The Biosphere

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The Biosphere

• Chapter 3

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What is ECOLOGY

• 1866 German Biologist Ernst Haeckel first coined
  the term ecology.
• Came from the Greek word oikos meaning house
• Defined today as the study of interactions among
  living organisms and their environment

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The Biosphere
ECOSYSTEM
community
population
individual
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Energy Flow

• The sun is the main source of energy for life on
  earth.
• lt 1 of all sunlight that reaches earth is used
  by living organisms.
• What happens to the rest?

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• Most is reflected off as heat energy.

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Producers or Autotrophs

• Use sunlight or chemicals to make their own
  food.
• Examples

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Photosynthesis

• 6CO2 6H2O C6H12O6 6O2
• Performed on land by plants and in water by algae.

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Can organisms make their own food without the aid
of sunlight?

• Chemosynthesis using chemical energy to make
  carbohydrates.
• Usually performed bacteria found in harsh
  environments
• Ocean vents, volcanoes, hot-acidic

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Consumers or heterotrophs

• Herbivores
• Carnivores
• Omnivores
• Detritivores
• Decomposers

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Food Chains
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Food Webs

• More complex than food chains
• A complex net of interactions among organisms.
  (interdependence)

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Trophic Levels

• Each location or step in a food chain or food web
  represents a trophic level.
• Examples producers, primary consumers, secondary
  consumers, etc.

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Ecological pyramids

• Only about ten percent of the energy available
  within a trophic level is transferred to
  oragnisms at the next higher level.

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Other pyramids

• Biomass and numbers

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Cycles of matter

• Unlike energy, matter is constantly being
  recycled in an ecosystem.
• Known as biogeochemical cycles

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Transpiration

• The release of water from the leaves of plants.
• Water is exchanged through a plants stomata.
• Evaporation is the second process that releases
  water into the atmosphere.

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Carbon Cycle

1. Biological processes (photosynthesis,
   respiration, decomposition)
2. Geochemical processes (volcanoes)
3. Biogeochemical (fossil fuels)
4. Human activity (factories, deforestation, car
   exhaust)

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Nitrogen Cycle

• All organisms need nitrogen to live.
• Most abundant gas in atmosphere (80)
• Nitrogen gas is unusable for plants
• Must be fixed or changed into the nitrate or
  nitrite form by bacteria in the soil. Known as
  nitrogen fixation

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Phosphorus cycle

• P is important in the production of DNA and RNA.
• Unlike water,oxygen, and nitrogen, phosphorus is
  NOT found in the atmosphere. Found in rocks and
  minerals.

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Nutrient Limitation

• When a single nutrient is scarce for a particular
  ecosystem and limits the growth of organisms in
  that ecosystem.
• Assignment page 83-84 1-10, 12, 15, 16, 18, 22,
  23, 29
• Page 85 1-7