BIOMES & FOOD SECURITY – EXAM NOTES

1. DETAILED NOTES

What is a Biome

A biome is a large natural region of the Earth that shares similar climate, soil, vegetation and productivity. These environmental characteristics determine which plants and animals can survive there.

Biomes are sometimes referred to as ecosystems because they include living organisms interacting with their environment.

Four Key Characteristics of Biomes

  1. Climate – temperature and rainfall patterns.

  2. Soil – nutrient levels, moisture and composition.

  3. Vegetation – dominant plant types.

  4. Productivity – the ability of the biome to support plant and animal life.

Major Global Biomes

Forest

  • The most biologically diverse ecosystems on Earth.

  • Home to over half of all known plant and animal species.

  • Support about 1.7 billion people worldwide.

Types

  • Tropical rainforest

  • Temperate forest

  • Taiga (boreal forest)

Importance

  • Absorb solar energy

  • Store carbon

  • Produce oxygen

  • Provide food, medicines and materials

Threat

  • Deforestation, which reduces biodiversity and increases carbon emissions.

Desert

Deserts are extremely dry regions with very low rainfall.

Characteristics

  • Sparse vegetation

  • Extreme temperatures (very hot or very cold)

  • Many animals are nocturnal to avoid heat.

Examples

  • Sahara Desert (hot)

  • Antarctica and the Gobi Desert (cold)

Around 300 million people live in deserts.

Grasslands

Grasslands are transitional zones between forests and deserts dominated by grasses.

Characteristics

  • Few or no trees

  • Support grazing animals

  • Moderate rainfall (250–900 mm per year)

Importance

  • Highly valuable for livestock grazing and agriculture

  • Provide habitat for birds, reptiles and mammals.

Threat

  • Overgrazing, which can lead to desertification.

More than 1 billion people live in grassland regions.

Tundra

Tundra occurs in extremely cold regions beyond the treeline.

Characteristics

  • Very short growing season

  • Vegetation includes grasses, mosses and lichens

  • Permanently frozen soil layer called permafrost

Types

  • Arctic tundra

  • Antarctic tundra

  • Alpine tundra

Tundra ecosystems are very vulnerable to climate change.

Aquatic Biomes

Aquatic biomes cover most of Earth’s surface and are divided into:

Freshwater

  • Lakes

  • Rivers

  • Wetlands

Marine

  • Oceans

  • Coral reefs

  • Estuaries

Aquatic environments provide:

  • Food

  • Medicines

  • Important habitats

  • Coastal protection

Factors That Influence Biomes

Climate

Climate is the main factor controlling biome distribution.

Two key climate variables:

  1. Temperature

  2. Precipitation (rainfall)

These determine which plants and animals can survive in a biome.

Latitude

Latitude affects the amount of solar energy received.

  • Equator

    • Sun’s rays hit directly

    • Higher temperatures

    • Tropical biomes

  • Poles

    • Sun’s rays spread out

    • Cooler temperatures

    • Polar biomes

Altitude

Temperature decreases as elevation increases.

Temperature drops about 0.65°C for every 100 metres in elevation.

Higher altitudes often have colder climates and different vegetation.

Mountain Ranges

Mountains affect rainfall patterns.

  • Moist air rises and cools on the windward side, causing rain.

  • Dry conditions occur on the leeward side, creating a rain shadow.

Rain shadows often lead to desert formation.

Ocean Currents

Cold ocean currents cool nearby air and reduce evaporation.

This leads to:

  • Less rainfall

  • Drier climates

Example: Western Australia receives less rainfall than eastern Australia.

Soil and Biomes

Soil influences what plants can grow in a region.

Soil characteristics depend on:

  • Temperature

  • Rainfall

  • Bedrock minerals

  • Vegetation

Soil quality affects:

  • Nutrient levels

  • Moisture

  • Biodiversity

  • Agricultural productivity

Australian Biomes

Australia has a diverse range of biomes including:

  • Tropical rainforests (north)

  • Savanna grasslands

  • Deserts (central Australia)

  • Temperate forests (south)

  • Wetlands

  • Coastal ecosystems

European settlement significantly modified these biomes through:

  • Land clearing

  • Irrigation

  • Wetland drainage

  • Introduction of new species

Importance of Biomes to Humans

Biomes support human wellbeing by providing:

  • Food

  • Medicine

  • Natural resources

  • Livelihoods

  • Tourism opportunities

Example: Grasslands

  • Ideal for farming and livestock

  • Origin of major food grains such as wheat and corn.

