Desert Biome


The different desert biomes around the world
The different desert biomes around the world

Background Information

Deserts make up one-fifth of the worlds land. They are usually located along the Tropic of Cancer or the Tropic of Capricorn. (The Desert Biome) . The deserts located near the mountains are formed by the "rain shadow" effect. The "rain shadow" effect is a process of how air moves up a mountain which makes it cold and lose its ability to hold any moisture, but when the air gets through and down the other side of the mountain the air becomes warmer and has the ability to hold moisture again. The more moisture the air can absorb, the less precipitation that area will have, which later forms a desert. (:::: What's It Like Where You Live? :::: ). Also, there two different types of deserts, hot deserts or cold deserts (look at the graph below to see the description of the hot and cold deserts). The fact that deserts typically have little to no vegetation causes them to have extreme temperatures. They are made up of sand, rocks, and gravel and receive very little rainfall each year. (The Desert Biome)

Rain Shadow Effect
Rain Shadow Effect

(Chapter 3)
desert_dunes.jpg
Dunes of the Namib Desert
(Dunes)

Climate

In the desert, the temperature varies greatly from day to night. During the day, temperatures rise to over 100 degrees Fahrenheit, and it drops below freezing at night. The temperatures are so extreme because of the lack of vegetation and there are only about 10 or 20 percent of humidity to trap the climate. Sometimes it gets so hot in the daytime that it can cause mirages, or hallucinations.
One type of storm that is found in the desert is the whirlwind. Whirlwinds can come unexpectedly from the ground at any time of the year. A whirlwind forms when the hot air and the cold air collide and start to spin very quickly. Although whirlwinds do not typically last very long, they can be extremely devastating to anything in their path. Dust devils are basically just miniature whirlwinds. They don't do nearly as much damage, but you still wouldn't want to be hit by one. Sandstorms are also quite common in the desert, and can be deadly if you get caught out in one. The flying sand can strip away skin if it is moving fast enough. A sandstorm can be started by a mere 12mph wind.
(Allaby, 76-77)

external image desert_graph.jpg
(ISB 202: Ecosystems: Energy Flow and Trophic Structure)


Precipitation

Deserts receive less than 25cm of rain each year. (Lisowski, Marylin and Jones Linda C, 64). From December to March, deserts receive the most rain of the year, and each of those months can receive up to 1.3cm of rain. Also, in hot deserts the main precipitation is only rain (about 10 or less inches per year), but in cold deserts they receive either fog or snow. Some parts of deserts don't receive any rain at all in a year. The humidity is extreme in these areas almost impossible to live in.
(Desert Plants)

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(Marietta College Main Biomes Page )

Sunlight

The sunlight is the ultimate form of life for all the plants in the desert. The sun is the only reason there are actually plants in the desert because once the plants obtain little water from little rain fall sunlight helps them to bloom or grow. But the ultra violent rays from the sun make it very hard for animals to live there that's why there aren't many animals in the desert. The sun shines in the desert for half the day to more than half the day. So in the summer where it doesn't get dark fast the sun is out even longer making the desert impossible to travel on in some places because it never cools down. During the afternoon the suns raise can heat the desert well over 100 degrees. For some animals this can be fatal without shade, but most burrow underground or hide under trees until night. During the day the power of the sun makes it very hard to find animal in the middle of the day because not many animals can last in that extreme heat. (Desert). The sunlight is the ultimate life form in the desert because without it nothing could grow or make food.
(World Builders: Desert Biomes E Viau CSULA )



Animal species

Despite the deserts uninviting appearance, many different species of animals actually survive there. The reason that the animals that dwell there don't die is that they have adaptations that have evolved over time to desert life. For example, camels have developed the ability to store large amounts of water for long periods of time. The hump on a camel's back doesn't actually contain water, but a sort of blubbery fat that has a lot of water in it. Camels also have transparent eyelids, which enables them to see without getting sand in their eyes. There are many other types of animals that live in the desert as well. These include coyotes, as well as a variety of species of lizards and rodents. (Camel - Wikipedia, the free encyclopedia.)

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(Camel Pictures and Facts)

Animal

The fennec fox is the smallest fox in the world and are found in northern Africa. Their life span is only 7 to 10 years. Its body is approximately 37 to 41 centimeters and its tail is around 19 to 21 centimeters and only weigh about 3 pounds. Their scientific name is vulpes zerda and what makes these foxes different from other foxes around the world is its enormous ears. They use their ears for tracking their prays and it acts as a radiator by helping it lose excess heat. Also, their darks eyes provides them dark vision when hunting for food. In the daytime they stay inside their burrows, which are usually located on small hills where moisture is retained the longest. They are carnivores and their diet includes birds, small rodents, insects, and lizards. The fennec fox mostly get its water from their food too. (Fennec Fox ) Another interesting adaptation that the fennec fox has is that the entire surface area of its feet is covered in fur. This is so that when walking around on the hot desert sand, they will not burn their feet. Fennec foxes generally live in small communities containing around ten fennec foxes. As with most canines, male fennec foxes mark their territory with urine, and will also become quite aggressive during mating season. Fennec foxes will eat many things. The harsh conditions of the desert have made them willing to eat most anything edible that they can find in the desert. Their normal diet consists of plants, rodents, eggs, reptiles, and insects. (Fennec Fox, Fennec Fox Profile, Facts, Information, Photos, Pictures, Sounds, Habitats, Reports, News - National Geographic.)


