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KS4 Food Security
7.4.1 Tropic levels
- Know that trophic levels can be represented by numbers, starting at level 1 with plants and algae and that further trophic levels are numbered subsequently according to how far the organism is along the food chain:
Level 1: Plants and algae make their own food and are called producers.
Level 2: Herbivores eat plants/algae and are called primary consumers.
Level 3: Carnivores that eat herbivores are called secondary consumers.
Level 4: Carnivores that eat other carnivores are called tertiary consumers. Apex predators are carnivores with no predators.
- Know that decomposers break down dead plant and animal matter by secreting enzymes into the environment and that the small soluble food molecules then diffuse into the microorganism.
7.4.2 Pyramids of biomass
- Know that pyramids of biomass can be constructed to represent the relative amount of biomass in each level of a food chain and that trophic level 1 is at the bottom of the pyramid.
- Be able to construct accurate pyramids of biomass from appropriate data
7.4.3 Transfer of Biomass
- Be able to describe pyramids of biomass and explain how biomass is lost between the different trophic levels.
- Know that producers are mostly plants and algae which transfer about 1% of the incident energy from light for photosynthesis.
- Know that only approximately 10% of the biomass from each trophic level is transferred to the level above it.
- Know that losses of biomass are due to:
- not all the ingested material is absorbed, some is egested as faeces
- some absorbed material is lost as waste, such as carbon dioxide and water in respiration and water and urea in urine.
- Know that large amounts of glucose are used in respiration.
- Be able to calculate the efficiency of biomass transfer between trophic levels by percentages or fractions of mass.
7.5 Food production
220.127.116.11 Factors affecting food security
- Know that food security is having enough food to feed a population.
- Know that biological factors that are threatening food security include:
- the increasing birth rate has threatened food security in some countries
- changing diets in developed countries means scarce food resources are transported around the world
- new pests and pathogens that affect farming
- environmental changes that affect food production, such as widespread famine occurring in some countries if rains fail
- cost of agricultural inputs
- conflicts that have arisen in some parts of the world over the availability of water or food.
- Know that sustainable methods must be found to feed all people on Earth.
- Be able to interpret population and food production statistics to evaluate food security.
18.104.22.168 Farming techniques
- Know that the efficiency of food production can be improved by restricting energy transfer from food animals to the environment by limiting their movement and by controlling the temperature of their surroundings.
- Know that some animals are fed high protein to increase growth, such as fish grown in cages with restricted movement.
- Know that intensive farming includes raising battery chickens and calves in pens.
- Know that some people have ethical objections to some intensive farming methods.
- Be able to evaluate the advantages and disadvantages of modern farming techniques.
22.214.171.124 Sustainable fisheries
- Know that fish stocks in the oceans are declining.
- Know that it is important to maintain fish stocks at a level where breeding continues or certain species may disappear altogether in some areas eg cod in northwest Atlantic.
- Know that control of net size and the introduction of fishing quotas play important roles in conservation of fish stocks at a sustainable level.
126.96.36.199 Role of biotechnology
- Know that modern biotechnology techniques enable large quantities of microorganisms to be cultured in industrially controlled vats for food.
- Know that the fungus Fusarium is useful for producing mycoprotein, a protein-rich food suitable for vegetarians.
- Know that Fusarium is grown on glucose syrup, in aerobic conditions, and the biomass is harvested and purified.
- Know that genetically modified bacterium produces human insulin and when harvested and purified this is used to treat diabetics.
- Know that GM crops could provide more food or food with an improved nutritional value such as golden rice.
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