Food supply — Cambridge IGCSE Biology 0610 Revision Notes & Topical Questions

Section 1 of 24Intensive food production

Intensive food production

Intensive production

Intensive production producing food more efficiently from a finite amount of land and other resources.

Machinery

• Machinery replaces human labour and allows much larger areas to be farmed efficiently.

Chemical fertilisers

• Chemical fertilisers increase soil nutrients, so plants grow larger and produce more fruit.

Insecticides and herbicides

• Insecticides and herbicides kill unwanted insects and weeds, so there is less damage and less competition.

Selective breeding

• Selective breeding produces animal breeds and crop varieties that reliably give high yields.

Section 2 of 24Intensive livestock farming

Small area

• Small area animals use less energy on movement, so more goes into growth.

High-energy feed

• High-energy feed more energy is gained per unit of food digested.

Antibiotics

• Antibiotics given regularly to prevent disease.

Warm environments

• Warm environments animals spend less energy regulating body temperature.

Energy efficiency

• Energy efficiency less energy input is needed per unit of yield.

Section 3 of 24Advantages and disadvantages of intensive livestock farming

Advantages	Disadvantages
Less land is needed for large amounts of food	Ethical issues from cruel treatment of animals
Food is produced all year in controlled conditions	Natural habitats may be destroyed to make land available
Lower cost, so food is cheaper	Grazing land becomes a monoculture, reducing biodiversity
Reliable high yield	Overgrazing causes soil erosion
Less energy is lost per unit of food	Cattle produce methane, a greenhouse gas
	Waste washes into waterways and causes pollution

Section 4 of 24Monocultures

Monoculture

Monoculture growing only one type of crop on an area of farmland, such as oil palm trees in the Indonesian rainforest.

Advantage

Advantage machinery

• specialised machines for planting, weeding and harvesting raise efficiency and cut labour costs.

Advantage

Advantage yield

• conditions can be optimised for the single crop, giving higher yields.

Section 5 of 24Problems of monocultures

Biodiversity

• Biodiversity one plant variety feeds few herbivore species, which support few predator species.

Pests

• Pests ample food for a pest lets its population increase, and a disease can affect every plant.

Insecticides

• Insecticides harmless insects are also killed.

Pollution

• Pollution pesticides pollute the environment.

Resistance

• Resistance repeated use of the same chemical lets pests become resistant to it.

Section 6 of 24Improving food supply compared

Method	Benefit	Problem
Fertilisers	Higher yield	Run-off causes eutrophication
Pesticides	Fewer pests	Kill non-target species and build up in food chains
Machinery	Faster work	Fuel use and carbon dioxide
Selective breeding	Better crops	Less genetic variation
Monoculture	Efficient harvesting	Disease spreads and habitats are lost
Intensive livestock	Cheap meat	Welfare, disease, waste

Section 7 of 24More from the specification

1

Modern agricultural machinery and fossil fuels

• Modern agricultural machinery and fossil fuels transitioning farm machinery away from heavy fossil fuels provides a means to reduce agricultural emissions.

2

Agricultural Intensification and Modern Farming Techniques

• Mechanised machinery, synthetic chemical fertilisers, selective breeding,
  • and chemical pesticides have substantially elevated crop yields per hectare to feed expanding human demographics.

3

Negative Ecological Impacts of Monoculture

• Planting vast monocultures reduces local biodiversity, exhausts specific soil micronutrients,
  • and facilitates the rapid, unchecked dispersal of specialist insect pests and pathogenic diseases.

4

Environmental Consequences of Intensive Livestock Production

• Intensive animal husbandry generates significant methane emissions, consumes large volumes of agricultural grain feed,
  • and produces nutrient-rich slurry that threatens local aquatic ecosystems.

5

Fossil fuel

• Fuel formed from long-dead organisms.

6

Captive breeding

• Breeding endangered species in zoos or reserves.

7

Sustainable

• Able to continue without damaging resources for the future.

8

Conservation

• Protecting species and habitats.

9

Endangered

• At risk of extinction.

10

Extinction

• Loss of every member of a species.

11

Endangered species

• A species at risk of extinction.

12

Climate change

• Long-term changes in temperature and weather patterns.

13

Habitat destruction

• Damage or removal of the places where organisms live.

14

Global warming

• Rise in the mean temperature of Earth's surface and lower atmosphere.

Section 8 of 24Increasing food production

• The growing human population needs more food, so farmers increase yields with several methods.

Section 9 of 24Methods compared

Method	How it helps	Disadvantage
Fertilisers	Supply nitrate, phosphate and potassium so crops grow bigger	Run-off causes eutrophication
Pesticides	Kill pests, weeds and diseases that reduce yield	Kill beneficial insects and accumulate in food chains
Selective breeding	High-yield, disease-resistant varieties	Reduces genetic variation
Machinery	Faster planting and harvest on larger fields	Fossil fuel use and soil compaction
Greenhouses and hydroponics	Controlled light, temperature, CO2 and minerals	High cost and energy use
Irrigation	Water in dry regions	Salt build-up and water depletion

Section 10 of 24Monoculture and habitat loss

Monoculture

• Monoculture growing a single crop over a large area makes farming efficient.

