latitude is a big idea that helps us understand many other geographic features in africa, including...
TRANSCRIPT
LATITUDEA GEOGRAPHIC “BIG IDEA”
WITH MANY CONSEQUENCES IN
AFRICA
Latitude is a big idea that helps us understandmany other geographic features in Africa,
including patterns of rainfall, natural vegetation,animals, fires, floods, crops, early civilizations,
trade,languages, slavery, and diseases like malaria.
Africa is the second largest continent(three times as big as the U.S.)
Here is Texas, at the correct size and latitude.
Most of Africa iscloser to the equator
than any part ofthe United States.
Equator
The equator runs throughthe middle of Africa.
This means that Africais a good place to studythe effects of latitude,because any process
that depends on latitudewill occur twice in Africa,
once north and once southof the equator.
The equator runs throughthe middle of Africa.
The continent extendsalmost the same distance
north and southof the equator.
North
South
Equator
For example, there is a belt of rainy weather
that forms where the sun is almost straight up in the sky.
This Equatorial Rainy Beltis always close to the equator,
but it moves a few degrees of latitude north and south in different seasons.
Click to see how.
In March,the Rainy Belt isnear the equator.
The blue area gets more than 4 inches per month.
The blue area gets more than 4 inches per month.
In June,the Rainy Belt is
north of the equator.
The blue area gets more than 4 inches per month.
In September,the Rainy Belt is
back near the equator.
The blue area gets more than 4 inches per month.
In December,the Rainy Belt is
south of the equator.
The Zambezi Rivertends to make floodswhen the Rainy Belt
is south of the equator.
In summer, the famous Nile River of Egyptand the Niger of West Africa
are likely to flood.
When the Rainy Belt moves north, the famous Nile River of Egyptand the rivers of West Africa
(like the Niger) are likely to flood.
In your history books,you probably read thatfloods were importantfor the development
of ancient civilizations.
The important thingto remember is that
the number of rainy days per year
depends on latitude.
At low latitudes(near the equator),
it is hotand rainyin everymonth.
The important thingto remember is that
the number of rainy days per year
depends on latitude.
Near theTropic ofCancerand theTropic of
Capricorn,it hardly
ever rains.
Near theTropic ofCancerand theTropic of
Capricorn,it hardly
ever rains.
The important thingto remember is that
the number of rainy days per year
depends on latitude.
Near theTropic ofCancerand theTropic of
Capricorn,it hardly
ever rains.
And inbetween,
the numberof rainy
daysdependsmainly
on latitude.
Farther from the equator
meansfewer days
of rain.
A satellite imageclearly shows the effectof the different numbers
of rainy daysat different latitudes.
Rainforest
Grassland
Desert
The latitude bandsare also very obvious
on a map of ecoregions.
The main thingthat “messes up”
the east-westalignment of
natural regionsis the cooler
highland areasof east Africa.
Rainforest
Grassland
Desert
The influence of latitudeis especially obvious
when we examinethe places where fires
are likely to occurin different seasons.
In July, when theEquatorial Rainy Belt
is north of the equator,there are a lot of fires
in the shrublandssouth of the equator.
In January, when theEquatorial Rainy Belt
is south of the equator,fires are more commonnorth of the equator.
1. The desert areasnear the Tropic of Cancer
do not have enough plants to provide fuel for a wildfire.
2. The rainforest areasnear the Equator
have so much rain, the trees growing there
are too wet to burn.
If we show both fire mapsat the same time, we see
two basic principles:
The influence of latitudeis also obvious
when we look at wheredifferent kinds of animals
are likely to be found.
Chimpanzees, gorillas, and many kinds of birds
live in the tall treesnear the equator.
Camels are by farthe largest animals you might see in the desert
near the Tropic of Cancer.
Grasslands and savannasare the home of manyfamous large animals,
including giraffes, zebras, antelope, elephants,lions, and cheetahs.
Put all the animalson the map of rainy days,
and you can see how different animals liveat specific latitudes.
The highlands of east Africa
are coolerand drier than
the lowlandrainforest.
The main food cropsalso tend to grow
at specific latitudes(where each crop gets
the amount of rain it needs).
In the past, peoplelived in the latitudes
where they could hunt,grow food, or raise cattle.
This line of starsshows the capitalsof ancient empires.
The ancient empiresall had their centers
in the grasslandsnear fields of millet.
That is just dry enoughto avoid the diseases
(like malaria)that are commonin rainier places.
