Introduction to Ecology

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Introduction to Ecology

• Ecology- study of the interactions between
  organisms and the biotic and abiotic components
  of their environment.
• Interconnectedness or Interdependence
• All organisms interact with other organisms in
  their surroundings and with the abiotic factors
  of their environment.
• Their survival depends on these interactions.
• Effects ?any changes in the environment can
  spread through the network of interactions and
  affect organisms that appear far removed from the
  changes.

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Levels of Organization

• Ecology is organized into five levels
• Organism? Population? Community? Ecosystem?
  Biosphere

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Ecosystem Components

• Biotic- living components
• Six kingdoms
• Eubacteria
• Archaebacteria
• Protista
• Fungi
• Plantae
• Animalia

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Ecosystem Components

• Abiotic- nonliving factors
• Temperature
• Humidity
• pH
• Salinity
• Oxygen concentration
• Amount of sunlight
• Availability of nitrogen
• Precipitation (rainfall)

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Niche

• Habitat- the place where an organism lives
• Niche- the specific role of a species within its
  environment
• Includes
• (1) range of conditions that the species can
  tolerate
• (2) the resources it uses
• (3) the method by which it obtains resources
• (4) the number of offspring it has
• (5) its time of reproduction
• (6) all other interactions within its environment

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Energy Transfer

• Flow of Energy
• Sun? Autotrophs? Primary consumer? Secondary
  consumer? Tertiary consumer
• Producer (Autotroph)
• Example
• Plants
• some Protists
• some Bacteria

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Energy Transfer

• Most producers are Photosynthetic
• Terrestrial ecosystems, plants are the major
  producers.
• Aquatic ecosystems, photosynthetic protists and
  bacteria are the major producers
• Some bacteria are Chemosynthetic
• Uses inorganic molecules, like sulfur dioxide, to
  produce carbohydrates.

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Energy Transfer

• Consumers
• All Animals, most Protists, all Fungi, and many
  Bacteria
• Types
• Herbivores
• Carnivores
• Omnivores
• Detritivores- consumers that feed on dead
  organisms or animal waste.
• Example turkey vulture, many bacteria, fungi
• Decomposers, bacteria and fungi, are detritivores
• Break down complex molecules into simpler
  molecules
• Release nutrients back into the environment.

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Energy Transfer

• Trophic level- an organisms position in a
  sequence of energy tranfers.
• Food chain
• Food web
• 10 of the energy of a given trophic level is
  passed on to the next trophic level.

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Ecosystem Recycling

• The Water Cycle
• Movement of water is between these various
  reservoirs
• Ocean, lakes, rivers, streams
• Atmosphere
• Groundwater
• Three important processes
• Evaporation
• Transpiration
• Precipitation

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Ecosystem Recycling

• Carbon Cycle
• Photosynthesis and cellular respiration form the
  basis of this cycle
• Carbon exists in the atmosphere as CO2
• Sources of CO2
• Cellular respiration, combustion, decomposition

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Ecosystem Recycling

• Nitrogen cycle
• Recycling nitrogen
• Ammonification- decomposers break down proteins,
  nucleic acids (DNA), urine, and dung, to
  ammonium.
• Nitrification- soil bacteria take up ammonium and
  oxide it into nitr ite and nitrates
• Plants use nitrates to form amino acids
• Denitrification- anaerobic bacteria break down
  nitrates and release nitrogen gas into the
  atmosphere

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Ecosystem Recycling

• Nitrogen cycle
• Importance of nitrogen
• Needed to make proteins and nucleic acids
• Nitrogen gas (N2) makes up 78 of the atmosphere
• Plants can utilize nitrogen in the form of
  nitrates (NO3) and Ammonium (NH4)
• Nitrogen fixation N2 to NH4
• Nitrogen-fixing bacteria
• Mutualistic relationship between bacteria and
  plants
• Plants supple carbohydrates
• Bacteria produce usable nitrogen
• Other bacteria convert ammonium to nitrates
• Animals get nitrogen by eating plants or other
  animals

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