B6.2 Feeding the human race Flashcards
Factors affecting food security
Human population size
New/number of pests and pathogens
Changing diets
Global warming and climate change
High cost of farming methods
How food production can be increased
Maximise PHOTOSYNTHESIS
Using fertilisers (manure better long term)
Removing competition & pests
Pest resistant crops
High yield crops
GM crops
Intensive farming
Techniques aiming to produce maximum food product yield from minimum area of land through:
Using FERTILISERS and PESTICIDES to aid plant growth
Maximising animal growth rates
Minimising labour inputs by using machinery
Organic farming
Farming using more natural method of crop production and rearing animals,
avoiding the use of chemicals
Sustainable food production
Producing food in ways that can be continued indefinitely
Advantages and disadvantages of fish farming
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Fish protected from predators
Easier to catch
Other species not caught be acident (no bycatch)
Wild populations able to recover
Lower transport costs
Increase yields
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Disease can spread quicly as fish kept so close together
Fish are sometimes fed pellets of less valuable fish meaning other fish have a reduced food supply
Drugs used on farms can pollute surrounding water ways
High cost to set up
Expensive running costs
Fish welfare
How farmers can reduce pesticide and fertiliser usage
Use organic manure instead of manufactured fertilisers
Crop rotation
Biological control
Hydroponic system
Growing plants in a nutrient medium rather than in soil
Biological control
Control of pests by deliberately introducing natural predators of those pests
How can gene technology help agriculture
Beneficial genes added for pest resistance
Ability to grow in harsher conditions could be introduced / hardiness
How gene fertilisers and pesticides can help agriculture
Pesticides kill pests that could harm the growth of plant
Fertilisers provide plant with all nutrients it needs so that it can grow more quickly
Selective breeding
Breeding plants or animals for particular characteristics
How selective breeding is carried out
Decide which characteristic of the species is desirable
Select parents with high levels of this characteristic and breed them
Select best offspring
Breed again
Repeat for many generations unitl all offspring display desired traits
Disadvantages of selective breeding
Reduced gene pool (number of alleles)
Reduced variation
Increased suseptability to disease
Increased chance of inheriting genetic disease
Genetic engineering
Altering organism’s genome to produce an organism with desired characteristics
Potential benefits of using genetic engineering in agriculture
Increased crop yield
Crops modified to synthesise vitamins
Drug production
Pest resistance
Hardiness (surviving minimum temperatures)
Risks of genetic engineering
Health problems
Allergic responses
Cross-pollination
Loss of native species
Disruption of ecosystems
How new genes are introduced into an organism
Genes which code for a desired characteristic are identified
Organism genes are cut using restriction enzymes to create sticky ends
DNA from bacterial plasmid is also cut to produce sticky ends using same restriction enzymes
Gene is inserted into bacterial plasmid along with a marker gene (antibiotic resistance / luminescence)
Ligase enzymes used to rejoin sticky ends and form a transgenic bacteria
Transgenic bacteria incubated and allowed to grow
Transgenic bacteria tested for marker using UV light or growth upon antibiotic plate indicating only those resistant survive and contain the desired gene
Easier:
Restriction enzymes cut donor DNA at specific base sequences (either side of the desired gene)
They make a staggered cut, resulting in ‘sticky ends’
Same restriction enzymes are also used to cut open the bacterial plasmid
Ligase enzymes then rejoin DNA strands at the sticky ends inserting the new gene into the plasmid DNA
Transgenic organism
Organism that contains foreign DNA
Food security
Ability of human populations to access food of sufficient quality and quantity
Antibiotic resistant genes as markers
Insert an antibiotic resistance gene (gene marker) into plasmid at same time as inserting gene coding for the desired characteristic
Transfer bacteria to an agar plate containing the antibiotic
Incubate, and allow time for bacteria to grow
All bacterial colonies present contain antibiotic resistance marker gene and therefore also the desired gene