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(Dkimages - discover - animals - Fennec Fox (Vulpes zerda) )
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(Desert Biomes )

The caracal, also called desert lynx is a desert cat that is slightly larger than a puma. The caracal normally hunts at twighlight, but the temperature can affect its hunting pattern. If it is really cold out, such as in the winter, the caracal will hunt only in the daytime. Also, if it is extremely hot out, like in the summer, it will hunt only at night. (Allaby, 118). The caracal generally hunts in dry, open country, such as the desert, and will hunt prey up to the size of a small deer. The caracal is the largest member of Africa's small cats family. (Allaby, 102). Male caracal can weigh up to 40 pounds. They are between 16-20 inches tall and 35-39 inches long. The black tufts on the top of the ears tend to be about 1.75 inches long. (Caracal ) An interesting fact about caracals is that they do not like sandy deserts at all, so they are found in slightly more rocky terrain. Caracals usually use rock crevices as their living area and mating cave. A caracal's gestation period lasts for approximately 69-78 days, and will typically give birth to 1-6 cubs. The cubs are then nursed for 10-25 weeks. Like the fennec fox, the caracal also marks its territory with urine. Caracals are strictly carnivorous, and they stalk their prey before pouncing upon it. The existence of the caracal both benefits and deters the human race. One good thing for humans about these cats is that they can be easily tamed, and some people even use them for hunting. One bad thing, however is that caracals are extremely good jumpers, so they tend to be able to jump into farmers' livestock and kill them. (ADW: .)

caracal.jpg
(Fauna Species )

Plants

Even though there is little to no precipitation in the desert plant life is still found. The saguaro cactus is one that grows in the desert. It stores the water in the limb at the time it rains and that water can last up to 5 months. Also, the barrel cactus, brittle bush, chainfruit cholla, cresote bush, desert ironwood, etc. grow. But, due to the low precipitation little plant life is able to grow so there aren't many flowers or beautiful plants. The little plant life also makes it very hard for plant eaters to find food very hard for plant eaters to find food.
(Desert Plants )

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Barrel Cactus

(Types of Cactus)

Energy Flow

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(World Builders: Hot Desert Food Chain E Viau CSULA )

Food Pyarmid
Food Pyarmid

(World Builders: A Food Pyramid in the Hot Desert Biome )

