B6.2 - Food Security Flashcards Preview

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Flashcards in B6.2 - Food Security Deck (41)
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1

describe 5 biological factors affecting levels of food security

- increasing human population
- changing diets in wealthier population
- new pests and pathogens
- environmental change
- sustainability and cost of agricultural inputs

2

why does an increasing human population affect food security?

more people = more food needed

3

how does changing diets in wealthier countries affect food security?

- each person wants good food (ie. imported), or more meat (less security)

4

how does climate change affect food security?

- global warming causes more droughts
- higher desertification
- unpredictable rain

5

positives of higher CO2 levels in the air?

- they may increase crop yields (for photosynthesis)

6

how does increasing agriculture costs affect food security?

- more expensive to grow food/store/distribute

- so price is too high for other people to afford

7

define food security

the ability of human populations to access food of sufficient quality and quantity

8

state 5 agricultural solutions to the demands of the growing human population

- hydroponics
- biological control
- gene technology
- fertilisers
- pesticides

9

describe hydroponics

- growing crops by replacing soil with mineral solution
- can control growth by changing temperature

10

positives of hydroponics

- mineral solution can be recycled
- plants grow quickly
- more plants can grow n the same space (can be stacked on top of each other)

11

negatives of hydroponics

very expensive

12

describe biological control

- release a natural predator
- to kill pests where a crop is being grown

13

disadvantages of biological control?

- may affect other organisms in the food web
- predator may be hard to control

14

advantages of biological control

is an alternative to pesticide, so an organic farming method

15

how would gene technology solve the demands of a growing human population?

produce them to have better yields (disease resistant, pest resistant)

16

how do herbicides and pesticides solve the demand of a growing human population?

- remove animals that eat crops
- herbicides get rid of competing crops

17

negatives of pesticides and herbicides?

- reduces biodiversity
- pesticides may pass up the food chain

18

difference between intensive farming and organic farming?

organic = avoid use of chemicals, smaller yields

intensive = main goal is maximum yield (ie. caged animals = maximum energy for mass and not movement)

19

define sustainable food production

producing food that can be continued for an indefinite period of time

20

how to prevent overfishing?

- fish quotas (numbers + type of fish caught in that area)
- limit mesh size (ie. bigger holes)
- reared in rivers (cages)

21

negatives of fishing in a cage?

- disease spread quickly
- disease can spread to wild population

22

what is selective breeding?

when humans breed certain plants or animals which have desirable characteristics (ie. may use it to increase crop yield)

23

3 step process in which selective breeding occurs?

1) select individuals with desirable characteristics + breed together
2) breed best offspring
3) repeat over many generations

24

disadvantages of selective breeding?

- reduces gene pool (vulnerable to new pathogens)
- increased chances of inherited diseases

- unforeseen physical problems (too heavy to walk)

25

how has selective breeding affected food plants?

- wheat has large ears
- generally in a way to increase crop yield
- wheat ripens at the same time

26

define genetic engineering

a process which involves modifying the genome of an organism to introduce desirable characteristics

27

state the steps carried out to genetically engineer an organism

1) a gene is identified for the desired characteristic

2) gene is cut from the rest of DNA by restriction enzymes

3) DNA taken from bacterium (ie. plasmid/ring of DNA)

4) same restriction enzyme cuts open the plasmid

5) ligase enzymes rejoin cut out gene and plasmid ring at sticky ends

6) modified vector is placed into a bacterium

7) bacteria then reproduces through binary fission

28

define the term 'transgenic bacteria'

bacteria which have DNA from another organism

29

when producing insulin from bacteria:
a) what gene is taken from humans
b) how is it produced?

a) insulin gene removed from human DNA
b) transgenic bacteria reproduce + produce insulin (a lot of it)

30

what is used to see if cells incorporate foreign genes?

- insert antibiotic resistant gene, if cells survive after adding antibiotics, gene has been taken up

- insert gene markers (like glow in the dark ones)