MODULE 7

• ecosystem


  unit including all the organisms interacting with each other (biotic community) in a given area interacting with the physical environment
• ecosystem 


  first unit in the ecological hierarchy that is complete
• ways of understanding ecosystems

  1. Population-community approach
  2. Process-function approach
• Population-community approach


  -ecosystems as networks of interacting populations (structure and components)

  -abiotic environment as backdrop
• Process-function approach


  -ecosystems as pathways of matter and energy

  -functions and processes are more important than organisms performing them
• downside of population-community approach

  fails to see the bigger picture
• downside of process-function approach

  misses out importance of some species
• calcification process 


  corals convert carbonate ions in the seawater into usable forms (calcium carbonate minerals) that form their skeleton
• hypothetical food web (structure)

  1. basal species
  2. intermediate species
  3. top predators
• keystone species


  create or modify habitats AND influence interactions among species
• keystone species


  impact>abundance
• example of keystone species

  wolves, corals
• ecosystem engineers


  any organism that modifies a habitat
• 2 types of ecosystem engineers

  allogenic engineers and autogenic engineers
• allogenic engineers


  modify the environment by modifying materials from one form to another
• allogenic engineers examples


  beaver and trees
• autogenic engineers


  modify the environment by modifying themselves
• autogenic engineers examples


  corals and trees
• landscapes


  heterogeneous area composed of several ecosystems
• landscape ecology


  landscape structure and process
• Landscape elements

  1. Landscape matrix
  2. Landscape patch
  3. Landscape corridor
• landscape matrix 


  the primary 'cover type' in the landscape; greater flora and fauna
• landscape patch


  homogeneous area that differs from the surrounding matrix
• landscape corridor


  a strip of environment connecting 2 or more landsape patches of similar habitat
• complexity theory 


  based upon a conceptual model in which entities exist in a hierarch of interrelated organizational levels
• parameters of a complex system

  numerosity, non-linearity, connectivity, autonomy & adaptation
• numerosity


  number of elements in different levels to the hierarchy within our system
• non-linearity


  interactions and feedback loops over time
• connectivity


  indicates the degree of how things flow in networks
• autonomy & adaptation


  enables self-organization and the process of evolution that shapes complex systems on macro scale (ecological memory)
• examples of complex systemzy


  ecosystems, economies, transportation networks, neural systems (brain)
• dimensions of ecological complexity

  spatial, temporal, and structural
• spatial


  distribution defines the spatial extent of a population/ecosystem
• spatial complexity example


  vegetation patterns and species distribution
• edge effect


  more biodiversity at the borders of 2 or more habitats
• ecotone 


  wide border
• edge 


  marks the perimeter of each patch
• border


  place where the edge of one patch meets with the edge of another
• temporal


  the time series of different variables describing the dynamics of a system
• temporal complexity can be derived from

  1. changes in population
  2. effects of changes in climate and weather
  3. extinction rates
  4. invasion rates
  5. succession (primary and secondary)
  6. predator and prey cycles