Interactions Within Communities

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

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

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.

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

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

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.

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.

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

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