When you reach out to him or her, you will need the page title, URL, and the date you accessed the resource. transition zone in northern Africa between the Sahara Desert in the north and the savanna ecosystems in the south. This method relies on cutting and burning forests to create fields for crops. During a sudden storm, water scours the dry, hard-baked land, gathering sand, rocks, and other loose material as it flows. Mexican access to the Colorado, which has its delta in the Mexican state of Baja California, was ignored. About 90 major, inhabited oases dot the Sahara. Over time, the Ghaggar changed course and now only flows during the rainy monsoon season. Covering key study areas within the AQA, OCR & Edexcel specifications. Halfway there, an enormous sandstorm swallowed the entire group. The largest hot and dry desert in the world is the Sahara Desert in Northern Africa. Small pores in the leaves, called stomata, take in carbon dioxide. Deserts. Articles from Britannica Encyclopedias for elementary and high school students. Some desert vultures urinate on their own legs, cooling them by evaporation.Many desert animals have developed ingenious ways of getting the water they need. Also called a wadi. Officially a desert is an area that gets less than 10 inches of precipitation a year. A flash flood like this can sweep away anything and anyone in its path. one of the seven main land masses on Earth. The Sahara is a sandy desert with giant sand dunes. Fossils and artifacts show that lime and olive trees, oaks, and oleanders once bloomed in the Sahara. The fennec fox, for example, is native to the Sahara Desert. process by which liquid water becomes water vapor. Stocktrek Images / Getty Images. In geography, a desert is a landscape form or region that receives very little precipitation. rapid depletion of plant life and topsoil, often associated with drought and human activity. From Longman Dictionary of Contemporary English desert island ˌdesert ˈisland noun [countable] SG a small tropical island that is far away from other places and has no people living on it Examples from the Corpus desert island • If you were abandoned on a desert island, you would have total personal sovereignty to do exactly what you want. The amount of evaporation in a desert often greatly exceeds the annual rainfall. Coasts can therefore provide migration corridors for salt-tolerant plants, and in some cases the drifting of buoyant seeds in ocean currents can provide a transport mechanism between coasts. Hydrogen molecules in the fat combine with inhaled oxygen to form water. They are found along the Tropic of Cancer, between 15 and 30 degrees north of the Equator, or along the Tropic of Capricorn, between 15 and 30 degrees south of the Equator. Interior DesertsInterior deserts, which are found in the heart of continents, exist because no moisture-laden winds reach them. These developing countries use Lake Chad’s shallow waters for agriculture, industry, and hygiene. Nanoclay keeps the sand moist, clumping it together and preventing it from blowing away.Deserts Get HotterRising temperatures can have huge effects on fragile desert ecosystems. Life in the DesertPlants and animals adapt to desert habitats in many ways. tree or shrub native to the hot deserts of North America. method of agriculture where trees and shrubs are cleared and burned to create cropland. art and science of raising and harvesting fish and other seafood, such as shrimp or crabs. Rocky, boulder-strewn plateaus cut by dry, usually steep-sided valleys… long, loose robe or tunic made of thin cloth, usually white and worn by Arabic men. Desert Geography . Examples of terrestrial ecosystems include the tundra, taigas, temperate deciduous forests, tropical rainforests, grasslands, and deserts. Between 8000 and 3000 BCE, for example, the Sahara had a much milder, moister climate. The main types of deserts include hot and dry deserts, semi-arid deserts, coastal deserts, and cold deserts. Start revising A-level & GCSE with 7 million other students. Excess nitrates can choke freshwater ecosystems. Desertification is a type of land degradation in drylands in which biological productivity is lost due to natural processes or induced by human activities whereby fertile areas become increasingly arid. thick layer of glacial ice that covers a large area of land. This desert was created purely by poor environmental management and is seen as one of the worst environmental disasters. seasonal change in the direction of the prevailing winds of a region. The Sahara is not the only desert to have dramatic climate change. According to some definitions, any environment that is almost completely free of plants is considered desert, including regions too