Biology Standard 1, Objective 1.

Title: Starburst Energy Pyramid

Description: Students will model energy transfer through an ecosystem using Starburst candy as the energy.

Time Needed: 50 minutes

Materials: Two bags of starburst per class. (You can reuse them or let kids eat them after the activity. Students can be asked to bring them in.)

Procedures: 1) Count the number of individual Starbursts candies in the two bags. Read the introduction and procedures with the class so they what data they are collecting. 2) Set up the energy pyramid by placing students in the positions shown in the drawing below). 3) All the students need to be facing the same direction and about 10 to 15 feet apart from the row before them and at least arms with apart from the students next to them. 4) The student in the "sun" role throws the starbursts a handful (5-10) at a time over their shoulder to the "Producers". The "Producers" cannot take steps to get the starbursts but can only reach with their hands. 5) Record the number of starburst transferred to the "Producers" and then have the "Producers" throw to the next energy level, the "Primary Consumers". When they throw, the "Producers" all need to throw at the same time, again behind their backs. The "Primary Consumers" however, can take only one step in whichever direction needed. 6) Record the number of starbursts transferred and continue to the next energy level. This time the "Secondary Consumers" can take two steps. Again the "Primary Consumers" need to throw at the same time over their back. 7) Record and continue to the tertiary consumer. Record the final number and be sure students observe the energy lost by looking at all the starbursts on the ground before they pick them up. 8) Have the students reflect on the activity. These are the types of questions I ask the before we go inside: 1. How is this energy pyramid similar to the energy pyramids in real life? 2. Why did we use starbursts? 3. Why couldn't the producers move to get food? 4. Why could the consumers move to get food? 5. Why could the secondary and tertiary consumers take more than one step (they generally have a greater range)? 6. How is this activity a poor model of a real energy pyramid? 7. In real life how does energy get “lost” or used up? 8. Why did or didn’t the Tertiary Consumer get any starbursts? 9) Sometimes the consumers are more effective at capturing food than the plants are and then the numbers are off. Adjust the size of the energy pyramid for next class or do another trial to see if they get better numbers. You may wish to have the producer students take off a sweater or use their shirt to capture more starbursts. Then you can discuss how some organisms are more efficient and can out compete others. 10) Once inside work as a class through the energy transfer data to calculate the percent of energy lost or transferred by each energy level. (You might expect the numbers to be between 15-20% energy transferred to the 3 consumer).

Example: Starting Starburst 200 Producers received 26 – 87% energy loss, 13% transferred 1 Consumers received 5 – 80% loss, 20% transferred 2 Consumers received 1 - 80% loss, 20% transferred 3 Consumers received 1 – 0% loss, 100% transfer

Thanks to Jamie Carling (Monticello HS) for submitting this activity.

Student Sheet Name ______Period

Title: Starburst Energy Pyramid

Introduction: When you eat dinner, how much of the food energy in the dinner goes to increase your biomass? 100% efficiency would mean that every pound you ate would add a pound to your weight. As you may know and be thankful for, this does not happen. Ecological efficiency refers to the percentage of energy passed on from one organism to the next in a food chain or pyramid. In this activity you will use a model to discover the amount of energy lost as it moves up the food chain.

Procedures: 1. Your teacher will assign you to play an important part in the food chain. Stand where directed. Make sure you understand how many steps you are allowed to take.  Producers take no steps (just like trees)  Primary Consumers may take one step  Secondary Consumers may take two steps  Tertiary Consumers may take three steps

2. Make sure that you throw the candy over your shoulder and don’t look at where it is going. 3. Participate in the class discussion that takes place outdoors. 4. You may be asked to model the scenario again. 5. Record the data and answer the analysis questions.

Data:

Trophic Level Round 1 Round 2 Sun Producer 1st Consumer 2nd Consumer 3rd Consumer

Analysis:

1. What happened to the number of Starbursts (the energy) as they moved through the food chain? 2. To calculate the percentage of energy lost at each level, divide the energy that was available at the start (in this example, 20,126 Kcal) by the amount of energy on the level. In this example, the producer level has 100%, although you know that all the available sun energy has NOT been captured. The next level is calculated by dividing 1,996 by 20,126 and multiplying by 100%. Using a calculator and rounding off, 10% of the energy remains on this level. Fill in the boxes for the 2nd and tertiary consumers:

3. Calculate the percentage of energy transferred for our model:

3. Why is the box at the base of the food pyramid larger than the top level?

4. A huge portion of the energy in the world is lost. For example sunlight: only about 20% of the sunlight even makes it to plants and algae. Most of the energy from the sun is lost in space, reflected by clouds and water, or absorbed by the earth itself. How much energy is lost on average for the energy pyramids above? 5. Explain how ninety percent of the energy is lost from a cow before it ever even reaches you.

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As organisms die and decompose in the soil, their energy is not gone. For example, a dead tree can be cut and burned to produce heat, a different type of energy. Write three other example of dead organism providing energy long after it is gone.

1)______

2)______

3)______

6. The starburst demonstration was a model of how an energy pyramid can work. Like all models it has weaknesses that make it unrealistic in some respects, name at least one.

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Bonus: One kilocalorie is the amount of energy required to heat one kilogram of water by 1 degree Celsius. The regular human needs about 2,000kilocalories (Calories) to survive each day in a healthy manner. If we were able to transfer ten percent of our energy to heat water (instead of using it to live) how hot would a kilogram of water be at the end of the day?