The major Hot Deserts of the World
Name
Location
Size
Physical
Features
Some Plants & Animals
Special Facts
Arabian
Arabian Peninsula
900,000 mi2
2,300,000 km2
Covered almost entirely by sand; has some of the most extensive stretches of sand dunes in the world.
acacia, oleander, saltbush
desert locust, dromedary camel, gazelle, lizard, jackal, oryx
Nomadic Bedouin tribes have travelled through the Arabian Desert for thousands of years.
Australian (Great Sandy, Victoria, Simpson, Gibson, and Sturt)
Australia
890,00 mi2
2,300,000 km2
(1/3 of Australia)
Great Sandy, Victoria, and Simpson are sandy; Gibson and Sturt are stony.
acacia, casuarina tree, eucalyptus, saltbush, spinifex grass
blue-tongued lizard, dingo, fat-tailed mouse, kangaroo, marsupial mole, rabbit-eared bandicoot, sand goanna, spinifex hopping mouse, throny devil
Aborigines have lived in the Australian deserts for over 30,000 years.
Chihuahuan
North Central Mexico and Southwestern United States (Arizona, New Mexico, Texas)
175,000 mi2
455,000 km2
High plateau covered by stony areas and sandy soil. Many mountains and mesas.
cacti, chihuahuan flax, creosote bush, lechuguilla, mesquite, mexican gold poppy
coyote, diamondback rattlesnake, javelina, kangaroo rat, roadrunner
Largest North American desert. Big Bend National Park located here; more species of birds seen in Big Bend than in any other National Park in the U.S.
Kalahari
Southwestern Africa
200,000 mi2
520,000 km2
Covered by sand dunes and gravel plains.
acacia, aloe
gazelle, gerbil, ground squirrel, hyena, jackel, sandgrouse, springbok
Bushman have lived in the Kalahari for 20,000 years.
Mojave
Southwestern United States (Arizona, California, Nevada)
25,000 mi2
65,000 km2
Covered by sandy soil, gravelly pavement, and salt flats.
creosote bush, desert sand verbena, joshua tree, mesquite
bighorn sheep, chuckwalla, coyote, jackrabbit, sidewinder, zebra-tailed lizard
Death Valley located in this desert.
Monte
Argentina
125,000 mi2
325,000 km2
Covered by sand and soil
cardon cactus, creosote bush, paloverde
armadillo, cavy, jaguarundi, puma, tinamou, tuco-tuco
Very similar to the Sonoran Desert
Sahara
Northern Africa
3,500,000 mi2
9,100,000 km2
Covered by mountains, rocky areas, gravel plains, salt flats, huge areas of dunes. Areas in the central sometimes get no rain for years at a time.
acacia, grasses, tamarisks
addax antelope, dorcas gazelle, fennec fox, horned viper, jackal, jerboa, sandgrouse, spiny-yailed lizard
Largest desert in the world. Fewer than 2 million inhabitants (mostly nomads such as the Tuareg). Crossed by Arab caravans since the 10th century.
Sonoran
Southwestern United States (Arizona, California) and parts of Mexico (Baja Peninsula, Sonora)
120,000 mi2
312,000 km2
Covered by sand, soil, and gravelly pavement. Gets more rain than any other North American desert.
agave, coulter's globemallow, creosote bush, desert mariposa lily, mesquite, ocotillo, paloverde, saguaro
coati, elf owl, gila monster, kangaroo rat, pack rat, roadrunner, sidewinder, tarantula
Most complex animal-plant community of any desert.
One of the most beautiful deserts in the world.
Thar
India and Pakistan
77,000 mi2
200,000 km2
Majority of desert covered by sand dunes; rest covered by gravel plains
acacia, euphorbias, grasses, shrubs
black buck, dromedary camel, great Indian bustard, Indian spiny-tailed lizard, jackel, sandgrouse
Small villages of ten to twenty houses scattered throughout the Thar.
(:::: What's It Like Where You Live? :::: )

The major Cold Deserts of the World
Name
Location
Size
Physical
Features
Some Plants & Animals
Special Facts
Atacama
Coasts of Peru and Chile
54,000 mi2
140,000 km2
Covered by sand dunes and pebbles. One of the driest areas on earth.
bunchgrass, cardon cactus, tamaruga trees
lizards, llama, Peruvian fox, nesting area for many seabirds
Only a few thousand people (mostly farmers) live in the inland desert areas.
Large deposits of sodium nitrate are found in the desert. Sodium nitrate is used to make gunpowder.
Gobi
Northern China and Southern Mongolia
450,000 mi2
1,200,000 km2
Covered by sandy soil and areas of small stones called "gobi."
camel's thorn, grasses
bactrian bamel, gazelle, gerbil, jerboa, lizards, onager, wolf
Crossed by Genghis Khan in the early 13th century. Many nomads now settling on government-run farms.
Great Basin
Western United States (Idaho, Nevada, Oregon, and Utah)
158,000 mi2
411,000 km2
Covered by sand, gravel, and clay.
Many moutains ranges, basins, and large expanses of salt flats.
greasewood, sagebrush, shadscale
bighorn sheep, jackrabbit, pocket mouse, poor-will, pronghorn antelope, sage thrasher, side-blotched lizard
Great Salt Lake located here.
Iranian
Iran, Afghanistan, and Pakistan
150,000 mi2
390,000 km2
Covered by coarse gray soil, stony pavement, and salt flats.
grasses, pistachio trees, shrubs
monitor lizard, onager, oryx, scorpion
World's largest salt flat located here.
Namib
Coasts of Southwestern Africa
52,000 mi2
135,000 km2
Covered by sand dunes along the coast and gravel farther inland.
aloe, bunchgrass, lichens, welwitschia
darkling beetle, fringe-toed lizard, golden mole, jackal, sidewinder, viper, web-footed gecko
Coast of the Namib Desert is world's greatest source of gemstones.
Takla Makan
Western China
600,000 mi2
1,600,000km2
Covered by sand dunes and rocky soil.
grasses, shrubs
bactrian camel, jerboa, long-eared hedgehog, gazelle
The word "Takla Makan" means "place from which there is no return."
Crossed by Marco Polo in the 13th Century.
Turkestan
Parts of the Middle East and Southwestern Russia
215,000 mi2
559,000 km2
Covered mostly by extensive stretches of sand dunes.
alhagi shrub, saxaul tree, sedges, thick ground cover
desert tortoise, gazelle, gerbil, saiga antelope
Crossed by caravans following silk route from China in Europe in ancient times.
The great city of Samarkand, once a cultural and religious center of central Asia, was located here.
(:::: What's It Like Where You Live? :::: )


(BBC Discovery Channel Planet Earth: Desert 5)


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