cold to support vegetation—i.e., “frigid deserts.” Other definitions use the term to apply only to hot and temperate deserts, a restriction followed in this account. performing a task with skill and minimal waste. A jackrabbit’s long ears contain blood vessels that release heat. When rain finally comes, the seeds sprout rapidly. A desert is a very dry area of land where few plants and animals can live. (7000-3000 BCE) moist, temperate climate of the present-day Sahara Desert during the Neolithic Subpluvial period. People often modify rivers to help distribute and store water in a desert. Other articles where Semidesert is discussed: Asia: Semidesert and desert: Through inner Kazakhstan and Mongolia stretches a zone of semidesert, and in Middle Asia, the Junggar (Dzungarian) Basin, the Takla Makan Desert, and Inner Mongolia, there is a belt of temperate-zone deserts. animal that has adapted to live in the desert. Over 50% of this area is deflated desert pavements. 3.1.2.4 Desertification. People have adapted to life in the desert for thousands of years.One thing all deserts have in common is that they are arid, or dry. You cannot download interactives. I've been through the desert on a rock with no name. Synonym Discussion of desert. Learn more. Free. A desert is a large area of land, usually in a hot region, where there is almost no water, rain, trees, or plants. They are caused by cold ocean currents, which run along the coast. collection of tiny particles that acts as a binding agent to materials such as sand or plastics. It gives way to the Central Plateau to the west with the Kalahari Desert located further inwards. “Nanoclay” is a substance sprayed on desert sands that acts as a binding agent. minecraftsam2018. For a list of selected deserts of the world, see below. This is not entirely true, however, as it is only the world's largest hot desert. b. the most valuable, upper layer of soil, where most nutrients are found. (1989, 1993). GCSE Geography Revision notes. The largest hot desert biome (the subtropical Sahara) stretches over 3.5 million square miles or 9 million square kilometers. organ that removes the waste products from blood and helps regulate general health. These features differ from those of wetter regions, which are often gently rounded by regular rainfall and softened by lush vegetation.Water helps carve desert lands. Snakes and lizards are familiar desert reptiles. Also called industrial agriculture. all forms in which water falls to Earth from the atmosphere. The vast majority of the geographic features in the desert include only sand or rocks and gravel. Although some deserts are very hot, with daytime temperatures as high as 54°C (130°F), other deserts have cold winters or are cold year-round. The driest desert is the Atacama Desert … coal, oil, or natural gas. People and the DesertAbout 1 billion people live in deserts. The ancient Anasazi peoples of the southwestern United States and northern Mexico constructed huge apartment complexes in the rocky cliffs of the Sonoran Desert. Deserts are the driest places on Earth—they get fewer than 10 inches (25 centimeters) of rain a year. Deserts also probably existed much earlier, during former periods of global arid climate in the lee of mountain ranges that sheltered them from rain or in the centre of extensive continental regions. process by which plants turn water, sunlight, and carbon dioxide into water, oxygen, and simple sugars. Economies are often molded by the location and cultures of which they are apart. This warming has effects beyond simply making hot deserts hotter. In desert: Environment Stony plains called regs or gibber plains are widespread, their surface covered by desert pavement consisting of coarse gravel and stones coated with a patina of dark “desert varnish” (a glossy dark surface cover consisting of oxides of iron). region of southwest Asia and northeast Africa. The FAO and forestry service have provided nursery’s to grow seeds and seedlings. Deserts are extremely dry, by definition. Comprehensive notes on key topics throughout the GCSE (14-16 Years Old) Geography studies. tall grass that is harvested to extract sugar from its sap or juice. It is one of Earth’s major types of ecosystems, supporting a community of distinctive plants and animals specially adapted to the harsh environment. When rare, heavy rains flood the deserts, rocks and sand are swept away. Water lost to evaporation and transpiration in a desert exceeds the amount of precipitation; most deserts average less than 25 cm (9.75 inches) of precipitation each year, concentrated in short local bursts. Deserts are areas that receive very little precipitation. The environmental impact of dams was not considered when the