help to support the population

Less chemicals such as pesticides are required, and less water may be required , so less environmental damage and use of resources

Question 41

What are the disadvantages of using GM crops?

Answer 41

Many regard them as unnatural, as genes are transferred between species

Farmers who don’t use the GM variety can’t compete and go out of business

GM crops that produce their own pesticides or herbicides may contain chemicals that damage our health

Herbicide resistant GM crops can be sprayed with huge quantities of herbicides resulting in more damages to the environment

Genes may escape into the environment due to cross breeding with wild plants

Question 42

What does biological control use?

Answer 42

Natural predators of a pest species as a way to keep their population size low

Question 43

Give an example of biological control

Answer 43

The ladybird is a natural predator of the aphid.
They can be introduced to reduce the aphid population to a manageable size

Question 44

What are the risks of biological control?

Answer 44

Control species might not survive in a new environment

Control species might bring new diseases into the new environment

Control species might become a pest species