What is the difference between commensalism and parasitism ?

The difference between commensalism and parasitism are:


  • In this association, one organism is benefited while the other remains unaffected.

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  • There is no involvement of food. E.g. woodpeckers peck holes for nesting in tree trunks. After they abandon these holes, blue birds, use them for nesting.


  • In this association, an organism lives in / on the body of another organism and derives benefit from it.
  • Nutrition is obtained by the parasite at the expense of the host. E.g. ticks in dogs.