Science 7 Topic #4

1. Science 7 Topic #4 How Organisms Interact

2. Biotic vsAbiotic • Biotic • Living parts of an ecosystem • Ex. Humans, bacteria, insects, plants, etc • Abiotic • Non-living parts of an ecosystem • Ex. Air, water, soil, sun , minerals

3. The Roles of Organisms in an Ecosystem • Niche: • The role of an organism within its ecosystem that allows that ecosystem to survive and function efficiently • Can help explain why organisms act and interact as they do • Must look at what it eats, where it lives, and how it interacts with other organisms in its ecosystem

4. Producers • Are able to make their own food • Consumers • All organisms that consume/eat producers or other organisms to obtain their energy • 3 types • Herbivores: eats plants • Carnivores (predators/prey): eats meat • Omnivores: eats both meat/plants

5. Food Chains • A model that shows how energy stored in food passes from organism • Always starts with the SUN • Even though an animal eats a plant to obtain their energy they still rely on the Sun indirectly • Energy flow • The movement of energy, starting from the Sun, and passing from one organism to the next • Only 10 percent of energy is transferred to the next individual

6. Food Webs • Network of interconnected food chains • Can be large and complicated

7. Pyramid of Numbers • The number of individual organisms at each level of a food chain; the number of organisms decreases with each level higher in the food chain • There is a greater number of organisms at the bottom of the food chain than at the top • Does not indicate how much energy is consumed • Biomass • The total mass of all the organisms in an ecosystem

8. The Clean-Up Squads • Scavengers • Organisms that feed on dead or decaying plant or animal matter • Eat the dead material and break down the large carcasses into smaller pieces during digestion • Decomposers • Do not actually eat dead material • Grow in or on the dead/waste material