Introduction of the desert

The Desert

" The Desert "  When we say the word the desert they lead us to the introduction of the desert in all its aspects .
the desert are mainly found around the tropic of Cancer and tropic of Capricorn in Northern and Southern Hemispheres respectively. The common definition of the desert is a region that receives less than 25cm of rain a year on average.
When people think of the desert, the following image comes to their minds : hot and arid land, vast expanses of sand, soil of reddish brown color, a sky of brilliant blue, no or very few plants, cacti, spiny leaves and camel is the only animal that they can think of.

The truth is not like that. It is not very common to find sand in the desert, but small rocks, pebbles and loose gravel on the surface layer instead. Only 15% of the world' s the desert surface is pure sand. (Parts of the desert and Arabia sahara).
The Desert occupies about one fifth to one third of the earth' s surface. The rainfall pattern is not a seasonal one. Instead, rain usually falls in the form of sudden, violent thunderstorms. There may be several storms in a year or none for several years. The " average rainfall each year" is not calculated based on one year' s rainfall, but on the total rainfall in a long period of time.
 In the Western imagination the word “ the desert” most often evokes a landscape of endless gigantic sand dunes, dazzling white under a cloudless hot-blue sky and a blazing sun.
This landscape of the imagination is likely to be empty— deserted—except, perhaps, for a caravan of nomads and camels that inches slowly across the horizon, or a lone man stumbling, sun-blackened and sun-parched, through the heat haze. Or there may even be an emerald-green oasis, where tents are set out in the shade of a palm grove—though this, of course, may be nothing but a tantalizing mirage. This is the magnificent and exotic landscape of movies such as David Lean’s Lawrence of Arabia (1962) and Bernardo Bertolucci’s The Sheltering Sky (1990), and of countless adventure stories of intrepid travelers and explorers.
This idealized or classic landscape is not pure fantasy: parts of the Sahara, Arabian, and other the deserts fit quite well with this image—though perhaps with less Technicolor vibrancy. The stereotype does, however, contain some misleading notions, of which the most notable is that all the deserts are hot, and that heat is crucial in defining what constitutes a desert. Temperature actually plays a secondary role or no role in such definitions—not all the desert are hot, and even so-called hot deserts are not hot all the time.

The Gobi Desert deep within Central and East Asia, for example, has relatively cool but erratic temperatures even in summer and can be brutally cold in winter, and in the Sahara temperatures can easily plummet to 4°C (39°F) at night. Modern geographers also recognize the category of the polar the desert, applying it to all of Antarctica and parts of the Arctic (notably Greenland), where temperatures day and night stand at the opposite extreme to those of daytime hot deserts.

Even a brief perusal of the photographs included in this site will suggest a much more varied, and even nebulous, notion of what is—or is sometimes—meant by the term “the desert There are vast gravel plains, gleaming expanses of sun-baked salt, and rugged, eroded landscapes of pinnacles, canyons, and rock arches. There are deserts smothered with flowers and blooming cacti; there are others studded with oil wells or scarred by quarries. Some are washed by the ocean and bathed in fog, and some are ice-encrusted polar wildernesses. One of the surprising facts encountered in this site is that only 20 to 30 percent of the world’s deserts are covered by sand, and that the world’s great deserts in fact encompass a huge variety of terrains, not only relative to each other but sometimes within their own boundaries. There is, moreover, little exotic about the desert biome— almost 20 percent of the earth’s land surface is desert, and there are deserts in almost every continent and at every latitude. Of the continents only Europe has no the desert area.
For many peoples of the world the desert is not a remote fantasy but a reality that impinges on their everyday lives.
pictures of the desert
Limestone columns rise from the Pinnacle Desert in Western Australia.
The hardened columns, which have been exposed by weathering
in this coastal region, range from only a few centimeters to 5
meters (16 ft.) in height.

Conventional wisdom depicts the desert as almost devoid of vegetation or wildlife, save perhaps for a sidewinding snake or rearing scorpion. It is seen as abandoned by human beings, who in this hostile environment are thought of as interlopers or aliens, there only because they are on their way to somewhere else or because they have fatally lost their way. 

this is animals of the desert [ scorpion animal desert ]

In our articles next we shall see how many deserts, despite their dearth of water—the precondition for the survival of life—in fact provide a remarkably fertile habitat for plants, animals, and humans alike, each of which have found ingenious ways of making the best of the desert. Plants store water through months of drought or blossom and seed after rare rainfall in a matter of days, transforming bare landscape into dazzling fields of color. Animals live by night or burrow deep underground, or—as in the case of reptiles—are physiologically adapted to withstand the desert’s temperature extremes.
Humans living in and on the fringes of deserts have developed unique lifestyles that usually feature nomadism—a fluid way of life that is able to adapt swiftly and creatively
to the vicissitudes of this harsh environment. Some of the world’s earliest civilizations— including those of ancient Egypt and Mesopotamia—formed on the margins of great deserts, where the strenuousness of life called for the utmost in human endeavor.

this is animals in the desert [ Chameleon animal desert ]