Ecology

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Ecology

• Why is the world important?
• 3/17/2008

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Definition

• The study of interactions between organisms and
  their surroundings.

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Biosphere

• All the living and nonliving things on the
  planet. (all the biotic and abiotic factors)

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Main source of energy

• sun
• all organisms use the suns energyeither
  directly or indirectly.

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What Shapes an Ecosystem?

• Abiotic vs Biotic Factors
• Abiotic factors anything that is NONLIVING that
  affects the environment.
• Biotic factors anything that is LIVING that
  affects the environment

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Producers

• also called autotrophs
• harness sunlight through photosynthesis
• organisms can also use chemical energy to produce
  carbohydratescalled chemosynthesis
• Collectivelyproducers are known as the first
  trophic level

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Consumers

• also called heterotrophs
• Herbivores (second trophic level)
• Carnivores (third trophic level)
• omnivores
• detritivores
• decomposers

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Feeding Relationships

• Food webs and food chains

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Food Chains
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Figure 3-8 A Food Web
Food Web Note how organism serve as a food source
for many individuals web of energy flow
Section 3-2
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Cycles of Matter

• Carbon Cycle
• Nitrogen Cycle
• Phosphorus Cycle
• Water Cycle

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The Carbon Cycle

• Carbon Dioxide is released into the atmosphere
• burning of fossil fuels
• waste from cellular respiration
• decaying organisms
• Plants take in CO2 during photosynthesis.
• Animals eat plants
• Animals decompose

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The Nitrogen Cycle

• All organisms need nitrogen to make amino acids.
• 78 of the atmosphere is nitrogen gas.
• Plants must convert the nitrogen to a usable
  form. (nitrates) This is called nitrogen
  fixation.

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• Bodies of dead organisms contain nitrogen (in
  ammonia) as well as waste products.
• Bacteria help convert the ammonia back to
  nitrogen gas.

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The Phosphorus Cycle

• Phosphate can be found on earth in water, soil
  and sediments.
• The slowest cycle
• Makes up DNA, ATP and part of the lipid bilayer
  of cell membranes.

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• Most commonly found on rock formations and ocean
  sediments as salts.
• The salts are released through weathering,
  usually dissolve in soil water and are absorbed
  by plants.
• Phosphates return to soil through decay

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The Water Cycle

• Bill Nye

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Nutrient Limitation

• Rate at which organic matter is created primary
  productivity
• Ecosystem is limited by a single nutrient
  limiting nutrient
• Increase limiting nutrient create large growth of
  producers (i.e. algal bloom)

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Habitat vs. Niche

• Habitat is the PLACE an organism lives.
• Niche is HOW an organism lives.

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Community Interactions

• Competition
• Organisms compete for the same resource
• food
• nesting sites
• mates
• water
• oxygen
• sunlight
• nutrients

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• Predation
• Organism must hunt and kill another organism for
  food.
• Prey must have ways to avoid being captured.

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Organism relationships

• Mutualism
• Organisms that benefit from a relationship with
  each other.
• EX. Pollination
• Commensalism
• One organism benefits from a relationship the
  other organism is neither harmed nor helped.

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• Parasitism
• A relationship in which one organism lives on or
  in another organism without immediately killing
  it.
• Defense skin, immune system, mucus, earwax

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Ecological Succession

• A series of predictable changes over a period of
  time until a climax community is reached.
• There are 2 types
• Primary
• Secondary
• both require small fast growing pioneer species

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Primary Succession

• A community develops on a surface where no
  ecosystem has existed before. (bare rock, sand
  dune, an island from a volcanic eruption)

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Secondary Succession

• A replacement of a species that follows a
  disruption of an ecosystem.
• Disruption may be from a forest fire, a strong
  storm or human activities.

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Marine Ecosystem

• Whale fall community
• Organisms living on dead whale carcus
• Starts with large whale death and sinking to
  bottom
• Tissues gone small organisms survive on whale,
  and sediment dwellers
• Whale skeleton left--bacteria break down

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Compare/Contrast Table
Section 4-3
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Freshwater Pond Ecosystem
Section 4-4
Spoonbill
Duck
Water lilies
Frog
Dragonfly
Mosquito larvae
Duckweed
Phytoplankton
Snail
Pickerel
Diving beetle
Trout
Hydra
Crayfish
Snail
Benthic crustaceans
Freshwater Ecosystem
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