PHYSICAL GEOGRAPHY OF AFRICA AND SOUTHWEST ASIA

 

This activity looks at the geographic patterns of landforms, vegetation and climate in Africa and adjacent areas of Southwest Asia.  Like the previous activities, it uses Geographic Information Systems technology to explore the dramatic differences from place to place across this vast area.  You will work with computer maps of vegetation, landforms, precipitation and population density.  You will also use the computer to view landscape photographs that illustrate various aspects of the physical environment.

·        Broad patterns in the physical geography of Africa and Southwest Asia:

·          Dynamic links among rainfall, elevation and vegetation

·          Location of major desert regions

·          Location of major grassland savannas

·          Location of major tropical rainforest areas

·          Links between the physical environment and population densities

·        Characteristics of the physical landscapes of Africa and Southwest Asia:

·          Deserts and desert oases

·          The margin of the desert and the savanna

·          Tropical highlands

·          Tropical rainforests

·          Human activities and the environment

We'll begin the activity by identifying the broad regional patterns of vegetation.  First, use the Maps button to retrieve the vegetation map from the electronic map atlas:

·        Press the Maps button

·        Select Vegetation

·        Select Map All Vegetation Types

 

Use the Scantron form to respond to the numbered questions below.

 

1.      What type of vegetation is represented by the bright green color found in Central Africa and the coastal portions of West Africa?

a.    Temperate grassland

b.   Tropical savanna

c.    Tropical rainforest

d.   Mediterranean scrub

e.    Desert

 

 

2.      What type of vegetation surrounds the tropical rainforest on the north, south, and east?

3.      What type of vegetation lies just north of the tropical savanna in North Africa?

4.      What type of vegetation lies just south and southwest of the tropical savanna in southern Africa?

5.      What type of vegetation lies at the very northernmost and southernmost edges of the continent of Africa?

 

Notice the symmetry of vegetation patterns from north to south across the African continent.  The tropical rainforest lies near the center of the continent along the equator.  As latitude increases on either side of the equator, tropical savanna appears, then desert, then Mediterranean scrub.

Precipitation is one of the most important factors that control the distribution of vegetation.  Compare the patterns of vegetation you have already observed with patterns of precipitation.

 

·        Press the Maps button

·        Select Precipitation

·        Select Map All Precipitation Ranges

 

6.    What are the two dominant rainfall categories of the tropical rainforest areas of Africa?  (Bubble in 2 answers. You can redraw the vegetation map to compare if you are unsure.)

a. Over 80 inches

b.40 to 80 inches

c. 24 to 40 inches

d.16 to 24 inches

 

7.    What is the dominant rainfall category in the desert areas of North Africa and Southwest Asia? (You can redraw the vegetation map to compare if you are unsure)?

a. Less than 4 inches

b.4 to 8 inches

c. 8 to 16 inches

d.16 to 24 inches

Precipitation totals in the tropical savanna can vary.  Generally, it is greater than eight inches but less than eighty inches.  The total amount of precipitation is not the key factor that generates tropical savanna vegetation.  Instead, the seasonality of the precipitation is most important.  Tropical savannas receive heavy precipitation in the summer months but have a marked dry season during the rest of the year.

Be sure you are viewing the Precipitation Map, and notice that narrow bands of gradually increasing precipitation mark the region of tropical savanna lying between the deserts of North Africa and the rainforests of Central Africa.  This is the region of tropical savanna known as the Sahel.  It is a transition zone between the Sahara Desert to the north and tropical rainforest to the south.  It is the driest part of the tropical savanna, generally less than eight inches of precipitation.

 

8.    In the Sahel, the climate varies more as you move

a. along meridians (north-south)

b.along parallels (east-west)

 

Precipitation across the Sahel varies considerably from year to year.  Some years are dry, with precipitation levels resembling the desert to the north; some years are wet with rainfall levels similar to those of the rainforest to the south.

To gain insight into the characteristics of these vegetation/precipitation zones you will be viewing photographic images of the areas.  When viewing the photos, it is important to understand where they are located relative to the vast area of North Africa and Southwest Asia.  You can view a map showing the locations of each of the groups of photos:

 

·        Press the Maps button

·        Select Landscapes

·        Select Map All Landscapes

 

Each of the blue squares is linked to a landscape photo.  If you want to view the photos:

 

·        Press the Maps button

·        Select the region you want to view

·        Press the Zoom button

·        Select an appropriate area to zoom in on

·        Click on each of the blue boxes

 

 

 Tropical Rainforest

 

 

The bulldozers in the bottom of the photo show the size scale of the photo.  Study the top-right part of the photo where the vegetation is (not the area that has been cleared), and answer the following question:

 

9.    Consider the types of plants (trees, shrubs, or grasses), height of the vegetation, color of vegetation, density of vegetation, and the percentage of ground covered with vegetation. Which best describes the vegetation?