Habitat loss

• Habitat loss it removes hedgerows and wild plants, so habitats and biodiversity are lost.

Pests and disease

• Pests and disease spread rapidly.

Clearing

• Clearing fields are often cleared of trees and wetlands, reducing the wildlife they support.

Section 11 of 24Intensive animal farming and energy efficiency

Energy loss

• Energy loss energy is lost at each trophic level, so feeding people on crops is more efficient than on meat.

Confinement

• Confinement animals are kept in confined, warm conditions and given high-energy feed.

Efficiency

• Efficiency less energy is lost in movement and as heat, giving more meat or eggs per unit of food.

Section 12 of 24Fish farming and overfishing

Fish farming

• Fish farming raising fish in enclosures protects wild stocks.

Problems

• Problems it can spread disease and pollute water.

Overfishing

• Overfishing removing fish faster than they reproduce makes populations collapse.

Solutions

• Solutions quotas, bigger net mesh sizes and protected breeding areas.

Section 13 of 24Sustainable food production

Crop rotation

• Crop rotation including legumes restores nitrate.

Biological control

• Biological control and integrated pest management reduce pesticide use.

Organic fertilisers

• Organic fertilisers such as manure used in sensible amounts.

Wildlife strips

• Wildlife strips maintaining hedgerows keeps biodiversity.

Reducing waste

• Reducing waste reduce food waste and consider plant-rich diets.

Sustainable production

• Sustainable production meets present needs without damaging resources for future generations.

Section 14 of 24Evaluating food production methods

Yield data

• Yield data compare fields with different treatments, such as no fertiliser or added nitrate.

Percentage increase

• Percentage increase change in yield divided by original yield × 100.

Balance

• Balance weigh the benefit of higher yields against environmental harm and cost.

Section 15 of 24More from the specification

More from the specification

Sustainable agriculture and fossil fuels

• Sustainable agriculture and fossil fuels reducing diesel machinery dependent on fossil fuels provides an ecological means to enhance crop yield efficiency.

Intensive livestock farming and environmental impact

• Intensive farming of livestock increases food yield for expanding human populations but produces vast quantities of greenhouse gases like carbon dioxide and methane.

Deforestation of tropical forests

• Humans clear large areas of native forests for cattle grazing and arable agriculture, releasing stored carbon dioxide and accelerating global climate change.

Endangered species and habitat loss

• Large-scale land clearance destroys natural ecosystems,
• which is one of the primary reasons why numerous native plant and animal species become endangered.

Conservation strategies for biodiversity

• Habitat conservation, sustainable agriculture,
• and captive breeding programs are essential methods to protect endangered species and mitigate the ecological footprint of humans.

Intensive livestock farming and environmental impact

• Intensive farming of livestock increases food yield for expanding human populations but produces vast quantities of greenhouse gases like carbon dioxide and methane.

Deforestation of tropical forests

• Humans clear large areas of native forests for cattle grazing and arable agriculture, releasing stored carbon dioxide and accelerating global climate change.

Endangered species and habitat loss

• Large-scale land clearance destroys natural ecosystems,
• which is one of the primary reasons why numerous native plant and animal species become endangered.

Conservation strategies for biodiversity

• Habitat conservation, sustainable agriculture,
• and captive breeding programs are essential methods to protect endangered species and mitigate the ecological footprint of humans.

Climate change

• Long-term changes in temperature and weather patterns.

Habitat destruction

• Damage or removal of the places where organisms live.

Global warming

• Rise in the mean temperature of Earth's surface and lower atmosphere.

Captive breeding

• Breeding endangered species in zoos or reserves.

Intensive farming

• Producing as much food as possible from limited land and resources.

Species

• A group of organisms that can reproduce to produce fertile offspring.

Conservation

• Protecting species and habitats.

Carbon

• Element with four valence electrons that forms the backbone of organic molecules.

Endangered

• At risk of extinction.

Extinction

• Loss of every member of a species.

Section 16 of 24Making food production more intensive

Intensive production

Intensive production producing more food from a limited area of land and finite resources.

Need

• Need the human population is increasing, so more food is needed.

Machinery

• Machinery tractors and harvesters replace human labour and allow larger areas to be farmed efficiently.

Chemical fertilisers

• Chemical fertilisers increase nitrates, phosphates and potassium, so plants grow larger and give higher yields.

Pesticides

• Pesticides insecticides kill insect pests, herbicides kill weeds that compete for light, water and minerals, and fungicides control disease.

Selective breeding

• Selective breeding produces crop varieties and animal breeds that reliably give high yields or resist disease.

