Ecology -

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Ecology -

• How Ecosystems Work

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Where does energy come from?

• All energy in an ecosystem stems from the sun.
  Producers make this energy into useable energy
  for consumers.

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Producers

• Makes own food (autotroph)
• Photosynthesis
• Carbon Dioxide Water Solar Energy
  Sugar (carbohydrate) Oxygen

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Consumers

• Get energy from other organisms (heterotrophs)

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Types of consumers

• Herbivore
• Carnivore
• Omnivore
• Decomposer

• Cow, sheep, deer, grasshopper.
• Lions, hawks, snakes, spiders.
• Bears, pigs, humans.
• Fungi, bacteria

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Exception to sun rule

• Deep in oceans where the sunlight can not get,
  there are ecosystems around hydrothermal vents.
  Energy stems from bacteria that convert hydrogen
  sulfide into make their own food.

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Cellular Respiration

• Used to get energy out of carbohydrates
• Sugar Oxygen Carbon Dioxide Water
  Energy

Sugar C6H12O6



CO2
H2O
Energy
oxygen
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Transfer of Energy

• Energy is transferred from one organism to
  another when one organism consumes another.
• Each time energy is transfers it is called a
  trophic level.

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Trophic Levels can be expressed through food
chains and food webs.















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Food Chain
A sequence in which energy is transferred from
one organism to another.
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Food Web

• Because most animals eat more than one type of
  food, a food web shows multiple chains linked
  together.

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Energy pyramid

• The tree is the lowest trophic level and has the
  highest amount of energy.
• Each increasing trophic level has less energy
  available to it due to loss of heat and other
  conversions.

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Trophic levels

• Ecosystems rarely have more than 4-5 trophic
  levels because there simply is not enough energy
  to support higher levels.

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The Cycling of Materials

• In an ecosystem materials are constantly reused.
  
• The Carbon cycle
• The Nitrogen cycle
• The Phosphorus cycle

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The Carbon Cycle

• Carbon is an essential component of proteins,
  fats, and carbohydrates which make up all
  organisms.

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The Carbon Cycle

• Carbon is cycled between
• Land-limestone fossil fuels
• Atmosphere-Carbon dioxide
• Water-Dissolved with in
• Organisms-protein, fats, carbohydrates
  bones/shells

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Fossil Fuels

• Left over stored carbon from bodies of dead
  organisms from millions of years ago.
• Burning of fossil fuels along with natural
  burning of wood or forests 6 billion metric
  tons of CO2
• Half of this stays in the atmosphere, causes
  global warming

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The Nitrogen Cycle

• Organisms use nitrogen to build proteins to build
  new cells.
• 78 of the gases in the atmosphere.
• Most organisms cannot use atmospheric Nitrogen.

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Nitrogen Fixing Bacteria

• Fix atmospheric nitrogen into chemical compounds
• Roots of legumes or in soil

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Decomposing Bacteria

• Break down the wastes of animals, leaves and
  other decaying organisms to return the Nitrogen
  to the soil.
• Bacteria break some of the nitrogen into nitrogen
  gas

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The Nitrogen Cycle

• Nitrogen cycles by
• Atmosphere-Nitrogen gas
• Bacteria-Nitrogen fixing and decomposing

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The Phosphorus Cycle

• Phosphorus is an essential element for bones and
  teeth in animals.
• This cycle is slow and does not normally occur in
  the atmosphere because Phosphorus does not
  normally occur as a gas.

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The Phosphorus Cycle

• Phosphorus cycles
• Earth-soil, rock, fertilizers
• Water-sinks to bottom
• Decomposition of plants and animals

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Fertilizers

• Fertilizers contain nitrogen and phosphorus to
  help stimulate rapid growth and bigger plants.
• Excess can enter terrestrial and aquatic
  ecosystems leading to rapid growth of algal
  blooms. Algae can deplete oxygen available to
  fish and other aquatic life.

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Acid Precipitation

• Burning coal, wood, or oil releases nitric oxide
• Combines with oxygen and water vapor to make
  nitric acid (dissolves in rain snow)

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How Ecosystems Change

• Ecological succession
• Primary succession.
• Secondary succession.
• Old-field succession.

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Ecological Succession

• Gradual process of change and replacement of the
  types of species in a community.
• May take hundreds or thousands of years.

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Primary Succession

• Occurs on a surface where no ecosystem existed
  before.
• Rocks, cliffs, and sand dunes

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Secondary Succession

• Occurs in ecosystems that have been disturbed by
  humans, animals, or natural processes such as
  storms, floods, earth, quakes, and volcanos.

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Pioneer Species

• The first organisms to colonize a newly available
  area and begin the process of ecological
  succession.
• Make it more habitable for other species to move
  in.

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Climax Community

• A final stable community.
• Still will continue to change in small ways over
  time.

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Old-field Succession

• Occurs when farm land is abandoned.
• Grass/weeds (w/in 1 year)
• Perennial plants/grasses (w/in 2 years)
• Shrubs (w/in 3-10 years)
• Pine forest (about year 20)
• Oak forest (about 150 years)

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Succession

• Primary succession takes much longer than
  secondary succession.
• Pioneer species generally tends to be lichens
  that break down the rocks (can live without
  soil). Mosses may then grow, etc. starting the
  succession process.