Ecosystem: Stability and Change

1
Ecosystem Stability and Change
2
Stability

• Is the ability to withstand or recover from
  externally imposed changes or stress
• resistance, persistence, or inertia
• Resilience
• Constancy-maintain certain size
• Applies to organisms, populations, communities
  ecosystems, and the ecosphere
• Provided that these external stresses are not too
  severe

3
Factors Contributing to Ecosystem Stability

• Food Web Complexity
• Homeostatis- internal systems counteracting
  external stress.
• Continuous Dynamic Change
• Movement of Matter and Energy
• Replacement of Organisms
• Ecological Succession- the natural replacement
  of one community in particular area with a
  different, and usually more complex community,
  over a period of time

4
Primary Succession
5
Secondary Succession
6
Secondary Succession
7
(No Transcript)
8
(No Transcript)
9
Tolerance Range/Limits

• Minimum and maximum limits for physical
  conditions (such as temperature) and
  concentration of chemical substances beyond which
  no members of a particular species can survive.

10
(No Transcript)
11
Limiting Factor Principles

• Too much or too little and any abiotic factor
  can limit or prevent growth of a population of a
  species in an ecosystem, even if all the other
  factors are at or near the optimal range of
  tolerance for the species

12
Law of Tolerance

• The existence, abundance, and distribution of a
  species in an ecosystem are determined by whether
  the levels of one or more physical and chemical
  factors fall with the range tolerate by the
  species.

13
(No Transcript)