AQA Geography - The Living World

Ecosystems

A natural system made up of plants, animals and the physical environment. There are complex interrelationships between the biotic (living) and the abiotic (non-living) components.

Living Components (Biotic)

Plants, animals, producers, carnivores, herbivores.

Non-Living Components

Climate, temperature, rainfall, soil, water, water temperature, light levels.

Producers

Convert energy (by photosynthesis) from the sun into glucose. e.g. plants.

Consumers

Get energy through eating the producers.

Food Chain

Shows the direct links between producers and consumers in the form of a simple line.

Food Web

Shows all the connections between producers and consumers within an ecosystem in a complex way.

Nutrient Cycling

Minerals necessary for plant growth are extracted from the soil and water. These are then passed through the food chain before being returned to the soil by decomposers.

Decomposers

When plants or animals die, these organisms break them down and help to recycle nutrients making them available again for the growth of plants or animals.

Epping Forest

An example of an ecosystem - a temperate deciduous woodland.

Oak, elm, ash and beech.

Deciduous trees found in Epping Forest - TDF.

Polar climate/ecosystem

Artic/Antarctic

Cold air sinks at the North and South poles creating very low temperatures and dry conditions. In Antarctica, temperatures can drop below -50 degrees Celsius.

Foxes, owls, sparrowhawks.

Secondary consumers or top carnivores. Predators found in Epping Forest -TDF.

Global Biomes

Large scale ecosystems e.g. tundra, deserts, tropical rainforest, temperate deciduous forests.

Tropical rainforests

Close to the equator.

High temperatures and heavy rainfall due to low pressure belt along the equator. This creates ideal conditions for the vegetation to grow.

Global Atmospheric Circulation

The worldwide system of winds and pressure belts, which transports heat from tropical to polar latitudes.

Hot deserts

30 degrees N and S of the equator.

Sinking air at subtropical high pressure belts stops clouds from forming. This creates high daytime temperatures and low rainfall. Night time temperatures are very low.

The Layers in the Rainforest

The Emergent Layer - 45/50 m

The Canopy - 30m

The Under canopy Layer - 15m

Forest Floor - 0m

Buttress roots

Massive triangular ridges, help to support the base of tall trees and help transport water. Helps gas exchange by increasing surface area.

Animal Adaptations in the Rainforest

Birds live in the canopy feeding on nectar from flowers.

Most species are found in the canopy where there is the most light e.g. monkeys and sloths.

Soil in the Rainforest

Latosol or laterite.

Infertile as heavy rainfall leaches away nutrients.

Nutrients are found at the surface where dead leaves decompose rapidly in the hot, humid conditions. This is the humus layer.

Climate in the Rainforest.

-Warm and wet conditions.

-High rainfall - 2000+mm a year.

-High temperatures - 27 degrees Celsius throughout the year.

-The sun is ahead most of the time.

-Humid due to high levels of transpiration.

-Intense rainfall due to low pressure giving convectional rainfall.

Tundra location

From the Arctic Circle to 60-70 degrees N e.g. Alasks, Canada & Northern Europe. There are only very small areas in the S. hemisphere due to lack of land at these latitudes.

Emergents

Very tall (50m+) trees such as Kapok trees - have adapted to grow taller to get the most light and have no branches so there is no wasted energy.

Epiphytes

Plants which live on branches, taking nutrients from the air and the tree and use insects to pollenate. This allows the plant to receive more sunlight.

Lianas

These are thick parasitic vines that use tree trunks to reach the sunlight, getting nutrients from the tree and the air.

Commercial Farming

Rainforest has been replaced with crops like soybean in Amazonia. The amount of rainforest cleared for this has doubled between 1990 and 2010.

Subsistence Farming

Tribal people in the rainforest hunt and gather their food from the forest and grow some food in cleared pockets of forest.

This farming is small scale and sustainable.

-One method of clearing the land is a slash and burn technique, using fire to clear the land.

-The burning creates valuable nutrients that helps plants to grow.

The value of the Amazon Rainforest

Minerals provide the region with vast natural resources including oil, gas and gold.

