1. Interactions Within Ecosystems p.663-670

2. Competition Competition is the struggle between organisms to survive in a habitat with limited resources. One species may die off if it cannot get the resources it needs Organisms that survive have adaptations that enable them to reduce competition – eating different food, living in a different place etc.

3. Predation Predation is an interaction in which one organism hunts and kills another for food. The predator is the organism that does the killing The prey is the victim; the organism that gets caught

4. Predator Adaptations Some species have adaptations that can help them catch and kill their prey – cheetah can run fast, jellyfish’s tentacles can paralyze tiny animals

5. Prey Adaptations An organism’s physical characteristics can help protect it from getting eaten

6. Symbiosis Symbiosis is a close relationship between two species that benefits at least one of the species There are three types of symbiotic relationships: –Mutualism –Commensalism –Parasitism

7. Mutualism Mutualism is a relationship in which both species benefit Saguaro and long-eared bats

8. Commensalism Commensalism is a relationship in which one species benefits and the other is neither helped nor harmed Red-tailed hawks and saguaro

9. Parasitism Parasitism involves one organism living on or inside another organism and harming it The organism that benefits is called a parasite The organism that lives on or in is called a host Tapeworms living in a dog