II. Community Interactions(Chp 48)

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II. Community Interactions (Chp 48)

• Def. all the populations of organisms
  inhabiting a common environment and interacting
  with one another
• Types of Interactions
• A. Competition
• 1. Competitive exclusion - when two species
  use the same limiting resource, one is always
  eliminated e.g.
  Paramecium caudatum and P. aurelia

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• 2. Ecological niche - an organisms role in the
  environment (its profession, not its address)
• a. Fundamental niche - determined by the
  physiological limits of the organism
• b. Realized niche - the portion of the
  fundamental niche actually utilized due to
  interactions with other species
• e.g. Chthamalus and Balanus barnacles
• c. Niche Partitioning closely related
  organisms that require the same resource will
  overlap little to to allow competing species to
  coexist
• e.g. five species of warblers

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Think You Know Everything??????????

• The liquid inside young coconuts can be used as
  a substitute for blood plasma.
• No piece of paper can be folded in half more
  than seven (7) times.
• Donkeys kill more people annually than plane
  crashes.
• You burn more calories sleeping than you do
  watching television.
• Oak trees do not produce acorns until they are
  fifty (50) years of age or older.
• The first product to have a bar code was
  Wrigley's gum.
• The king of hearts is the only king without a
  mustache.
• American Airlines saved 40,000 in 1987 by
  eliminating one (1) olive from each salad served
  in first-class.
• Venus is the only planet that rotates clockwise.
• Apples, not caffeine, are more efficient at
  waking you up in the morning.

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• B. Predation - eating of live organisms by
  animals, plants, or fungi
• 1. Population control
• 2. Increases species diversity - keystone
  predators maintain diversity by controlling the
  number of potentially dominant species
• Sea Stars (Pisaster) control abundance of
  mussels and barnacles
• Periwinkles (snails) control diversity of algal
  species

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• 3. Drives evolution of predator and prey
  species
• a. Speed, strength, teeth, intelligence
• b. Defensive adaptations in plants
• i. Structures - thorns and spines
• ii. Chemicals - nicotine, morphine,
  strychnine (poison), and cinnamon, cloves, or
  peppermint (distasteful)
• c. Defensive adaptation in animals
• i. Concealment and camouflage - freezing,
  burrows, protective coloration, warning
  coloration, disguised appearance (walking
  stick, peppered moth, frog looking like bird
  dropping)
• ii. Disagreeable taste, odor, or spray - stink
  bug, monarch butterfly, bombardier
  beetle

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Bombardier beetles (Brachinus spp.) inject an
explosive mixture of hydroquinone, hydrogen
peroxide plus several potent catalysts into a
reaction chamber in the abdomen. Catalase breaks
down the hydrogen peroxide into water and oxygen
gas. Peroxidase oxidizes hydroquinone into
benzoquinone. The mixture of chemicals and
enzymes volatilizes instantly upon contact with
the air, generating a puff of "smoke"" and an
audible popping sound. This caustic flatulence is
totally controlled by the beetle, otherwise it
might accidentally blow up its rear end. The
explosive discharge apparently discourages
predators, either by chemical irritation, heat or
repugnance. The temperature of the explosive
mixture of gasses and fluids is over 100 degrees
Celsius, the boiling point of water.
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• iii. Mullerian mimicry - using similar warning
  coloration
• e.g. Yellow jacket, sandwasp
• iv. Batesian mimicry - harmless species mimics
  unpalatable or dangerous species
• e.g. viceroy and monarch butterflies, flies
  and bees, hawkmoth larva and snake

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Most dust particles in your house are made from
dead skin. The first owner of the Marlboro
Company died of lung cancer. So did the first
"Marlboro Man." Walt Disney was afraid of
mice. Pearls melt in vinegar. It is possible to
lead a cow upstairs...but not downstairs. A
duck's quack doesn't echo, and no one knows
why. Dentists have recommended that a toothbrush
be kept at least six (6) feet away from a toilet
to avoid airborne particles resulting from the
flush. Richard Millhouse Nixon was the first
U.S. president whose name contains all the
letters from the word "criminal." The second?
William Jefferson Clinton. Turtles can breathe
through their butts
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• C. Symbiosis - close and long term association
  between two species,
• e.g. lichens fungi algae

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• 1. Parasitism - one organism benefits, one is
  harmed
• - Plasmodium (malaria) -mosquito
• - tapeworm
• 2. Mutualism - beneficial to both organisms
• - nitrogen-fixing bacteria
• - PS algae in coral tissues
• - acacias and ants
• - protists in termite gut
• - mycorrhiza roots and fungi
• - Leaf-cutter ant and fungus
• 3. Commensalism - beneficial to one, no effect
  on other (hitchhikers)
• - barnacles attached to whales
• - worm in sea cucumber's anus
• - clownfish and anemone

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