IV.Ecology

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IV. Ecology

• Definitions
• Symbiotic Relationships
• Biogeochemical Cycling
• Ecological Succession
• Georgias barrier islands An example of
  ecosystem dynamics

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A. Definitions

• Ecology
• The study of the interaction of populations of
  living organisms with other populations and with
  the environment
• Population
• A group of individuals, all of the same species
• Community
• A group of different populations
• Physical factors in the environment
• Oxygen concentration, salinity, temperature,
  rainfall, etc.

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B. Symbiotic relationships

• Symbiosis
• A relationship between two species
• Usually involves close physical contact
• The major types are mutualism, commensalism,
  parasitism, and predator-prey relationships

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B. Symbiotic Relationships

• Mutualism
• A symbiotic relationship between two species
• In which both species benefit
• Example
• Microbes in the stomach of cattle are responsible
  for the digestion of cellulose (fiber in grass
  hay)
• The cattle benefit because they use the glucose
  from the cellulose digestion
• The microbes benefit because they get a warm,
  moist, protected place to live

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B. Symbiotic Relationships

• Commensalism
• A symbiotic relationship between two species
• In which one species benefits, and the other
  species is neither helped nor harmed
• Example
• Small worms living attached to the shells of
  loggerhead sea turtles
• The worms benefit because they get to travel
  through nutrient-rich waters as the sea turtle
  swims around (worms attached to the docks are
  stuck there)
• There is no direct benefit to the turtle having
  worms stuck on its back, nor does there seem to
  be any harm done

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B. Symbiotic Relationships

• Parasitism
• A symbiotic relationship between two species
• In which one species benefits, and the other
  species is harmed
• The species that benefits is called a parasite,
  and is typically much smaller than the other
  species (the host)
• Example
• Pathogenic microorganisms that cause disease in
  humans, animals, and plants

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B. Symbiotic Relationships

• Predator-prey relationship
• A symbiotic relationship between two species
• In which one species captures kills the other
  species for food
• The species are generally about equal in size
• The term is usually applied to animal species (or
  certain types of protozoan species)
• Example
• Lions and wildebeests, cougars and rabbits, etc.

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C. Biogeochemical cycling

• Definition
• The carbon cycle
• The nitrogen cycle

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Carbon Cycle
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Nitrogen Cycle
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D. Ecological Succession

• Definition
• A series of changes in the ecological community
  that inhabits an area or region
• Occurs because the activities of living organisms
  (and nonbiological physical factors) change the
  conditions of a region (for example, soil
  chemistry) so that the region becomes more
  conducive to a different group of organisms

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Bare Rock Succession

• An example of primary succession Succession
  beginning in an area or surface on which there
  has never been life before

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Old Field Succession

• An example of secondary succession Succession
  that occurs in a region in which life has existed
  before, but in which the previous community
  structure has been disrupted
• Frequently seen in North Georgia where cultivated
  fields (e.g. old cotton or soybean fields) are
  abandoned and no longer cultivated

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Old Field Succession
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D. Ecological Succession

• Beach succession Another example of secondary
  succession
• The normal flora of humans A medical example

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E. Georgias Barrier Islands

• Formation of the barrier islands
• Beach building and erosion processes
• Beach ? dune ? shrub zone ? maritime forest
  succession
• Salt marsh / estuarine ecosystems
• Web siteshttp//www.sherpaguides.com/georgia/bar
  rier_islands/index.htmlhttp//www.sherpaguides.co
  m/georgia/coast/northern_coast/ossabaw_island.html
  http//web.utk.edu/ctmelear/ossabaw/movies/ossab
  awscenery.html