1. Bell Ringer What does an organism need to survive? Where does life on earth begin? Can you think of life that does not begin with the sun?

2. Bell Ringer What does an organism need to survive? Energy Where does life on earth begin? For the most part, life begins with energy from the sun. Can you think of life that does not begin with the sun? Organisms near hydrothermal vents at the bottom of the ocean depend on sulfur as the initial energy source. These bacteria use a process called chemosynthesis, taking hydrogen sulfide and oxidizing it, thereby releasing energy.

3. How Ecosystems Work Part I

4. Energy Flow Energy from the sun enters an ecosystem when a plant uses sunlight to make sugar molecules is a process called photosynthesis. The process of breaking down food to yield energy is called cellular respiration. Producer is an organism that makes it own food (autotroph). Consumer is an organism that gets their energy by eating other organisms (heterotroph) Decomposer is a consumer that gets their food by breaking down dead organisms.

5. Energy Transfer Each time one organism eats another organism, a transfer of energy occurs Food Chain – A sequence in which energy is transferred from one organism to the next as each organism eats another organism. Food Web – Many feeding relationships Trophic Level – The transfer of energy through each step of a food chain or web.

6. Energy Pyramids & Energy Loss Energy Pyramids – Each layer represents a trophic level – The lowest trophic layer represents the most energy. – Amount of energy decreases moving up trophic levels. – Producers  Primary Consumers  Secondary Consumers  Tertiary Consumers How Energy Loss Affects an Ecosystem – The more energy lost the less amount of organisms at trophic level. – The loss of energy from trophic level to trophic level limits the number of trophic levels in the ecosystem.