structures were built. Study a physical map of the world. Turbans are also much longer—up to six meters (20 feet)!Desert dwellers have also adapted their shelters for the unique climate. substance an organism needs for energy, growth, and life. For example, it is thought that the saltbush or chenopod family of plants reached Australia in this way, initially colonizing coastal habitats and later spreading into the inland deserts. cloud that produces thunder and lightning, often accompanied by heavy rains. Vegetation is scattered due to poor soil quality, and plants tend to have needle-like leaves that reduce water loss. Migration between discrete desert regions also has been relatively easier for those plants adapted to survival in saline soils because such conditions occur not only in deserts but also in coastal habitats. gradual changes in all the interconnected weather elements on our planet. Deserts usually get at most 50 centimeters (20 inches) of rainfall a year, and the organisms that live in deserts are adapted to this extremely dry climate. all the different kinds of living organisms within a given area. The Nile provides the most reliable, plentiful source of freshwater in the region. Deserts don't necessarily have to be hot. The desert environments of the present are, in geologic terms, relatively recent in origin. The island’s central plateau is now a barren desert.Rapid population growth also can lead to overuse of resources, killing plant life and depleting nutrients from the soil. These spinning columns of dirt can rise hundreds of feet in the air. (?1050-970 BCE) king of ancient Israel and major religious figure for Judaism, Christianity, and Islam. However, a significant degree of commonality exists among the plant families that dominate different desert vegetations. This spacing gives some desert regions a desolate appearance. But in cities, structures like buildings, roads, and parking lots hold on to daytime heat long after the sun sets. process by which living organisms obtain food or nutrients, and use it for growth. However, some birds, such as the roadrunner, have adapted to life in the desert. In 2011, Jeddah was struck by a sudden thunderstorm and flash flood. The air then cools and forms clouds that drop moisture on the windward (wind-facing) slopes. Fossil fuels formed from the remains of ancient plants and animals. Geography of the Sahara Desert . Daytime temperatures in the Chihuahua can climb beyond 37°C (100°F), while nighttime temperatures can dip below freezing (0°C or 32°F). Weathering. Every year, about 6 million square kilometers (2.3 million square miles) of land become useless for cultivation due to desertification. Some deserts may get a lot of rain all at once. Such migration was particularly easy between northern and southern desert regions in Africa and in the Americas during intervals of drier climate that have occurred in the past two million years. The type of terrestrial ecosystem found in a particular place is dependent on the temperature range, the average amount of precipitation received, the soil type, and amount of light it receives. Many escape the heat in cool burrows they dig in the ground. remote, sparsely populated interior region of Australia. desert. Desert definition is - arid land with usually sparse vegetation; especially : such land having a very warm climate and receiving less than 25 centimeters (10 inches) of sporadic rainfall annually. structure that serves to interrupt an air current or flow of wind. This explains why distinct regional economies develop to serve the unique needs of people. In 1997, British pilot Andy Green set the land speed record in Black Rock Desert—1,228 kilometers per hour (763 miles per hour). National Geographic Headquarters The roots of a mesquite tree, for example, can reach water more than 30 meters (100 feet) underground. Desert environments are so dry that they support only extremely sparse vegetation; trees are usually absent and, under normal climatic conditions, shrubs or herbaceous plants provide only very incomplete ground cover. Their seeds may lie dormant for years during long dry spells. an underground layer of rock or earth which holds groundwater. But, when rain does fall, it can vary a lot. A desert is a region of land that is very dry because it receives low amounts of precipitation (usually in the form of rain, but it may be snow, mist or fog), often has little coverage by plants, and in which streams dry up unless they are supplied by water from outside the area. Average temperatures range from 28 to 39 degrees Fahrenheit in winter and 70 to 79 degrees in summer. Few organisms can withstand the freezing, dry climate of Antarctica.Changing DesertsThe regions that are deserts today were not always so dry. long, thin, loose cloak worn by some Muslim women. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. Tiny, high windows let in only a little light and helped keep out dust and sand. Areas facing reduced precipitation include areas with some of the largest deserts in the world: North Africa (Sahara), the American Southwest (Sonoran and Chihuahuan), the southern Andes (Patagonia), and western Australia (Great Victoria). Browse and study today! (2500-1500 B.C.E.) These shimmering waves confuse the eye, causing travelers to see distorted images called mirages. Updates? People, animals, and plants all surround these oases, which provide stable access to water, food, and shelter.When groundwater doesn’t seep to the surface, people often drill into the ground to get to it. Rainwater, including water from flash floods, collects in large depressions called basins. Most desert birds are restricted to areas near water, such as river banks. Lesson-1-STARTER. Desertification has severely reduced the wetland habitats surrounding the lake, as well as its fishery and grazing lands.Desertification is not new. Today, people value desert resources and biodiversity. These robes of loose cloth can be adjusted (folded) for length, sleeves, and pockets, depending on the wearer and the climate. Other major deserts include the Arabian Desert in the Middle East, the Gobi Desert in Northern China and Mongolia, and the Kalahari Desert in Africa. Less than 50 years ago land in this region of the Sahel was productive Savannah, but is now dry desert because of decades of climate change and over intensive farming, forestry and land degradation. arid area found in the interior of continents, formed because no moisture-laden winds reach them. An abaya is a sleeveless cloak that protects the wearer from dust and heat. Lesson 1 Location of Deserts Lesson 2 Characteristics of Deserts Lesson 3 Desert Landforms and Plant Adaptations Lesson 4 Animal Adaptations Lesson 5 Desert Tourism Lesson 6 Desert Survival. Desert animals have evolved ways to help them keep cool and use less water. They may be only slightly warmer than the surrounding desert.Deserts can hold economically valuable resources that drive civilizations and economies. Others are dry expanses of rock, sand, or salt flats.Kinds of DesertsThe world’s deserts can be divided into five types—subtropical, coastal, rain shadow, interior, and polar. petroleum from a specific reservoir that can be successfully brought to the surface. developed, densely populated area where most inhabitants have nonagricultural jobs. material remains of a culture, such as tools, clothing, or food. Some xerocoles avoid the sun by resting in scarce shade. The roadrunner, native to the deserts of North America, obtains water from its food. Some areas of the Atacama are often covered by fog. fan-shaped deposit of eroded material, usually sediment and sand. Many desert cities, from the American Southwest to the Middle East, rely heavily on such aquifers to fill their water needs. These oases are supported by some of the world’s largest supplies of underground water. Desert: Receiving less than 10 inches of precipitation annually. remnant, impression, or trace of an ancient organism. Deserts, also known as arid lands, are regions that receive less than 10 inches of precipitation a year and have little vegetation. Death Valley, in the U.S. states of California and Nevada, is a rain shadow desert. More than 30 percent of the grasslands of Argentina, Chile, and Bolivia are faced with desertification. activity that produces goods and services. A lot of the birds that live in the desert leave the area when the temperature becomes too extreme. Clothing is versatile and based on robes made of rectangles of fabric. a material that humans take from the natural environment to survive, to satisfy their needs, or to trade with others. area made fertile by a source of fresh water in an otherwise arid region. The Gobi is also in the rain shadow of the Himalaya mountains to the south.Polar DesertsParts of the Arctic and the Antarctic are classified as deserts. Cacti dominate the Sonoran Desert vegetation near Tucson, Arizona. The Hohokam used the canals to irrigate their crops. Atacama Desert. a mound or ridge of loose sand that has been deposited by wind. Omissions? Then it might not rain again for months—or even years! Climate scientists predict that global warming will lead to more rainfall in some regions, but less rainfall in other places. The hard, flat surface of desert salt flats are often ideal for car racing. Almost the entire continent of Antarctica is a polar desert, experiencing little precipitation. Humans who live in the desert usually grow crops to sustain themselves, but they need to be near natural springs and wells in order to do this. A region of permanent cold that is largely or entirely devoid of life. They are hard, rock covered areas. This is very extreme and it has led to a lot of plants in the desert having short life cycles that are prompted by rainfall. Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. How to use desert in a sentence. use of resources in such a manner that they will never be exhausted. Drilling into aquifers provides water for drinking, agriculture, industry, and hygiene. available supply of materials, goods, or services. A belt of subtropical deserts extends through the Large areas of desert soil are irrigated by water pumped from underground sources or brought by canal from distant rivers or lakes. Air transportation and the development of air conditioning have made the sunny climate of deserts even more accessible and attractive to people from colder regions. Some count six (forest, grassland, freshwater, marine, desert, and tundra), others eight (separating two types of forests and adding tropical savannah), and still others are more specific and count as many as 11 biomes. Some deserts may get a lot of rain all at once. Many countries are working to reduce the rates of desertification. Also called an arroyo. But there are other types of deserts as well. Sometimes, rock is carved into tablelike formations such as mesas and buttes. These activities include overgrazing of livestock, deforestation, overcultivation of farmland, and poor irrigation practices. The desert biome covers about one-fifth of Earth’s surface. Diane Boudreau People often overuse natural resources to survive and profit in the short term, while neglecting long-term sustainability. The Sahara Desert is almost the size of the entire continental United States. Desert Habitat. At night, these areas cool quickly because they lack the insulation provided by humidity and clouds. Get exclusive access to content from our 1768 First Edition with your subscription. Desert parks, such as Death Valley National Park, California, attract thousands of visitors every year. domesticated animal used by humans for transporting goods. The animals do not store water in their humps, as people once believed. New York was built on wetland habitat, and Atlanta was built in a wooded area. Interior deserts are sometimes called inland deserts.The Gobi Desert, in China and Mongolia, lies hundreds of kilometers from the ocean. small, loose grains of disintegrated rocks. system or order of a nation, state, or other political unit. Hot deserts are usually found between the latitudes of 15°and 35°, located close to the Tropic of Cancer and the Tropic of Capricorn. Deserts may seem lifeless, but in fact many species have evolved special ways to survive in the harsh environments. In some deserts, plants have unique leaves to capture sunlight for photosynthesis, the process plants use to make food. Most moisture falls as rain before it reaches the land, eg The Namib desert in Africa. ‘Subtropical deserts and tropical savannahs and rainforests have similarly expanded and contracted, imposing their morphogenetic overprint on older landscapes.’ ‘He'd taken to spending long periods of time in the parkland, or out in the desert beyond the planted area, doing what, Annie didn't know.’ (2600-1500 BCE) metropolis of the Indus Valley civilization, in what is today Pakistan. If desert communities use groundwater faster than it is replenished, water shortages can occur. Water for irrigation is transported from hundreds of kilometers away, or drilled from hundreds of meters underground.Oases in desert climates have been popular spots for tourists for centuries. Deserts are threatened mainly by overuse of water and climate change as with increasing temperatures, wildfires, droughts, dust- and sandstorms occur more frequently and lead to desertification. More than half of the proven oil reserves in the world lie beneath the sands of the Arabian Desert, mostly in Saudi Arabia. So, despite the presence of millions of liters of water, there is actually little available for plants and animals.The largest desert in the world is also the coldest. Dromedary camels, native to the Arabian and Sahara deserts, can lose up to 30 percent of their body weight without harm. The highest temperature on Earth was recorded there: 56.7 C (134.1 F).The largest polar desert is Antarctica, at 13 million square kilometers (5 million square miles). Lake Chad is a source of freshwater for four countries on the edge of the Sahara Desert: Chad, Cameroon, Niger, and Nigeria. money earned after production costs and taxes are subtracted. 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