Energy Pyramid. mouse plant. snake. eagle. Which population contains the most available energy?

Transcription

1 Skill Development/Guided Practice 1. mouse plant eagle snake Which population contains the most available energy? If a population of snakes consumes a population of mice that contain 3,000 kcal of available energy, how much energy is transferred to the population of snakes? If 5,000 kcal of energy is transferred from a population of plants to a population of mice, how much energy was stored in the plants?

2 Skill Development/Guided Practice (continued) 2. fish algae raccoon coyote Which population contains the least available energy? If a population of raccoons consumes a population of fish that contain 7,000 kcal of available energy, how much energy is transferred to the population of raccoons? If 200 kcal of energy is transferred from a population of raccoons to a population of coyotes, how much energy was stored in the raccoons?

3 Independent Practice Name 1. flowers toad alligator butterfly Which population contains the least available energy? If a population of alligators consumes a population of toads that contain 400 kcal of available energy, how much energy is transferred to the population of alligators? If 80,000 kcal of energy is transferred from a population of flowers to a population of butterflies, how much energy was stored in the flowers?

4 Independent Practice (continued) 2. plankton orca shrimp seal Which population contains the most available energy? If a population of seals consumes a population of shrimp that contain 12,000 kcal of available energy, how much energy is transferred to the population of seals? If 950 kcal of energy is transferred from a population of seals to a population of orca, how much energy was stored in the seals?

5 Models of Energy Flow 1. Ecologists, people who study how plants and animals live in the environment, use food chains and food webs to model the energy flow through an ecosystem. 2. Like any model, food chains and food webs are a simple representation of the flow of energy. 3. Each step in a food chain or food web is called a trophic (TROH fihk) level. 4. Autotrophs 1 make up the first level in all ecosystems. 5. Heterotrophs 2 make up the remaining levels. 6. With the exception of the first level, organisms at each trophic level get their energy from the trophic level before it. 1 an organism capable of making its own food 2 an organism that cannot make its own food Internal Context Clue * eco(system) Food Chains 7. A food chain is a simple model that shows how energy flows through an ecosystem. 8. Arrows are used to represent the one-way energy flow which typically starts with autotrophs and moves to heterotrophs. 9. In a grassland food chain, grass uses energy from the Sun to makes its own food (autotroph). 10. A rabbit (heterotroph) gets its energy from eating the grass. 11. A snake (heterotroph) gets its energy from eating the rabbit. 12. Finally, a hawk (heterotroph) gets its energy from eating the snake. 13. Each organism uses a portion of the energy it gets from the organism it eats for cellular processes to build new cells and tissues. 14. The remaining energy is released into the surrounding environment and no longer is available to these organisms. Food Webs 15. Feeding relationships usually are more complex than a single food chain because most organisms feed on more than one species. 16. For example, birds eat a variety of seeds, fruits, and insects. 17. The model most often used to show the feeding relationships in an ecosystem is a food web. 18. A food web is a model showing the many interconnected food chains and pathways in which energy flows through a group of organisms. Ecological pyramids 19. Another model that ecologists use to show how energy flows through an ecosystem is the ecological pyramid. 20. This is a diagram that can show the relative amounts of energy, biomass, or numbers of organisms at each trophic level. 21. For example, in a pyramid of energy, approximately 90 percent of all energy is not transferred to the level above it. 22. This happens because most of the energy contained in the organisms at each level is consumed by cellular processes or released to the environment as heat. 23. Usually, the amount of biomass (the total mass of living matter at each trophic level) decreases at each trophic level.