Gradients Mechanisms

  1. What determines what lives where?
    • energy flow
    • nutrient cycling
    • limiting factors / resource tolerance
    • competition
    • predator-prey relationships
    • symbiotic relationships
    • succession / disturbance

  2. Why is there so much stuff that lives by the equator?
    • equatorial- constant, high solar energy
    • favorable climate with no seasonality
    • lots of energy to pass on to next trophic level
    • Old and relatively stable
  3. energy cycle
    Image Upload 2
  4. symbiosis
    • an interaction between two organisms living together in intimate association
    • evolved together (coevolution)
  5. Succession
    process of change in community/ecosystem structure & function over time

    • flora / fauna composition
    • soil development
    • microclimate
  6. Primary Succession
    • new surface is exposed; not previously vegetated
    • soil development begins at the same time
    • (sand dunes, plants growing in cracks of pavement, ect.)
  7. Secondary Sucession
    • old vegetation/ecosystem removed
    • intact soil exposed (relatively)
    • ex: wildfires, volcano erruptions
  8. benefits of succession:
    • soil development
    • increased biomass
    • increased organic matter / humus
    • greater efficiency of nutrient cycling
    • increased diversity (animals)
  9. (I) Disturbance:
    "discrete, punctuated killing, displacement, or damaging of one or more populations that directly (or indirectly) creates an opportunity for new populations to become established"
  10. (II) Disturbance
    "a relatively discrete event that disrupts the structure of an ecosystem, community or population & changes resource availability or the physical environment"
  11. disturbance regime
    pattern of natural disturbance for an area
  12. Intensity of disturbance
    physical energy of the disturbance
  13. Severity of disturbance
    ecological effect on organisms, community, &/or ecosystem
  14. Frequency of disturbance
    average number of disturbance events over a given time period
Card Set
Gradients Mechanisms
NRES midterm