 

a.       Gray-green shrubs and some trees; moderately dense; ground fully covered

b.      Brown and yellow grasses and shrubs; ground mostly covered

c.       Tall, dense green trees and shrubs; ground fully covered.

d.      Reddish-yellow tall grasses and some trees; ground sparsely covered

 

 

This is a photo of the Sahel.   Remember that the Sahel lies at the boundary where tropical savanna is changing to desert.  Consequently, it is the driest part of the tropical savanna zone.

 

10.  Is the vegetation look like a good place for grazing animals?

a. Yes, grass is abundant

b.No, there is mostly rock and dirt

 

11.  Why are recurring famines a problem in the Sahel?

a. Water management methods are primitive

b.Urban dwellers use up the water

c. Water wells are undependable

d.Summer rains are undependable

 

12.  Look at the color of the grass and the leafiness of the tree in the foreground. Do they suggest that the photo was taken in a drier or wetter rainfall year in the Sahel?

a. Drier

b.Wetter

 

 

 

13.  Does it appear from the photo that this is one of the drier or wetter rainfall years in the Sahel?

a. Drier

b.Wetter

 

 

This photo illustrates the vegetation that is typical of the tropical savannas that receive more precipitation than in the Sahel.  Notice the broad grasslands with drought tolerant trees scattered throughout the landscape.

 

14.  What is the precipitation category in this part of the tropical savanna?

a. Less than 4 inches

b.4 to 8 inches

c. 8 to 16 inches

d.16 to 24 inches

 

15.  Remembering that tropical savanna climate has a marked seasonality of precipitation, check the vegetation and sky conditions. Which seasonal change is taking place?

a. End of wet season, beginning of dry season

b.End of dry season, beginning of wet season

16.  What is the precipitation category of this part of the tropical savanna?

a. 8 to 16 inches

b.16 to 24 inches

c. 24 to ­40 inches

d.over 80 inches

 

17.  Compared to the drier parts of the tropical savanna, the vegetation in this photo is:

a. Denser, with more trees

b.Sparser, with fewer trees

 

Remember that tropical savannas vary in the amount of precipitation they receive, from as little as eight inches to as much as 40 and even sometimes 80 inches.  This difference in precipitation makes for differences in vegetation, with the wetter savannas having more trees and usually more luxuriant grasslands.  The important characteristics which unites all savannas into one vegetation/precipitation zone is the seasonality of the precipitation; i.e., tropical savannas receive heavy precipitation in the summer months but have a marked dry season the rest of the year.

 

This is a picture of the pyramids of Giza in the Sahara Desert. 

 

18.  What is the precipitation category in this zone?

a. Less than 4 inches

b.4 to 8 inches

c. 8 to 16 inches

d.16 to 24 inches

 

19.  What vegetation, if any, can be seen in the photo?

a. Moss on the north side of pyramids

b.No vegetation is visible

 

Little vegetation grows in the Sahara Desert.  However, there are scattered locations in the Sahara where oases provide water from underground that can support the growth of vegetation in a very small area around the water source.

 

20.  What environmental hazard is threatening the plants in this desert oasis?

a. Wind-blown sand dunes

b.Wind-blown smog

c. Wind-blown grasshoppers

d.Strong winds

 

21.  What is the precipitation category range of this location?

a. 4 to 8 inches

b.8 to 16 inches

c. 16 to 24 inches

d.24 to 40 inches

 

What makes this climate unique is that the rainfall comes in the winter, while the dry season occurs in summer.  This is the opposite of the tropical savanna vegetation type. Winters are cool compared to the tropical areas, with occasional frost.

 

22.  What is an important human activity that is found in Mediterranean climates?

a. Raising crops requiring warm, dry summers and cool winters (e.g. citrus)

b.Raising crops requiring moderate summers winter cold (e.g. apples)

c. Raising crops requiring year-round heat and moisture (e.g. bananas)

 

· Before continuing, press the Reset Map button.

