B6.2 Feeding The Human Race

Question 1

Define food security

Answer 1

The ability of the human population to access affordable food of sufficient quality and quantity

Question 2

What factors affect food security? (Name 3)

Answer 2

Increasing human population
Climate change
Changing diets
New pests + pathogens
Sustainability
Cost of agricultural inputs

Question 3

Efficient farming is…

Answer 3

…where you produce the maximum yield from the limited land available

Question 4

Improving efficiency: Maximising photosynthesis

Answer 4

Light, water + temperature levels controlled

Question 5

Improving efficiency: Using fertilisers

Answer 5

Help soil to remain fertile for the plant to grow

Question 6

Improving efficiency: Removing competition and pests

Answer 6

Herbicides to kill weeds, insecticides to kill insects, fungicides to destroy disease-causing fungi

Question 7

Improving efficiency: Choosing crop varieties carefully

Answer 7

Using crop varieties that are pest resistant or produce a higher yield

Question 8

Why are 100% of crops not harvested?

Answer 8

Disease
Pests
Weeds

Question 9

What is intensive farming?

Answer 9

Produce maximum yield from minimum area of land
Eg fertilisers + pesticides, maximising animal growth rates, minimising labour inputs by using machinery

Question 10

What is organic farming?

Answer 10

Uses natural methods of producing crops / rearing animals, avoids use of artificial chemicals
Yields are smaller so products more expensive

Question 11

Sustainable food production is…

Answer 11

Producing food in ways which can be continued indefinitely

Question 12

Overfishing causes problems such as…

Answer 12

Reduction in some populations of fish species
Fish population cannot regenerate
Long term problem

Question 13

Solutions to overfishing?

Answer 13

Limiting type / number of fish caught in an area
Limiting mesh size of nets
Fish farming

Question 14

Advantages of fish farming?

Answer 14

Protect fish from predators
Easier to catch
Allows wild populations to recover

Question 15

Disadvantage of fish farming?

Answer 15

Close confinement; disease spreads quickly

Question 16

Sustainable farming methods include…

Answer 16

1. Using manure (introduces minerals back into soil)
2. Crop rotation (allows land to recover)
3. Biological control (use natural predators to control pest population)
4. Gene technology (makes organisms able to grow in poor conditions/ resistant to disease / resistant to pests)

Question 17

Define hydroponics

Answer 17

A technique used to grow plants without soil

Question 18

What are the 3 advantages of hydroponics?

Answer 18

1. Plants gain all minerals from specially treated water
2. Can easily control limiting factors
3. Maximise area - quick to harvest

Question 19

Define selective breeding

Answer 19

The process by which humans breed animals and plants with desired characteristics

Question 20

Give 3 examples of desired characteristics in animals

Answer 20

Dairy cattle to produce more milk
Meat productions
Chickens to lay larger / more eggs
Temperament

Question 21

Give 3 examples of desired characteristics in plants?

Answer 21

Wheat plants producing lots of grain
Tomato plants with high yields
Disease resistance
Large / unusual flowers

Question 22

How does a farmer selectively breed organisms?

Answer 22

1. Decide on a desired characteristic
2. Select parents with this characteristic
3. Breed these individuals
4. Select best offspring to breed
5. Repeat over generations

Question 23

Disadvantages of selective breeding: Reducing the gene pool of a species

Answer 23

If a new disease arises there may not be any organisms containing the gene for resistance. The species may become extinct

Question 24

Disadvantages of selective breeding: Increases chance of genetic disease

Answer 24

Could lead to problems within specific organisms. Eg lots of Dalmatians are deaf

Question 25

Disadvantages of selective breeding: May create physical problems in specific organisms

Answer 25

Could lead to problems in quality of life (could be costly to treat)

Question 26

Define genetic engineering

Answer 26

Altering an organism’s genome to produce an organism with desired characteristics

Question 27

How are organisms genetically engineered?

Answer 27

1. Identify the gene that codes for the characteristic 2. Remove gene from donor organism 3. Insert gene into host organism, often a bacterium

Question 28

Enzymes are used to… The two enzymes are called…

Answer 28

…move a gene between genomes …restriction enzymes and ligand enzymes

Question 29

How do restriction enzymes work?

Answer 29

Cut donor DNA at specific base sequences (either side of desired gene) Make a staggered cut leaving “sticky ends” Same restriction enzyme is used to cut open bacterial plasmid

Question 30

Sticky ends = ?

Answer 30

Exposed unpaired based on the ends of the DNA strands produced by restriction enzymes

Question 31

How do ligase enzymes work?

Answer 31

Rejoin DNA at sticky ends Both host and DNA have same sticky ends, so new gene is joined into plasmid DNA

Question 32

Name some concerns about genetic engineering

Answer 32

GM crops could escape + breed with weeds making “super weeds” Parents could pick genes for their babies making “designer babies” We do not know the long term health effects of eating GM crops

Question 33

Define biotechnology

Answer 33

The use of biological process or living organisms to manufacture products

Question 34

Define biological control

Answer 34

Using a natural predator to control a pest population

Question 35

What are foreign genes

Answer 35

Genes inserted into an organism from a different species

Question 36

What is a genome

Answer 36

The organism’s complete genetic material

Question 37

What is a vector

Answer 37

Used to transfer genetic material into an organism

Question 38

Define yield

Answer 38

Amount of agricultural product produced