Example: Coral reefs

  • Protect coastlines

  • Provide food

  • Support fishing and tourism industries

  • Important sources of medical compounds.

Global Food Production

Staple Foods

Staple foods are foods eaten regularly that make up a large part of a person’s diet.

Common staple foods include:

  • Wheat

  • Rice

  • Maize

  • Potatoes

  • Cassava

  • Fish

Rice, wheat and maize provide 60% of global food energy.

The Green Revolution

The Green Revolution increased food production through:

  • High-yield crop varieties

  • Fertiliser use

  • Irrigation

  • Agricultural technology

This greatly increased cereal production in developing countries.

Modifying Biomes for Agriculture

Humans modify natural environments to increase food production.

Irrigation

Artificial watering of crops.

Used to:

  • Increase yields

  • Grow crops in dry regions.

Greenhouses

Glass or plastic structures used to grow crops.

Benefits:

  • Controlled climate

  • Protection from pests

  • Year-round crop production

Fertilisers

Substances added to soil to increase nutrients.

Benefits:

  • Higher crop yields

  • Improved plant growth.

Land Reclamation

Creating new land from water or improving degraded land.

Example: Netherlands creating farmland from the sea.

Food Security

Definition

Food security exists when people have reliable access to sufficient, safe and nutritious food.

Four Dimensions

  1. Availability

  2. Access

  3. Utilisation

  4. Stability

Food Insecurity

Food insecurity occurs when people do not have consistent access to enough food.

Over 850 million people worldwide are undernourished.

Causes

  • Poverty

  • Population growth

  • Conflict

  • Weak economies

  • Natural disasters

  • Climate change

Land Degradation

Land degradation reduces land quality and agricultural productivity.

Major causes:

  • Soil erosion

  • Salinity

  • Desertification

  • Biodiversity loss

  • Pest invasion

Competition for Land

Land is also used for:

  • Urban expansion

  • Industry

  • Biofuel production

This reduces available farmland and can threaten food security.

Climate Change and Food Production

Climate change affects food production through:

  • Rising temperatures

  • Changing rainfall patterns

  • Increased droughts

  • Sea-level rise

  • Spread of pests and diseases

Some regions may benefit from longer growing seasons, but many will experience lower agricultural productivity.

Reducing Food Waste

About one-third of all food produced globally is wasted.

Reducing food waste can:

  • Improve food security

  • Reduce greenhouse gas emissions

  • Save resources such as water and land.

First Nations Australian Land Management

Before European colonisation, First Nations Australians used sustainable land management practices.

Cultural Burning

Controlled fires were used to:

  • Maintain grasslands

  • Promote plant growth

  • Reduce bushfire risk

  • Attract animals for hunting.

Sustainable Farming

First Nations Australians:

  • Took only what was needed

  • Allowed resources time to regenerate

  • Managed land carefully for long-term sustainability.

2. VOCABULARY

Biome
Climate
Vegetation
Productivity
Precipitation
Latitude
Altitude
Rain shadow
Ocean currents
Soil fertility
Deforestation
Desertification
Permafrost
Irrigation
Greenhouse horticulture
Fertiliser
Land reclamation
Staple food
Green Revolution
Food security
Food insecurity
Land degradation
Urbanisation
Biofuel
Climate change
Biodiversity
Cultural burning

3. KEY PHRASES / KEY TERMS AND DEFINITIONS

Biome
A large geographic region with similar climate, soil, vegetation and animal life.

Climate
The long-term pattern of temperature and precipitation in a region.

Precipitation
Any form of water that falls from the atmosphere, including rain, snow or hail.

Latitude
The distance north or south of the equator, affecting climate and temperature.

Altitude
The height of a location above sea level.

Rain Shadow
A dry area on the leeward side of a mountain range where little rainfall occurs.

Permafrost
A permanently frozen layer of soil found in tundra regions.

Deforestation
The clearing or removal of forests, often for agriculture or development.

Desertification
The process where fertile land becomes desert due to drought, deforestation or poor land management.

Staple Food
A food that is eaten regularly and forms a major part of a population’s diet.

Green Revolution
A period of major agricultural improvement using high-yield crops, fertilisers and irrigation.

Food Security
When people have reliable access to enough safe and nutritious food.

Food Insecurity
A situation where people lack consistent access to sufficient food.

Land Degradation
The decline in land quality caused by erosion, salinity, pollution or desertification.

Irrigation
The artificial application of water to land to support agriculture.

Biofuel
Fuel produced from biological materials such as crops.

Cultural Burning
A traditional land management practice used by First Nations Australians involving controlled fires to maintain ecosystems.