B6.2 Flashcards
What is food security?
Ability of human population to access affordable food of sufficient quality and quantity
What factors affect food security?
- increasing human population
- changing diets (richer people eat a varied diet with meat that is energy intensive to produce than plants products)
- climate change means more droughts and deserts will expand, but increase in CO2 can mean increased yield of crops
- New pests and pathogens may evolve
How can food production be increased?
- maximising photosynthesis with controlled factors in a greenhouse
- using fertilisers to help a plant remain fertile
- removing competition and pests
- planting varieties of crops that are pest resistant or produce a higher yield
What is intensive farming?
Techniques that aim to produce the maximum food product yield from minimum area of land by:
- using fertilisers and pesticides to aid plant grwoth
- maximising animal growth rates
- minimising labour inputs by using machinery
What is organic farming?
Uses more natural, methods of producing crops and rearing animals and avoids the use of artificial chemicals
Yield is generally smaller so products may be more expensive
What is sustainable food production?
Producing food in ways that can be continued indefinitely
Example is fish farming
What is fish farming?
Fish are a valuable source of protein
Due to overfishing many populations have reduced so international organisations have fishing quotas that provide limits for the number of fish that can be caught in a n area
To allow enough fish to survive and reproduce to maintain their population
Size of fishing nets also must have bigger holes so that smaller, younger fish can escape and only mature full grown fish are caught
How can we reduce the use of pesticides and fertilizers?
- Farmers replace soil nutrients by spreading manure
- crop rotation is when different crops are planted each year to maximise plant growth
- biological control is when the natural relationships between pests and predators are exploited by farmers
- Gene technology, developing crops that are more resigantbto pests and diseases
What is a hydroponic?
When a plant is grown in water containing dissolved minerals to receive the minerals it needs
Grown in different mediums from soil
Plants grow much quicker
What is selective breeding?
When plants and animals are bred for particular characteristics
Plant scientists use it for our growing population
To produce the highest yield, the best plants and animals are chosen to breed with
Crops with high resistant to disease would be used
They could cross the two to get disease resistant and high yielding crops
How does a farmer selectively breed?
1) decide which characteristic of the species is desirable
2) select a parent with high levels of this characteristic
3) breed from these individuals
4) select the best offspring and breed again
5) repeat for many generations
How has wheat changed from selective breeding?
- had small ears with few seeds, now has large ears with many seeds
- had brittle stalk that’s ears often fall off, now stronger stalks that ears stay on
- ears ripened at different times, now ears ripen at the same time
- stalks grew to different heights, now grow to the same height
What are the disadvantages of selective breeding?
- reduces number of alleles of a species, reduces variation so species would go extinct easily
- increases chance of inheriting a genetic disease
What is genetic engineering?
A way to alter an organisms genome to produce an organism with desired characteristics as selective breeding is a very long process over many generations
What are the benefits of genetic engineering in agriculture?
Cotton - to increase crop yield from the same area of land
Corn - to produce toxins that kill insects
Bacteria - to produce medical drugs such as insulin or drugs to treat animals
How is a genetically engineered organism produced?
1) take genes from another organism that codes for this characteristic
2) these are foreign genes
3) they out the forgpeign genes into the plant or animal cells at an early stage of the organisms development
4) as the organism develops it displays the characteristic coded for by the foreign genes
What are the risks of genetic engineering?
- eating genetically engineered organisms may less to health problems
- genetically engineered crops may cross pollinate with wild plants and introduce the new gene to wild plants which could disrupt the balance of the ecosystem
- may seem unethical
How are organisms genetically engineered?
1) identify gene that codes for desired characteristic
2) remove that gene from the donor organism
3) insert it into the host organism
How and why is bacteria genetically engineered?
To produce useful substances like hormones, vaccines and antibiotics
P.g 203 diagram
1) restriction enzymes cut the donor DNA at a specific base sequences and make a staggered cut leaving a few exposed unpaired bases on the end of the DNA strands
2) these are sticky ends
3) the same restriction enzymes are cut open the bacterial plasmid
4) ligase enx
Zymes then rejoin the DNA strands at the sticky ends and the new gene is joined into the plasmid DNA
How do scientist check the gene has successfully transferred into the hosts genome?
Add a gene for antibiotic resistance which is a gene marker
1) insert antibiotic resistance gene into the plasmid at the same time as inserting the gene with the desired characteristics
2) transfer the bacteria to a plate containing the selected antibiotic and incubate to allow the bacteria to grow
3) any bacterial colonies will survive because of the marker gene
What is biotechnology?
Use of biological processes or living organisms to manufacture products
When a natural predator of pests are added to the environment
Example is GM organisms
How are GM organisms created?
When foreign genes are transferred into an organism
Used when referring to plants and animals
golden rice- created when a gene taken from a daffodil is placed into the rice and produces beta-carotene which the body uses to make vitamin A
Bt corn - produced by inserting a gene into maize from the bacteria which codes for a protein that is poisonous to insects pests
How do you genetically modify an organism?
Same as genetic engineering but with an extra step
Engineered bacterium or virus carries the modified gene into a plant or animal cell
How do you calculate the percentage increase from a graph?
Percentage change = final value - initial value / initial value
