2. 10% Rule Only 10% of the energy present at one feeding is passed on to the next feeding level

3. Commensalism A symbiotic relationship between species in which one species is helped and the other is unaffected

4. Energy Pyramid Diagram that demonstrates the flow of energy through a food chain

5. Mutualism A symbiotic relationship between two species in which both species benefit

6. Parasitism A symbiotic relationship in which one organism (parasite) benefits and the other (the host) is generally harmed but not killed

7. Symbiosis A close relationship between two species

8. Producer An organism that can make it’s own energy through photosynthesis or chemosynthesis

9. Primary Consumer In a food chain, organisms that eat producers

10. Secondary Consumer In a food chain, an organism that feeds on herbivores (plant-eaters); also called a predator

11. Tertiary consumers In an ecosystem, a predator that feeds on other predators

12. Decomposers An organism that breaks down tissue and releases nutrients and carbon dioxide back into the ecosystem

13. Omnivore an organism that eats both plants and animals.

14. Herbivore An organism that feeds only on plants

15. Natural Selection Process by which organisms change over time as those with traits best suited to an environment pass their traits to the next generation.

16. Survival of The Fittest A natural process resulting in the evolution of organisms best adapted to the environment

17. Food Chain Series of stages that shows the transfer of energy from producers to consumers to decomposers

18. Food Web In an ecosystem, arrangement of several overlapping food chains

19. Predator Animal that kills and eats other animals

20. Host Organism that supports a parasite

21. Parasite Organism that feeds on cells, tissues or fluids of another living organism

22.  The state of the environment at a specific time

23.  An organism that can produce its own food using light, water, carbon dioxide, or other chemicals

24.  An animal that can't make its own food supply, so they have to eat other things, like plants or other animals,

25. Carbon Cycle The continual transfer of carbon dioxide and oxygen between living things and the environment

26. Water Cycle Cycle in which water moves through the environment, through the process of evaporation, condensation and precipitation

27. Nitrogen Cycle In the environment, the movement of nitrogen between the living and non-living parts of an ecosystem