What is a desert

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The dry Namib Deser,the sou th we ste rn African coast. The rain flows through the soil and rivers and the water is. carried back to the sea where the water cycle starts over again. In hot deserts the high temperatures cause any moisture. to evaporate very quickly,Inland deserts far from the sea. Most rain falls near the coast Deserts can form in the middle. of large continents where they are sheltered from the winds. that bring rain clouds either by distance from the ocean or. by mountains, As clouds blown in from the ocean rise over a mountain rain. falls The air that is left is dry and as it moves further inland. it has no rain to release This is the reason the centre of the. Kalahari and Australian deserts are dry,Coastal deserts by the sea. PHOTO KAREL TOMEI, Water does not evaporate from a cold ocean as quickly as it.
does when the water is warm Air blown onto the coast from. a cold ocean contains no moisture to fall as rain, During the day water evaporates from the land further helping. to make a desert At night the land cools and some of the. moisture in the air above the land condenses to form fog. Cold ocean currents flow up the west coast of Africa Benguela. current and South America Humboldt current from Antarctica. This cold water breaks the water cycle creating the Atacama. America is a cold desert Antarctica is also an extreme example and Namib deserts. of a cold desert, Coastal deserts are found on the west coast of continents. They have warm summers and cool winters and are often called. Are all deserts sandy, cool deserts Examples of coastal deserts are the Namib Desert Not all deserts are shifting sands or barren rock Some like. in south western Africa and the Atacama Desert in South the Australian desert are a sea of spinifex and acacia shrubs. About 20 per cent of the earth s deserts are sandy made up. Semiarid deserts receive between 250mm and 350mm of of dunes and large areas of sandplains In other places the sand. rain The summers are long and dry with moderate temperatures has been blown away resulting in stony deserts covered by. between 20 C and 30 C Any rain usually falls in the winter pebbles and gravel. months Over one third of Australia is semiarid desert. Some deserts such as those which hug sections of the Orange. River in the Kalahari Desert are made up of large exposed. Why are deserts dry rocks The rocky desert forms as the desert is eroded by wind. and water that can fall very briefly but very rapidly. To understand why deserts are dry you need to consider the. water cycle, On earth water follows a path called the water cycle The sun s. Living in the desert, energy heats water making it evaporate from the land and sea People have lived in deserts for many thousands of years.
As the water vapour rises it cools and forms clouds Wind may Some groups known as nomads keep moving to find food. blow the clouds over land and as the clouds are blown upward and water Some live off their herds of animals Others hunt. over hills and mountains the water droplets cool and fall as rain and gather Today very few people still live like this. 2 WH AT IS A DESERT, of sand with dunes up to 300 metres high and bare gravel. Great deserts of plains Inland the Kalahari is an immense tract of deep sands. the Southern Hemisphere and acacia savanna These are different deserts with different. possibilities for people but with shared histories. The great deserts of the Southern Hemisphere form a band. along the Tropic of Capricorn at 23 degrees South The Namib Desert is a narrow desert in which floodwaters from. nearby highlands rejuvenate its dry rivers Dry channels often. Atacama Desert in South America have wells and springs tapping underground water. The Atacama in Chile is a narrow desert bordered by the sea In contrast the Kalahari is immense and as AV Hodson a. on one side and the Andes mountains and a high plateau called Bechuanaland Protectorate policeman said in 1912 it is not. the altiplano on the other quite an ordinary desert In some parts it is covered with thick. The Atacama is the driest place on earth Imagine a vast bush Its good rains are quickly lost in the deep sands making. undulating plain wrote one Scottish traveler in 1851 whereon the Kalahari the most difficult of the southern deserts for. no trace of life is seen where no insect shows itself where no people The local Tswana people call it kgalagadi literally. plant grows and where the mummies of mules of horses and great thirst A. of human beings are seen dried and decomposed and you. may have a faint picture of the Atacama A Australian deserts. Almost half of Australia is arid country often referred to as the. In parts of the Atacama rain does not fall for many years and. outback There are many different regions within the arid zone. life is sustained by fog, of Australia each with its own characteristics Sand dunes. dominate the Simpson Tanami,Namib and Kalahari Deserts of southern Africa. Great Victorian and Great Sandy, Much of southern Africa is made up of two great deserts. PHOTO CHRISTIAN VARGO,deserts The Nullarbor Plain and.
On the south western coast the Namib forms a barren strip. Barkly Tablelands are flat and,smooth while the Gibson Desert. and Sturts Stony Desert contain,low rocky hills,A large part of Australia s arid. region known as the rangelands,are grazed by cattle. Red sand dunes,of Central Australia,mib Desert after rain. Flood plains of the Na, A Mike Smith curator from Extremes Survival in the Great Deserts of the Southern Hemisphere exhibition National Museum of Australia Canberra 2005.