Malaria is transmittedby mosquitoes that live
in the latitudes that havelong rainy seasons.
(It makes sense, no?)
The floods of the Nilemade the soil better,but they also allowedmalaria mosquitoesto live in a desert.
The ancient citieswere the centers
of trading networksthat reached all the way
to India and China.
to India 1000 miles
Not surprisingly,they used camel caravansto carry the trade goods.
One very interestinginfluence of latitude
is on human languages.
In rainy environments,people could find almosteverything they needed
close to home.
When people don’t travel,the languages of each
community is likelyto become different.
Dryland people were luckyto have horses and camels,because they had to travel,often very long distances,
in order to find food and to trade for things
they couldn’t get at home.
To do their trading,they needed to haveat least one language
that they could useover a large area.
The language mapis especially important when we “fast forward”
to look at the slave tradeand colonial claims.
Seven differentEuropean countries
claimed coloniesin different parts
of Africa.
It is plausiblethat it was easierto capture slavesin areas where
people livedin small groups
and spoke many different
languages.
When European countriesdivided Africa into colonies,
they did not pay much attentionto the natural dividing lines
between environmentsor language regions.
Why might thatbe a problem?
The natural bordersbetween environmentsand language regionsrun mainly east-west(following lines of latitude),
but the colonial bordersoften go north-south,
especially in West Africa.
Think about what that meansfor countries like Nigeria,Ghana, Benin, or Mali.
This presentation showed one way to use the clickable mini-Atlas - to help us investigate some consequences of the big idea of latitude,
with examples from Africa.
Latitude affects:
Climate – because the number of rainy days goes down as you go from the equator to the Tropic lines
Plants and animals – because different plants require different amounts of rain, and different animals eat different kinds of plants.Floods and fires – which occur at specific latitudes in different times of the year
Economy – because people grow different crops and hunt/herd different animals at different latitudes
Disease – because diseases like malaria and yellow fever occur in hot, rainy places close to the equator
Languages, empires, colonization, slave trading, and many other aspects of African history also have latitudinal patterns.
QUESTIONVERSION
What is one consequence
of the fact that mostof the continent of Africais closer to the equatorthan the state of Texas?
Equator
The equator runs throughthe middle of Africa.
Why does this factmake Africa
a good “laboratory”to study the effects
of latitude?
The equator runs throughthe middle of Africa.
The continent extendsalmost the same distance
north and southof the equator.
North
South
Equator
Click to watch this animation,
then explain whythe process it shows
is important.
What happens nearthe Zambezi River
in this season?
In summer, the famous Nile River of Egyptand the Niger of West Africa
are likely to flood.
What happensnear the Nile
and Niger Riversin this season?
Why were these river events
important in history?
Describethe
climatenear theequator.
Near theTropic ofCancerand theTropic of
Capricorn,it hardly
ever rains.
Describethe
climatenear theTropic ofCancerand theTropic ofCapricorn
Near theTropic ofCancerand theTropic of
Capricorn,it hardly
ever rains.
Describe the climatebetween
the equatorand theTropic lines.
Interpret the colorson this satellite image.
Focus especially on the effect of latitude.
Why dograsslandsgrow near
the equatorin east Africa?
Why do firesoccur in these latitudes
at this time of year?
Why do firesoccur in these latitudes
at this time of year?
1. Why are fires rarein this area?
2. Why are fires rarein this area?
(It’s a different reason!)
Here are two questionsabout the geographic
pattern of fires in Africa:
The influence of latitudeis also obvious
when we look at wheredifferent kinds of animals
are likely to be found.
Why do chimpanzees,gorillas, and many birds
live here?
What other animalsmight be seenin this area?
Why are large catslike lions and cheetahscommon in this area?
Describe the relationships
between rainfalland animal life.
Describe therelationships
between rainfalland food crops.
What do thesenumbered starts
represent?
Why do they occurin this line pattern?
What is the main linkbetween ancient empires
and millet farming?
What is the main linkbetween the climate
and the diseasecalled malaria?
How can malariaoccur in thisdry region?
Make a generalizationabout the patternof trade in Africa.
to India 1000 miles
What is the linkbetween ancient empires
and these animals?
How can the numberof human languages
be influenced bythe number of monthsin the rainy season?
Finally,how can languagesbe an important partof the colonial era?
Why did so manyEuropean countries
claim coloniesin Africa?
What is the relationshipbetween colonial bordersand the natural bordersbetween ecoregions?
Why is this importantfor foreign policyin Africa today?
