The Desert Land of Extremes.

Ask your students to describe a desert scene, and they will likely respond with the familiar image of a hot, flat, and sandy place devoid of animals and plants. But the real world of deserts is more interesting and varied. Ask the class to consider each of the following:

* The Sahara, in northern Africa, is the largest desert in the world. It covers 3.5 million square miles (about the size of the United States) and has immense sand dunes, gravel plains, and jagged mountains. Plants are sparse and wildlife is rare here; areas in the central Sahara may go for years at a time without rain.

* The Sonoran Desert, in the southwest United States, is colorful and vibrant, the ground covered by the variegated textures of sand, soil, and gravel. The Sonoran receives more rain than any other North American desert and supports a rich community of plants, such as saguaro cacti and desert lilies, and animals, including horned lizards, hawks, and roadrunners.

Just by your comparing the Sonoran and the Sahara, students will easily recognize that deserts can be vastly different. Expand this view with our cross-curricular unit, packed with information and lessons in culture, geography, art, literature, and research skills.

SCIENCE

Defining Deserts

We've seen how deserts can differ from one another, but what distinguishes a desert from, say, a forest or swamp? Have each child finish this sentence: "A desert is[ldots]" Next, have a volunteer look up the definition of the word desert in a dictionary and read it aloud. Finally, share with the class the fact that scientists do not always agree on a single definition for a desert. Some claim that a desert is any area that receives less than 10 inches of rainfall a year (with most of that small amount of moisture lost through evaporation from the sun's heat). Other experts rely on soil type (gravel, sand) or plant life (cacti, trees) to determine desert status. As different as the world's deserts can be, they all share one characteristic--dryness.

SCIENCE

Desert Communities

As children know, all animals must have water, food, shelter, and space to survive. Tell them that a desert is a community made up of plants and animals living side by side in mutually beneficial relationships. These living things help one another to meet certain needs under extremely hot and dry conditions. Teach these concepts by making copies of the reproducible on page 52 for each child. It features a scene from the Sonoran Desert in the southwest United States. Have children color the picture. Introduce the animals bordering the desert scene and read aloud the information about each from the section "Animal Instincts," below. Then hold a class discussion about where these animals might choose to eat and seek shelter if they lived in the habitat pictured. Have the children draw a line from each animal to the place it would likely choose to live or eat.

SCIENCE/VOCABULARY BUILDING

Animal Instincts

* Roadrunner: Eats lizards, snakes, and insects. Builds nests of twigs in the paloverde tree (a leafless tree with lime-green bark and needles).

* Kangaroo rat: Eats plant seeds. Recycles water within its own body, producing very little waste (urine). Burrows underground to avoid the heat.

* Sidewinder rattlesnake: Eats lizards, snakes, and insects. Seeks shelter under rocks, bushes, trees. Suns itself when the temperature is moderate.

* Peccary: Eats prickly pear cactus fruit for food and moisture. Receives shade and protection from the mesquite tree (a spiny tree with edible pods).

* Fringe-toed lizard: May live in abandoned kangaroo-rat burrows. Eats leaves, flowers, and insects. Stores fat in its tail for energy.

* Scorpion: Hunts at night for insects and lizards. Kills with its venomous, stinging tail. Takes shelter under racks or near plants in the day. Dangerous to humans.

* Gila woodpecker: Lives in holes drilled into the saguaro cactus. Helps the cactus reproduce by eating the fruit and spreading its seeds.

* Spadefoot toad: Eats desert grasses and wildflowers. Burrows underground to escape the heat.

LITERATURE CONNECTION

Way Out in the Desert

Way Out in the Desert, by T.J. Marsh and Jennifer Ward (Rising Moon, 1998), adapts the names of Sonoran desert plants and animals to the tune of "Over in the Meadow." Read the lyrics aloud to your class; younger children will enjoy the rhythm, rhyme, and counting skills that are introduced. Challenge older students to research and write their own versions of the song featuring animals from a different world desert. For example, they may write about Saharan animals such as the addax antelope, dorcas gazelle, and spiny-tailed lizard. Bind the finished works into a book to create a "Way Out in the Desrt" class collection.

LANGUAGE/PROBLEM SOLVING

Desert Triplets

Invite students to figure out what the three desert-related words in each riddle below have in common. In researching the answers in the dictionary, encyclopedia, or on the Internet, they'll learn a lot about the world's deserts--and perhaps try writing their own triplets.

* Sonoran, Sahara, Arabian (names of deserts)

* Sparse rainfall, dry air, extreme temperatures (characteristics of a desert)

* Pincushion, Teddy Bear, ice plant (desert cacti)

* Sidewinder, diamondback, horned viper (names of desert snakes)

* Mesa, dune, butte (desert landforms)

* Shade, burrows, night dwelling (ways in which animals beat the desert heat)

* Bushmen, Aborigines, Tuareg (desert peoples)

ART/SCIENCE/CREATIVE WRITING

Create a Critter

After completing the "Desert Communities" activity on page 50, ask students to "invent" their own specially adapted desert animals, using colored markers and collage materials (paper, stickers, cloth scraps). Explain that the new creature must be equipped to live with little water, sparse food, and under intense heat. Then have students name their animals and write a paragraph on the creature's distinctive features and desert-survival adaptations (for example, how does the animal handle the heat, conserve water, protect itself; and find food in the desert?).

CULTURAL STUDIES

Nomad Cuisine

The African Tuareg people of the Sahara are nomadic--they move from place to place, following the rain in search of new grazing areas for their camels, goats, and sheep. Introduce these desert dwellers to children by letting them taste a piece of a date. Explain that this fruit grows on date palm trees found in oases--desert areas where plant life can exist thanks to the presence of springs or well water. Nomads may purchase dates from merchants at these sites, a natural location for villages. Large oases may be studded with thousands of date trees; smaller ones might support only one or two trees, with several families sharing the fruit. To close, have students vote pro or con on the taste of dates.

Multimedia Resources

Danger in the Desert, by T.S. Fields (Northland Publishing, 1997). Read aloud this fiction book about two boys who are kidnapped and must survive in the desert with no water! Scary but engaging. Ages 8-12.

Sahara: Vanishing Cultures, by Jan Reynolds (Harcourt Brace, 1991). Simple text tells about Manda, a young boy of the Saharan Tuareg tribe. Ages 8-12.

Cactus Hotel, by Brenda Z. Guiberson (Henry Holt & Company, 1995). Follows a saguaro cactus's life story. Ages 5-10.

All About Deserts, by John Sanders (Troll Communications, 1997). This Q&A book presents basic information about deserts. Ages 8-12.

Ann Flagg has been an educator for 13 years. She currently teaches kindergarten and first- through third-grade science lab.