Deserts

PPt. by,

Robin D. Seamon

• Dry/ arid lands (no humidity)

• Less than 10 inches of rain a year.

• 1/5 Earth’s land surface

• Sand & gravel

• Supports little plant life because not enough moisture; soil is too dry

• A land of EXTREMES

TWO KINDS OF DESERTS:

1.Hot desert

• Near equator, HOT days, COLD nights

(136 degrees F in day, 40 degrees F at night)

1.Cold desert

• Arctic deserts where nothing can grow due to cold and dryness

• Near the Poles

HOT DESERTS

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COLD DESERTS

Pictures

http://sciences.unlv.edu/desertsurvivors/images/generalimages/antarctic1.jpg

http://www.uen.org/utahlink/activities/loadimg.cgi?p=/uploads/3794_a_antarc.jpg

Average Yearly Rainfall

1160

92

285

3.5 11

2088

281

28

365

15538 4.5

611

0

500

1000

1500

2000

2500

City, Country

ADAPTATIONS

PEOPLE:

•Farming in river valleys; wells, oasis

•Cities: bring water in through pipelines (Las Vegas)

•N. American villages make adobe/mud houses

•Africa/Asia: herders live in tents/long robes•1 How to survive a DESERT (Man vs. Wild) directions

•2 How to survive a DESERT (Man vs. Wild) hydration

•3 How to survive a DESERT (Man vs. Wild) water (not saved)

ADAPTATIONS

PLANTS:

•After rains, desert flowers

•Deep roots OR long, broad roots to take in more water

•Store water (Saguaro)

•Waxy leaves & stems

•No leaves

•Spikes for protection

ADAPTATIONS

ANIMALS:

•(insects, spiders, reptiles, birds, mammals)

•Nocturnal: out at night when cooler

•Burrows underground where cooler

•Dormant during the day

•Keeping cool tricks: RABBIT keeps cool by big ears like air conditioning

WEATHER:

Rain-shadow effect: makes deserts on one side of a mountain.

•warm air rises up the mountain and cools. As it cools, it rains down. The dry cool air sinks as the air mass moves over the other side of the mountain:

FACTS:

•Sahara (AFRICA)- largest desert (3.5million square miles= the size of the US)

•Atacama (S. AMERICA)- driest, no rain for over 200 years.

•Mojave & Sonora (USA)

•Gobi- cold winters

•Sahel- (AFRICA)

•Kalihari-

VOCABULARY:

•mirage: heat and thirst make you see things that aren’t there

•oasis: water holes in the desert

•arroyo: dry stream beds

•mesa: water erosion leaves these flat hills

•buttes: small mesas

•dunes: piles of sand made by the wind

•arid: dry

•sand seas: vast regions covered by sand

Changing Deserts

•Desertification: making deserts

•Near equator, air moving over land; at 15-35 degrees latitude, air has already lost its moisture & is now dry & hot

•Separated from ocean by mountains

•Cold ocean wind blowing on land

•Change in climate

•Erosion: overgrazing & deforestation

•Reclaiming deserts: irrigating them

Desert Debate:

Should deserts be reclaimed?

Yes, because… No, because…

Saguaro

Cactus

http://www.succulent-plant.com/other/squirrel.jpg

DESERT