Feeding the Future

Feeding the Future

The world's population keeps growing. The land, the seas and the fresh water available to feed it do not. **Food security** means having enough safe food to feed a population. It is not the same thing as producing enough food globally: food has to reach the people who need it, at a price they can pay, year after year. Anything that pushes demand up, or supply down, or gets in the way between the two, is a threat to it. This final Biology module weighs up the ways we produce more food, and the costs that come with each of them. (All of 4.7.5 is **Biology-only**.)

What threatens it?

Select ALL THREE situations that would threaten food security.

• A new virus begins killing wheat plants in a country that exports grain worldwide
• A drought lasting several years in a major grain-growing region
• A conflict that closes the ports a fertiliser supply passes through
• Birth rates falling steadily across most of the world
• The price of fertiliser halving over two years
• A new wheat variety that yields a fifth more grain per hectare

Farming for efficiency

An animal is a leaky way to turn plants into food. Most of what it eats is spent staying alive rather than becoming meat, and the energy it burns is energy that never reaches your plate. So intensive farming reduces the leaks: • **Limit the animals' movement**, because moving costs energy. • **Control the temperature** of their surroundings, because keeping warm costs energy too. Less energy lost to movement and warmth means more of the food becomes **biomass**, and biomass is what gets sold. **Fish farming** raises supply the same way, though it brings its own welfare and disease problems in crowded pens.

Two calves

Two identical calves eat exactly the same amount of the same feed. One is kept in a warm barn with little room to move. The other roams an exposed hillside. Which gains more mass, and why?

• The barn calf, because energy not spent moving or keeping warm is available for growth
• The hillside calf, because exercise builds muscle and muscle is mass
• Both the same, because they ate exactly the same amount
• It cannot be predicted without knowing the breed

Efficiency against welfare

This is one of the few places in the specification where the exam wants an argument rather than a fact. Both columns below are true at the same time, and an answer that gives only one of them cannot reach the top band:

Weigh it up

Extended-response practice. In about 40 words, evaluate restricting the movement of farm animals to make meat production more efficient. Structure your answer around:

• the efficiency benefit (more of the feed becomes meat)
• the animal-welfare concern
• a clear conclusion that comes down on one side

Saving the fisheries

Fish stocks have fallen sharply through **overfishing**. Two controls do most of the work, and each targets a different way of taking too much:

Manage the fishery

You advise the authority managing a collapsing fishery. Make the calls.

• A quota is introduced. Boats now throw undersized fish back dead, because those fish would count against the quota. What does that tell you?
• Both measures are in place and the stock recovers for two good seasons. The industry asks for the quota to be lifted entirely. What do you advise?
• A neighbouring country refuses to set any limit on the same shared stock. What does that do to your measures?

Why a collapse?

Taking too many adult fish does not just mean a smaller catch next year. It can end the fishery altogether. Why?

• Fewer adults left means fewer young produced, so each year starts from a smaller stock than the last
• The remaining fish move away to somewhere they are not being caught
• The fish that survive grow smaller each generation
• The boats become less efficient at finding the remaining fish

Biotech on the menu

Two biotechnologies appear in this specification, and they solve different problems. **GM crops.** A gene, often taken from a **bacterium**, is transferred into a crop plant. The commonest genes give **resistance to insect pests** or **tolerance of a herbicide**, so less of the crop is lost between sowing and harvest. The plant is not made to grow faster; less of it is lost. **Mycoprotein.** The fungus ***Fusarium*** is grown in a fermenter on glucose syrup in aerobic conditions, then harvested and purified into a protein-rich food. It needs no animal and very little land, which is why it appears in a food-security topic at all. Both are contested, and the specification expects you to know that: concerns about GM include effects on wild plants and insects, and on who controls the seed supply.

Make mycoprotein

Put the stages of producing mycoprotein into the order they happen.

• The fermenter is sterilised, so that nothing else is growing in it before anything is added
• Glucose syrup is added as the food source, along with a nitrogen supply
• Fusarium is added and grown in aerobic conditions at a controlled temperature and pH
• The fungal biomass is harvested from the fermenter
• It is purified and dried to produce mycoprotein

What does it buy?

A farmer plants a GM maize carrying a bacterial gene that makes the plant toxic to a beetle larva. Compared with the same maize grown conventionally on the same field, what is the most likely result?

• A larger harvest from the same area, because less of the crop is lost to the beetle
• The plants grow faster and reach harvest sooner
• The crop needs much less water and fertiliser
• The grain contains more protein per kilogram

Which problem does it solve?

Course complete

Food security is threatened by a rising population, new _____, environmental change, rising input costs and conflict. Farming is made more efficient by restricting movement and controlling _____, which raises the welfare objection an exam answer has to weigh. Fishing stays sustainable through quotas and a larger net _____, both protecting the breeding stock. Mycoprotein is made from the fungus _____, grown on glucose syrup in aerobic conditions and then harvested and purified.