The Amazon is one of the world's greatest carbon sinks.

The rainforest's biodiversity and wildlife habitats are of global importance.

Rates of Deforestation

Tropical rainforests are the most endangered ecosystem on earth. Every 2 seconds, one hectare is destroyed.

40% of the world's deforestation occurs in Brazil and Indonesia. The rates in Brazil are decreasing but in Indonesia are increasing.

Medicine in Brazil

-25% of medicines come from rainforest plants.

-More than 2000 tropical rainforest plants have anticancer properties.

Resources in Brazil

-Trees provide valuable hardwoods as well as nuts, fruits, minerals, crude oil and rubber. Mahogany is a very expensive hardwood.

Sustainable Management of Brazil

-Ensures the rainforest remains a lasting resource for future generations.

-Allows valuable resources to be used without causing long term damage to the environment.

Selective Logging

The removal of only mature, damaged or particularly valuable trees. This must also include replanting.

Conservation and Education

Rainforest can be preserved in conservation areas such as national parks or nature reserves. These areas can be used for education, scientific research and tourism.

Ecotourism

-Countries like Brazil, Costa Rica, Belize and Malaysia have promoted their countries for ecotourism.

-This aims to introduce people to the natural world to benefit local communities and protect the environment for the future.

-Through income generated by ecotourism, local people and governments benefit from retaining and protecting rainforest trees.

International Agreements

Global organisations such as the Forest Stewardship Council (FSC)promotes sustainable management by identifying timber from renewable sources.

Debt Reduction

Some countries have borrowed money to fund developments.To pay of these debts, some have raised money for massive deforestation programs. Recently, some donor countries and organisations have reduced debts in return for agreements that rainforests will not be deforested.

Sustainable Development

The use of natural resources such as the rainforest in a way that preserves them for the future, but at the same time allows economic development.

Drip tips

Many plants have pointy ends to allow the excessive rain to drip off.

Soil erosion

The roots of trees bind the soil together. Deforestation causes the soil to become loose and easily be washed away by heavy rain. This can pollute water supplies.

Road building

The Trans-Amazonain Highway stretches for 4000km and opens up the Amazon to further explotation.

Permafrost

the permanently frozen ground below the soil surface in the arctic tundra.

Active layer

the upper layer of frozen soil that thaws briefly during the summer

Arctic willow

A plant which grows close to the ground to avoid the strong winds. This has a fast life cycle which allows it to bloom in the short Arctic summer.

Soil in the tundra

Thin and infertile as there is little vegetation to provide organic content. Frozen in winter and waterlogged in summer.

Caribou

These animals migrate long distances across the Arctic roaming for food. They have sharp hooves to scrape through the ice and double layers of fur to trap heat.

solifluction

This takes place in the summer when the top layer of soil flows downhill over the frozen ground beneath.

Population distribution in Alaska

Sparse. Less than 1 per km2. Mostly along the coast and in the south. Centres in Anchorage and Fairbanks.

Oil industry in Alaska

Provides 100 000 jobs and contributes 1/3 of the state's income - $40 billion.

Oil spills

The Exxon Valdez spill in 1989 and a broken pipe in 2006 caused huge damage to the fragile ecosystem in Alaska.

Fishing in Alaska

Employs 1 in 10 Alaskans. Provides 78 500 jobs and brings in $6 billion dollars to the local economy.

Mineral extraction in Alaska

Alaska was the gold rush state but in 2013 the Pebble Mine was closed down following protests from the Native American community.

Energy production in Alaska

50 HEP plants and geothermal energy make this area a major source of renewable energy.

Wilderness

a remote and largely uninhabited area.

International Agreements to protect cold environments

Countries in the far north and indigenous people have established the Arctic Council to promote sustainable development and conservation.

Arctic National Wildlife Refuge

National Parks and protected areas have been established to conserve the tundra. Barack Obama banned oil exploration here.

NGOs

Organisations such as Greenpeace have campaigned for the establishment of a 'global sanctuary' in the Arctic.