7.5 Food production Flashcards
Food production
Food security is having enough food to feed a population.
That population’ could represent a group of people on a range of different scales, from a particular a family, to a town, to a region or even a whole country.
Food security gives an indication of how much food is available.
Factors threatening food security
Changing population
Changing diets
Changing environments
Pests and pathogens
Costs
Conflicts
Sustainable methods of farming and producing food are needed in order to overcome food shortages and help populations whose food security is under threat.
Sustainable food production involves making enough food but ensuring this is done without using resources (such as water and soils) faster than these resources can be renewed and used again.
Farming techniques
The efficiency of food production can be improved by restricting energy transfer from food animals to the environment. This can be done by:
limiting their movement – livestock are kept in small pens or cages so that they use less energy moving around.
controlling the temperature of their surroundings – livestock are kept at their optimum temperature so that they use less energy regulating their body temperatures themselves.
Movement and staying warm are two main processes that require the energy released in respiration.
If livestock don’t have to carry out these processes, there is more energy available for growth.
In addition, some animals are fed high protein foods to increase growth.
Ethical objections to farming techniques
Some people have ethical objections to some modern intensive farming methods.
Keeping livestock in very confined spaces (factory farming) is controversial because disease can spread easily and many people think it is unethical to make animals live in unnatural and uncomfortable conditions.
Modern farming techniques include - use of fertiliser, keeping livestock in small cages and hedgerow removal.
Fish stock
Fish stocks (the populations of fish that we catch for food) in the oceans are declining.
This is mainly due to overfishing.
This could potentially result in:
Some species of fish completely disappearing in certain areas or even going extinct (eg. we are at risk of losing cod completely in the north-west Atlantic)
Ocean food chains being disrupted, affecting many other aquatic species.
Fewer fish for human consumption – this would be especially problematic for populations that rely on fish as a main source of food.
For these reasons, it is important to maintain fish stocks at a level where breeding continues.
Sustainable fisheries are required to achieve this – these are fisheries in which the overall population size of fish species does not decrease, because the number of fish caught does not exceed the number of new fish born.
Control of nets
Control of net size and the introduction of fishing quotas play important roles in the conservation of fish stocks at a sustainable level.
Increasing the size of gaps in fishing nets can help in two main ways:
Fewer unwanted species will be caught and killed, as they can escape through larger net gaps.
Juvenile fish of the fish species being caught can escape through larger net gaps, meaning they can reach breeding age and have offspring before they are caught and killed. This ensures the population of the fish species being caught can be replenished.
In addition to tighter controls on net size, fishing quotas that limit the number and size of particular fish species that can be caught in a given area have been introduced by many countries to stop species becoming overfished.
Biotechnology
Biotechnology involves the alteration and use of living organisms to produce products for human use.
Some forms of biotechnology have been around for thousands of years eg. agriculture and selective breeding to produce better foods.
Modern biotechnology techniques include genetic modification and the ability to culture large quantities of microorganisms for food.
Biotechnology may be able to help provide sufficient food for the increasing human population.
Microprotein
The fungus Fusarium is cultured on an industrial scale in fermenters
These fermenters are large vats that can be kept at the optimum pH and temperature for Fusarium to grow.
The fungus is grown in aerobic conditions and provided with glucose syrup as a food source.
The fungus grows and multiplies within the fermenter.
The fungal biomass is then harvested and purified to produce mycoprotein
Mycoprotein is a protein-rich food.
Production of insulin
Genetic engineering is changing the genetic material of an organism by removing or altering genes within that organism, or by inserting genes from another organism.
The organism receiving the genetic material is said to be ‘genetically modified’, or is described as a ‘transgenic organism’.
The DNA of the organism that now contains DNA from another organism as well is known as ‘recombinant DNA’.
The gene for human insulin has been inserted into bacteria which then produce human insulin which can be collected and purified for medical use to treat people with diabetes.
Genetic modification of bacteria to produce human insulin
The gene that is to be inserted is located in the original organism – the gene for insulin production is located within a human chromosome.
Restriction enzymes are used to isolate or the human insulin gene, leaving it with ‘sticky ends’ (a short section of unpaired bases).
A bacterial plasmid is cut by the same restriction enzyme leaving it with corresponding sticky ends.
The plasmid and the isolated human insulin gene are joined together by DNA ligase enzyme.
If two pieces of DNA have matching sticky ends, DNA ligase will link them to form a single, unbroken molecule of DNA.
When the bacteria reproduce the plasmids are copied as well and so a recombinant plasmid can quickly be spread as the bacteria multiply and they will then all express the human insulin gene and make the human insulin protein.
The genetically engineered bacteria can be placed in a fermenter to reproduce quickly in controlled conditions and make large quantities of the human protein.
