Chapter 5, 6, 7 Vocabulary

6. A process where excess nutrients cause too much algae to grow, reducing oxygen in the water.
9. _______ Currents Movement in the mantle that causes tectonic plates to move.
12. An organism that makes its own food, usually through photosynthesis (e.g., plants).
13. Continental _______ The idea that continents have slowly moved to their current locations.
14. The process plants use to make their own food using sunlight, carbon dioxide, and water.
15. An organism that breaks down dead plants and animals, returning nutrients to the soil.
16. An organism that gets its energy by eating other organisms.

1. The principle that in undisturbed rock layers, the oldest layers are on the bottom.
2. Tiny plant-like organisms in the ocean that produce oxygen through photosynthesis.
3. An area in a body of water with low oxygen, where most marine life cannot survive.
4. An area of land where all water drains into a common outlet like a river or lake.
5. ________ Ridge A mountain range on the ocean floor formed by plates pulling apart.
7. _______ Level A level in a food chain or food web based on how an organism gets its energy.
8. A system of connected food chains showing how energy moves through an ecosystem.
10. The theory that Earth’s outer layer is made of large plates that move over time.
11. Water that flows over the land surface and can carry pollutants into bodies of water.