Geography Revision

Food Chain: a flow of energy between animals and plants in an ecosysytem

Producer: starts the food chain, gets energy from the sun and makes it through photosynthesis

Primary Consumer: eats the producer

Secondary Consumer: eats the primary consumer

Tertiary consumer: eats the secondary consumer

Food Web: shows a more complex energy transfer in an ecosystem

The whole animal has not been eaten as there is feathers/bones left.

Energy has been used for: hunting,respiration,reproduction and excretition

• Birth rate
• Death rate
• Gross National Income (GNI) - takes an average and it does not represent everyone in the country
• Unemployment
• Doctors per year
• Infant moratality rate

The Demographic Transition Model (The DTM) uses changes in birth and death rate to establish how developed a country is

• Economic Investment
  
• Debt Relief - Tied Aid
• Fairtrade - producer/farmer getting a fair price - more expensive to buy - farmer gets the money (SOCIAL PREMIUM) - community gets more money - government - infrastructure - education - healthcare

Physical

• natural disasters
• poor soil
• poor weather conditions

Economic

• land locked
• poor trade lines
• debt

Historical

• war/conflict - money spent on weapons not development
• colonisation - 1960s Europe ruled over African nations - exploitation of rersources/people
• buildings damaged

I agree to some extent that human activity is the cause of desertification on the fringes of hot deserts. Desertification is degradation of land and vegetation, soil erosion and the loss of top soil and fertile land.

An example of this is population growth. Population growth is when the population grown and puts pressure on the land as more crops need to be grown. This can result in land close to existing deserts being overgrazed; this means that there are too many animals to be supported by the limited vegetation. When the vegetation has been destroyed the land will turn to desert.

Another example of this is overgrazing. Overgrazing is when vegetation is stripped from the desert and then farmers leave cattle grazing the smae field for too long. This can result from the need to produce more food and can lead to the soil becoming exhausted; it will turn to dust and become infetile. The ground will get exposed to rain, wind and sun and the soil will go dry and it would erode.

A way to reduce desertification  is appropriate technology . Appropriate technology is when water slows down so it gives more time to infiltrate soil. It will reduce desertification as it involves using methods and materials that are appropriate to their level of development. For example in rural parts of Burikina Faso lines of stones have been use to reduce soil erosion (0.5m to 1.5m high). This way to reduce desertification increases crops by 50%; its simple; stops soil erosion by trapping sediments behind rocks; more crops grow.

Another way to reduce desertification is water and soil management. Soil and water managemnt is when crops are planted repeatedly in the same area, keeps draining the land of the smae nutrients neede for that plants growth. It will reduce desetification as the high rate of eveaporation in hot deserts leads to a build up of salts on the surface. For example The Tal Rimah Rangeland Rehabillitation Project aims to reverse the desertification caused by overgrazing. This way to reduce desertification reduces plants dying; to heavy of rainfall; breaks soil and washes it away.

To conclude, human activity do cause desertification but humans are also trying to reduce desertification at the same time.