Geography GCSE: UNIT 1A – The Living World

Just notes on The Living World. 

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  • Created by: Iqra H
  • Created on: 05-06-12 19:55

Ecosystems

An ecosystem is a community of living organisms (plants and animals) sharing an environment. The largest ecosystems are called biomes.

A decomposer is an organism that gets its energy by breaking down dead material. Bacteria and fungi are decomposers.

A change to one part of an ecosystem has an impact on other parts:

·         Hot, dry summers à reduced plant growth à fewer berries for birds à number of sparrows and threshers fall àfewer birds for sparrowhawks to hunt, so the number of sparrowhawks falls.

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World Ecosystems

Tropical forests are found near the equator in Central and South America, parts of Africa and Asia. They are hot and humid and contain a huge variety of plants and animals - around half of the entire world's species. The trees are mostly hardwood. The climate is called equatorial.

Desert is the driest and hottest of areas. The world's largest desert is the Sahara in North Africa. Areas of scrub land that border the desert are called desert scrub.

Temperate deciduous forests contain trees that lose their leaves and are found across Europe and USA. The weather is mild and wet. 

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Hot, Wet Climates have Tropical Rainforests

Areas Central America, north and east South America (the Amazon), central Africa and south east Asia.

Climate Hot, wet climates with no definite seasons

Soil Isn’t very fertile as heavy rain wash nutrients away.

Plants adaptations:

·         Adapted to heavy rainfall – thick waxy leaves with pointed tip (drip-tips)

·         Tall trees have buttress roots to support their trunks.

·         The trees are deciduous – they drop their leaves in drier periods to reduce water loss.

  • Climbing plants use the tree trunks to climb to reach light.
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Hot, Dry Climates have Hot Deserts

Areas North Africa, the Middle East, south west USA, large parts of Australia.

Climate Very little rainfall. Temperature varies during day / night.

Soil Shallow, gravelly texture.

Vegetation structure plant growth is sparse due to little rainfall.

 

Plant adaptations:

·         Roots are either very long to reach water or spread out to catch as much water as possible when it rains.

·         Cacti have swollen stems to store water. Thick, waxy skin to reduce water loss.

  • Cacti and some bushes have small, spiky leaves to reduce water loss.
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Mild, Wet Climates have Temperate Deciduous Forest

Areas Most of Europe, south east USA, China, Japan.

Climate – Four seasons.

Soil – Is deep and fertile

Vegetation structure

·         Tree layer (30 m)

·         Shrub layer (5-20 m)

·         Undergrowth (less than 5 m)

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Mild, Wet Climates have Temperate Deciduous Forest

Plant adaptations:

· The trees are deciduous hence they drop their leaves during autumn and grow new ones in the spring therefore, it reduces water loss.

  • Wild flowers grow on the forest floor in spring before the tress grow leaves and block out the sunlight.
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CASE STUDY – TEMPERATE DECIDUOUS FOREST

The New Forest, National Park, covers 375 km2 in Hampshire.

Used for:

Timber

· Produces 50,000 tonnes of timber.

Timber products

· Local mills make fencing products out of the timber.

Farming

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CASE STUDY – TEMPERATE DECIDUOUS FOREST (Continued

Recreation

· Approximately 20 million visitors come to the New Forest per year.

· Many recreational activities available such as: cycling, walking, watching wildlife, fishing, golf, special events (New Forest and Hampshire County Show)

 Sustainability of the forest

· Areas with no trees are either replanted or restored to other habitants.

· Walkers and cyclists are encouraged to stay on footpaths and cycle paths to reduce damage.

  • Recreational users are encouraged to act responsibly.

 

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CASE STUDY – TROPICAL RAINFOREST-DEFORESTATION

There are five main causes for deforestation:

Farming

· Cleared for subsistence farms or commercial cattle ranches.

Commercial logging

· To make money.

Population pressure

· Increase in population results to needing more space, so trees are cut down to make space.

Road building

· Increase in settlement and industry so more roads need to be built.

Mineral extraction- Minerals are mined and sold.

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Impacts of Deforestation

Environmental Impacts:

· Fewer trees result to fewer habitats and food source for animals and birds.

· No trees to hold soil together, and heavy rainfall results to soil erosion.

  • If lots of soil from deforested areas is washed away into the river, it may kill fish and the water will be undrinkable, and this may also cause flooding due to the fact that the river bed has been raised.

Social Impacts:

· The quality of life for local people improves as there are more jobs.

· Livelihoods of some local people are destroyed due to deforestation which can cause the loss of animals and plants which people depend on.

  • Some native tribes are forced to move off land due to deforestation.
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Impacts of Deforestation (Continued...)

Economic Impacts:

· Logging, farming and mining create jobs for people.

  • Money is made from selling timber, mining and commercial farming.

Political Impacts:

  • Pressure from foreign governments to stop deforestation.
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TROPICAL RAINFOREST – SUSTAINABLE MANAGEMENT

 Sustainable Logging:

·         Only some trees such as the old ones are felled.

·         This would be less damaging rather than felling all the trees. If few trees are taken, the forest would be able to keep its structure.

