1. SYMBIOSIS
A close relationship between two organisms in which one organism lives near, on, or even inside another organism, and in which at least one organism benefits.

2. So, what does the word mean?
Symbiosis comes from the Greek words sym, meaning “together”, and bios, meaning life.

3. Symbioses are placed into three categories:
Commensalisms
Mutualism
Parasitism

4. COMMENSALISM
ONE OF THE ORGANISMS BENEFITS AND THE OTHER IS NOT HARMED BY THE ASSOCIATION.

5. Examples of commensalisms
An osprey ( a large hawk) builds its nest high in the branches of a tree. Smaller birds like sparrows and wrens build their nest under the osprey’s for protection from their enemies.
Dozen of tiny mites live at the base of the hairs that make up your eyebrows. You can not see them, they are microscopic. Don’t worry, everyone has them!

6. MUTUALISM
Both organisms benefit from the relationship.

7. How are these two creatures in a mutual relationship?

8. This is how…
A small insect called an aphid is taken care of by a species of ants in exchange for meals of honeydew, which the aphid releases and the ant eats. The ant moves the aphid from leaf to leaf in exchange for the sweet honeydew. The ant protects the aphid from the weather and any aphid-devouring animals.

9. This is very interesting!!
The best example of mutualism involve microorganisms that live inside, yes, INSIDE the body of much larger partners.
In return, they help their partner in some way.
Bacteria that live inside your digestive system help to produce certain vitamins that your body needs.

10. PARASITISM
One organism benefits and the other is harmed.

11. These are just a few examples of parasites that live on or in a much larger host.

12. Special Note
Ecologists often regard parasitism and predation as being different forms of the same basic kind of interaction.
In predation and almost all examples of parasitism one organism eats another organism.
In predation, the predator usually kills its prey before it eats it.
In parasitism, the PARASITE usually lives on or in a much larger organism and feeds on it while it is still alive. The parasite’s unlucky “partner” is called its HOST.
Parasites usually do not kill their host, although many weaken it greatly.

13. In a most parasitism relationships the parasite does not kill its host, however…
A certain wasp lays its eggs on caterpillars. The eggs hatch into wormlike young wasps that burrow into the body of the caterpillar. The young wasps feed on the caterpillar’s tissues, avoiding the caterpillar’s major organs so that it stays alive. After about days, the young wasps chew their way out of the dying host’s body and spin cocoons.
Cuckoos and a few other type of birds lay their eggs in other birds’ nest. When the baby cuckoo hatches, it pushes the eggs and young of its foster parents out of the nest. The foster parents are tricked into feeding and caring for the intruder as if it were their own offspring.