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Openaq Pulse Saltmrsh Prairie Fire Lagoon Climax Species Specarea

Cooperative Existence


If one population depends on another one and vice-versa, we speak about cooperative existence or collaboration. Both populations grow until they reach a steady state, which depends on the growth and mortality rate of both populations.


  • A small fish that lives as a parasite on a bigger fish cleaning its skin
  • A fungus and algal cells that form together the flowerless plant lichen
  • Diagram


    Q1, Q2 = Populations 1 and 2
    R = growth factor
    K1-8 = increasing and decreasing factors




    The graph shows the changes of Q1 (green) and Q2 (red) over a time period.
    Source code:

    "What if" Experiments:

  • If one of the two species started with a much higher inicial population, how would it affect the level of the steady state
  • How do the growth and mortality rates of one population affect the level of the steady state