Chapter 3 Section 2 Energy Flow

1. Chapter 3 Section 2 Energy Flow

2. Producers… • Sunlight is the main energy source for life on Earth. • Less than 1% of the sun’s energy that reaches Earth is used by living things. • Not all organisms obtain energy from the sun. • Some types of organisms rely on the energy stored in inorganic chemical compounds. • Mineral water from underground or hot springs.

3. Producers… • In fact only plants, some algae, and certain bacteria can capture energy from sunlight or chemicals and use that energy to produce food. • Autotrophs are organisms that use sunlight or chemicals to produce its own food. • They are also called producers. • Producers are essential to the flow of energy through the biosphere.

4. Producers… • The best-known autotrophs are those that harness solar energy through a process known as photosynthesis. • Photosynthesis is the process that uses light energy to convert carbon dioxide and water into oxygen and energy rich carbohydrates such as sugars and starches. • Sunlight + CO2 + H2O  O2 + C6H12O6

5. Producers… • Life without light… • Chemosynthesis is the process where organisms use chemical energy to produce carbohydrates. • Occurs in several types or bacteria that represent a large portion or autotrophs. • Occurs in remote places on Earth like volcanic vents on the deep ocean floor and hot springs in Yellowstone park, or even tidal marshes.

6. Consumers… • Heterotrophs are organisms that rely on other organisms for their energy and food supply. • They are also called consumers. • Different heterotrophs are: • Herbivores • eat plants only. • Carnivores • Eat animals • Omnivores • Eat both plants and animals • Detritivores • Eat dead matter. • Also called decomposers

7. Feeding Relationships… • Energy flows through an ecosystem in one direction, from the sun or inorganic matter to autotrophs and then to various heterotrophs. • Food Chains are a series of steps which organisms transfer energy by eating and being eaten • Food Webs link all the food chains in an ecosystem together.

8. Feeding Relationships… • A Trophic Level is each individual step in a food chain or food web. • Producers make up the first trophic level. • Consumers make up the second, third, or higher levels. • Each consumer depends on the trophic level below it.