Sahara Desert The Sea of Sand

The Sea of Sand: In ancient times, Egypt and Kush did very little trade with West Africa. They had heard that West Africa had wonderful things – gold, salt, ivory. They knew that West Africa needed iron. They wanted to trade with West Africa, but the Sahara Desert was in the way.
Can you imagine a desert that stretches all the way from New York to California? Or one that runs all the way from Maine to Mexico? The Sahara Desert is the largest desert in the world!
The Sahara Desert is not only big - it's also hot. It's one of the hottest places on earth. During the day, the temperature can be 130 degrees. As miserable as you would be from the heat, it’s the dryness that makes it a desert. There is so little water. It hardly ever rains. The Sahara perhaps enjoys three inches of rain a year, and even that is speckled. It might rain in one place and not rain again in the same place for years. It’s no wonder that the Sahara Desert is called the Sea of Sand.
Oasis: An oasis is a wet rest stop. It’s a small section of desert that is fed by underground streams of water. In these tiny sections of the desert, there are green plants and cool water. Even though there are many oases in the Sahara, the Sahara is so big that you might have to travel a day or even weeks to reach one. In the meantime, you are exposed to hot, very hot shifting sand dunes that seem to run forever.
Desert Life: In spite of the horrible conditions for humans, there is life in the desert. There are poisonous snakes and poisonous spiders. There are many animals and plants in the desert, but the Sahara is not a geographically friendly place for humans. You can see why people were a bit reluctant to cross the Sahara in search of anything, including trading partners.

The Gobi Desert is one of the driest deserts in the world. In the Gobi, there is at least the hope of water, although an oasis is rare.
The Taklamakan Desert, China's other desert, is nicknamed the Sea of Death. It offers poisonous snakes, frequent sand storms, boiling days, freezing nights, and intense water shortages. The Sea of Death is not a small desert. In fact, it is the second largest desert in the world.
DESERTS
Grade Level: 6th gradePresented by: Jane Conner and Elaine Benen, Forestville Elementary School, Great Falls, VALength of Unit: Nine Lessons (16 Days)
I. ABSTRACT
This unit, Deserts, explores the mysteries of some of the most unfriendly but beautiful places on earth, and it introduces students to the geography of the Middle East. Students will learn the definition of a desert, how and why deserts have developed in certain areas; they will also learn about the location, landforms and special features of the world’s greatest deserts. This geography unit is integrated into other disciplines, including reading and research, writing, and art. Activities designed to accommodate the four learning styles are included in each lesson.
II. OVERVIEW
A. Concept Objectives
1. Students will gain an understanding of the geology of the world’s greatest deserts.
2. Students will develop an understanding of desert formation, naturally and
man-made.
3. Students will develop an awareness of the variety and uniqueness of desert landforms.
4. Students will develop an awareness of the adaptations living things must make in
order to survive in desert environments.
5. Students will develop an awareness of the location of the Middle East.
B. Core Knowledge Sequence to be covered
1. Formation of deserts
2. Great deserts of the world
3. Geography of the Middle East
4. Composition of a business letter
5. Writing poetry
C. Specific skills to be taught
1. Define and identify various desert features.
2. Identify the way deserts are formed.
3. Compare and contrast adaptions of living things to a desert habitat.
4. Locate the world’s greatest deserts.
5. Research information about the world’s greatest deserts.
6. Access web sites for information about a specific desert from bookmarked sites on the internet.
7. Locate countries, major cities and major landforms of the Middle East.
8. Create a haiku about a specific desert.
9. Produce a standard business letter.
III. BACKGROUND KNOWLEDGE
A. For teachers
1. Lerner, Carol. A Desert Year. New York: Morrow Junior Books, 1991.
2. MacQuitty, Miranda. Eyewitness Books: Desert. New York: Alfred A. Knopf, 1994.
3. Parker, Steve and Jane. The Changing World: Deserts & Dry Lands. San Diego:
Thunder Bay Press, 1996.
B. For students
1. Maps and globes
2. Deserts
3. Mediterranean region
4. Weather/meteorology
IV. RESOURCES
A. Audio-Visual Aids
Desert Dwellers. Poster. Scholastic, Inc.
Deserts. Filmstrip. National Geographic Society, 1987.
Exploring a Desert Habitat. Poster. Frank Schaffer Publications.
Eyewitness: Desert. Videotape. DK Vision, 1996. 35 min.
B. Books
Amsel, Sheri. Habitats of the World: Deserts. Austin, Texas: Raintree Steck- Vaughn Publishers, 1993.
Arnold, Caroline. First Facts: A Walk in the Desert. New Jersey: Silver Press, 1990.
Arnold, Caroline. Watching Desert Wildlife. Minneapolis: Carolrhoda Books, Inc., 1994.
Bernard, Robin. Deserts. New York: Scholastic Professional Books, 1995.
Berry, C. E., ed. Sky and Earth. Alexandria, Virginia: Time-Life Books, 1992.
Clark, John, et al. Encyclopedia of Our Earth. New York: Shooting Star Press, Inc., 1995.
Cloudsley-Thompson, John. The Living Earth: Desert Life. London: Aldus Books Limited, 1975.
Dixon, Dougal, ed. The Planet Earth (Volume 4). Chicago: World Book, Inc., 1992.
Follman, Ilene. Life in the Desert. St. Louis, Missouri: Milliken Publishing Company, 1995.
Guiberson, Brenda Z. Cactus Hotel. New York: Henry Holt and Company, 1991.
Higginson, Mel. This Earth of Ours: Deserts. Vero Beach, Florida: The Rourke Corporation, Inc. 1994.
Hirsch, E. D., ed. A First Dictionary of Cultural Literacy. New York: Houghton Mifflin Company. 1996.
Hirsch, E. D., ed. What Your Sixth Grader Needs to Know: Fundamentals of a Good Sixth-Grade Education. New York: Dell Publishing, 1993.
Lerner, Carol. A Desert Year. New York: Morrow Junior Books, 1991.
Macquitty, Miranda. Eyewitness Books: Desert. New York: Alfred A. Knopf, 1994.
Madgwick, Wendy. Cacti and Other Succulents. Austin, Texas: Steck-Vaughn Library, 1992.
Parker, Steve and Jane. The Changing World: Deserts and Dry Lands. San Diego, California: Thunder Bay Press, 1996.
Sands, Stella. Kids Discover: Deserts. New York: Kids Discover, 1994.
Sayre, April Pulley. Exploring Earth’s Biomes: Desert. New York; Twenty-First Century Books, 1994.
Sebranek, Patrick and Meyer, Verne and Kemper, Dave. Write Source 2000. Boston: D. C. Heath and Company, 1995.
Siebert, Diane. Mojave. New York: Thomas Y. Crowell, 1988.
Taylor, Barbara. Desert Life. New York: Dorling Kindersley, Inc., 1992.
Classroom Atlas. Chicago: Rand McNally, 1996.
World Book’s Young Scientist (Volume 4). Chicago: World Book, Inc., 1993.
C. Compact Disks
ClarisWorks 4.0. Compact Disk. Claris Corporation, 1996.
Earth Explorer. Compact Disk. Sunburst, 1996.
Eyewitness Encyclopedia of Science. Compact Disk. Dorling Kindersley, 1995.
Grolier Multimedia Encyclopedia. Compact Disk. Mindscape, Inc., 1997.
Maps and Facts. Compact Disk. Broderbund, 1994.
Microsoft Bookshelf ‘95. Compact Disk. Microsoft Corporation, 1995.
Microsoft Encarta ‘95. Compact Disk. Microsoft Corporation, 1995.
3D Atlas. Compact Disk. Multimedia Corporation, 1994.
The Writing Center. Compact Disk. The Learning Company, 1993.