Section 17 of 24Intensive livestock farming

Housing

• Housing animals are kept in small spaces, fed high-energy food and often kept in warm buildings.

Energy use

• Energy use energy that would go to movement and temperature regulation goes into growth.

Efficiency

• Efficiency less energy input is needed per unit of food produced.

Section 18 of 24Advantages and disadvantages

Advantages	Disadvantages
Less land needed for a large amount of food	Ethical concerns about animal welfare
Food produced all year in controlled conditions	Disease spreads rapidly among crowded animals, leading to antibiotic use
Lower cost, so cheaper food	Waste can wash into waterways and cause pollution
Reliable high yield	Methane from cattle contributes to global warming

Section 19 of 24Monocultures

Monoculture

Monoculture a large area planted with one type of crop, such as wheat, maize or oil palm.

Benefits

• Benefits allows specialised machinery and optimal growing conditions, so efficiency and yield are high.

Section 20 of 24Problems of monocultures

Biodiversity falls

• Biodiversity falls one plant species supports few herbivores and few predators.

Pests increase

• Pests increase food is abundant for them and all crops are equally susceptible to a disease.

Pesticide use

• Pesticide use heavy use causes pollution and pesticide resistance in pests.

Soil nutrients

• Soil nutrients used up if the same crop is grown repeatedly, so fertiliser is needed.

Crop rotation

• Crop rotation helps avoid this.

Section 21 of 24Environmental and ethical balance

Resource use

• Resource use farming uses large amounts of water and fossil fuels.

Soil erosion

• Soil erosion occurs when land is overgrazed or ploughed without ground cover.

Habitat destruction

• Habitat destruction cultivating more land often destroys habitats.

Sustainable approaches

• Sustainable approaches organic farming, crop rotation and biological control using natural predators.

Section 22 of 24More from the specification

1Crop selective breeding as a means

• Crop selective breeding as a means artificial selection for high-yield, disease-resistant plant cultivars provides a vital means to ensure sustainable global food supplies.

2Deforestation and Atmospheric Carbon Dioxide

• Clearing large tracts of forests and burning trees releases stored carbon dioxide into the atmosphere while reducing global photosynthetic uptake, contributing directly to enhanced global warming.

3Biodiversity Loss and Endangered Species

• Habitat destruction caused by humans clearing forests threatens endangered species with extinction,
• reducing biodiversity and disrupting ecological food chains.

4Forest Conservation Strategies

• Conservation programs protect natural ecosystems through sustainable logging, replanting trees,
• and establishing nature reserves,
• which maintain atmospheric oxygen and carbon cycles while safeguarding wildlife.

5Climate change

• Long-term changes in temperature and weather patterns.

6Captive breeding

• Breeding endangered species in zoos or reserves.

7Conservation

• Protecting species and habitats.

8Carbon

• Element with four valence electrons that forms the backbone of organic molecules.

9Endangered

• At risk of extinction.

10Extinction

• Loss of every member of a species.

Section 23 of 24Key terms

Term	Meaning
Intensive farming	Producing as much food as possible from limited land and resources.
Monoculture	Growing one type of crop on a large area.
Selective breeding	Humans choosing which individuals breed to improve yield.
Fertiliser	A substance supplying plant nutrients such as nitrate.
Pesticide	A chemical that kills pests.
Biodiversity	The number of different species in an area.

Term	Meaning
Hydroponics	Growing plants in nutrient solution without soil.
Irrigation	Supplying water to crops artificially.
Overfishing	Removing fish faster than they can reproduce.
Crop rotation	Growing different crops in turn, including legumes.
Biological control	Using natural predators to control pests.
Sustainable	Able to continue without damaging resources for the future.

Term	Meaning
Intensive farming	Producing large amounts of food from limited land.
Herbicide	A chemical that kills weeds.
Insecticide	A chemical that kills insect pests.
Fungicide	A chemical that controls fungal disease.
Pesticide resistance	The ability of pests to survive a pesticide.
Monoculture	Growing a single crop over a large area.

Section 24 of 24Exam technique

1

Saying intensive farming produces less food — it produces more from limited land.

2

Saying fertiliser kills fish directly — run-off causes eutrophication, which removes oxygen.

3

Forgetting the benefit before the problem — name both for each method.

4

Saying monoculture increases biodiversity — it reduces it.

1

Saying fertiliser has no environmental cost — run-off causes eutrophication.

2

Saying pesticides kill only pests — they also kill beneficial insects.

3

Saying fish farming has no problems — it can spread disease and pollute water.

4

Saying sustainable farming means lower yields only — it aims to meet needs without damaging resources.

1

Saying intensive animal farming wastes energy — it reduces energy lost in movement and heat.

2

Saying monocultures support many species — they support few.

3

Saying pesticide resistance never develops — repeated use selects resistant pests.

4

Ignoring the ethical issue — animal welfare is a key disadvantage.