B6.2 Feeding the human race Flashcards
Name five factors that affect food security.
- Human population size
- New/number of pests and pathogens
- Changing diets
- Global warming and climate change
- High cost of farming methods
How can we increae food production?
- Maximise photosynthesis
- Using fertilisers (manure better longterm)
- Removing competition & pests
- Pest resistant crops
- High yield crops
- GM crops
What is intensive farming?
Techniques that aim to produce the maximum food product yield from the minimum area of land through:
- Using fertilisers and pestisides to aid plant growth
- Maximising animal growth rates
- Minimising labour inputs by using machinery
What is organic farming?
Farming using more natural method of crop production and rearing animals, and avoiding the use of chemicals.
What is meant by sustainable food production.
Producing food in ways that can be continued indefinitely.
Identify the advantages and disadvantages of fish farming.
Advantages
- 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
Disadvantages
- 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 can farmers reduce pesticide and fertiliser usage?
- Use organic manure instead of manufactured fertilisers
- Crop rotation
- Biological control
What is a hydroponic system?
Growing plants in a nutrient medium rather than in soil.
What is biological control?
Control of pest by deliberately introducing natural predators of the pest.
How can gene technology help agriculture?
Beneficial genes for pest resistance or the ability to gorw in harsher conditions could be introduced.
How can gene fertilisers and pesticides help agriculture?
- Pesticides kill pests that could harm the growth of the plant
- Fertilisers provide the plant with all the nutrients it needs so that it can grow more quickly
What is selective breeding?
Breeding plants or animals for particular characteristics.
Describe how selective breeding is carried out.
- Decide which characteristic of the species is desirable
- Select paretns with high levels of this characteristic
- Breed from these individuals
- Select the best offspring
- Breed again.
- Repeat for many generations unitl all offspring display the desired traits.
What are the disadvantages of selective breeding?
- Reduced gene pool (number of alleles)
- Reduced variation
- Increased suseptability to disease
- Increased chance of inheriting genetic disease
What is genetic engineering?
Altering an organisms genome to produce an organism with desired characteristics.
How are new genes introduced into an organism?
- The genes that code for a desired characteristic are identified
- The organism genes are cut using restriction enzymes to create sticky ends
- The DNA from a bacterial plasmid is also cut to produce sticky ends using the same restriction enzymes
- The gene is inserted into the bacterial plasmid along with a marker gene (antibiotic resistance / luminescence)
- Ligase enzymes used to rejoin the 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.
