Background Information• Africa is the world’s second largest continent.• It is about four times the size of the mainland United States.• The African terrain varies from desert to tropical rainforest, to mountainous regions and fertile river valleys.
The Sahara Desert• It’s the largest desert in the world taking up over 25% of Africa’s land and is continues to grow.• The Sahara was formed thousands of years ago because of a shift in the earth’s tilt on the axis and it caused great climate changes.• The desert is expanding because of the misuse of the surrounding land.
Sahara & Sahel• The sahel region is located south of the Sahara and is being cleared for farming and is overgrazed by herds of animals.• Destruction of plants has led to wide- spread soil erosion, which has resulted in more land for farming and herding.• As the land continues to erode it is becoming one with the desert to the north.
The Nile River• It is the largest river in the world and is over 4,000 miles long extending from south of the equator northward to the Mediterranean Sea.• Throughout history people have lived in Egypt and Sudan have settled along the banks of the Nile which flooded yearly depositing rich silt on the land.• The floods also brought destruction and death when they came at the wrong time or too fiercely.• At times the floods would not come at all and great droughts would result.
Levees and Dams• In an attempt to control the water levees and dams have been built for thousands of years.• In the 1960’s a large dam was built near the town of Aswan, Egypt.• The Aswan Dam peaks at more than 12,000 feet and hold nearly 6 trillion cubic feet of water in its reservoir, Lake Nasser.• The dam has been able to prevent flooding, but allows for year-round irrigation.
Negative Effects of the Aswan Dam• The rich silt that was once deposited on the land and to deltas is no longer carried downstream, but instead builds up behind the dam.• Without the 40 tons of silt being deposited farmers have had to utilize chemical fertilizers, which can be harmful to the land in the future.• The loss of silt has led to erosion of the river- banks and the delta.• The loss of nutrients has led to the decline in the animal life near the river.
Extinction of Animals• Another environmental concern is the number of animals facing extinction through the lost of habitat (home) and hunting.• Many of the species located in Africa are now endangered.
Wildlife & Land in Africa• Flamingos are attracted to the lakes of the Great Rift Valley because they contain alkaline, which is known as baking soda.• Mount Kilimanjaro in Tanzania is the highest mountain in Africa.• Madagascar is the 4th largest island in the world.• Today, efforts are being made to preserve what is left of the forest and exotic animals.
Human Conflict• Humans’ needs for food and income by farming and herding drive them to destroy the land.• Extreme poverty leads starving people to destroy the natural plant life, which protects the soil and provides habitats.• The worst problems persists the most where the population is greatest.• Environmentalists are trying to work with people to preserve what is left of the land and animals.
Checking for Understanding1. Generally describe the physical geography of Africa.2. Explain how desertification occurred and continues to occur in the Sahara Desert.3. Explain the importance of the Nile river and the controversy surrounding the Aswan Dam that was built to control it.4. Describe the great rift Valley and how it was formed.5. Describe some of the environmental problems facing the African continent AND why they are difficult to solve.6. Explain factors that affect the population density of the African continent. Include examples to support your claim.