What is a symbiotic relationship?

A symbiotic relationship is one in which two organisms from different species interact.

Take for example, the symbiotic relationship between a whale and the barnacles that live on the whale's skin. While the whale filter-feeds, it faces difficulties from the surrounding detritus that affects its vision in the water. Meanwhile, the barnacles get food in terms of the detritus the whale emits, and do not have to search for food. This is a mutualistic relationship, what one would call a 'win-win' relationship between organisms.

There are five different kinds of symbiotic relationships:

  1. Mutualism, where both species benefit
  2. Commensalism, where one species benefits, the other is unaffected
  3. Parasitism, where one species benefits, the other is harmed
  4. Competition, where neither species benefits
  5. Neutralism, where both species are unaffected