Transcript Physical Geography of Africa PPT

Bell Ringer
List three thing that you know about Africa:
•
One about the physical geography of Africa
•
One about the people of Africa
•
One about Africa’s history
Physical Geography of Africa
Welcome to Africa
•
Second largest
continent 11,700,000
sq. mi.
•
17% of the world’s
population.
•
2 ½ times the size of
the U. S.
• Huginormungantic.
Climate





Desert
Tropical Wet
Tropical Wet and
Dry
Semiarid
Marine West
Coast
How much of Africa is
covered with
rainforests or jungles?
Vegetation

Desert
 Savannah
– grasslands

Rain Forest
– Rains up to 17 ft. per year
– Covers 37 countries.
– 15% of the land surface of
Africa.
What internal forces are shaping Africa?
• Seismic Activity & Plate Tectonics
Ups and Downs
Africa’s Plateaus
 Lowlands along the coast.
 Most of Africa is at least
1,000 ft. above sea level.
 Austin = 450 ft above sea
level
 Africa = Plateau Continent
Basins and Rivers

Basin = depression
 Basins collect water which
feed rivers.
 Africa’s rivers are bad for
transportation.
– Waterfalls
– Rapids
– Gorges
Victoria Falls straddles the border of Zambia and Zimbabwe.
Victoria Falls is located on the Zambezi river in south central
Africa. Victoria Falls has the sixth largest flow rate of all the water
falls in the world and water plummets 355 feet before reaching the
bottom.
Sahara Desert
North Africa
•3,500,000 square miles, bigger than “Lower
48 States”
•Temperatures can range from 25*F to 130*F
or more on the same day!
(The very dry air of the desert holds little moisture and thus holds
little heat so as soon as the sun sets, the desert cools considerably.
Clear, cloudless skies also help to quickly release heat at night.)
•Only 20% is sand dunes. The rest is ordinary
desert.
-- A sand dune is an accumulation of sand formed by
the wind, by waves and by eroding sandstone.
•Major aquifers lie deep beneath the surface
in several areas.
•Limits Transportation and communication
between northern and southern Africa
What is the Sahel?



Narrow band of dry grassland used for
farming and ranching – separates Desert from
Tropical climate zones and has semi-arid
climate.
Desertification – ruining of land due to human
activities and climate changes
Caused by
– Farming
– Overgrazing of livestock
– Cutting down too many trees for wood


Q: What is “slash and burn”?
A: Slash and burn is a farming technique in which people cut down and burn
trees to create farmland. While it quickly clears land, it can destroy some
plant species.
Question: What is the result of the above?
creation of more desert!
The Sahel covers 14.9 billion hectares of the earth’s surface.. The landscape varies from flat terrain to lofty sand
dunes and mountains.
How much land makes up a hectare? 1 hectare is 100m x 100m = 10,000 square meter or
2.47105381 Acres
Kalahari Desert
Southern Africa
 Name means “Great Thirst”
in Tswana (a local language)

Receives more precipitation than traditional
deserts and therefore is host to more animals
than most deserts.

Home to the African people
known as the San or
“Bushmen.”
They were the first known human inhabitants of the
Kalahari.

Habitat of Meerkats and many
other unique species.
The Kalahari is one of Africa’s last wildlife paradises.
Animals that live in the region include hyenas, lions,
meerkats, several species of antelope, and many types of
birds and reptiles.
Vegetation in the Kalahari consists of
dry grassland and scrubby acacias.
Grasses thrive during the summer
rainy season.
Nile River

North and East Africa

Longest river in world, 4180 miles
(Amazon is 3969, Mississippi is
3896 miles).

Two rivers, Blue Nile and White
Nile, feed the river, which drains
from Lake Victoria.
What are the Blue Nile and the White Nile?
The two major tributaries of the Nile River are the Blue Nile and
White Nile. The striking difference between them is their color and
origin. The Blue Nile, which begins in the mountains of Ethiopia,
starts off with a bright blue color. As it passes through Sudan,
however, it picks up black sediment that gives it a darker hue. The
White Nile, which begins in the forests of Rwanda and flows through
Lake Victoria, is a whitish-gray color, due to the light gray sediment it
carries. Although the White Nile is longer than the Blue Nile, the Blue
Nile carries around two-thirds of the Nile's water supply.


About 160 million people live in the Nile River basin, in 10
countries.
Aswan Dam in Egypt, provides power and water.
Aswan Dam

Lake Nasser created
by this dam

Control floods on
the Nile River, but
sunk ancient ruins.

