Community Interactions

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Chapter 4

• Community Interactions
• Biomes

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Community Interactions

• Community Interactions powerfully affect an
  ecosystem
• Types of Interactions
• Competition Organisms of the same or different
  species try to use the same resource in the same
  place and at the same time
• EX Different species of lizards in a desert
  compete by eating same type of insect
• COMPETITIVE EXCLUSION STATES NO TWO SPECIES CAN
  OCCUPY THE SAME NICH IN THE SAME HABITAT AT
  THE SAME TIME
• Predation One organism captures and eats another
  organism. Predator/Prey relationship.
• EX A bobcat captures and feeds on rabbits
• Symbiosis Means Living Together. Organisms
  live closely together. Three types of Symbiosis
  are
• 1. Mutualism Both species benefit. EX Bees
  receive pollen from flowers and flowers are
  pollenated from bees.
• 2. Commensalism One species benefits and the
  other is neither helped nor harmed. EX
  Barnacles that live on a whales skin
• 3. Parasitism One organism lives on or in
  another and harms it. EX Fleas living on a dog

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Ecological Succession

• Ecological Succession The concept that
  ecosystems are constantly changing in response to
  natural human disturbances.
• Can occur gradually over time or in response to a
  sudden natural disturbance
• As an ecosystem changes, old inhabitants die out
  new inhabitants move in causing further changes
  in the community
• 2 Types of Ecological Succession
• Primary Succession Occurs on land where no soil
  exists
• EX Volcanic eruption results in new island being
  formed. Ash allows for lichens algae to grow.
  Algae lichens break down rocks and turn them
  into soil allowing for plants to grow.
• Secondary Succession Occurs when there is some
  sort of disturbance that does not remove soil.
• EX Forest fires result in trees releasing seeds.
  Certain plants are adapted to regular cycles of
  fire their seeds will not sprout unless exposed
  to fire.
• EX Land is cleared for farming, but then
  abandoned. Allows for new plants that werent
  there before to have resources to grow

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Primary Succession
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Secondary Succession
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Biomes

• Biome a group of ecosystems that have the same
  climate and dominant communities of organisms.
• Species are able to adapt in order to live in
  different biomes. EX Desert Kangaroo Rats have
  kidney adaptations that allow them to conserve
  water
• Microclimate The climate in a small area differs
  from the climate around it.
• EX Certain streets in San Francisco are often
  blanketed in fog while sun shines brightly just a
  few blocks away

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The Major Biomes

• Tropical Rain Forest
• Tropical Dry Forest
• Tropical Savannah
• Desert
• Temperate Grassland
• Temperate Woodland and Shrubland
• Temperate Forest
• Northwestern Coniferous Forest
• Boreal Forest
• Tundra

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Tropical Rain Forest

• Hot wet year round
• Orchids, ferns, vines, climbing plants
• Sloths, jaguars, anteaters, monkeys, toucans,
  parrots, butterflies, boa constrictors, anacondas
• Found in South Central America, Southeast Asia,
  parts of Africa, Southern India, Northeastern
  Austraila
• EX Belem, Brazil

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Tropical Rain Forest
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Tropical Dry Forest

• Rainfall is seasonal and NOT year round
• Generally warm year round, alternating wet and
  dry seasons
• Tall, deciduous trees, aloes and succulents
• Tigers, monkeys, elephants, rhinoceroses, hogs,
  deer, snakes, lizards
• Parts of Africa, South Central America, Mexico,
  India, Australia
• EX Chennai, India

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Tropical Savanah

• Receives more rainfall than deserts but less than
  tropical dry forests
• Mainly grasslands with isolated trees
• Warm temperature, seasonal rainfall
• Tall perennial grasses, drought tolerant shrubs
• Lions, leopards, cheetahs, hyenas, elephants,
  giraffes, baboons, zebras
• Large parts of Africa, Southern Brazil, Northern
  Australia
• EX Mombasa, Kenya

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Desert

• Low precipitation, variable temperatures
• Cacti and succulents
• Mountain lions, gray fox, bobcats, mule deer,
  bighorn sheep, tortoises, rattlesnakes, lizards
• Africa, Asia, Middle East, United States, South
  America, Australia
• EX Yuma, AZ

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Temperate Grasslands

• Warm to hot summers, cold winters, moderate
  precipitation
• Perennial grasses and herbs
• Coyotes and badgers, wolves, grizzly bear,
  rabbits, prairie dogs, hawks, owls, snakes
• Central Asia, N. America, Australia, Central
  Europe
• EX Dallas, TX

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Temperate Woodland Shrubland

• Hot, dry summers, cool, moist winters
• Woody evergreen shrubs
• Coyotes, fox, bobcats, mountain lions, deer,
  rabbits, squirrels, lizards, snakes
• West coast of N. and S. America, Mediterranean
  Sea area, South Africa, Australia
• EX Los Angeles, CA

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Temperate Forest

• Cold winters, warm summers, fertile soil,
• Deciduous trees, some conifers, mosses and fern
• Deer, black bear, bobcats, squirrels, raccoons,
  skunks, songbirds
• Eastern US, SE Canada, most of Europe, Parts of
  Japan, China Australia
• EX Philadelphia, PA

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Northwestern Coniferous Forest

• Mild temperatures, precipitation during fall,
  winter, spring, rocky acidic soils
• Douglas Fir, spruce, redwoods
• Bear,elk, deer, beavers, owls, bobcats, weasels
• Pacific coast of northwestern US and Canada from
  northern California to Alaska
• EX Seattle, WA

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Boreal Forest

• Long, cold winters, short, mild summers, high
  humidity
• Needleleaf conifers such as spruce and fir,
  berry-bearing shrubs
• Timber wolves, lynxes, moose, beavers
• North America, Asia, and northern Europe
• EX Fairbanks, Alaska

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Tundra

• Stong winds, low precipitation, short summers,
  long cold winters, permafrost
• Mosses, lichens, short grasses
• A few birds and mammals that can stand harsh
  conditions, artic fox, caribou
• Northern North America, Asia, Europe
• EX Barrow, Alaska