D. Encyclopedia: “Desert.” World Book Encyclopedia, 1994.
E. Internet Addresses
“The A-Z of Camels.” [Online] Available http://ww.arab.net/camels/, (17 November 1997).
“The Desert.” [Online] Available http://hagar.up.ac.za/egypt/odyssey/week1/desert.
html (05 November 1997).
“Desert Environment.” [Online] Available http://www.desertusa.com/desert.html
(17 November 1997).
V. LESSONS
A. Lesson One (1 day): Introduction to Deserts
1. Objectives
a. Students will define “desert.”
b. Students will identify and define various features of deserts.
2. Materials
a. Children’s Book: Siebert, Diane. Mojave. New York: Thomas Y. Crowell, 1988 (A similar children’s book about deserts may be substituted.)
b. Chart paper and markers
c. Video: Eyewitness: Desert, 1996.
d. Teacher prepared study guide (Appendix A)
e. Student pencils
3. Key Vocabulary
a. Arid: dry
b. Desert: an area of land where less than 10 inches of rain falls per year
c. Evaporation: when a liquid turns into vapor or gas
d. Precipitation: water reaching the surface of the Earth (rain, sleet, snow,
frost, and dew)
4. Procedures/Activities
a. Read aloud Mojave by Diane Siebert to introduce the unit.
b. Prepare a KWL chart
(1) K: Students will brainstorm what they think they know about
deserts. Teacher will put ideas on chart paper.
(2) W: Students will brainstorm several questions about deserts
they would like answered
(3) L: Complete at the end of the unit (optional)
c. Show video Eyewitness: Desert: students will take notes from video on
study guide provided by teacher.
d. Class discussion about desert features will follow the video and students
will complete study guide.
5. Evaluation/Assessment
a. Teacher will evaluate students on oral responses following the video.
b. Teacher will check students’ study guides for completeness and accuracy.
6. Standardized Test/State Test Connections
a. Oral communication
b. Listening skills
B. Lesson Two (1 Day): Formation of Deserts
1. Objectives
a. Students will identify ways deserts are formed by presenting an oral summary of information
b. Students will illustrate ways deserts are formed.
2. Materials
a. Manila paper (12x18 sheet) and crayons for each student
b. Overhead projector
c. Transparencies
(1) Weather Patterns (Appendix B)
(2) Cloud Cover (Appendix C)
(3) Rain Shadow (Appendix D)
3. Key Vocabulary
a. Desertification: the creation of new deserts and dry areas from more moist or damper lands by human activities like farming or draining away water
b. Rain shadow: rain falls on the sides of mountains that face a water source
rather than on the sheltered sides of mountains
4. Procedures/Activities
a. Review study guide from Lesson One
b. Discuss weather patterns, cloud cover, rain shadow, and desertification
using transparencies
c. On manila paper, illustrate how deserts are formed.
(1) Title a piece of manila paper “How Deserts are Formed.”
(2) Fold the paper into four equal rectangles and draw pictures to
illustrate (label illustrations).
(a) Weather patterns
(b) Cloud cover
(c) Rain shadow
(d) Desertification
5. Evaluation/Assessment
a. Teacher will evaluate students’ oral responses.
b. Teacher will check students’ illustrations for understanding of the four
concepts presented in the lesson.
6. Standardized Test/State Test Connections
a. Listening skills
b. Identifying main ideas
C. Lesson Three (2 Days): Desert Landforms
1. Objectives
a. Students will identify various hot and cold desert landforms.
b. Students will identify causes of desert landforms.
2. Materials
a. Paper and pencil for each student
b. Research materials from school library
c. Vocabulary list for each student created by teacher (Appendix E)
3. Key Vocabulary
a. Alluvial fan: a fan-shaped deposit of sedimentary materials at the mouth
of a ravine
b. Arroyo: a deep gully cut by an intermittent stream
c. Butte: a hill that rises abruptly from the surrounding area and has sloping
sides and a flat top
d. Dune: a ridge or hill of wind-blown sand
e. Erosion: wearing away the land by physical methods such as rubbing and
scraping, and carrying away the eroded results such as rock particles
f. Groundwater: water under the ground, in spongy rocks and in cracks,
crevices, caves, and tunnels
g. Mesa: a flat-topped elevation with one or more clifflike sides
h. Mirage: an optical phenomenon creating the illusion of water
i. Oasis: a fertile area in a desert where groundwater can reach the surface
because of the rock formations
j. Sediment: finely divided solid material that settles to the bottom of a
liquid
k. Wadi: a valley, gully, or riverbed that remains dry except during the
rainy season
4. Procedures/Activities
a. Teacher will briefly discuss desert landforms with class.
b. Students will go to the library to complete “Desert Landforms Vocabulary.” (Students may work in pairs, but each student should complete written work.)
c. Students should write descriptive paragraphs about desert landforms incorporating their notes and vocabulary from “Desert Landforms
Vocabulary” into their final paragraphs.
5. Evaluation/Assessment
a. Teacher will evaluate students’ definitions for accuracy.
b. Teacher will evaluate students’ paragraphs for accuracy and for the components of a well-written descriptive paragraph.
6. Standardized Test/State Test Connections
a. Research skills
b. Descriptive writing
c. English grammar/mechanics
D. Lesson Four (1 Day): Life in the Desert
1. Objectives
a. Students will list how plants have adapted to desert life.
b. Students will list how animals have adapted to desert life.
c. Students will compare and contrast adaptions made by plants and animals.
2. Materials
a. Chart paper and markers
b. Pictures of desert plants and animals
c. “Life in the Desert” handout prepared by teacher (Appendix F)
d. Venn Diagram prepared by teacher (Appendix G)
e. Pencils and paper for students
3. Key Vocabulary
a. Adapt: to make fit
b. Dormant: when a living thing remains still and inactive, as though asleep,
to save energy and survive bad conditions
c. Photosynthesis: catching the energy in sunlight and converting it into the
energy in foods and nutrients for living and growing
d. Nocturnal: active at night
e. Succulent: having fleshy tissues designed to conserve moisture
f. Bactrain: a camel with two humps
g. Dromedary: a camel with one hump
4. Procedures/Activities
a. Teacher will discuss desert plant and animal life (showing pictures of plants and animals that live in the desert).
b. Students will read “Life in the Desert” and make list of adaptations made by plants and list of adaptations made by animals.
c. Teacher and class will discuss individual lists and make one class list of adaptations on chart paper.
d. Students will complete Venn Diagrams comparing plant and animal adaptations.
5. Evaluations/Assessment
a. Teacher will evaluate students’ oral responses.
b. Teacher will check Venn Diagrams for accuracy.
6. Standardized Test/State Test Connections
a. Reading comprehension
b. Comparison and contrast
E. Lesson Five (3 Days): Great Deserts of the World
1.Objectives
a. Students will locate world’s greatest deserts on map.
b. Students will research specific information about world’s greatest deserts.
c. Students will orally present information from their research.
2. Materials
a. Blank world map prepared by teacher for each student (Appendix H)
b. Markers or colored pencils and paper
c. Atlases
d. Research materials available in the library
3. Key Vocabulary
a. Erg: continuous expanse of sand
b. Sahel: narrow band of grassland that separates the desert from the grasslands of the central African plains
c. Shamel: northwesterly wind on Arabian Peninsula causing frequent sandstorms
d. Sinks: low areas that may hold water; they lie in valleys
e. Steppe: dry grassland in the Gobi Desert
4. Procedures/Activities
a. Students will be given a blank map and will locate greatest deserts. (1) Arabian Peninsula
(2) Australia
(3) Chihuahuan Desert
(4) Gobi Desert
(5) Kalahari Desert
(6) Mojave Desert
(7) Patagonia
(8) Sahara Desert
(9) Sonoran Desert
b. Students will research specific information about each desert and record it.
(1) location
(2) size
(3) temperature
(4) rainfall
(5) interesting fact
c. Students will present information to their 3rd grade buddies and display student-made maps.
5. Evaluation/Assessment
a. Teacher will evaluate students’ maps for accuracy.
b. Teacher will evaluate students’ research.
6. Standardized Test/State Test Connections
a. Map skills
b. Research skills
D. Lesson Six (One Day): Geography of the Middle East
1. Objectives
a. Students will locate countries of the Middle East.
b. Students will locate major cities, bodies of water, and landforms in the Middle East.
2. Materials
a. Map
b. Globe
c. Pictures or slides of the Middle East
d. Student atlas
e. Blank map of the Middle East for each student (Appendix I)
3. Key Vocabulary
a. Peninsula: land surrounded by water on three sides
b. Gulf: a part of ocean or sea extending into the land
4. Procedures/Activities
a. Brainstorm what countries are in the Middle East and locate them on a map and globe.
b. Show pictures or slides of the Middle East emphasizing the desert areas.
c. Locate the following places in the Middle East and place them on blank map:
(1) Landforms and geographic areas
(a) Arabian Peninsula
(b) Anatolian Peninsula
(c) Taurus Mountains
(d) Atlas Mountains
(e) Sahara Desert
(f) Arabian Desert
(g) Mesopotamia
(2) Bodies of water
(a) Tigres River
(b) Euphrates River
(c) Mediterranean Sea
(d) Red Sea
(e) Black Sea
(f) Arabian Sea
(g) Persian Gulf
(3) Major cities
(a) Alexandria
(b) Cairo
(c) Mecca
(d) Jerusalem
(e) Damascus
(f) Baghdad
(g) Teheran
(h) Istanbul
5. Evaluation/Assessment
a. Teacher will evaluate students’ oral responses.
b. Teacher will check students’ maps for completion and accuracy.
6. Standardized Test/State Test Connections
a. Geographical terms
b. Map and globe skills
G. Lesson Seven (3 Days): Desert Travel Brochure
1. Objectives
a. Students will research information about a specific desert.
b. Students will create a travel brochure of a specific desert.
2. Materials
a. Research materials found in library
b. White paper (8 1/2x11)
c. Crayons, markers, or colored pencils
d. Travel brochure assignment (Appendix J)
3. Key Vocabulary
a. Brochure: pamphlet or booklet, particularly containing descriptive or
advertising information
b. Pamphlet: unbound booklet
4. Procedures/Activities
a. Discuss travel brochures (Appendix J) and assign students to make a travel brochure about a desert of their choice.
b. Research individual deserts.
c. Create travel brochure.
5. Evaluation/Assessment
a. Teacher will evaluate students’ research skills.
b. Teacher will evaluate students’ travel brochures.
6. Standardized Test/State Test Connections
a. Research skills
b. Advertising techniques
H. Lesson Eight (2 Days): Desert Haiku
1. Objectives
a. Students will recall information about deserts.
b. Students will create original haikus.
2. Materials
a. Research materials about deserts.
b. White construction paper (9x12)
c. Water colors
d. Fine tipped black markers
e. Paper and pencils
f. Examples of haiku poetry
3. Key Vocabulary
a. Haiku: an unrhymed verse form of Japanese origin having three lines containing 5, 7, and 5 syllables respectively, usually about nature
b. Water color wash: to cover with a thin coat of water color paint
4. Procedures/Activities
a. Introduce haiku poetry to students.
b. Create individual haiku about deserts.
c. Using water colors of desert colors, have students apply a water color wash to white construction paper; allow to dry overnight.
d. On dry water color wash, use fine tipped black pen to write haiku and illustrate.
5. Evaluation/Assessment
a. Teacher will evaluate students’ understanding of deserts from information in haiku.
b. Teacher will evaluate students’ haikus for proper poetic form.
6. Standardized Test/State Test Connections
a. Research skills
b. Poetic form
I. Lesson Nine (2 Days): Desert Business Letter
1. Objectives
a. Students will compose a business letter using accepted form.
b. Students will complete business letter using word processing skills.
2. Materials
a. List of organizations to contact about protection of deserts (Appendix K)
b. Paper and pencil
c. #10 envelope and stamp
d. Computer and word processing program
3. Key Vocabulary
a. Business letter: letter written for a specific purpose which includes a heading, inside address, salutation, body, closing, and signature
b. #10 Envelope: an envelope measuring approximately 9 1/2 x 4 1/4 in.
4. Procedures/Activities
a. Discuss form of a business letter.
b. Students write business letter to organization requesting information about desert conservation.
c. Students revise and edit letters.
d. Complete final letter on computer and mail.
5. Evaluation/Assessment
a. Teacher will evaluate students’ letters for content and form.
b. Teacher will evaluate students’ use of technology.
6. Standardized Test/State Connections
a. Business letter form
b. Technology skills
VI. CULMINATING ACTIVITY
A. Desert Review
1. Objective: to measure what students learned about deserts
2. Materials: KWL Chart from Lesson One
3. Key Vocabulary: no new vocabulary introduced
4. Procedures/Activities: complete KWL Chart (what students have learned about deserts) as a class and record on chart.
5. Evaluation/Assessment: teacher will evaluate students’s responses to KWL Chart.
6. Standardized Test/State Test Connections: recall of information
B. Desert Test
1. Objective: to measure what students learned about deserts
2. Materials: Desert Test ( Appendix L)
3. Key Vocabulary: no new vocabulary introduced
4. Procedures/Activities: students tested
5. Evaluation/Assessment: teacher will evaluate student’s tests
6. Standardized Test/State Test Connections
a. Test taking skills
b. Recall of information
VII. HANDOUTS/STUDENT WORKSHEETS
A. Appendix A (Deserts: A Study Guide)
B. Appendix B (Weather Patterns)
C. Appendix C (Cloud Cover)
D. Appendix D (Rain Shadow)
E. Appendix E (Desert Landforms Vocabulary)
F. Appendix F (Life in the Desert)
G. Appendix G (Plants and Animals Adapt to Desert Climates)
H. Appendix H (Deserts of the World)
I. Appendix I (The Middle East)
J. Appendix J (Desert Travel Brochure)
K. Appendix K (Environmental Organizations)
L. Appendix L (Desert Test)

The Sahara is the biggest desert in the world
Its parched, forbidding landscape took shape over thousands of years, but even today, the Sahara is constantly changing.
Why is this desert so important to Africans? How do people survive its harsh, dry climate? And is the Sahara getting bigger, or smaller?
By studying satellite photos, some scientists have come to believe that the Sahara regularly shrinks and grows. In the early 1980s, the Sahara's southern edge expanded into the Sahel, a dry band that separates the desert from the savanna. But by the mid-1980s this area was green and wet again.
The Sahara receives less than three inches of rain a year; Chicago's annual precipitation, its combined rainfall, snow and sleet, is 33.34 inches (84.68 cm). Even in the Sahara's wettest areas, it may rain twice one week and not rain again for years.
For centuries caravaneers have traveled through the Sahara desert. Even though there are many oases in the Sahara, the desert is so immense that travelers may go for days to reach them.

Oases make trade possible between the ports of North Africa and savanna markets further south. Without these wet rest stops for humans and animals, crossing the desert would be almost impossible.
As the world's biggest desert, the Sahara covers a third of the African continent-an area about the size of the United States.
What makes the Sahara a desert?
The Sahara is one of the hottest places on Earth. Even though temperatures there may rise to 136 F (57.7 C), its dryness, not heat, that makes a place like the Sahara a desert. The frozen continent of Antarctica is so dry that some scientists consider it a desert, too.
As the world's largest desert, the Sahara receives less than three inches (7.6 cm) of rain a year. Even in its wettest areas, rain may arrive twice in one week, then not return for years.
Image of oasis from University of Pennsylvania Multimedia database.
The Sahara is blown dry
Many thousands of years ago, the Sahara was a green home to water-loving animals, like hippos. Then the climate changed. Today rising and falling winds pull moisture away from the desert, but they rarely bring rain.
A wind by any other name...
Many of the Sahara's winds have special names:
Haboob is the Arabic name for a wild, sand-laden wind.
Khamsin, also Arabic, means "50 days." This wind sweeps across the desert from March through May, filling the air with sand.
The name of the desert wind harmattan comes from a word in the West African language Twi that means "to tear your breath apart."
Image of hippos from University of Pennsylvania Multimedia database. The Sahara is more than sand dunes
Sand dunes make up only about 15 percent of the Sahara, but the desert is so huge (about three and a half million square miles or 5.63 million sq km) that even a single dune may be enormous. The sand dune known as the Libyan Erg is as big as France.
About 70 percent of the Sahara consists of rocky plains covered with stones and gravel. Shale and limestone plateaus or mountain ranges make up the rest. S


This desert is in south California. It is called Death Valley. Death Valley is part of a bigger desert. All deserts are very dry. Many deserts are very hot. The plants that you see in this picture are sometimes called sagebrush. Some of the plants that grow in this desert can dry up and blow around. The plants that are blown around are called tumbleweeds.
What is a Desert Like?
The hot desert is a land of extremes: extreme heat and extreme dryness; sudden flash floods and cold nights. Because deserts are such a harsh environment, deserts often have names likes "Death Valley," "the empty quarter," and "the place from where there is no return."
Dryness Deserts are usually very, very dry. Even the wettest deserts get less than ten inches of precipitation a year.
In most places, rain falls steadily throughout the year. But in the desert, there may be only a few periods of rains per year with a lot of time between rains. When it does rain, there may be quite a downpour! After the rain, desert flowers bloom.
Hot During the Day, Cool at Night Everyone knows that during the day many deserts are hot, very hot. Temperatures in excess of 100 degrees fahrenheit are not uncommon. Yet at night, the same deserts can have temperatures fall into the 40s or 50s? Why?
Other biomes are insulated by their humidity (water vapor in the air). Temperate deciduous forests, for example, may have 80 percent humidity or more during the day. This water reflects and absorbs sunlight and the energy it brings. At night the water acts like a blanket, trapping heat inside the forest.
Since deserts usually have only between 10 and 20 percent humidity to trap temperatures and have so few trees and other vegetation to retain heat, they cool down rapidly when the sun sets, and heat up quickly after the sun rises.
DESERTS
Grade Level: 6th gradePresented by: Jane Conner and Elaine Benen, Forestville Elementary School, Great Falls, VALength of Unit: Nine Lessons (16 Days)
I. ABSTRACT
This unit, Deserts, explores the mysteries of some of the most unfriendly but beautiful places on earth, and it introduces students to the geography of the Middle East. Students will learn the definition of a desert, how and why deserts have developed in certain areas; they will also learn about the location, landforms and special features of the world’s greatest deserts. This geography unit is integrated into other disciplines, including reading and research, writing, and art. Activities designed to accommodate the four learning styles are included in each lesson.
II. OVERVIEW
A. Concept Objectives
1. Students will gain an understanding of the geology of the world’s greatest deserts.
2. Students will develop an understanding of desert formation, naturally and
man-made.
3. Students will develop an awareness of the variety and uniqueness of desert landforms.
4. Students will develop an awareness of the adaptations living things must make in
order to survive in desert environments.
5. Students will develop an awareness of the location of the Middle East.
B. Core Knowledge Sequence to be covered
1. Formation of deserts
2. Great deserts of the world
3. Geography of the Middle East
4. Composition of a business letter
5. Writing poetry
C. Specific skills to be taught
1. Define and identify various desert features.
2. Identify the way deserts are formed.
3. Compare and contrast adaptions of living things to a desert habitat.
4. Locate the world’s greatest deserts.
5. Research information about the world’s greatest deserts.
6. Access web sites for information about a specific desert from bookmarked sites on
the internet.
7. Locate countries, major cities and major landforms of the Middle East.
8. Create a haiku about a specific desert.
9. Produce a standard business letter.
III. BACKGROUND KNOWLEDGE
A. For teachers
1. Lerner, Carol. A Desert Year. New York: Morrow Junior Books, 1991.
2. MacQuitty, Miranda. Eyewitness Books: Desert. New York: Alfred A. Knopf, 1994.
3. Parker, Steve and Jane. The Changing World: Deserts & Dry Lands. San Diego:
Thunder Bay Press, 1996.
B. For students
1. Maps and globes
2. Deserts
3. Mediterranean region
4. Weather/meteorology
IV. RESOURCES
A. Audio-Visual Aids
Desert Dwellers. Poster. Scholastic, Inc.
Deserts. Filmstrip. National Geographic Society, 1987.
Exploring a Desert Habitat. Poster. Frank Schaffer Publications.
Eyewitness: Desert. Videotape. DK Vision, 1996. 35 min.
B. Books
Amsel, Sheri. Habitats of the World: Deserts. Austin, Texas: Raintree Steck- Vaughn Publishers, 1993.
Arnold, Caroline. First Facts: A Walk in the Desert. New Jersey: Silver Press, 1990.
Arnold, Caroline. Watching Desert Wildlife. Minneapolis: Carolrhoda Books, Inc., 1994.
Bernard, Robin. Deserts. New York: Scholastic Professional Books, 1995.
Berry, C. E., ed. Sky and Earth. Alexandria, Virginia: Time-Life Books, 1992.
Clark, John, et al. Encyclopedia of Our Earth. New York: Shooting Star Press, Inc., 1995.
Cloudsley-Thompson, John. The Living Earth: Desert Life. London: Aldus Books Limited, 1975.
Dixon, Dougal, ed. The Planet Earth (Volume 4). Chicago: World Book, Inc., 1992.
Follman, Ilene. Life in the Desert. St. Louis, Missouri: Milliken Publishing Company, 1995.
Guiberson, Brenda Z. Cactus Hotel. New York: Henry Holt and Company, 1991.
Higginson, Mel. This Earth of Ours: Deserts. Vero Beach, Florida: The Rourke Corporation, Inc. 1994.
Hirsch, E. D., ed. A First Dictionary of Cultural Literacy. New York: Houghton Mifflin Company. 1996.
Hirsch, E. D., ed. What Your Sixth Grader Needs to Know: Fundamentals of a Good Sixth-Grade Education. New York: Dell Publishing, 1993.
Lerner, Carol. A Desert Year. New York: Morrow Junior Books, 1991.
Macquitty, Miranda. Eyewitness Books: Desert. New York: Alfred A. Knopf, 1994.
Madgwick, Wendy. Cacti and Other Succulents. Austin, Texas: Steck-Vaughn Library, 1992.
Parker, Steve and Jane. The Changing World: Deserts and Dry Lands. San Diego, California: Thunder Bay Press, 1996.
Sands, Stella. Kids Discover: Deserts. New York: Kids Discover, 1994.
Sayre, April Pulley. Exploring Earth’s Biomes: Desert. New York; Twenty-First Century Books, 1994.
Sebranek, Patrick and Meyer, Verne and Kemper, Dave. Write Source 2000. Boston: D. C. Heath and Company, 1995.
Siebert, Diane. Mojave. New York: Thomas Y. Crowell, 1988.
Taylor, Barbara. Desert Life. New York: Dorling Kindersley, Inc., 1992.
Classroom Atlas. Chicago: Rand McNally, 1996.
World Book’s Young Scientist (Volume 4). Chicago: World Book, Inc., 1993.
C. Compact Disks
ClarisWorks 4.0. Compact Disk. Claris Corporation, 1996.
Earth Explorer. Compact Disk. Sunburst, 1996.
Eyewitness Encyclopedia of Science. Compact Disk. Dorling Kindersley, 1995.
Grolier Multimedia Encyclopedia. Compact Disk. Mindscape, Inc., 1997.
Maps and Facts. Compact Disk. Broderbund, 1994.
Microsoft Bookshelf ‘95. Compact Disk. Microsoft Corporation, 1995.
Microsoft Encarta ‘95. Compact Disk. Microsoft Corporation, 1995.
3D Atlas. Compact Disk. Multimedia Corporation, 1994.
The Writing Center. Compact Disk. The Learning Company, 1993.
D. Encyclopedia: “Desert.” World Book Encyclopedia, 1994.
E. Internet Addresses
“The A-Z of Camels.” [Online] Available http://ww.arab.net/camels/, (17 November1997).
“The Desert.” [Online] Available http://hagar.up.ac.za/egypt/odyssey/week1/desert.
html (05 November 1997).
“Desert Environment.” [Online] Available http://www.desertusa.com/desert.html
(17 November 1997).
V. LESSONS
A. Lesson One (1 day): Introduction to Deserts
1. Objectives
a. Students will define “desert.”
b. Students will identify and define various features of deserts.
2. Materials
a. Children’s Book: Siebert, Diane. Mojave. New York: Thomas Y. Crowell, 1988 (A similar children’s book about deserts may be substituted.)
b. Chart paper and markers
c. Video: Eyewitness: Desert, 1996.
d. Teacher prepared study guide (Appendix A)
e. Student pencils
3. Key Vocabulary
a. Arid: dry
b. Desert: an area of land where less than 10 inches of rain falls per year
c. Evaporation: when a liquid turns into vapor or gas
d. Precipitation: water reaching the surface of the Earth (rain, sleet, snow,
frost, and dew)
4. Procedures/Activities
a. Read aloud Mojave by Diane Siebert to introduce the unit.
b. Prepare a KWL chart
(1) K: Students will brainstorm what they think they know about
deserts. Teacher will put ideas on chart paper.
(2) W: Students will brainstorm several questions about deserts
they would like answered
(3) L: Complete at the end of the unit (optional)
c. Show video Eyewitness: Desert: students will take notes from video on
study guide provided by teacher.
d. Class discussion about desert features will follow the video and students
study guide provided by teacher.
d. Class discussion about desert features will follow the video and students
will complete study guide.
5. Evaluation/Assessment
a. Teacher will evaluate students on oral responses following the video.
b. Teacher will check students’ study guides for completeness and accuracy.
6. Standardized Test/State Test Connections
a. Oral communication
b. Listening skills
B. Lesson Two (1 Day): Formation of Deserts
1. Objectives
a. Students will identify ways deserts are formed by presenting an oral summary of information
b. Students will illustrate ways deserts are formed.
2. Materials
a. Manila paper (12x18 sheet) and crayons for each student
b. Overhead projector
c. Transparencies
(1) Weather Patterns (Appendix B)
(2) Cloud Cover (Appendix C)
(3) Rain Shadow (Appendix D)
3. Key Vocabulary
a. Desertification: the creation of new deserts and dry areas from more moist or damper lands by human activities like farming or draining away water
b. Rain shadow: rain falls on the sides of mountains that face a water source
rather than on the sheltered sides of mountains
4. Procedures/Activities
a. Review study guide from Lesson One
b. Discuss weather patterns, cloud cover, rain shadow, and desertification
using transparencies
c. On manila paper, illustrate how deserts are formed.
(1) Title a piece of manila paper “How Deserts are Formed.”
(2) Fold the paper into four equal rectangles and draw pictures to
illustrate (label illustrations).
(a) Weather patterns
(b) Cloud cover
(c) Rain shadow
(d) Desertification
5. Evaluation/Assessment
a. Teacher will evaluate students’ oral responses.
b. Teacher will check students’ illustrations for understanding of the four
concepts presented in the lesson.
6. Standardized Test/State Test Connections
a. Listening skills
b. Identifying main ideas
C. Lesson Three (2 Days): Desert Landforms
1. Objectives
a. Students will identify various hot and cold desert landforms.
b. Students will identify causes of desert landforms.
2. Materials
a. Paper and pencil for each student
b. Research materials from school library
c. Vocabulary list for each student created by teacher (Appendix E)
3. Key Vocabulary
a. Alluvial fan: a fan-shaped deposit of sedimentary materials at the mouth
of a ravine
b. Arroyo: a deep gully cut by an intermittent stream
c. Butte: a hill that rises abruptly from the surrounding area and has sloping
sides and a flat top
d. Dune: a ridge or hill of wind-blown sand
e. Erosion: wearing away the land by physical methods such as rubbing and
scraping, and carrying away the eroded results such as rock particles
f. Groundwater: water under the ground, in spongy rocks and in cracks,
crevices, caves, and tunnels
g. Mesa: a flat-topped elevation with one or more clifflike sides
crevices, caves, and tunnels
h. Mirage: an optical phenomenon creating the illusion of water
i. Oasis: a fertile area in a desert where groundwater can reach the surface
because of the rock formations
j. Sediment: finely divided solid material that settles to the bottom of a
liquid
k. Wadi: a valley, gully, or riverbed that remains dry except during the
rainy season
4. Procedures/Activities
a. Teacher will briefly discuss desert landforms with class.
b. Students will go to the library to complete “Desert Landforms Vocabulary.” (Students may work in pairs, but each student should complete written work.)
c. Students should write descriptive paragraphs about desert landforms incorporating their notes and vocabulary from “Desert Landforms
Vocabulary” into their final paragraphs.
5. Evaluation/Assessment
a. Teacher will evaluate students’ definitions for accuracy.
b. Teacher will evaluate students’ paragraphs for accuracy and for the components of a well-written descriptive paragraph.
6. Standardized Test/State Test Connections
a. Research skills
b. Descriptive writing
c. English grammar/mechanics
D. Lesson Four (1 Day): Life in the Desert
1. Objectives
a. Students will list how plants have adapted to desert life.
b. Students will list how animals have adapted to desert life.
c. Students will compare and contrast adaptions made by plants and animals.
2. Materials
a. Chart paper and markers
b. Pictures of desert plants and animals
c. “Life in the Desert” handout prepared by teacher (Appendix F)
d. Venn Diagram prepared by teacher (Appendix G)
e. Pencils and paper for students
3. Key Vocabulary
a. Adapt: to make fit
b. Dormant: when a living thing remains still and inactive, as though asleep,
to save energy and survive bad conditions
c. Photosynthesis: catching the energy in sunlight and converting it into the
energy in foods and nutrients for living and growing
d. Nocturnal: active at night
e. Succulent: having fleshy tissues designed to conserve moisture
f. Bactrain: a camel with two humps
g. Dromedary: a camel with one hump
4. Procedures/Activities
a. Teacher will discuss desert plant and animal life (showing pictures of plants and animals that live in the desert).
b. Students will read “Life in the Desert” and make list of adaptations made by plants and list of adaptations made by animals.
c. Teacher and class will discuss individual lists and make one class list of adaptations on chart paper.
d. Students will complete Venn Diagrams comparing plant and animal adaptations.
5. Evaluations/Assessment
a. Teacher will evaluate students’ oral responses.
b. Teacher will check Venn Diagrams for accuracy.
6. Standardized Test/State Test Connections
a. Reading comprehension
b. Comparison and contrast
E. Lesson Five (3 Days): Great Deserts of the World
1.Objectives
a. Students will locate world’s greatest deserts on map.
b. Students will research specific information about world’s greatest deserts.
c. Students will orally present information from their research.
2. Materials
a. Blank world map prepared by teacher for each student (Appendix H)
b. Markers or colored pencils and paper
c. Atlases
d. Research materials available in the library
3. Key Vocabulary
a. Erg: continuous expanse of sand
b. Sahel: narrow band of grassland that separates the desert from the grasslands of the central African plains
c. Shamel: northwesterly wind on Arabian Peninsula causing frequent sandstorms
d. Sinks: low areas that may hold water; they lie in valleys
e. Steppe: dry grassland in the Gobi Desert
4. Procedures/Activities
a. Students will be given a blank map and will locate greatest deserts. (1) Arabian Peninsula
(2) Australia
(3) Chihuahuan Desert
(4) Gobi Desert
(5) Kalahari Desert
(6) Mojave Desert
(7) Patagonia
(8) Sahara Desert
(9) Sonoran Desert
b. Students will research specific information about each desert and record it.
(1) location
(2) size
(3) temperature
(4) rainfall
(5) interesting fact
c. Students will present information to their 3rd grade buddies and display student-made maps.
5. Evaluation/Assessment
a. Teacher will evaluate students’ maps for accuracy.
b. Teacher will evaluate students’ research.
6. Standardized Test/State Test Connections
a. Map skills
b. Research skills
D. Lesson Six (One Day): Geography of the Middle East
1. Objectives
a. Students will locate countries of the Middle East.
b. Students will locate major cities, bodies of water, and landforms in the Middle East.
2. Materials
a. Map
b. Globe
c. Pictures or slides of the Middle East
d. Student atlas
e. Blank map of the Middle East for each student (Appendix I)
3. Key Vocabulary
a. Peninsula: land surrounded by water on three sides
b. Gulf: a part of ocean or sea extending into the land
4. Procedures/Activities
a. Brainstorm what countries are in the Middle East and locate them on a map and globe.
b. Show pictures or slides of the Middle East emphasizing the desert areas.
c. Locate the following places in the Middle East and place them on blank map:
(1) Landforms and geographic areas
(a) Arabian Peninsula
(b) Anatolian Peninsula
(c) Taurus Mountains
(d) Atlas Mountains
(e) Sahara Desert
(f) Arabian Desert
(g) Mesopotamia
(2) Bodies of water
(a) Tigres River
(b) Euphrates River
(c) Mediterranean Sea
(d) Red Sea
(e) Black Sea
(f) Arabian Sea
(g) Persian Gulf
(3) Major cities
(a) Alexandria
(b) Cairo
(c) Mecca
(d) Jerusalem
(e) Damascus
(f) Baghdad
(g) Teheran
(h) Istanbul
5. Evaluation/Assessment
a. Teacher will evaluate students’ oral responses.
b. Teacher will check students’ maps for completion and accuracy.
6. Standardized Test/State Test Connections
a. Geographical terms
b. Map and globe skills
G. Lesson Seven (3 Days): Desert Travel Brochure
1. Objectives
a. Students will research information about a specific desert.
b. Students will create a travel brochure of a specific desert.
2. Materials
a. Research materials found in library
b. White paper (8 1/2x11)
c. Crayons, markers, or colored pencils
d. Travel brochure assignment (Appendix J)
3. Key Vocabulary
a. Brochure: pamphlet or booklet, particularly containing descriptive or
advertising information
b. Pamphlet: unbound booklet
4. Procedures/Activities
a. Discuss travel brochures (Appendix J) and assign students to make a travel brochure about a desert of their choice.
b. Research individual deserts.
c. Create travel brochure.
5. Evaluation/Assessment
a. Teacher will evaluate students’ research skills.
b. Teacher will evaluate students’ travel brochures.
6. Standardized Test/State Test Connections
a. Research skills
b. Advertising techniques
H. Lesson Eight (2 Days): Desert Haiku
1. Objectives
a. Students will recall information about deserts.
b. Students will create original haikus.
2. Materials
a. Research materials about deserts.
b. White construction paper (9x12)
c. Water colors
d. Fine tipped black markers
e. Paper and pencils
f. Examples of haiku poetry
3. Key Vocabulary
a. Haiku: an unrhymed verse form of Japanese origin having three lines containing 5, 7, and 5 syllables respectively, usually about nature
b. Water color wash: to cover with a thin coat of water color paint
4. Procedures/Activities
a. Introduce haiku poetry to students.
b. Create individual haiku about deserts.
c. Using water colors of desert colors, have students apply a water color wash to white construction paper; allow to dry overnight.
d. On dry water color wash, use fine tipped black pen to write haiku and illustrate.
5. Evaluation/Assessment
a. Teacher will evaluate students’ understanding of deserts from information in haiku.
b. Teacher will evaluate students’ haikus for proper poetic form.
6. Standardized Test/State Test Connections
a. Research skills
b. Poetic form
I. Lesson Nine (2 Days): Desert Business Letter
1. Objectives
a. Students will compose a business letter using accepted form.
b. Students will complete business letter using word processing skills.
2. Materials
a. List of organizations to contact about protection of deserts (Appendix K)
b. Paper and pencil
c. #10 envelope and stamp
d. Computer and word processing program
3. Key Vocabulary
a. Business letter: letter written for a specific purpose which includes a heading, inside address, salutation, body, closing, and signature
b. #10 Envelope: an envelope measuring approximately 9 1/2 x 4 1/4 in.
4. Procedures/Activities
a. Discuss form of a business letter.
b. Students write business letter to organization requesting information about desert conservation.
c. Students revise and edit letters.
d. Complete final letter on computer and mail.
5. Evaluation/Assessment
a. Teacher will evaluate students’ letters for content and form.
b. Teacher will evaluate students’ use of technology.
6. Standardized Test/State Connections
B. Desert Test
1. Objective: to measure what students learned about deserts
2. Materials: Desert Test ( Appendix L)
3. Key Vocabulary: no new vocabulary introduced
4. Procedures/Activities: students tested
5. Evaluation/Assessment: teacher will evaluate student’s tests
6. Standardized Test/State Test Connections
a. Test taking skills
b. Recall of information
VII. HANDOUTS/STUDENT WORKSHEETS
A. Appendix A (Deserts: A Study Guide)
B. Appendix B (Weather Patterns)
C. Appendix C (Cloud Cover)
D. Appendix D (Rain Shadow)
E. Appendix E (Desert Landforms Vocabulary)
F. Appendix F (Life in the Desert)
G. Appendix G (Plants and Animals Adapt to Desert Climates)
H. Appendix H (Deserts of the World)
I. Appendix I (The Middle East)
J. Appendix J (Desert Travel Brochure)
K. Appendix K (Environmental Organizations)
L. Appendix L (Desert Test)
Contact us © 1997 Core Knowledge Foundation.

Desert
Introduction
sahara[enlarge]
The desert is a dry, hot, and sometimes waterless place that is very vast. Deserts take up 8.6 million square miles (22 million square kilometers) of the earth's surface. Deserts receive less than 10 inches (25 centimeters) of rain annually. One of the driest deserts in the world is the Atacama Desert. This desert acquires below one inch (2.5 centimeters) a year. Some of the worlds largest deserts, the Sahara, Australian, and the Arabian, lie between latitude 30° south and latitude 30° north. This latitude belt has constant high pressure, which keeps low-pressure air that forms rain clouds, out of the area.
death valley[enlarge]
Most deserts are very hot. In Death Valley, a part of the Mojave Desert, temperatures are known to reach 190° F (88° C). The Great Basin desert, however, is at a higher elevation and can get very cold in the winter. Even hot deserts can get cold during the night, because hot air dissipates very quickly once the sun goes down.
great basin[enlarge]
The Mojave and the Great Basin in the southwestern United States are sheltered by mountain ranges, which stop rain clouds from advancing into the deserts.
The Atacama rarely accumulates rain clouds because of the cold Humboldt currents in the Pacific Ocean. When rain clouds pass over this cold current they lose their rain before reaching land.
Location
map of deserts [enlarge]
Some major deserts can be found in North America; namely the Sonoran, Chihuahua, Mojave, and the Great Basin. Other deserts, which can be found in Australia, are the Great Victoria and the Great Sandy. South America has deserts in Patagonia and Argentina. The Atacama region can also be found in South America. Most of the Arabian Peninsula is covered in desert. This massive desert extends northward into Syria. The Negev desert of Israel is also considered a part of this desert. Deserts also cover large areas in Africa. In fact, the Sahara, which is the largest desert in the world, covers 3.5 million square miles (9 million square kilometers), almost a quarter of the entire northern portion of Africa. Other African deserts include the Kalahari of Southwestern Africa, and the Danakil of Ethiopia. Quick Question:The largest desert in the world, the Sahara in Africa, covers 3.5 million square miles (9 million square kilometers).
Climate
Deserts are all dry, arid places, but they are not always hot. Some deserts can be cold most of the year depending on their location. At night, hot air from the day dissipates and, in some areas, temperatures can drop below freezing.
namib desert[enlarge]
Many hot deserts lie in the subtropical zones. The Sahara Desert is the World's largest desert and covers 3.5 million square miles (9 million square kilometers), making it larger than the whole Australian continent. Temperatures during the day can soar over 100° F (38° C), but drop below freezing at night. Another hot desert can be found in the Namib Desert in southern Africa. Most cold deserts are found in higher latitudes and higher elevations. They are usually found between the subtropics and polar regions. Some cold deserts include the Gobi Desert of central Asia, the Pataonian Desert of South America, and the Great Basin Desert in the southwestern United States.
Hot and cold deserts, no matter where they are located, are always dry. Arid regions are characterized by having less than 20 inches (500 millimeters) of rain annually. Although, most deserts only receive 10 inches (25 centimeters) per year.
Quick Question:Even at night, hot air from the day continues to linger in hot deserts.
Land Formation
Scientists have discovered that deserts used to be lands where water and grasslands ruled. The Sahara used to be a place where ancient humans roamed and lived with many other animals only 10,000 years ago. Cave paintings show animals wandering in grass, yet the Sahara became a barren desert some 5,000 years later. Some scientists believe that slow temperature change probably caused plants to die and the soil to erode.
alluvial fan[enlarge]
Water and wind erosion has slowly shaped deserts and will continue to do so. When rare, heavy rains flood the deserts, rocks and sand are swept away. As the rocks and sand are swept through valleys they make them deeper and wider. The water eventually pushes the rocks in low areas of the valley, called playas, or to the foot of slopes. This loose rock can pile up at the foot of these slopes and form large piles of rocks, called alluvial fans or cones. When other alluvial fans collide, together they form bajadas (or bahadas).
butte[enlarge]
Canyons, plateaus, buttes, and mesas are all formed by water erosion. Plateaus are high areas that have not been affected by water erosion, except when canyons slice into them. Rivers that wash away soft rocks and sand slowly form canyons. Parts of plateaus can also be eroded away into large islands called mesas. As water and wind erode mesas, slowly they shrink in size and become a butte.
yardang[enlarge]
Winds also work with water to cause erosion. As powerful winds pick up dust, they can create dust and sandstorms that can reach 9,500 feet (3,000 meters) into the air. Winds can even roll large rocks on the ground. Pebbles and sands are usually lifted 5 feet (1.5 meters) above the ground. Most of the erosion in the deserts are caused by the wind. Wind erosion causes different formations in cliffs and large rocks. The wind can wear out small caves in cliffs, form rock pillars, arches, mushroom rocks, and yardangs. Mushroom rocks look like large rocks leaning on skinny pillars. Yardangs are overhanging ridges with steep sides.
arc formed by errosion[enlarge]
The sand itself and rocks are also shaped by the wind. Rocks can be rounded by wind and also form strange shapes called zeugen. Zeugens usually take the shape of a wave when they have been undercut by the wind (Lye,14). The desert surface itself can be changed by the wind. Wind can cause depressions in the desert surface in a process called deflation. As loose dust and sand grains are blown away, basins are formed. Eventually these basins turn into aquifers. Water helps stabilize rocks and sand in the area.
transverse dunes[enlarge]
The largest basin formed by the wind can be found in the Quattara depression in Egypt. One-fifth of the world's deserts are covered in sand. The others are covered in rocks or hard, bare rock. The ones covered in sand have ever moving sand dunes. There are three different types of sand dunes, all of which are formed by the wind. Transverse dunes form at right angles to strong, prevailing winds. Crescent dunes form crescent shaped dunes ahead of the prevailing winds. Star shaped dunes are formed when winds frequently change direction.Quick Question:Canyons, plateaus, buttes, and mesas are all formed by wind erosion.
Plant Adaptations
flowers after a rain[enlarge]
Plants need to conserve moisture and energy in the dry desert. Many plants slow down growth for half of the year to conserve moisture. Many others also lose their leaves when temperatures become too intense. When the short rain season comes, plants burst into color, sprouting leaves and flowers.
organ pipe cactus[enlarge]
Many large cacti, like the barrel and organ-pipe cacti, store large amounts of water in their thick stems and pulpy interior. Another large cacti that has adapted perfectly to the desert environment is the saguaro cactus. The saguaro grows on the northern and southern slopes of the Sonoran Desert. Here it grows in gravel and rocky soils, usually between he heights of 2,000 and 3,500 feet (610 to 1,068 meters).
saguaro[enlarge]
The saguaro extracts water from its environment every chance it gets. Its roots are only a few inches (2.5 centimeters) deep in the soil, so it can soak up as much rain and dew before it evaporates. A giant saguaro can soak up to a ton of water during a heavy rain.
The saguaro also has a spongy inside layer that helps distribute water in the plant. Its outside skin is pleated, so when more water is absorbed its outside can expend to make room.
Growth is also very slow for the saguaro. It can take thirty years or more before the saguaro can reach a few feet (1.5 meters) high. After eighty years pass, the plant can be 20 feet (6 meters) tall and still not be full-grown. Two centuries may pass before the plant reaches its mature height. By growing slowly, the saguaro expends less energy, food, and water, making it fully adapted to the desert.
octillo[enlarge]
Water conservation is very important for all plants in the desert. Many plants achieve this by losing their leaves in one fashion or another. Acacia trees and the ocotillo, a shrub, both shed their leaves during long bouts of dryness. Shedding leaves not only prevents the loss of moisture from evaporation, but also slows the growth of the plant. Slowing growth helps plants use less water, food, and energy during hot seasons.
A large number of desert plants begin as seeds. Seeds can survive without water for indefinite periods of time. Seeds only begin to sprout when the rain washes away anti-sprouting chemicals on their shells. After the rains, the seeds will sprout when the temperatures become more moderate. After these plants sprout they may not live very long, because many desert plants sprout, mature, flower, and then die in a very short period of time.
joshua tree[enlarge]
Other plants don thin, knife-like leaves that prevent water loss by giving the sun a smaller area to evaporate water. Others, like the Joshua tree, have needle-like leaves with a waxy resin that prevents much water from evaporating. Another type of plant, called living stones, exposes only a few of its leaves to the sun. The rest of the plant remains underground, safe from the sun and heat. Other plants remain hydrated with their deep roots. The mesquite tree has roots that can extend 100 feet (30.5 meters) into the ground, tapping water from underground aquifers.
creosote[enlarge]
Many plants in the desert are located many feet (meters) away from one another. One reason may be that moisture is limited so plants must space out. Another concept is that some plants are poisonous to others. Roots of the creosote bush have chemicals on them just for the purpose of keeping other plants out of their way.
One problem to plants living in or near sand dunes was the constant changing and movement of the dunes. When dunes move, it can uproot plants. Plants needed to adapt to dune areas. So, grasses and shrubs living in dune areas have developed long, tough roots to hold onto sand dunes. After more plants move into the area, they anchor the dune down with their roots and not even wind can move them.
Quick Question:The saguaro cactus reaches maturity and its full height in ten years.
Animals
african elephant[enlarge]
Most desert animals are medium to small in size. However, some larger animals live on the edges of deserts. Elephants are known to live in areas of the Kalahari Desert in southern Africa. These large animals maintain their body heat through their ears. When blood vessels in their ears enlarge, heat from the blood and skin is then released into the air. Lions can also be seen in the Kalahari. However, they only stay there for short periods of time, maybe just to catch a meal, because they are not quite adapted to the desert.
Quite a few of the animals that live in the deserts get water through their food. Roadrunners extract their water from lizards, insects, small snakes, and other animals. Tortoises get their water from cacti and other plants. Lizards obtain their water supply from plants and insects.
gemsbok[enlarge]
The gemsbok, which is a type of oryx, or antelope, roam free in the Kalahari and Namib Deserts. In order to obtain food and water, the gemsbok eats a melon called the tschamma. They dig with their front teeth to find the fruit and its roots under the soil.
addax[enlarge]
Probably the best adapted animal in the desert is the addax, which is a close relative to the oryx. It does not need to drink because it receives enough water to survive from the plants it eats. Scientists believe that the addax has a special lining in its stomach that stores water in pouches to use in times of dehydration.Storing water is also necessary for the survival of the desert tortoise. It has two water saving cabins under its shell that holds water it gets from the cacti it eats.
gila monster[enlarge]
Some animals store fat instead of water to survive. The Gila monster and Egyptian spiny tailed lizard save fat in their large tails. When food is unattainable, they live off of this fat and even the moisture it provides.Conserving energy and water is very important to every animal in the desert. They conserve water by keeping cool. Some animals, like the addax, are active during the coolest times of the day: in the morning, evening, and after dark. During the hottest times of the day, the addax digs a hole with its hooves and lies down in it until the temperature goes down.
Most animals in the desert are light in color. Colors which are light, absorb less heat from the sun than those that are dark. This is why most animals have light skin, fur, scales, or wings.
fennec fox[enlarge]
Finding food and avoiding predators is very important to all animals in the desert. Since most desert animals search for food at night, they must adapt to the night life. An example of this is the numerous species of the desert fox. They will hunt rodents, insects, lizards, and other small creatures. Some of these foxes are the kit fox of North America, the sandfox of Asia, and the bat-eared fox and fennec of Africa. All of these foxes have large ears that get rid of excess heat and provide them with sensitive hearing so that they can catch their prey in the dark.
bat-eared fox[enlarge]
Deserts foxes, like the bat-eared and fennec fox of Africa, also burrow into the ground. These burrows have several chambers that are lined with vegetation. A whole fox family can live in these chambers. Other animals that use burrows for underground homes are skunks, badgers, and other medium sized mammals.Birds, like hawks and eagles, however, do not hunt at night. They rely on their keen vision during the day to catch their prey.
kangaroo rat[enlarge]
Some animals use great defenses to discourage their predators. The tiny kangaroo rat, which is no larger than a few inches (centimeters), has powerful hind legs and feet. Their incredible speed makes them hard to catch. They can cover almost 1,200 feet (366 meters) in a minute. They can even jump and change directions in mid air.
pupfish[enlarge]
Amazingly, fish also live in the desert. They live in springs and small rivers. In Death Valley National Monument, located in Nevada, a few hundred Devil's Hole pupfish live above a limestone shelf in a spring hole. This spring hole is only 30 square yards (25 square meters) in area. All the pupfish members breed and carry out their whole life in this tiny spring hole. This is the closest known range any vertebrate has ever lived in. Other fish that live in springs and streams are the Moapa dace and the Leon Springs pupfish.
Quick Question:The addax does not need to drink water because it receives enough water to survive from the plants it eats.
Animal Adaptations
desert tortoise[enlarge]
Animals need to be well adapted to the arid climate of the desert. They need to regulate their body temperature all day and all night. Mammals and birds have it the easiest when it comes to body heat regulation. Their body heat remains stable as long as they are not in the heat for prolonged periods of time. In the cold night weather, they remain warm as long as they eat enough food to produce energy. Reptiles and amphibians body temperatures mirror that of the deserts. They have no internal way to regulate their body temperature.
desert hedgehog [enlarge]
To prevent over heating, both reptiles and animals make burrows to escape the heat. Burrows can remain at a much cooler temperature during the day and a much warmer temperature during the night. Some animals come out of their burrows in the early morning and afternoon, before the heat gets too overwhelming. Other animals only come out during the night, which is one reason why the daytime in the desert can seem so lifeless.
During the hottest, driest times of the year, some animals estivate. Estivation is like hibernation except these animals are not avoiding the cold, but the sweltering heat. By estivating, animals conserve more moisture.
Quick Question:Reptiles have no internal way to regulate their body temperature.
Insects / Other Animals
trap door spider[enlarge]
There are countless insects and animals that live under the desert floor. Deserts are especially populated with a group of invertebrates called arachnids. Arachnids have a hard outer covering called an exoskeleton. Exoskeletons prevent moisture from escaping their bodies. This feature makes them well adapted to the desert. Arachnids include spiders and scorpions that get their water source from the animals they eat. A common arachnid in North American and Australian deserts is the trap-door spider. This clever spider sets traps for its prey. The trap-door spider digs a long, narrow burrow in the ground and then lines the inside and opening of the burrow with webbing. The spider then covers the opening with soil and vegetation and waits in the burrow until an insect stops over the hole. The spider then jumps out, grabs the insect, and drags it forcefully into the hole.
tarantula[enlarge]
A large spider that lives in the Americas and the Mediterranean is the tarantula. These spiders can grow to be bigger than a person's hand. Tarantulas hunt snakes, insects, baby birds, and lizards. These spiders will bite people, yet they are not poisonous. Some poisonous spiders include the black widow and the brown recluse.
desert scorpion[enlarge]
Scorpions are another group of arachnids that have large, and sometimes poisonous, pinchers. They use these pincers to catch their prey. Scorpions eat a diet that consists mostly of insects. They do not always use their stingers against prey; sometimes they are used for defense. There are two other groups of arachnids that are harmless to people. These are whip scorpions and wind scorpions. Both groups do not have stingers or pincers like other scorpions. Wind scorpions burrow under the sand during the day and only come out at night to hunt for small insects.
Some desert animals live only a short time to mate and deposit eggs before they die. Sometimes there may be many years between the time the adults mate and when the eggs actually hatch. A scientific study done in 1955 in the Mojave Desert proved this seemingly impossible delay in hatching true. The study started when a dry lake bed was flooded for the first time in twenty-five years. Shrimp from eggs laid twenty-five years ago, when the lake last held water, hatched. These eggs held enough moisture all those years to survive until conditions were right for them to hatch.

The sidewinder rattle snake travels easily over the sand in an s-shaped loop. The looped part anchors the snake to the sand while the rest of its body pulls it foreword.Another desert snake is the sand viper. The snake uses camouflage to hide itself in the sand. It hides by partly covering itself with sand which matches perfectly with its pale skin color.
Quick Question:Arachnids are a group of vertebrates that include spiders and scorpions.