11.4. Cooperation

   Intra-specific cooperation results in increased reproduction and/or survival of
   organisms in groups as compared to isolated organisms. This is called group
   effect which was first analyzed Allee (1931) and is often called "Allee effect".

   [allee.gif]

   Group effect results in the increase of population growth rate with increasing
   population density when density is low. There is more danger of extinction in
   populations with group effect because there is a minimum population density below
   which population declines until it is gone.

   Cooperation between different species is relatively rare in nature and we will
   not study its models. Usually it has a form of [1]symbiosis.

   [2][back.gif] [3][up.gif] [4][forward.gif]
     ____________________________________________________________________________

   [5]Alexei Sharov 4/14/97

References

   1. http://c.gp.cs.cmu.edu:5103/prog/webster?symbiosis
   2. http://alexei.nfshost.com/PopEcol/lec11/niche.html
   3. http://alexei.nfshost.com/PopEcol/lec11/compet.html
   4. http://alexei.nfshost.com/PopEcol/lec12/dispers.html
   5. http://alexei.nfshost.com/~sharov/alexei.html