1. Interactions Within Communities

2. Where does the energy in an ecosystem come from?
Producers
Organisms that uses an outside energy source to make energy-rich molecules
Most producers contain chlorophyll in order to carry out the photosynthesis reaction

3. Consumers Herbivores Carnivores
Organisms that cannot make their own energy-rich molecules
Obtain energy by eating other organisms
4 categories of consumers
Herbivores Carnivores
Omnivores Decomposers

4. What is a food chain? Food chains:
illustrate how consumers obtain energy from other organisms in an ecosystem.
Simple model of the feeding relationship in an ecosystem
Ex. Deer eat shrubs, mountain lion eat deer.
Arrows represent transfer of energy.

5. Symbiotic Relationships
Symbiosis: any close relationship between species.
Three types of symbiotic relationships:
Mutualism
Commensalism
Parasitism

6. Definition: a symbiotic relationship in which both species benefit.
Mutualism
Definition: a symbiotic relationship in which both species benefit.
Examples:
lichens (made up of algae and fungus): algae supplies energy to both organisms, fungus provides a protected space for algae to live

7. Commensalism
Definition: a symbiotic relationship in which one organism benefits and the other organism is not affected.
Examples:
Clown fish (Nemo) and anemone: tentacles do not sting clown fish, fish is protected from predators. Anemone is not affected.

8. Parasitism
Definition: a symbiotic relationship in which one organism benefits but the other organism is harmed.
Examples:
Roundworms and dogs/cats: worm attaches to intestine and feeds on nutrients, animal can have pain, bloating diarrhea and possible death.
Parasitic wasp lays eggs in caterpillar. Eggs hatch and then eat their way out.

9. How does a habitat differ from a niche?
A niche is how an organism survives, obtains its food and shelter, finds a mate, cares for its young, and avoids danger.
These things are all requirements of the species for its survival

10. Visualizing Main Ideas Draw and complete Visualizing Main Ideas at the end of Chapter 20, Section 3 in Glencoe Texas Science Grade 7.