How Ecosystems Work

1. How Ecosystems Work Environmental Science Ms. Moore 10/10/13

2. Life Depends on the SUN • Energy from the sun enters an ecosystem when a plant uses sunlight to make sugar molecules in a process called photosynthesis. • 6CO2 + 6H2O + solar energy  C6H12O6 + 6O2 • CARBON DIOXIDE + WATER + SUN YIELDS CARBOHYDRATES + OXYGEN

3. So, What eats What?

4. Types of Consumers

5. Energy Transfer • A food chain is a sequence where energy is transferred from one organism to the next as each organism eats another. • A food web shows many feeding relationships that are possible in an ecosystem.

6. Tropic Levels • Each step where energy is transferred in a food chain is known as a trophic level. • Energy pyramid: • Producers: 1,000x energy • Primary Consumers: 100x energy • Secondary Consumers: 10x energy • Tertiary Consumers: 1x energy

7. Mini Lab • In groups of 3-4: • Create a food chain: each person will act as an organism of your choice • Create a food web poster including 10 organisms: draw and label each organism (example on page 130) • Create a trophic pyramid: each person will create their own pyramid in the groups • Answer questions along with pyramid project

8. The Cycling of Materials • The CARBON CYCLE cycles carbon between the atmosphere, land, water, and organisms.

9. The NITROGEN CYCLE is a process where nitrogen is cycled between the atmosphere, bacteria, and other organisms. • All organisms need nitrogen to build proteins (cells) • Nitrogen fixing bacteria: alter nitrogen so we can use it

10. The PHOSPHORUS CYCLE is the movement of phosphorus from the environment to organisms and then back to the environment • Needed to form bones and teeth in animals

11. How Ecosystems Change • Ecological Succession is a gradual change of all or some of the species in a community • Primary Succession occurs on a surface where no ecosystem existed before (rocks, sand dunes) • Secondary Succession occurs on a surface where an ecosystem has previously existed

12. Secondary Succession • Pioneer species: the first orgfanisms to colonize any newly available area • Climax community: a final and stable community • Example: Volcanic eruption • See page 138

13. Fire and Secondary Succession • Natural fires caused by lightning is a natural cause of secondary succession. • Example: Yellowstone’s fires • Case Study on page 138-139

14. Old-Field Succession • Old-Field Succession: occurs when farmland is abandoned • pioneer grasses and weeds grow rapidly and produce many seeds to cover abandoned land • Figure 19 on page 140