57 terms

IGCSE CIE Geography - Climate and Natural Vegetation


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A biological environment consisting of all the living organisms within a particular area and the factors that interact with the organisms e.g. weather, soil, air and water.
Food Chain
Shows the feeding connections between organisms within an ecosystem.
Nitrogen Cycle
The recycling of nitrogen through the ground and atmosphere.
Trophic Level
The position of an organism in a food chain.
Producer (Autotroph)
Any vegetation that produces complex organic compounds from simple inorganic molecules using energy from the light or inorganic chemical reactions.
Consumer (Heterotroph)
An organism that requires organic compounds to grow. It eats plants and / or animals.
Apex Predator
The top predator in a food chain in the top trophic level.
An organism that only consumes meat.
An organism that only eats vegetation.
An organism that eats both meat and vegetation.
Organisms that break down dead or decaying matter. They are vital to the nitrogen cycle as decomposition releases nitrogen into the atmosphere.
Examples of Human Activities that Disrupt Food Chains
Hunting for species for meat or parts.
Deforestation: loss of habitat, removal of organic matter, increased water erosion and removal of producers.
Mining causes pollution to ecosystems.
Tourism disrupts animals and reduce their territory.
Urbanisation and road building can destroy habitats, increase accidents, pollution and noise.
Dams can flood habitats and change water courses from flowing to stationary.
Distribution of Tropical Rainforests
Close to the equator.
Examples of Famous Tropical Rainforests / Areas with Tropical Rainforests
The Congo Basin in central and west Africa.
The Amazon in Brazil, Ecuador, Peru and Bolivia.
SE Asia (Malaysia, Thailand, Vietnam, Indonesia and the Philippines).
North-east Australia
Southern India and Sri Lanka
Central America
The removal and cutting down of trees.
The replanting of trees once they have been cut down.
Planting trees in an area that previously did not have trees.
Importance of Tropical Rainforests
Flood control
Control of soil erosion
Source of nutrients to humus layer in soil
Medical remedies
Cash crops and agricultural products
Home to indigenous groups
Reasons for Deforestation
Cattle ranching
Subsistence farming
HEP (use rivers that run through rainforests)
Road building
Urban growth
Population growth
Timber (hardwoods)
Problems Caused by Deforestation
Biodiversity loss
Reduced photosynthesis
Silting of rivers
Silting of seas and oceans
Breaking of the nutrient cycle (soils' nutrients washed away by flooding etc).
Loss of indigenous homes
Reduced rainfall
Hunter Gathering
The hunting of wild animals and gathering of wild fruits.
Shifting Cultivation
Deforesting one area, growing crops for a number of years, and moving to a new location.
Slash-and-Burn Farming
The burning down of an area of rainforest to allow for farming. The area is cleared quickly and the ash fertilises the soil.
Land Degradation
The reduction in quality and quantity of soil due to vulnerability to erosion as the humus layer is removed.
Fallow Periods
Not using land for a period of time in order for it to regain fertility.
Tropical Rainforest Climate
Close to the equator.
Temperature constant between 25℃ - 30℃.
Experiences convection rainfall as it is close to the equator where temperatures are warm.
Sometimes experiences rainstorms due to a build up of humidity.
Tall trees > 50 metres in the rainforest.
25 - 35 metre-trees, containing 50% of the wildlife in rainforests.
Shrub Layer
Layer of dense vegetation near the ground. Sunlight is limited so vegetation and organisms have adapted to living in dim light.
A bundled vine that climbs up trees to gain sunlight.
Strangler Figs
Grows around the outside of a tree, slowly draining its nutrients. When the host tree dies it does as well.
Buttress Roots
Large roots that support the tree and maximise absorption of nutrients.
Fan Palms
Trees with large leaves to catch sunlight and water from rainfall.
Humus Layer
Decaying biological matter in soil that provides most of its fertility.
Trees in the rainforest all shed leaves at different times, meaning that the rainforest stays green most of the time.
Drip-Tip Leaves
Leaves that allow water to drip down onto the ground to avoid it being damaged by high amounts of rainfall.
Animals in Tropical Rainforests
Large mammals: Tigers (SE Asia), Jaguars (Central and South America), Leopards (Africa)
Smaller mammals: Sloths, primate, lemurs.
Species: Birds, amphibians, reptiles, insects etc.
Threats to Animals in Tropical Rainforests
Habitat loss due to deforestation.
Climate change
Pollution (especially affecting amphibians and reptiles).
Sustainable Forestry
Forestry that does not cause permanent damage to any ecosystem and can be maintained.
Protecting Tropical Rainforests
Creation of national parks.
Rainforest sales
Consumer labelling (FSC)
Sustainable forestry
Bans on rainforest products e.g. animal skins and hardwood.
Global initiatives / global treaties
Recycling, reducing and reusing
Rainforest Sales
Selling parts of rainforest to allow polluters to offset their pollution.
Consumer Labelling (FSC)
The Forest Stewardship Council labels products that have been produced sustainably and lets consumers buy sustainable wood products only.
Distribution of Deserts
Close to the equator.
Examples of Famous Deserts
Sahara (Northern Africa)
Kalahari (South Africa)
Atacama (South America)
Gobi (Central Asia)
Arabian (Middle East)
Great Victoria and Great Sandy (the Outback in Australia)
Mojave and Chihuahuan (North America)
Desert Climates
Extremely dry and arid.
< 250mm precipitation per annum.
Dry environment caused by dry air.
Lack of moisture means that there are limited clouds, and so deserts are exposed to radiation from the sun.
Radiation can come and escape freely as there are no clouds: day temperatures are very high and night temperatures are very low.
High diurnal (daily) temperature range.
Succulent Plants
E.g. Cactus: flat, fleshy plants that are able to store water in their leaves, trunks and roots.
Ephemeral Plants
Plants with short life cycles and can take advantage of short wet seasons to be pollinated.
Role of Long and Wide Roots of Plants
Maximises water absorption by plants and increases stability in loose soil.
Use of Spiky and Waxy Surface on Plants
Protection; animals do not eat or damage them.
Nocturnal Animals
Many animals emerge in night time only; during the day they burrow down in the sand.
How do camels survive in the desert?
Store fatty tissue in their humps which releases water and fat upon metabolism, allowing them to survive in the desert.
Threats of Human Activity to Deserts
Extraction of resources
Tourists damaging dunes
Overgrazing and overcultivation killing the limited amount of vegetation.
Deforestation of limited amount of trees
Toyotarisation: Driving of 4 by 4 vehicles across the desert, disturbing wildlife and killing vegetation and creating dust storms.
The process of land being turned into desert.
Human Causes of Desertification
Fertiliser and pesticide use (soil does not have enough time to recover nutrition and is vulnerable to degradation)
HYV and GM crops encourage overcultivation.
Unsustainable water use
Physical Causes of Desertification
Rising temperatures
Decreasing amounts of rainfall
Flash floods (causing soil degradation).
Wind (increasing soil erosion by wind).
Problems Caused by Desertification
Dust storms
Reduced crop yield
Solutions to Desertification
Crop rotation and fallow periods allow nutrients to return to the soil.
Shelter belts (areas of forest to reduce wind and water erosion of soil).
Reforestation and afforestation
Grazing quotas (limiting number of animals that can graze on an area of land).
Population control