Provides water and
power for Egypt
Congo River Basin
•Central Africa
•Covered in dense jungle
•2nd Longest in Africa, 2900 miles long.
The Congo Rainforest
The Congo Rainforest is the 2nd largest rainforest on Earth, next to the Amazon, and stretches across
the Democratic Republic of Congo (as well as other countries) with the Congo River running
through it. Being in a tropical wet climate, the rainforest experiences over 60 inches of rainfall.
Crops such as bananas, pineapples, cocoa, tea, and coffee are grown here.
“Killer Lakes”
Africa has three lakes that are
situated atop pockets of magma.
These pockets keep the lake water
filled with CO2.
Lake Nyos, Camaroon
Lake Monoun, Camaroon
Lake Kivu: on the border of
Rwanda and Democratic
Republic of Congo in East
Africa.
How did Lake Nyos suddenly kill 1,700 people?
Lake Nyos had long been quiet before it happened. Farmers and migratory herders in the West African country of
Cameroon knew the lake as large, still and blue.
But on the evening of Aug. 21, 1986, farmers living near the lake heard rumbling. At the same time, a frothy spray
shot hundreds of feet out of the lake, and a white cloud collected over the water. From the ground, the cloud grew
to 328 feet (100 meters) tall and flowed across the land. When farmers near the lake left their houses to investigate
the noise, they lost consciousness.
The heavy cloud sunk into a valley, which channeled it into settlements. People in the affected areas collapsed in
their tracks -- at home, on roads or in the field -- losing consciousness or dying in a few breaths. In Nyos and Kam,
the first villages hit by the cloud, everyone but four inhabitants on high ground died.
The valley split, and the cloud followed, killing people up to 15.5 miles (25 kilometers) away from the lake. Over the
next two days, people from surrounding areas entered the valley to find the bodies of humans and cows lying on the
ground.
By Aug. 23, the cloud had mostly blown away, and the silence had lifted. After being unconscious for up to 36
hours, some people revived to find, horrifically, that their family members, neighbors and livestock were dead.
What Happened?
Scientists reasoned that CO2 had been trapped in the bottom of Lake Nyos for a long time, held down by 682 feet (208
meters) of water. On the day of the eruption, however, something external triggered the release of gas. Most likely, it
was a rockslide from one of the lake's walls. When the falling rocks sunk to the bottom of the lake, they pushed up
some gas. Then most of the gas bubbled up.
When the CO2 concentration was 15 percent or less, people lost consciousness and later revived. Individuals who
inhaled more than 15 percent CO2 stopped breathing in minutes and died.
Result
Under the right circumstances, this gas could explode out
like a Coke bottle fizzing out.
This gas has killed thousands in the past, and will do so again in the future.
Serengeti Plain
East Africa, between Kenya and Tanzania
Most of Africa is flat grasslands, home to
many wild animals (elephants, giraffes,
antelope, rhinos). The most famous is the
African Lion.
The Serengeti Plain is one of the world’s largest savanna’s (tropical grassland), and can support millions of
different animals such as zebras, lions, cheetahs, giraffes, gazelles, and many more. Rainfall in this region is
seasonal and alternates between a wet and dry season. Along with the seasonal rains are dueling winds. The hot,
dry harmattan comes from the Sahara and is welcomed after the wet season as it dries up the moisture in the air.
Cool, humid air is also brought from the southwest. When these two winds collide tornadoes are common
through the Serengeti.
Mt. Kilimanjaro

East Africa, on Serengeti Plain
 Inactive volcano, 19,000 ft tall.
 Has glaciers on its peak.
 Popular tourist destination.
The volcanic summit of Kilimanjaro is located along the eastern branch of the Great Rift Valley. Rising to 19,341 feet
Kilimanjaro it is the tallest peak in Africa. Shifting tectonic plates millions of years ago formed not only the Great
Rift Valley, but also Kilimanjaro. The plate movements created a series of faults where Kilimanjaro and the Great
Rift Valley lie. Volcanic eruptions from Kilimanjaro helped form what is currently the Great Rift Valley.
Great Rift Valley
•East Africa
•“Horn of Africa” slowly pulling away
from Africa
•The Great Rift Valley pulled apart
over millions of years, faults (cracks)
appeared in the earth –the land sank to
form many long steep slopes called
escarpments.
Escarpments separate two level land surfaces and are
formed by one of two processes: erosion and faulting.
•Tectonically very active, many
volcanos and frequent earthquakes
Lake Victoria





Lake Victoria is the largest lake in Africa and the source for the White Nile River.
It is located between the east and west branches of the Great Rift Valley.
Lake Victoria is located in three different countries including Uganda, Kenya, and
Tanzania.
It is the 2nd largest freshwater lake in the world with only Lake Superior in the
United States surpassing it (sq. meters).
Lake Victoria is relatively shallow at only a depth of 270 feet.
Rift Lake System
Several major lakes along the Great Rift
Valley, including:
Lake Victoria – one source of the Nile
River, very shallow (84m)
Lake Tanganikya – deepest lake in
Africa, 2nd largest in world by volume
Lake Nyasa – largest number of
freshwater fish species anywhere.
Ample water supplies, so large
populations in this part of Africa.
Olduvai Gorge

Part of “Great Rift Valley”, which is full
of fossils.

Oldest hominid (pre-human) fossils , 2
million years old.

-Homo Habilis - Its name, which
means ‘handy man’, was given in
1964 because this species was
thought to represent the first stonetool maker. Lived from approximately 2.33
to 1.4 million years ago


-Homo Erectus -
oldest known
early humans to have possessed
modern human-like body proportions.
Lived between about 1.89 million and
143,000 years ago
Discovered by Louis and Mary Leakey in
1950’s. Whole family were
paleoanthropologists.
Political Map of Africa