Flashcards in B6.2 - Food Security Deck (41)
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
- biological control
- gene technology
- 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
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)