1. How do organisms interact? Chapter 2 Lesson 3

2. In an ecosystem, organisms compete for space, light, food, water, air, and nutrients Competition is the struggle among organisms for limited resources in an area.

3. Population density is a measure of a population’s size in relation to the size of where the population lives. You are here

4. The predator prey relationship A predator is an animal that feeds on other living animals. Prey is an animal that predators eat. What would happen if there are too many predators? What would happen if there aren’t enough prey for the predators to eat?

5. But we don’t like to compete… – Not all organisms in an ecosystem compete. Some live together in a relationship called symbiosis. Symbiosis is a close relationship between organisms of different species in which one or both of the organisms benefit. – There are three types of symbiosis

6. Parasitism is a relationship where one species benefits while the other is harmed. – A parasite is an organism that lives in or on another organism – The organism that a parasite lives in or on is called the host. Parasites are usually smaller than the host and don’t usually kill them, but can make them weaker

7. In this relationship, both organisms benefit.

8. In this relationship, one organism benefits and the other is neither helped, nor harmed. *Images provided by Google and AltaVista