The Sun
Precipitation (less than 25cm)
Water
Temperature
Latitude (usually between 30 degrees S and 30 degrees N )
Elevation-cold deserts are located in higher elevations
Ocean currents
Wind
Sand and soil is salty (minerals) because it is not washed away by water.
Rain shadow
Precipitation and temperature are very important. Scientists use over 30 yrs. Of temperature and precipitation data of a given area to create climatographs.
WHAT IS A DESERT?
A desert is a landscape form or region that receives little precipitation.
The main form of precipitation in a cold desert is snow or fog. The main form of precipitation in a hot desert is rain. But that's only ten inches or less of rain per year.
Many deserts are found in bands along 30 degrees latitude north and 30 degrees latitude south.
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| http://mlauni.pottsgrove.wikispaces.net/Nicole+Chu-Desert |
Some deserts located by mountains and are caused by the "rainshadow" effect. As air moves up over a mountain range, it gets cold and loses the ability to hold moisture -- so it rains or snows. When the air moves down the other side of the mountain, it gets warmer. Warm air can hold lots of moisture, so it doesn't rain as much, and a desert is formed.
FLORA
Baobab Tree or Adansonia Digitata
The baobab tree is also known as the tree of life and the upside down tree. They are found in many deserts and places around the equator. It bears leaves, aromatic flowers and fruit that are nicked named monkey bread. The baobab tree shelters and provides food, medicine and things for humans and animals. They can live up to hundreds to thousands of years and can grow to be 25 meters tall.
Physical:
Flowers are large and white so they are visible at night for nocturnal pollinators, also sweetly scented.
Behavioural:
Found in warm climates is sensitive to frost and waterlogging (poorly drained soil).
The roots are not found in deep sanded areas, the roots cannot be anchored, and also moisture is not retained.
Physiological:
Trunks are fire resistant for the dry months.
In wet months the trunk is able to store thousands of liters of water because of the soft corky tissues.
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| http://langabi.name/gallery/mapungubwe05/Baobab_tree?full=1#image |
Creosote Bush
Its a shrub that grows in deserts of the USA and Mexico. They are able to live for hundreds of years and grow 4to 12 feet in height. It is able to live for at least 2 years without water. It bears yellow flowers and fuzzy small seeds. The Creosote bush produces many seeds, but has a very low survival tolerance.
Physical:
Leaves are thick and they have waxy cuticles, helps withstand droughts. Have a small surface area for water loss.
Roots can extend up to 4 meters long and are shallow to obtain any water that falls on the surface of the soil.
Behavioural:
Roots in sandy soil the roots go down to find water (underground wells).
Physiological:
The roots produce chemicals that kill other plants that come too close, so it is able to use all of the moisture
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| http://www.sunsetcities.com/desert-flowers/creosotebush.html |
FAUNA
Camels
Camels can have 1 hump (Dromedary) or 2 (Bactrian). The Dromedary camels live in hot deserts while the Bactrian is able to live in both cold and hot places. They inhabit Africa and Australia and are able to run 25 mph. They are herbivores that are able to grow 7 feet tall and can live 80 years.
Physical:
Strong longs legs keeps the body away from the hot sand, and carry them over a long distance.
Leathery patch on their knees protects it from the hot sand (when kneeling).
Padded hooves create a snowshoeing effect so it doesn’t sink.
Long eyelashes keep sand out of their eyes.
Nostrils can close to keep sand out of their nose.
Thick fur insolates heat in cold nights and reflects heat.
Behavioural:
Spit out some of the contents of their stomach to scare away threatening predators.
Physiological:
Humps are fatty tissues, can survive on fatty tissues when there is no food. The fat becomes water.
Sweat is only produced when the body temperature becomes 40 degrees C.
Kidneys are able to produce urine that is low in water.
Dung is dry to save water.
Fennec Fox
Fennec foxes are the smallest of the foxes. They live in the Sahara desert and in North Africa. There are omnivores (eat both plants and animals) and there diet consists of birds and their eggs, lizards, rodents, insects plants such as berries and fruits if available. They have a life span of about 10 to 12 years.
Behavioural :
Burrows to avoid the sun and retain moisture. Live in underground dens.
Nocturnal to avoid the sun and catch prey. (Many desert preys are nocturnal)
Physiological:
Large ears can hear their prey from a distance.
Kidneys are able to function with little water.
Physical:
Large ears get rid of excess heat.
Sand colour fur camouflages with the sand, also reflects heat.
Thick fir insolates heat during the night
Fur on their feet protect the feet from the hot sand (are like snowshoes), helps them dig.
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| http://i.zdnet.com/blogs/fennec-fox.jpg?tag=mantle_skin;content |
ENDANGERED SPECIES
Ocelot/ Leopardus Pardalis
About 100 ocelots are believed to live in the United States. The Ocelot eats a wide variety of animals such as birds and monkeys, which it catches in trees. It will also eat rodents, iguanas, lizards, crabs, frogs, tortoises, and domestic animals, which it catches on the ground and in the water. The Ocelot is a Nocturnal hunter which means it hunts at night.
It's geographical habitat extends from South Texas, across Central America, and down to South America as far a Argentina. It's ideal environment is the forest, especially humid and subtropical forestry, but it's range extends into desert environs. It is impossible to find two Ocelots with the same base color. The Ocelot is a excellent climber. The Ocelot will sleep stretched out in a tree.
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| http://technology.cincinnati.com/postcard/zoo11.html |
HAVE YOU HEARD OF …..SAND DUNES:
http://www.wordiq.com/definition/Desert
http://library.thinkquest.org/5788/
http://www.mbgnet.net/sets/desert/index.htm
http://www.thefreedictionary.com/sand+dune