B6.2 - Food Security Flashcards Preview

B4-B6 > B6.2 - Food Security > Flashcards

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

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


why does an increasing human population affect food security?

more people = more food needed


how does changing diets in wealthier countries affect food security?

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


how does climate change affect food security?

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


positives of higher CO2 levels in the air?

- they may increase crop yields (for photosynthesis)


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


define food security

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


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

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


describe hydroponics

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


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)


negatives of hydroponics

very expensive


describe biological control

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


disadvantages of biological control?

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


advantages of biological control

is an alternative to pesticide, so an organic farming method


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

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


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

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


negatives of pesticides and herbicides?

- reduces biodiversity
- pesticides may pass up the food chain


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)


define sustainable food production

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


how to prevent overfishing?

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


negatives of fishing in a cage?

- disease spread quickly
- disease can spread to wild population


what is selective breeding?

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


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


disadvantages of selective breeding?

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

- unforeseen physical problems (too heavy to walk)


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


define genetic engineering

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


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


define the term 'transgenic bacteria'

bacteria which have DNA from another organism


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)


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)