1. *Refer to Chapter 16 in your Textbook

2. Learning Goals: 1. I can describe interactions that occur in a community. 2. I can differentiate between the types of symbiosis.

3. Interactions within a Community: Predation: occurs when one organism hunts (predator) another organism (prey) to consume Example: A leopard seal (predator) hunts and eats an emperor penguin (prey) in Antarctica.

4. Interactions within a Community: Competition: fighting over a resource such as food, shelter, or a mate; can occur 2 ways: 1. Intraspecific: between the same species Ex. Hermit crabs compete for the biggest shell 2. Interspecific: between different species Ex. Sponges & coral compete for plankton

5. Interactions within a Community: Keystone Species: a species that has vital importance to its community; without the keystone species, the community would be drastically different Ex. Sea Otter – is a keystone species in a kelp forest. Sea otters feed on sea urchins, which feed on kelp. Without the sea otter, the sea urchins would over populate. If there are too many sea urchins, there would eventually be no more kelp forest!

6. Interactions within a Community: Symbiosis: “living together” occurs when 2 different species have a close relationship within a community. 3 types: 1. Mutualism 2. Commensalism 3. Parasitism

7. Types of Symbiosis: Mutualism: occurs when both species in the relationship benefit in some way Ex. Clownfish & sea anemone – fish gets a free home & also lures food in for the anemone to eat

8. Types of Symbiosis: Commensalism: occurs when 1 organism in the relationship benefits without affecting the other one Ex. The remora fish attaches himself to a shark to gain a free ride & protection from predators.

9. Types of Symbiosis: Parasitism: occurs when 1 organism in the relationship benefits while harming the other one Ex. A tapeworm lives inside a polar bears gut and feeds off his internal organs.