 

Elevation is another important influence on vegetation.  Let's look at the landforms of Africa and Southwest Asia.

·        Press the Maps button

·        Select Landforms

·        Select Map All Landforms

 

23.  Which landform type dominates the most area across Africa and adjacent Southwest Asia?

a. High plateaus

b.Hills and low plateaus

c. Plains

d.Mountains

 

Compare the spatial distribution of this dominant landform type with the dominant vegetation type (tropical savanna).  Pay close attention to Central Africa, that is the area immediately surrounding the tropical rainforest.

 

 

·        Press the Zoom button

·        Select Central and Southern Africa

 

24.  Which landform type is generally associated with the tropical savanna?  (You can redraw the vegetation map to compare if you are unsure.)

a. High plateaus

b.Hills and low plateaus

c. Plains

d.Mountains

 

Notice that the low elevation plains of the Congo River Basin are covered with tropical rainforest.  This is due to the fact that in the tropics the low elevation helps create the warm and moist conditions needed for this type of vegetation.  As elevation increases on the low hills and plateaus that surround the tropical rainforest, temperature and humidity decrease enough so that the tropical savanna vegetation takes over.

·        Press the Maps button

·        Select Landscapes

·        Select East Africa

 

25.  What vegetation category is shown in the photo?

a. Tropical savanna

b.Tropical rainforest

c. Mediterranean scrub

d.Alpine

 

 

· Before continuing, press the Reset Map button.

 

26.  What type of vegetation and amount of rainfall are most closely associated with the uninhabited areas?

a. Desert; >10 inches rainfall

b.Tropical savanna; >40 inches rainfall

c. Desert; < 10 inches rainfall

d.Mediterranean scrub; >10 inches rainfall

                

 

27.  Compared with Europe and India, how would you describe the population densities found in North Africa and Southwest Asia?

a. Higher

b.Lower

c. About the same

 

There are some important exceptions to the overall pattern of low population densities.  To see some of these areas more clearly, zoom in on the northern half of Africa.

 

·        Press the Zoom button

·        Select North Africa

 

South of the Sahara, you'll see scattered areas of higher density in areas of favorable soils along coastal West Africa, in parts of the Sahel where irrigation water is abundant, and the cooler East Africa Highlands.  In North Africa, you'll find higher densities in the northwest where the mountains of the Mahgreb provide moisture for irrigation.  Look carefully and you'll also see a narrow north-south ribbon of high population density in the eastern Sahara region of Egypt.

 

28.  What physical feature is this long, narrow oasis identified with?

a. Niger River

b.Great Rift Zone

c. Congo River

d.Nile River

 

·  Before continuing with the activity, press the Reset Map button

 

We have already seen a few ways in which the physical environment shapes human activity.  But humans also shape the physical environments in which they live.  To see a few of the ways that human activities impact the environment view the following photos:

 

29.  What method of farming is being illustrated and how does this affect the environment?

a. Slash and burn; enriches soil

b.Slash and dash; depletes soil

c. Slash and burn; depletes soil

d.Slash for cash; enriches soil

 

 

30.  What human activity is being illustrated and what effects might that have upon the environment?

a.  Plantation farming/less plant diversity

b. Solar energy generation/less pollution

c.  Greenhouse agriculture/fewer pesticides

d.      Oil refining/pollution hazard

 

 

31.  What human activity is being illustrated and how has it affected the environment?

a. Diamond mining/deforestation

b.Reforestation/improved plant diversity

c. Coal mining/acid rain

d.Gold mining/water pollution

 

 

32.  What human activity is being illustrated in this photo?

a. Irrigation dam

b.Ship building

c. Solar power generation

d.Wind power generation

 

Projects like this affect the environment in many ways.  A tremendous acreage of land and vegetation is flooded by the reservoir.  However, the water is can be used in this dry climate to grow crops and feed people.  Another possible effect is that countries could go to war if they get cut off from water because a neighboring country builds a dam.  Wars usually lead to environmental degradation.

·        Briefly describe the pattern of vegetation and precipitation that extends across Africa.  Comment especially upon the symmetrical pattern that is centered upon the equatorial portion of the continent and changes as latitude increases to the north and south.

·        Why do we say that the physical environment of North Africa is more like that of Southwest Asia than the rest of Africa?

·        What are the temperature and precipitation characteristics of the tropical rainforest?  (Be sure to mention seasonal distribution patterns)

·        For tropical savannas: