Ch 7 Desert Tundra Biomes Bellringer 39 1

Ch. 7 Desert & Tundra Biomes

Bellringer #39 1. 2. If you lived in the desert, what would the climate be like? Name a place in the U. S. that you could live and be in the desert. BE SPECIFIC!

Deserts A. Not all deserts are alike, but all receive very little rainfall during a year. B. Soils – rich in minerals but poor in organic material. 1. Very little top soil a. thus minerals don’t undergo “leaching”. 2. Easily blown away a. exposes the “pavement”

C. Two types of deserts in the U. S. 1. Cool Desert - located on the Eastern side of the Western Mountains. - such as the Rocky Mountains ex. Great Basin, Colorado Plateau, and the Red desert.

Great Basin Desert

2. Hot Deserts - located in the southwest regions of U. S. - Arizona, New Mexico, & West Texas ex. Chihuahuan Desert / Sonoran Desert

Chihuahuan (New Mexico) Sonoran (Arizona)

D. Desert Climates: 1. Limiting Factor - lack of precipitation a. rarely receive more than 25 cm/year b. lack of rain determines types of plants c. types of plants determine types of animals. 2. Temperature vary greatly: - 5 to 30 * C

E. Desert Plants and Their Adaptations 1. must be able to absorb scarce water from the ground.

2. Must also prevent the loss of water from their tissues. Succulents are plants with water filled tissues.

3. Shallow roots systems that grow over wide areas are another adaptation.

4. Other plants like the Mesquite tree have roots that extend 20 meters deep.

5. Aloe Plant

Bellringer #40 1. 2. Name two desert animals and how they are adapted to survive in the desert. Name one way that deserts can form.

Desert Animals

F. Desert Animals 1. many are nocturnal 2. Water loss adaptations a. protective shells b. scales 3. Heat adaptations a. long ears help release heat b. nocturnal life styles c. hollow fur help to insulate from heat

A. Formation of Deserts Found on all continents except Antarctica 1. Two Desert Belts a. Northern Belt (Tropic of Cancer) - located 23* North b. Southern Belt (Tropic of Capricorn) - located 23* South

B. Natural Desert Formation 1. Air over the equator receives the most direct sunlight. Direct sunlight raises temperatures and causes rapid evaporation and rainstorms over the equator. 2. As the dry air flows toward Earth’s poles they collect moisture from the lithosphere making the regions very dry.

3. Geographic features like mountains help create deserts. a. Rainshadow Effect: US winds move West to East. b. Warm moist air rises up over mountains. As it rises and cools most of the water drops as precipitation. c. When dry air reaches the Easterly side of the Mt. s it picks up moisture from the ground. Rainshadow Effect Animation

C. Desertification 1. Semiarid regions surround edges of desert. a. areas dry, but not as dry as a desert b. support communities of grasses/shrubs. Causes: overgrazing, topsoil erosion, bare land reflecting heat from sun

C. Desertification 2. Severe in: U. S. , Africa, China, Asia, S. America and Australia. * In Australia about 6 million Hectares per year become desert (size of Maine)

Bellringer #41 Look at the pictures below. 1. List 2 abiotic factors. 2. List 2 biotic factors. 3. Why are the pictures so different? l

Tundra

A. Windy, cold, dry region of land 1. located in Northern Hemisphere, south of the Polar Ice caps. 2. Southern Hemisphere Tundra region covered by water. 3. Covers 10% of Earth’s surface a. Fewer types of organisms live in the tundra than any other Biome b. Lack of Biodiversity makes tundra very fragile and unstable.

B. Tundra Climate 1. Receives less than 25 cm of rain/year. 2. Air temp. rarely over 10*C (50*F) a. below freezing almost all year b. most precipitation falls as snow/ice c. Temperature is the “Limiting Factor” d. B/C of low temps. Only the “active zone” thaws during the summer. e. the soil below this is the “permafrost”

f. Disrupting plants changes permafrost ex. Tracks from wagon wheels 100 yrs. ago

3. Rain can not drain through permafrost a. water collects forming bogs, marshes, ponds, and small streams. b. Areas serve as breeding ground for mosquitoes and black flies. c. Important link of food web for migrating birds.

Tundra Animals

Year around Animals Artic Fox Musk Oxen Polar Bears Wolverines Showshoe Hare Caribou (reindeer)

Caribou A large migratory mammal of the tundra. b. Thick hollow hairs act as insulation and helps reduce heat loss. c. Wide hooves to help move easily through snow or mud. a.

- Seasonal Animals Hundreds of waterfowl migrate to the tundra for their mating season. a. fewer predators in tundra b. less competition for food sources c. safer place than most to raise young.

Migratory Waterfowl bean goose, willow & white-tailed ptarmigan

Bellringer #42 1. 2. Why does water accumulate on the surface during the summer in the tundra? In the tundra, what insulates the ground during the winter? During the summer?

Tundra Plants

Common Tundra Plants - Plants tend to be small and grow close to ground. - Roots grow very close to surface b/c they can’t penetrate the permafrost. - Trees such as the willow or birch usually grow less than 1 meter tall.

Oil in The Tundra A. In 1968 geologists found a large oil deposit on the Northern slope of Alaska. 1. Contains 10 to 20 billion barrels of oil B. Completed in 1977 1. cost 10 billion dollars to build 2. paid for by eight oil companies 3. runs from Prudhoe Bay to Prince William Sound.

Trans Alaskan Pipeline

Trans Alaskan Pipeline

C. Reducing Environmental Destruction 1. Equipment is transported across the tundra on large trucks with rolligons rather than tires. 2. Developed pipeline to withstand extreme temperature changes ranging from -50*C to 35*C. 3. Built pipeline up in the air off of the permafrost, so as not to disrupt the migration of caribou.