1. 6.1 Relationships in the Ecosystem

2. Predators and Prey Predator= A consumer that actively hunts other living organisms. Prey= The organism that a predator eats.

3. Lynx and Snowshoe Hare Predator and prey population sizes are closely linked. A large prey population can support more predators than a small prey population.

4. Graph of Lynx and Hare The changing population size of the prey species controls the population size of the predator species.

5. Parasitism Parasitism= Is a relationship in which one organism feeds on the tissues or body fluids of another. Host= The organism on which a parasite feeds. Parasites are a density-dependent limiting factor because parasites are more successful in dense host populations.

6. Human Parasites

7. Symbiosis Symbiosis= Any relationship in which two species live closely together. 2 types: Commensalism and Mutualism

8. Commensalism Is a symbiotic relationship that benefits one species and neither helps nor harms the other.

9. Mutualism A symbiotic relationship in which both species benefit.

10. Review What is a parasite? Provide an example of two human parasites. Why are herbivores not considered to be parasites? Explain symbiosis and the two different symbiotic relationships.