Chapter 12 Lesson 3, "How Energy Flows Through Ecosystems"

Materials:

• Worksheet: "Energy Flow in an Ecosystem"

Objective:

• Students will explain why organisms need energy.
• Students will describe how energy flows through a food chain.
• Stud nets will compare the amount of energy available at different levels of a food chain.
• Students will explain how the amount of available energy affects the sizes of populations.

Anticipatory Set:* Have the students list the breakfast they ate this morning. Type it out on the screen. Then with the students help them trace back where the energy came from to create that item. Use an example of salmon sticks. Salmon ate herring in the ocean. The herring at a smaller fish. That smaller fish ate small crustaceans or zooplankton (microscopic animal-like organisms), those ate plankton that got there energy from the sun. Here is a question to think about while we complete this lesson: "If you wanted to use sunlight most efficiently to support the most human life on the planet what should humans eat?"

Teacher Input:* Have the students answer the question, "Where does most energy on Earth originate from?" What is energy? (the ability to do work or change something) Look around the room or out the window and list some sources of energy. Show the students some examples of where you might find energy. Stored chemical energy 1, Stored chemical energy 2, Stored chemical energy 3, mechanical energy 1, mechanical energy 2.

What things in your body need energy to work? How do you get energy? (great food) What process do plants use to store the suns energy? (photosynthesis explain this diagram) What is the main thing in this diagram that comes out of plants that we use for food. What is the process our body uses to get energy out of plant and animal tissue? (digestion, respiration)

What happens to the energy in an organism when it is eaten by another organism? Does all the energy of the producers flow though the food chain? How much is lost at each level? How it lost? Show the Energy pyramid 1, pyramid 2 (Alaska Pyramid) and explain how 90% of the energy at each level is lost, mainly as heat. If a community, food chain, or food web constantly loses energy why does it not run out? The alaska region in this picture looks bare why? Why does a rainforest look like it has much more life and energy?

Are there any communities that do not use the sun for energy? (there is an extra credit point in it if you can tell me where)

Hint: ( extremophiles)

Guided Practice:* Students will work with the instructor to answer the questions at the end of the section on Page 316.

Independent Practice:* Students will complete the worksheet, "Energy Flow in an Ecosystem"

Check for Understanding:* Students will take the quiz for Lesson 3.

Duration:

30 minutes + 10-15 for Independent Practice (Could be longer if taken for homework).

Alaska Content Standards Addressed in this lesson:

• SCI A-9 Students will understand the transfers and transformations of matter and energy that link living things and their physical environment, fro molecules to ecosystems. (Flow of Matter and Energy)
• SCI A-12 Students will distinguish the patterns of similarity and differences in the living world in order to understand the diversity of life and understand the theories that describe the importance of diversity for species and ecosystems.
• SCI A-14 Students will understand
  • the interdependence between living things and their environments:,
  • that the living environments consists of individuals, populations, and communities: and
  • that a small change in a portion of an environment may affect the entire environment (Interdependence);

• SCI A-15 Students will use science to understand and describe the local environment (Local Knowledge); and: