Nutrition and Energy Flow

1. Nutrition and Energy Flow

2. The Producers • Autotrophs are an organism that uses light from the sun to produce energy. • Producing energy from the sun is called photosynthesis. • Other organisms that depend on autotrophs for food are called consumers.

3. The Consumers • Heterotrophs cannot make their own food so they feed on other organisms. • A heterotroph that feeds on only plants is an herbivore (Ex. Grasshoppers) • Some heterotrophs feed on other heterotrophs (Ex. Lion) • Some heterotrophs feed on both autotrophs and heterotrophs (Ex. Dog or Cat).

4. Food Chain • Food chain is a simple model that shows how each living thing gets its food. • A food chain always starts with plant life and ends with an animal. • A food chain is drawn using arrows to indicate the direction of energy flow from one organism to the next. • Ex. Berries > Mice > Black Bear

5. Trophic Levels • Trophic level is a feeding step • So in the food chain example each animal would be a trophic level • Berries > Mice > Black Bear • Many different kinds of organisms eat a variety of foods, so a single species may feed at several trophic levels. • So black bears eat many different animals so on a food chain they wouldn’t always be eating mice but they might eat at a different trophic level. • A food chain represents only one possible route for the transfer of energy.

6. Ecological Pyramid • It shows how energy flows through an ecosystem or how energy goes from autotrophs (plants) to herbivores (only eat plants), to carnivores (eat other animals).

7. Energy Pyramid • Pyramid of energy shows the amount of available energy that is gained from eating decreases at each following trophic level.

8. Cycles in Nature • Some of the energy from food chains and webs is also transferred into the environment as heat generated by the body. • Matter is constantly recycled, it is never lost.

9. Water Cycle • Water comes down to the earth by way of rain, ice and snow (precipitation) and it also goes back to the sky by way of evaporation. Pg. 53 • Animals breath out water vapor in every breath and when they perspire or urinate water also returns to the environment.

10. Where do the drops of water that form on a cold can of soda come from?

11. The water vapor in the air condenses on the surface of the can because the can is colder than the surrounding air. • Same thing with dew on the grass in the morning.

12. Carbon Cycle • Carbon is the molecule of life. Pg. 55 • All life is based on carbon molecules. • During photosynthesis energy from the sun is used by autorophic organisms to convert carbon dioxide gas (co2) into energy rich carbon molecules (energy). • When the autotrophs and heterotrophs use these molecules then carbon dioxide is released and returned to the atmosphere.

13. Nitrogen Cycle • Nitrogen makes up 78% of the air. • Plants need nitrogen in a more usable form that is found in the ground so there are different bacteria that convert the nitrogen from the air to nitrogen in the soil. • Humans and animals get nitrogen from eating plants or animals that have eaten plants. • Nitrogen is put back into the soil and air through urine, waste, and decomposition.

14. Phosphorus Cycle • All organisms require phosphorus for growth and development. • Animals obtain phosphorus by eating plants. When the animals die they decompose and the phosphorus is returned to the soil to be used again.