Biological Communities

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Biological Communities

• Chapter 18

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18-1 How Organisms Interact in Communities

• Objectives
• Identify the distinguishing features of symbiotic
  relationships
• SCS B-6.1

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Species Evolve in Response to each other

• Interactions among species
• Insects/flowers
• Coevolution
• Predator/Prey relationships
• Predation is when one organism feeds on another

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• Symbiosis
• When two or more species live together in a
  close, long-term association.

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• Parasitism when one organism feeds on and
  usually live on or in another
• Example Ticks and dogs
• Ticks benefit, but dogs do not

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• Mutualism a symbiotic relationship in which
  both benefit from the relationship
• Example flowers and bees
• Flowers are pollinated and bees have food

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• Commensalism a relationship in which one
  organism benefits and the other neither is
  benefits or is harmed
• Example Spanish moss and trees
• Trees are not hurt nor benefit, but the moss
  benefits from additional sunlight

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18-2 How Competition Shapes Communities

• Objectives
• Describe the role of competition in shaping the
  nature of communities
• Distinguish between fundamental and realized
  niches
• Describe how competition affects an ecosystem
• Summarize the importance of biodiversity
• SCS B-6.1, 6.2

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• Common Use of Scarce Resources leads to
  competition
• Organisms compete for food, space, light,
  minerals, and water
• Resources must be in short supply if competition
  occurs
• Competition can limit how species use resources
• Competition can lead to extinction or elimination
  of a species

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• Niche the role of a species in a ecosystem
• How does the organism affect the environment
• If niches overlap it may cause competition
• Niches can vary in size

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• Predation can lesson competition
• Eliminates those species less adaptive
• Promotes biodiversity

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18-3 Major Biological Communities

• Objectives
• Recognize the role of climate in determining the
  nature of biological communities
• Describe how elevation and latitude affect the
  distribution of biomes
• Summarize the key features of the Earths major
  biomes
• SCS B-6.1, 6.2

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• Climate determines where species lives
• Climate is the prevailing weather conditions of
  an area
• Temperature and moisture
• Temperature and moisture determine biological
  communities

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Types of Terrestrial Biomes

• Tundra
• Taiga
• Desert
• Grassland
• Temperate Forests
• Tropical Rain Forests

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Tundra

• extremely short growing season (6 to 10 weeks)
• long, cold, dark winters (6 to 10 months with
  mean monthly temperatures below 32 F or 0 C.)
• low precipitation (less than five inches/year)
• Animals and animals Musk ox, artic hare and
  fox, permafrost (permanently frozen ground)

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Taiga

• Long, severe winters and short summers (50 to 100
  frost-free days) are characteristic, as is a wide
  range of temperatures between the lows of winter
  and highs of summer.
• Mean annual precipitation is 15 to 20 inches,
  but low evaporation rates make this a humid
  climate.
• Vegetation and Animals Conifers, beaver, lynx,
  deer, sparrows..

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Deserts

• Temperature Average of 38C (day), average of
  -3.9C (night)
•  Precipitation About 250 mm of rain per year
•  Vegetation Cacti, small bushes, short grasses
•  Animals in the desert coyotes, lizards and
  snakes, insects, and even some birds) are adapted
  for burrowing to escape the scorching heat of the
  desert sun

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Grasslands

• Temperature Dependent on latitude, yearly range
  can be between -20C to 30C  
• Precipitation About 500 to 900 mm of rain per
  year  
• Vegetation Grasses (prairie clover, salvia,
  oats, wheat, barley, coneflowers)
• Animals bison and antelope

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Temperate Forests

• Temperature -30C to 30C, yearly average is
  10C, hot summers, cold winters  
• Precipitation 750 to 1,500 mm of rain per year
   
• Vegetation Broadleaf trees (oaks, maples,
  beeches), shrubs, perennial herbs, and mosses
• Animals Deer, raccoons, and salamanders are
  characteristic inhabitants.

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Tropical Rain Forest

• Temperature 20C to 25C, must remain warm and
  frost-free
•  Precipitation 2,000 to 10,000 millimeters of
  rain per year
•  Vegetation Vines, palm trees, orchids, ferns
• Animals and plants monkeys, cat like mammals,
  reptiles, insects, diverse flowers, hard wood
  trees, and medicinal plants

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