1. Let’s Review Put the following in order from Largest to smallest:
Community
BIOSPHERE
Organism
Ecosystem
Population

2. Organism Interaction
Organism in an ecosystem must interact with each other and the environment in order to ensure their survival. Organisms have a role to play in their ecosystem.

3. Interactions with Environment
Natural selection – When nature selects the best characteristics suited for the environment. These characteristics are passed down to the offspring (children). Natural selection results in adaptation

4. How does natural selection work?
Individuals best suited for the environment will survive and produce offspring. The offspring will inherit this characteristic and pass it to their offspring. Ex. Long neck giraffes and short neck Giraffes Green Alligators and albino Alligators

5. Every organism has a variety of adaptations that are suited to its specific living conditions. Niche – The role of an organism in its environment. A niche can include: The type of food an organism eats How an organism obtains food The which organisms use that organism for food

6. Interactions Between Organisms
There are three major types of interactions among organisms: Competition, predation and Symbiosis

7. Competition- The struggle between organisms as they attempt to use the same limited resource. If two organisms share the same niche, one will eventually die off Adaptations reduce the need for competition. Ex. Birds and bats Roadrunner and Elf owl

8. Predation
Predation – When one organism kills another for food. The organism that does the killing is called the predator. The organism that is killed is called the prey.

9. Predation and population size
As the number of predators go up, the population of the prey will go down. Since the number of prey has gone down predators will begin to die. This causes the prey population to increase once again.

10. Predator Adaptations
Predators have adaptations that help them catch and kill prey. Ex. Cheetahs can run very fast. Jellyfish tentacles hang and contain poison. Sundew plant has a sticky substance that catches flies when they land

11. Prey Adaptations
Prey have adaptations that protect them from predators. Mimicry – To look like a more dangerous animal Warning Colors – Bright colors let predators know that the organism is poisonous Camouflage – Prey can easily hide from predators

12. Symbiosis
Symbiosis – A close relationship between organisms in which at least one will benefit Three Types: Mutualism Commensalism Parasitism

13. Mutualism – Both organisms benefit
Bacteria in your stomach – Bacteria gets protection from you. The bacteria help you digest vegetables

14. Commensalism – One species benefits and the other is neither helped nor harmed

15. Parasitism – One organism living on or inside an organism and harming it.
Parasites can live inside the host or on the surface of the host.

16. Parasitism
The organism that benefits is called the Parasite. The organism it lives on or in is called the host. Parasites normally do not kill their host. If they kill their host, they lose their source of food.