Tuesday, May 31, 2011

BLOG #7

Compare and contrast two biomes describe them in detail include pictures of plants and animals you are liklely to see.


DESERT BIOME: 
Deserts cover about one fifth of the Earth's surface and occur where rainfall is less than 50 cm/year. Although most deserts, such as the Sahara of North Africa and the deserts of the southwestern U.S., Mexico, and Australia, occur at low latitudes, another kind of desert, cold deserts, occur in the basin and range area of Utah and Nevada and in parts of western Asia. Most deserts have a considerable amount of specialized vegetation, as well as specialized vertebrate and invertebrate animals. Soils often have abundant nutrients because they need only water to become very productive and have little or no organic matter. Disturbances are common in the form of occasional fires or cold weather, and sudden, infrequent, but intense rains that cause flooding.

There are relatively few large mammals in deserts because most are not capable of storing sufficient water and withstanding the heat. Deserts often provide little shelter from the sun for large animals. The dominant animals of warm deserts are nonmammalian vertebrates, such as reptiles. Mammals are usually small, like the kangaroo mice of North American deserts.
Desert biomes can be classified according to several characteristics. The 4 major types of deserts are : HOT & DRY, SEMIARID, COASTAL, & COLD.

  • TUNDRA BIOME: 
Tundra is the coldest of all the biomes. Tundra comes from the Finnish word tunturi, meaning treeless plain. It is noted for its frost-molded landscapes, extremely low temperatures, little precipitation, poor nutrients, and short growing seasons. Dead organic material functions as a nutrient pool. The two major nutrients are nitrogen and phosphorus. Nitrogen is created by biological fixation, and phosphorus is created by precipitation.
 CHARACTERISTICS

  1. Extremely cold climate
  2. Low biotic diversity
  3. Simple vegetation structure
  4. Limitation of drainage
  5. Short season of growth and reproduction
  6. Energy and nutrients in the form of dead organic material
  7. Large population oscillations

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