Co-evolution is likely to happen when different species have close ecological interactions with one another. It is one of the main ways biological communities are organized.

Healthy reefs that grow on natural or human-made structures contain many, many species.  Over time reefs have evolved intricate relationships between different species based on the need for food and shelter.

Let’s Complicate things

Two organisms living in close relation is called symbiosis. Symbiotic relationships include:

  1. Predator/prey (and parasite/host) – one species in the relationship benefits at the expense of the other(s);
  2. Competition – this involves intra- and interspecies competition for resources like food or shelter;
  3. Mutualism – both species gain benefit from the relationship.

Oil platforms, seawall tiles and shellfish reefs all provide habitat where species have close ecological interactions, for example the interactions on shellfish reefs where oysters excrete a mucus-like substance that is rich in nutrients and provides food for small shellfish that in turn provide food for larger fish.