Chapter 16:  Ecosystems and Biomes

Ecosystems

10-31-2001

[ Exam-3 Coverage ]    [ Geog-100 Home ]

Ecosystem Components

 16-2: Abiotic and biotic components of ecosystems

Notice the directional arrows and pathways.  You should understand the sequences of Energy and Biotic and Abiotic components.  
  • What are Abiotic components? 
  • What are Biotic components?  
  • What is the fundamental energy source? 
  • How does this energy source vary at different locations around Earth?  
  • Where are Plants in the flow of energy and materials?  
  • Why are plants called the Producers, or for more emphasis, the Primary Producers?  
  • What is meant by Consumers?  
  • What are Herbivores?  
  • What are Carnivores? 
  • What are the sources of Energy and Materials for the preceding? 
  • Where do Humans fit in? 
  • What are the implications for energy and space efficiencies? 
  • What are Decomposers; what is their "role"? 
  • Why can they be called Recyclers?

Introductory Ecosystems Terminology
(You should learn  these terms, from the book.  Be attentive and careful with the definitions.  They are carefully constructed, on purpose.)

Diversity:  Myriad of life forms.  Diversity is thought to promote stability.

Ecosystem: A self-regulating association of plants and animals and their non-living physical environment.

Ecology: Study of relationships among organisms and their environment and among the various ecosystems in the biosphere.

Biogeography: Spatial ecology; the study of the geographic distribution of plants and animals.

Communities

  • Community: Subdivision within ecosystem

  • Habitat: Where. The environmental situation, actual, or suited

  • Niche: Function or "occupation of a life form.  Are several categories of niches.

    • Habitat niche

    • Trophic niche: 

    • Reproductive niche

    • Competitive exclusion principle: No two species can occupy the same niche with stability.

    • Symbiotic relationships

    • Parasitic relationships

 16-4:  How plants live and grow

Plants:  The Essential Biotic Component

  • "Ultimately, the fate of the biosphere rests on the success of plants and their ability to capture sunlight." [p. 493]

  • Leaf Activity

    • Stomata

  • Photosynthesis

    • Carbon Dioxide + Water (Under sunlight) ==> Glucose, carbohydrates

  • Net Primary Productivity

    • Biomass

 16-7:  Vertical and latitudinal zonation of plant communities

 

16-7b: Alpine tundra ecosystem  in the Colorado Rockies

 

16-7c: Timberline for a needle leaf forest in the Rockies

 

16-8: The carbon and oxygen cycles, simplified

Gaseous and Sedimentary Cycles

  • Hydrogen, Oxygen, Carbon = 99% of Earth's biomass

  • Oxygen and carbon cycles

    • Intertwined via plant photosynthesis

    • Plants take in carbon dioxide and release oxygen

    • Carbon dioxide sources

      • Plant and animal respiration

      • Volcanic activity

      • Combustion, especially of fossil fuels

        • Coal

        • Fuel oils, gasoline, jet fuel, etc

        • Natural gas

 

16-9: The Nitrogen cycle

Nitrogen cycle 

  • Nitrogen: principal gaseous component (78%) of atmosphere

  • Not consumable directly by plants

  • Nitrogen-fixing bacteria on root nodules of certain plants' roots

    • Dry (split) peas, lentils (Important Palouse products)

    • Alfalfa, others

  • Synthetic inorganic fertilizers to improve agricultural yields

    • More fixed nitrogen by humans than all other Earth sources

    • Accumulates in lakes and oceans

    • Dead zone on Gulf Coast

    • E. Washington, N. Idaho lakes

16-12: Ecosystem energy, nutrient and food pathways

Beginning questions, revisited:

Notice the directional arrows and pathways.  You should understand the sequences of Energy and Biotic and Abiotic components.  

  • What are Abiotic components? 
  • What are Biotic components?  
  • What is the fundamental energy source? 
  • How does this energy source vary at different locations around Earth?  
  • Where are Plants in the flow of energy and materials?  
  • Why are plants called the Producers, or for more emphasis, the Primary Producers?  
  • What is meant by Consumers?  
  • What are Herbivores?  
  • What are Carnivores? 
  • What are the sources of Energy and Materials for the preceding? 
  • Where do Humans fit in? 
  • What are the implications for energy and space efficiencies? 
  • Biomass Pyramids:  Efficiency of herbivores vs. carnivores  (Fig 16-14)
  • What are Decomposers; what is their "role"? 
  • Why can they be called Recyclers?

 

Stability and succession

Ecosystem Stability and Diversity
 

16-21: Lake-bog-meadow succession

 

16-21: Succession in a mountain lake

Limiting Factors

  • Low temperatures

  • High temperatures

  • Length of growing season

  • Lack of water

  • Excess surface/soil water

Climate Change:  Impacts on distribution of plants, and thereby, of animals

  • Global warming?

  • How fast can plants adapt/relocate?

16-17a:  Beech trees and climatic change

16-17b: Hemlock trees and climatic change

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