by Rose Helms & Dakota Cranfield


An interaction between two different organisms living in close physical association, typically to the advantage of both.

3 Types of Symbiosis

1. Commensalism - A relationship where one species obtains food or shelter from other species. It does not harm or help the other species.

Example: A spider building a web on a tree, or the birds that eat the insects off of cattle.

2. Mutualism - A relationship where both species benefit from each other.

Example: Dogs and Humans. The dogs provide companionship and protection and the humans provide food and shelter or bees that pollinate flowers.

3. Parasitism - A relationship where one species (the parasite) nourishes itself to the disadvantage of the other species (the host).

Example: Tapeworms. They do more damage to their hosts because they eat partially digested food and that deprives the host from food and nourishment.