Revision notes · Ecology

Food production

Factors affecting food security4.7.5.1

Definition: Food security is having enough food to feed a population.

Several biological, social, and environmental factors threaten global food security.

•An increasing human birth rate puts greater demand on global food supplies.
•Changing diets in developed countries mean scarce food resources are transported around the world.
•New pests and pathogens can destroy crops and livestock, leading to severe food shortages.
•Environmental changes, such as droughts caused by climate change, can trigger widespread famine.
•High costs of agricultural inputs (like seeds and fertilisers) and conflicts reduce food production and availability.

⚠️ Common mistake: Thinking food security only refers to the safety or quality of food, rather than having access to a sufficient quantity.

🧠 Remember: Remember PPEC: Population growth, Pests/pathogens, Environmental change, Cost/conflict.

Definition: Intensive farming involves using methods that restrict energy transfer from food animals to the environment to maximise growth yield.

Efficiency of food production can be improved by restricting energy losses from livestock.

•Restricting animal movement in small cages or pens reduces energy lost through respiration during muscle contraction.
•Controlling ambient temperature reduces the energy animals use to maintain body heat.
•Feeding livestock high-protein foods increases their rate of growth.
•Intensive farming raises ethical concerns regarding animal welfare and the rapid spread of diseases in crowded conditions.

⚠️ Common mistake: Thinking energy is lost directly as movement; energy is actually lost via respiration to supply energy for muscle contraction.

🧠 Remember: Less movement + warm temperature = less respiration = more energy converted to biomass.

Definition: Sustainable fisheries involve managing fish stocks so that breeding can continue and species do not become extinct.

Fish stocks in the oceans are declining due to overfishing and require strict management.

•Overfishing reduces fish populations to levels where age structure changes and breeding cannot replace lost numbers.
•Establishing fishing quotas limits the mass and species of fish that can be caught.
•Regulating net mesh size allows smaller, younger fish to escape so they can reach breeding age.
•Sustainable fishing ensures fish stocks remain at levels where harvest is balanced by natural reproduction.

⚠️ Common mistake: Assuming larger net mesh sizes catch smaller fish; a larger mesh size actually allows smaller fish to escape.

🧠 Remember: Big mesh lets small fish pass to reach breeding age.

Definition: Biotechnology is the use of biological organisms, cells, or processes to produce useful products such as food and medicine.

Modern biotechnology enables large quantities of food to be grown efficiently using microorganisms and genetic modification.

•The fungus *Fusarium is grown in fermenters to produce mycoprotein*, a protein-rich food suitable for vegetarians.
•Fusarium is grown under aerobic conditions* on glucose syrup, and the biomass is harvested and purified.
•Genetically modified (GM) crops can be engineered to provide improved nutritional value, such as Golden Rice producing Vitamin A.
•GM crops can also be engineered to be resistant to drought or pests, increasing overall crop yield.

⚠️ Common mistake: Forgetting that *Fusarium requires aerobic conditions* (oxygen) to respire and grow efficiently in the fermenter.

🧠 Remember: Fusarium needs glucose, oxygen (aerobic), and warmth to produce mycoprotein*.

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