·         The least damaging forms are “horse logging” or “helicopter logging” rather than using huge trucks.

(E.G. – Helicopter logging is used in Sarawak, Malaysia)

Replanting:

·         This means when trees are planted to replace the ones which are cut down.

·         This means that there will be more trees in the future.

  • In some countries, there are environmental laws to make logging companies replant trees when they cut down trees.
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TROPICAL RAINFOREST – SUSTAINABLE MANAGEMENT (Cont

Reducing Demand for Hardwood:

·         There is a high demand of hardwood from consumers like Mahogany.

·         This suggests that hardwood is becoming rare to find as people are chopping them down.

  • Strategies to reduce the demand for hardwood include heavily taxing imported hardwood or banning its sale.

Education:

·         Some local people don’t know the environmental impacts of deforestation – they often try to make money in the short-term to overcome poverty by illegal logging.

·         Educating the people would decrease the effect of the amount of people logging.

  • Also, you could educate them about alternative ways to make money. 
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TROPICAL RAINFOREST – SUSTAINABLE MANAGEMENT (Cont

Ecotourism:

·         This doesn’t harm the environment and benefits the locals.

·         Ecotourism provides a source of income to local people and so, they won’t have to log to gain a source of income.

  • Ecotourism improves the quality of life of people and is sustainable.

Reducing Debt:

·         Conservation swaps guarantee the money is spent on conservation.

(E.G. – In 1987, a conservation group paid off some of Bolivia’s debt in exchange for creating a rainforest reserve)

Protection:

·         Environmental laws can be used to protect rainforests.

  • Many countries have set up nature reserves and national parks within rainforests
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CASE STUDY – TROPICAL RAINFOREST

The Amazon: Brazil, Peru, Colombia, Venezuela, Ecuador, Bolivia, Guyana, Suriname & French Guiana. Area of 8 million km2

However, in 1970, 600,000 km2 was destroyed due to deforestation – there were many causes such as:

·         60% - cattle ranching

·         33% - subsistence farming

·         3% - logging

·         3% - mining

·         1%  - small scale commercial farming

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CASE STUDY – TROPICAL RAINFOREST (Continued...)

Environmental Impacts:

 

·         Habitat destruction and loss of biodiversity (E.G. – endangered species increased from 218 in 1989 to 628 in 2008)

 

  • The Amazon stores 100 billion tonnes of CO2 deforestation would release the CO2 and this causes global warming.

Social Impacts:

·         Native tribes being forced off land for cattle ranching (E.G. – the Guarani tribe, Brazil)

  • Conflict between landowners, subsistence farmers and native people (E.G. – in 2009, there were riots in Peru over rainforest destruction)

Economic Impacts:

·         Farming makes lots of money (E.G. – 2008, Brazil made $6.9 billion from trading cattle)

  • The mining industry creates jobs for people (E.G. – Buenaventura Mining Company)
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CASE STUDY – TROPICAL RAINFOREST (Continued...)

However, sustainable management strategies are being used such as:

Deforested areas are being replanted.

Some companies are reducing the amount of hardwood trees felled.

Ecotourism is being popular (E.G. Madre de Dios region, Peru)

Most countries have environmental laws.

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CASE STUDY – HOT DESERTS

Kalahari Desert: Botswana, Zimbabwe, Namibia & South Africa. Area of 260,000 km2

It gets very little rainfall, approx. 200 mm per year.

Boteti River only permanent river, however, temporary streams are created after rainfall.

Droughts

The Kalahari is densely populated, some native people live there (E.G. San Bushmen and the Tswana)

Farming cattle, goats and sheep is a big industry in the Kalahari.

However, there are negative impacts:

·         Overgrazing causes soil erosion.

·         Fences which have been put up blocks migration routes of wild animals.

·         Mining and farming = native people being forced off land.

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CASE STUDY – HOT DESERTS (Continued...)

There are management strategies carried out in the Kalahari:

·         Some people are trying to conserve water. (E.G.  Windhoek, Namibia)

·         Water supply is being increased by building dams.

·         Game reserves have been created for the native people to live to protect wildlife (E.G.  Central Kalahari Game Reserve, Botswana was set up in 1961 as a refuge for the Sans Bushmen)

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CASE STUDY – HOT DESERTS (Continued...)

Mojave Desert: California, Nevada, Utah & Arizona. Area of 57,000 km2

Gets less than 250 mm of rain per year.

Commercial farming in the area.

It is densely populated, but the population is increasing (Las Vegas, California)

Tourist destinations include Death Valley (1 million visitors per year) and the Grand Canyon.

However, there are negative impacts:

·         Rapid population growth.

·         Farming uses lots of water causing soil erosion.

·         Tourists reduce the amount of water resources, drop litter and damage plants as well as soil erosion.

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CASE STUDY – HOT DESERTS (Continued...)

There are management strategies carried out in the Mojave:

·         Water conservation schemes in the area (E.G. - the Mojave Water Agency)

·         Mojave Desert has four National Parks where native species are protected and there are rules set in place.

·         Some hotels in Las Vegas conserve water (E.G.  MGM Mirage Hotels)

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