Deserts

DefinitionA desert is an area

that receives less than 16 inches (40cm) of rain a year. The evaporation rate exceeds the precipitation rate.

One-third of the Earth's surface is covered in deserts.

Many of the ice-free regions of the Arctic and Antarctic are known as polar deserts

The largest sand desert in the world is the Sahara Desert. It is located in Africa and

covers 3,600,000 squares miles.

Kalahari DesertGobi Desert

Two other of worlds largest deserts are the Gobi Desert, located in China/Mongolia and

the Kalahari Desert, located in Africa.

Animals of the DesertDeserts are home to reptiles,

insects, birds and small mammals. Larger animals usually do not live in the desert because their large size makes it difficult to find shelter from the heat and they are not able to store water. However, there are some large animals that live in the desert.

Animal Adaptations

Desert animals have made adaptations to survive in the harsh desert environment

● Inactive during the day~ stay in shade of rocks and plants

● Burrow underground

● Nocturnal~ active at night

● Absorb water through plants, seeds and insects that they eat

● Many animals have big ears which help to keep their bodies cool

A well-known desert animal~the Arabian Camel

● Humps on a camel store fat, which breaks down into water and energy

● Camels can travel up to 100 miles without water

● Camels rarely sweat

● When camels drink, they soak up water like a sponge

● Large, tough lips enable them to pick at dry and thorny vegetation

● Bushy eyebrows and long eyelashes protect their eyes

● Thick footpads help navigate on rough terrain and desert sand

Desert Plants

Desert plants include sagebrush, creosote brushes and cacti. Short grasses are found in nearly all deserts. Desert plants have had to develop different ways to capture water in order to survive

Plant Adaptations● Small, spiny leaves limit

exposure to heat

● Glossy leaves reflect sun's rays

● Waxy leaves prevent moisture from escaping

● Some leaves only open at night when it's cool

● Long root systems go deep to reach underground water

● Spreading root systems just below the surface to capture water when it rains

Desert plants limit water loss through their leaf surface by the size, sheen, or texture of their leaves

The Famous Saguaro Cactus● The Saguaro is often called the desert's tallest

tree, but is a cactus

● The Saguaro is native to the Sonoran Desert and is only found in four other places~ Arizona, California, Sonora, Mexico, and Baja, Mexico

● It takes the Saguaro 14 years to grow three feet and 75 years to sprout its first arm

● The first flower doesn't appear until the cactus is 50 years old

● The tough, green skin is pleated like an accordion, enabling the cactus to expand as the roots soak up water

● Birds, like Gila Woodpeckers and Gilded Flickers, bore holes into saguaros and build nests inside

If you are able to connect to the internet, the above link will take you to a Bill Nye the Science

Guy's episode on Deserts that is available on YouTube. This video is a wonderful supplement

to a unit on Deserts.

http://www.youtube.com/watch?v=bhkzsJXHkeU

Sources

● en.wikipedia.org● http://commons.wikimedia.org● http://www.sciencekids.co.nz● http://animals.nationalgeographic.com● http://openclipart.org● Sydenham, S. & Thomas, R. Biomes

[Online] www.kidcyber.com.au [2002]