Biomes

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Biomes

• A major type of ecosystem with distinctive
  temperature, rainfall, and organisms.

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6 Types of Biomes

• 1. Deserts
• 2. Tundras
• 3. Grasslands
• 4. Forests
• 5. Freshwater
• 6. Marine

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Biomes

• Blue Planet Biomes - World Biomes

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7.1 Deserts

• They have different characteristics depending
  where they are in the world
• Home to different organisms
• Receive very little rain. This is a limiting
  factor
• Soils are rich in minerals but poor in
  organic material

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Leaching

• When rainwater that moves through the soil
  carries minerals deeper into the soil.
• Since there is little rainfall in the
  desert, there is little leaching.

• As a result, the upper part of the soil is
  rich in minerals
• Since little rainfall, there is lack of
  organic material, which is able to decay. This
  decayed organic material is important in topsoil,
  so there is hardly any desert topsoil

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Pavement

• This is the desert floor
• Made of hard baked sand, bare rocks or both
• This is due to wind blowing the loose, dry
  soil away

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Two Types of Deserts

• Cool Deserts
• Located between the Sierra Nevadas and Rocky
  Mountains. Found on eastern sides of western
  mountains.

• Hot deserts
• Located in the southwest, particularly
  California, Arizona, New Mexico and western Texas

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Desert Climate

• 10 - 25 cm (about 10 inches) or less of
  precipitation per year
• This determines the types of plants which
  determine the types of animals
• Rain usually falls during a short
  thunderstorm followed by a long period of dry
  weather

• Since the desert pavement is dry, most of
  the rain runs off and is not absorbed
• Lack of rain causes a lack of moisture.
  This affects the temperature of the desert.
  There is no blanket to absorb heat and hold in
  the warmth
• Desert has hot, hot days and cold nights

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Desert Organisms

• Adapted to survive two challenges.
• 1. Lack of water
• 2. Extreme temperatures
• Adaptations include behavior and structural
  changes.

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Desert Plants

•   Provide base of food web, so determine types
  of animals which live in the desert
•   Few plants survive because climate is too
  dry
• Must be able to absorb water from the ground

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Desert Plants

•   Must be able to prevent loss of water from
  their tissues
• Cacti are examples, they are called
  succulents.
• Spines are modified leaves
• They are able to store water for dry times
• Their spines also protect them against
  predators, which eat them
• Aloe Vera is native to Africa (not related to
  cacti)
• Some other plants have roots that are long
  and extend a long distance to get water. An
  example is the mesquite tree.
• Sagebrush is another example

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Desert Plants
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 Desert Animals

• Has many animals
• Insects, reptiles, birds and mammals
• Get most of their water from plants
• All animals have an outer coat that reduces
  water loss

•    Have adaptations to survive heat
• Kangaroo rat is an example
• Spend day in underground burrows and come
  out at night when it is cooler
• These animals are known as nocturnal animals

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Desert Animals