A desert is a barren area of land where little precipitation occurs and
consequently living conditions are threatening for plant and animal life. The
lack of vegetation exposes the vulnerable surface of the ground to the processes
of denudation. About one-third of the land surface of the world is arid or
semi-arid. Deserts are usually hot and barren places; yet they are also
beautiful. A few plants, rocks and dusty red-brown soil make up the
ingredients of most North American deserts where there is sufficient food and
water for certain animals to survive. Deserts cover more than one-fifth of the
Earth’s land and they are found on every continent. A place that receives less
than 10 inches of rain per year is normally considered a desert. They are part
of a wider classification of regions called “dry land”. These areas exist under a
moisture deficit, which means they repeatedly lose more moisture through
evaporation than they receive from annual precipitation.
Deserts are biologically rich habitats with a vast array of animals and plants that have adapted to harsh conditions there. Some deserts are among the planet’s last remaining areas of total wilderness. Yet more than one billion people, one-sixth of the Earth’s population, actually live in the desert regions.
Despite the common notion of deserts as dry and hot, there are cold deserts as well. One famous dry and hot place in the world with no visible rock or plant and barely any water is the Sahara desert. It is the largest hot desert in the world that reaches temperatures of up to 122 degrees Fahrenheit during the day. Some deserts are very cold, like the Gobi desert in Asia and the desert on the continent of Antarctica. Only about 10 percent of deserts are covered by sand dunes. The driest deserts get less than half an inch of precipitation each year and that is from condensed fog.
Desert animals have adapted ways to help them keep cool and use less _____ water. Camels, for example, can go for days without food and water. The hump stores fat, which can be used as both a food and a water source for the animal when the going gets tough. Camels also have thick hair in their ears for keeping out sand; they also sport closable nostrils, an eye membrane, and wide feet that act like snow-shoes in the land.
Desert plants may have to go without fresh water for years at a time. Some plants have adapted to the arid climate by growing long roots that tap water from deep underground. Other plants, such as cacti, have special means of storing and conserving water. Many desert plants can live to be hundreds of years old.
Some of the world’s semi-arid regions are turning into deserts at an alarming rate. This process, known as “desertification”, is not caused by drought, but usually arises from the demands of human population that settles on the semi-arid lands to grow crops and graze animals. The pounding of the soil by the hooves of livestock may degrade the soil and encourage erosion by wind and water. Global warming also threatens to change the ecology of deserts. Higher temperature may produce an increasing number of wildfires that alter desert landscape by eliminating slow-growing trees and shrubs and replacing them with fast-growing grasses.
Questions:
(a) Explain what you understand by ‘barren and dry land’.
(b) What do you understand by rich habitats ?
(c) How have desert animals and plants in arid climate adapted themselves to the use of less water ? (d) Describe the process of desertification.
(e) What are the camel’s two most visible features that make it perfect for deserts ?
Deserts are biologically rich habitats with a vast array of animals and plants that have adapted to harsh conditions there. Some deserts are among the planet’s last remaining areas of total wilderness. Yet more than one billion people, one-sixth of the Earth’s population, actually live in the desert regions.
Despite the common notion of deserts as dry and hot, there are cold deserts as well. One famous dry and hot place in the world with no visible rock or plant and barely any water is the Sahara desert. It is the largest hot desert in the world that reaches temperatures of up to 122 degrees Fahrenheit during the day. Some deserts are very cold, like the Gobi desert in Asia and the desert on the continent of Antarctica. Only about 10 percent of deserts are covered by sand dunes. The driest deserts get less than half an inch of precipitation each year and that is from condensed fog.
Desert animals have adapted ways to help them keep cool and use less _____ water. Camels, for example, can go for days without food and water. The hump stores fat, which can be used as both a food and a water source for the animal when the going gets tough. Camels also have thick hair in their ears for keeping out sand; they also sport closable nostrils, an eye membrane, and wide feet that act like snow-shoes in the land.
Desert plants may have to go without fresh water for years at a time. Some plants have adapted to the arid climate by growing long roots that tap water from deep underground. Other plants, such as cacti, have special means of storing and conserving water. Many desert plants can live to be hundreds of years old.
Some of the world’s semi-arid regions are turning into deserts at an alarming rate. This process, known as “desertification”, is not caused by drought, but usually arises from the demands of human population that settles on the semi-arid lands to grow crops and graze animals. The pounding of the soil by the hooves of livestock may degrade the soil and encourage erosion by wind and water. Global warming also threatens to change the ecology of deserts. Higher temperature may produce an increasing number of wildfires that alter desert landscape by eliminating slow-growing trees and shrubs and replacing them with fast-growing grasses.
Questions:
(a) Explain what you understand by ‘barren and dry land’.
(b) What do you understand by rich habitats ?
(c) How have desert animals and plants in arid climate adapted themselves to the use of less water ? (d) Describe the process of desertification.
(e) What are the camel’s two most visible features that make it perfect for deserts ?
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