WH AT I S A DE S E RT 3,Activity The water cycle,Activities You will need. Brainstorm with students what they know about deserts A small aquarium or clear plastic container. Ask students to draw what they believe is a desert or write Potting soil. down words and emotions that describe a desert Seeds of easy to germinate plant radish pea wheat. Ask if any student has lived in a desert environment or marigold. do people live in deserts, Using an atlas or globe ask students to locate desert regions What to do. of the world Where are these deserts located Are these Place potting soil into the bottom of the clear container. deserts hot cold or coastal deserts aquarium Plant a couple of seeds in the soil and water. Using an atlas or map locate the desert regions within the soil. Australia What are the main features of these desert regions Cover the container with a tight fitting lid or plastic wrap. does the name give you a clue What towns and rivers are Place in a sunny position. found in or near these desert regions Contact the Bureau Observe what happens to the water in this closed container. of Meteorology search the internet and library to collect Have students observe the different parts of the water cycle. weather data rainfall temperature for towns found in and. Have students observe the container for a few weeks. near desert regions, Ask students to record their observations in a journal. Discuss with students the terms biome ecosystem and. habitat Identify with students the biome that their school Extension activities. is part of Demonstrate evaporation by boiling water in a kettle and. Environment is your surroundings and can extend from have students observe what happens the steam rising is. the classroom out to the furthermost star in the known evaporation Alternatively measure a small volume of water. universe You are inside part of the environment and not into two shallow dishes leave one dish in a sunny spot and. viewing it like a picture on the wall the other in a shady spot Observe the water for a couple of. Biome a large natural area with its particular climate days What happens Evaporation is when water heats up. physical conditions plants and animals Earth can be and turns into vapour or steam. divided into several major biomes including deserts Demonstrate condensation by holding a bowl of ice over. tropical rainforests temperate forests grasslands boiling water What happens on the outside of the cold bowl. Antarctica region and marine ocean biome water vapour cools and condenses into liquid Condensation. Ecosystem is a community of living organisms together is when water vapour in the air cools and turns back into. with their non living surrounds air soil water light liquid. Habitat is where an organism is found or its home Demonstrate precipitation by leaving the bowl of ice. address near boiling water for a length of time What happens. Precipitation occurs when so much water condenses that. the air cannot hold it anymore Precipitation falls from the. clouds as rain hail or snow, Have students write a short story or poem about a drop of. water as it travels through the stages of the water cycle. Ensure students mention the terms precipitation,evaporation and condensation Begin the story with.
In a cloud high above the ocean lived a rain drop named. The wind started to blow the cloud towards the land. www couchdesign com au 3219,4 WH AT IS A DESERT,a l a d a p t a t i o n s t o. Ani m e r t,life in t h e d e s,Desert animals,Expiring allowing a species to survive. face many problems Rain is unpredictable in deserts Many desert animals expire die during long periods. from getting enough of drought However before death some animals leave a legacy These animals. complete their life cycle in very short periods of very good conditions They produce. water to function thousands of eggs which are capable of surviving years of dryness and scorching. effectively to preventing heat These eggs hatch when heavy rains fall and their life cycle starts over again. dehydration coping with Shield shrimps Triops are tiny fast growing crustaceans found throughout the. Australian desert regions,the heat of the day the, In puddles and lakes formed on claypans after heavy rain Shield shrimps grow. cold nights and finding almost before your eyes Tough resistant eggs produced by shrimps the last time. sufficient food while it rained have been blowing about the desert and when it rains they begin to hatch. in puddles and lakes,trying to survive, Within a week the shrimps grow to a length of about 1 5cm As the shrimps are. maturing the water in the puddle pools and lakes is rapidly evaporating such. Despite the problems, that the shrimps life is a race against time By the twelfth day when they are.
of desert life many about 3cm long hundreds of tiny eggs form on the underbodies of the females. Usually by this time all that remains of the pool or lake is a large muddy patch. animals thrive in the,of wet soil, desert as they have During the final hours of their brief lives the shrimps lay their eggs in the mud. evolved a wide array of As the last of the vanishing water becomes ever thickening mud they die in. large numbers,adaptations that allow them, The eggs can remain dormant resting for many years waiting for the next rain. to cope with to fall,the heat and lack of water,Most desert animals Evading the bad times. use one of three basic A second strategy used by desert animals is to leave when conditions. deteriorate Many bird species living in desert regions migrate to avoid the. methods expiring harsh conditions returning only in good seasons They often breed only after. evading or enduring significant rain has fallen and when there is enough food for their young. to thrive in the desert In the Australian deserts budgerigars Melopsittacus undulates travel. hundreds even thousands of kilometres when conditions become too dry. In good seasons they can be seen in their thousands while at other times. they are entirely absent, Unfortunately sometimes these drought evaders are caught in vegetation such as spinifex At night the desert comes alive. unable to flee soon enough and die in their thousands During when the nocturnal animals emerge to search for food These. a dry period in 1930 over five tonnes of dead budgerigars were animals hop slide wriggle and move around leaving their tracks. found at one waterhole in central Australia in the desert sand During the day the tracks left during their. night time adventure are often the only visible sign of their. CSIRO scientists in the 1970s discovered that desert birds. existence in the desert, have many other strategies that help them tolerate the.
harshness of the desert environment Often they can change. Fog harvesting beetles of the Namib Desert, their behaviour to reduce the effect of the heat and evaporation. Such behaviours include not hunting for prey during the hottest Stenocara beetles live in the cool coastal sand dunes of the. part of the day flying to water during the cool of the morning Namib Desert They depend on fog blown in from the misty. or afternoon avoiding fighting other birds and maintaining ocean to provide life giving water. long lasting bonds between pairs that avoid the necessity for Stenocara live among the sand dunes waiting for the arrival of. active elaborate display before breeding These behaviours mist and fog When fog is blown in from the ocean they travel. help birds to keep cool and conserve water to the top of a sand dune where they turn their body into the. wind straighten out their rear legs and lower their head The. My desert my home fog collects on their back forming droplets of water which roll. downwards into its mouth The beetles drink and survive. Imagine a world where water is in such short supply and so unpredictable that it determines the pattern of life Not just across the landscape or through the cycle of a year but across a decade a century or a millennium Deserts are difficult places for people because of their dryness their unpredictable ecology and also because they are patchy environments where food water and

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