1. Where does the flow of energy in an ecosystem begin? The sun provides the radiant energy necessary for all the organisms in an ecosystem. Autotrophs (or producers) are organisms that can use energy from sunlight or chemical compounds to make food. some algae plants some bacteria

2. How does an autotroph make food with sunlight? Autotrophs make glucose (food) through a chemical reaction called photosynthesis Equation: Light + 6 CO 2 +6 H 2 O  C 6 H 12 O 6 + 6 O 2 (light energy) + (carbon dioxide) + (water)  (glucose) + (oxygen)

3. Where does Photosynthesis Occur? It occurs in structures called chloroplasts, which are found in cells of autotrophic organisms (green plants and algae) Chloroplasts contain chlorophyll which makes producers green

4. Energy Conversion in Photosynthesis The energy Conversion: Light + 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 (energy) + (carbon dioxide) + (water)  (glucose) + (oxygen) Light (radiant) energy  chemical energy photons of light chemical energy in bonds

5. It takes a LOT of autotrophs to make food for the entire ecosystem!

6. Production of Energy in Ecosystems: Autotrophs Autotrophs are called “producers” because they produce food for non-producers. They use about 1% of the sunlight that hits the Earth in photosynthesis to make glucose. These “producers” are the foundation of food chains.

7. Heterotrophs in Ecosystems: Consumers Heterotrophs are organisms that obtain their energy from other organisms by consuming them. All of the energy needed by heterotrophs is produced by autotrophs Therefore, heterotrophs are called consumers

8. What is a Food Chain? Food Chain – Sequence of who eats whom in an ecosystem, shows how E is transferred Trophic Level – Position in a food chain 1.Producers (lowest trophic level) – Autotrophs (plants, some bacteria & some algae) 2.Primary (1 o ) Consumers (2 nd trophic level) – Primary consumers (herbivores) 3.Secondary (2 o ) Consumers (3 rd trophic level) – Secondary consumers (carnivores) 4.Tertiary (3 o ) Consumers (high trophic level) – Tertiary consumers (carnivores) 5.Decomposers – Consume dead organic matter and recycle it! (fungi, bacteria, worms)

9. Food Chains Sketch the food chain below in your notes Label the initial source of energy Label the producer, a primary consumer, a secondary consumer, and a decomposer Label the highest trophic level and the lowest trophic level Make sure arrows show direction of energy flow

10. Food Web A food web is a method for organizing the food connections in an ecosystem. Food webs are made of many food chains.

11. Energy Pyramids and Trophic Levels Energy pyramids show the feeding order of trophic levels. The size each level represents: Number of organisms Amount of biomass (mass of living organisms) Amount of energy within living organisms

12. How much energy is transferred? 1% of the sun’s energy reaching Earth is used by producers *10% of energy in each trophic level is passed on to next trophic level *90% of the energy is released as heat due to functions of the organism

13. Simple Food Chain Draw a simple food chain. Begin with the sun and insert one organism for each trophic level: Producer  1 st consumer  2 nd consumer  3 rd consumer decomposers What is lost in each energy transfer? How much? Which trophic level receives the most of the original energy from the Sun? Which trophic level has more biomass? Why?