Geography

Desert

Objective: To find out about the location, abiotic and biotic factors of the desert, its adaptations, air circulation the Hadley Cell and the process of desertification and how to stop the march of the desert.

Location – where on the Earth’s surface do we find deserts– distribution (using the handout indicate where the deserts are located and name the major areas – use your own devices).

Climate – deserts are found in certain areas due to its global location and the associated climate of the area (draw a climate graph on the graph paper (next page) using the following data – below)

J F M A M J J A S O N DRainfall(mm) 20 15 8 6 4 0 0 0 5 10 15 19Temp (c°) 12 14 16 25 27 33 33 32 28 22 15 13

Figure 1 Desert - North Africa

Abiotic and biotic factors

Abiotic factors - the parts of the ecosystem that are non-living. Abiotic factors play a major role in the environment and the abiotic factors that are specifically in deserts are temperature, bodies of water, rainfall, and soil. 

Biotic factors - the parts of the ecosystem that are living. Ecology essentially focuses on how living organisms interact with their environment. Biotic factors refer to both animals and plants. 

Figure 2 An oasis in the desert

Figure 3 Desert plants

The Hadley cell

The largest cells extend from the equator to between 30 and 40 degrees north and south, and are named Hadley cells, after English meteorologist George Hadley.

Within the Hadley cells, the trade winds blow towards the equator, then ascend near the equator as a broken line of thunderstorms, which forms the Inter-Tropical-Convergence Zone (ITCZ). From the tops of these storms, the air flows towards higher latitudes, where it sinks to produce high-pressure regions over the subtropical oceans and the world's hot deserts, such as the Sahara Desert in North Africa.

The Inter-tropical convergence zone (ITCZ) Using the map o the right and www.garsidej.wordpress.com explain the ITCZ.

Plant and animal adaptation

Plants

Animals

Desertification

What is desertification?

Factors responsible for desertification – physical and human – explain with diagrams.

Using the Sahel (N Africa) as a case study describe the effects of desertification upon this area and the people and governments are trying to rectify the situation?