Energy Flow through Organisms

Name: Lindsay Husta

Title of Lesson: Energy Flow through Organisms

Date of Lesson:

Length of Lesson: 55 minutes

Description of Class:

Name of Course: Biology

Grade Level: 9-12

Honors or Regular: Both

Source of the Lesson:

Me

TEKS Addressed:

(2) Scientific processes. The student uses scientific inquiry methods during field and laboratory investigations. The student is expected to:

(D) communicate valid conclusions; and

(9) Science concepts. The student knows metabolic processes and energy transfers that occur in living organisms. The student is expected to:

(D) analyze the flow of matter and energy through different trophic levels and between organisms and the physical environment.

(12) Science concepts. The student knows that interdependence and interactions occur within an ecosystem. The student is expected to:

(A) analyze the flow of energy through various cycles including the carbon, oxygen, nitrogen, and water cycles;

(B) interpret interactions among organisms exhibiting predation, parasitism, commensalism, and mutualism;

(D) identify and illustrate that long-term survival of species is dependent on a resource base that may be limited; and

(E) investigate and explain the interactions in an ecosystem including food chains, food webs, and food pyramids.

The Lesson:

I. Overview:

In this activity students determine which lizard is a carnivore should eat by constructing a carbon budget for 3 lizards.

II. Performance or Learner Objectives:

Students will be able to:

· List different uses of energy

· Classify different uses into pools

· Create a carbon budget for an organism

· Calculate the efficiency between trophic levels

· Apply their knowledge of carbon flow through an individual to the carbon dynamics of an food web

III. Resources, materials, and supplies needed:

IV. Safety considerations:

V. Supplementary materials, handouts:

· Worksheet

Teacher Says/Does

Student Says/Does

Engage:

Have students draw a possible food chain including Josephine the carnivorous llama as a predator. Review briefly the previous day’s work with food chain, producers, consumers, predators, ect.

Students draw a possible food chain with Josephine the carnivorous llama as a predator.

Students participate in an oral review of yesterday’s work.

Evaluate: Does the chain contain the sun, producers, consumers, and the llama? So the students remember and use trophic level, producers, and consumers?

Explore:

Have the students continue with the worksheet.

Why would a llama want to eat a lizard that consumed more insects?

What are things a lizard could expend energy on?

What categories could we divide these into?

The students create a story about the 3 lizards including how they got energy and how they used it.

Have students assign numerical values for each eaten insect and each activity.

Which lizard should Josephine eat?

If it ate more food, it would fatter and have more energy in it.

Growth, heat given off by inefficient fuel burning, running from predators, collecting food, keeping warm, cooling off, playing, reproducing, some isn’t digested and passes through the gut, homeostasis, rebuilding injured tissue, growing a new tail, being in a Geico commercial…

Heat, maintenance of tissues, undigested food, acquiring food, moving around, growth

Students list 10 activities for each of the 3 lizards including eating.

Students assign numerical values for each activity.

Students decide which lizard Josephine should eat.

Evaluate: Are students on task in filling out the worksheets. Are they able to interpret the graphs correctly? Can they make predictions based on the graphs.

Explain:

Have students explain their choices.

If you have a positive net carbon budget number what does that mean?

How about a negative?

Student reasons may include the following:

Total input of carbon/energy from eating minus outputs to the various pools

Eat the slowest one because Josephine will waste energy in chasing the fastest one, even if it has more carbon.

Eat the one quickest to catch, so Josephine will not expose herself to predators anymore than necessary.

Net carbon acquisition, new tissue, more energy stored

Lizards on a diet, losing carbon and energy stores.

Evaluate: Do students make logical arguments to support their statements?

Elaborate:

Have students make an energy flow diagram with arrows that represent the magnitude of the flow.

How could we determine the efficiency?

-What is the significance of 1, >1, <1

Which lizard was your most efficient?

Was that the one that you recommended Josephine eat?

In nature, there is about 10-15% efficiency between trophic levels.

What does that tell you about the amount of low versus high level organisms.

Go back to your first food chain diagram of the day. Add another top predator, a land-shark who feasts on llamas. Now, determine the amount of each level you would need to put into a terrarium if you wanted it to live.

Speaking of amount. What is a good way to measure amount of energy/carbon?

-think of beef jerky vs a brisket. Is there a nutritional difference? Is there a weight difference?

Students draw an energy flow diagram with large inputs (hopefully) and smaller arrows to other pools.

Inputs/outputs

Students determine which lizard was most efficient.

Yes, or no

Students may compare to their estimated efficiencies

More low level because so much energy is lost to the environment.

Add the land-shark

Students determine this either by starting with either the plants and dividing by 10 or the land-sharks and multiplying by 10 to get the amount of next level

Number, weight, volume

Dry weight

Evaluate: Are students paying attention and engaged? Are students using appropriate terminology? Can students appropriately use math in science? Are they making the connection between energy flow through and ecosystem and energy flow through an individual.

Just another choice faced by Josephine the carnivorous, but lazy, llama.

Josephine the carnivorous llama was one lazy gal. Good thing she happened to be quite the smart gal as well. She knew that when she captured and consumed a delectable lizard, she obtained the energy that she needed from the carbohydrates, lipids, and proteins contained in her meal. Just like you, she even knew that the lizard’s energy to make all those tasty molecules came from the insects it had eaten and so on down the food chain. Draw a possible food chain below:

Josephine went down to her favorite lizard yard where she hoped to find the perfect meal. Being lazy as she was, she wanted to catch only one lizard, but she wanted it to be the most nutritious lizard of all. So, she decided to watch the lizards for awhile to make her choice. She noticed that there were three lizards, and they were the exact same size as the start of the morning. She decided that she would count the number of insects that each ate, and then eat the lizard that had eaten the most insects. Why would she do that?

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However upon further inspection of the lizards’ behavior, she noticed that they were quite variable in how they used their energy. For example, she observed one lizard running about franticly escaping predators for a distance 72 yards. Another laid 13 precious eggs. Another defecated 13 pellets. List 10 things on which lizards expend energy. We will share these things with the class.

Now create 4-5 large categories to group the lizard carbon expenditures into.

For each of the three lizards create a story including 10 things that the lizard used energy for today. For example, lizard 1, Giorgi, woke up and ate 16 insects before being chased by a dog for 13 yards, he then sunned himself and all the while, his body had been maintaining homeostasis… You may wish to simply list the activities. Be sure to include a representative from all the categories.

Now assign numerical values to each of the activities in terms of energy. We are making a “carbon budget” which is a lot like a checking account. You get paid and money comes into your account; you buy awesome things and money goes out. It’s the same with carbon (energy), so just make some price tags for our little lizard friends. Fantastic, now let’s grab those calculators and start punching. Which lizard should Josephine eat?_________________because ____________ ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________.

Now draw the carbon/energy flow through an organism including all inputs and out puts. Make your arrows’ size reflect the amount of the flow (big fat arrows for large inputs or outputs and thinner arrows for smaller pools).