HOW DOES MATTER TRANSFER BETWEEN ORGANISMS Lesson 10.1

INTRODUCTION How are animals (like ourselves) and plants dependent on each other? Partners Go to 10.1 and fill in Chart

In cellular respiration, both plants and animals can use food molecules right away or store them for later use. What types of energy plants and animals can use? Using this information, how do you think that plants and animals are dependent on each other? Justify your answer Do plants need oxygen and food molecules? How do they get these substances? Do plants need carbon dioxide? How do they get this substance?

ANALYZING PRIESTLEY‘S EXPERIMENT In this activity you will consider the dependence in a simple environment between two organisms—a plant and a mouse. You will read about an important historic experiment using these two organisms. Using knowledge of photosynthesis and cellular respiration, predict the expected results if they changed the setup of the experiment.

MAKING SENSE 1)

MAKING SENSE 2 2. What chemical reactions are taking place in the plant? Write their chemical equations. Cellular respiration: Food molecules + oxygen → water and carbon dioxide Photosynthesis: Water and carbon dioxide → food molecules and oxygen

MAKING SENSE 3 AND 4 What molecules leave the plant? Can either the plant or mouse use them? During photosynthesis, the plant produces oxygen. The mouse and the plant can use the oxygen during cellular respiration. During cellular respiration, the plant produces carbon dioxide. The plant can use the carbon dioxide in photosynthesis. 4. What chemical reactions are taking place inside the mouse? Write the chemical equation. Cellular respiration: Food molecules + oxygen → water and carbon dioxide

MAKING SENSE 5 AND 6 5. What molecules leave the mouse? Can either the plant or the mouse use them? During cellular respiration, the mouse produces carbon dioxide. The plant can use the carbon dioxide in photosynthesis. 6. After a while, why was the mouse in the container without the plant not able to breathe? Why could the mouse in the container with the plant still breathe? The mouse without the plant ran out of oxygen because it was using oxygen, and there was no plant to produce more. The other mouse had a plant in its container that produced oxygen. 7. Why do mice (and most other organisms) need oxygen? Organisms need oxygen to react with food molecules during cellular respiration. During this chemical reaction, food provides energy to cells. Without oxygen, food molecules could not provide the energy that cells need to function.

MAKING SENSE 8

MAKING SENSE 9 AND 10 What is the difference between the chemical reactions happening in Questions 1 and 8? What is the reason for this difference? Photosynthesis is not happening in Question 8 because plants cannot perform photosynthesis in the dark. 10. Will there be a difference in the length of time the mice in Question 8 are able to breathe? Explain. The mouse without the plant will be able to breathe longer because it is the only organism using oxygen. In the other container, both the plant and the mouse are using oxygen.

MODELING THE CELLULAR RESPIRATION/PHOTOSYNTHESIS CYCLE

HOW DOES ENERGY MOVE BETWEEN ORGANISMS Activity 10.2

INTRODUCTION 1) We are going to continue studying the interdependence of plants and animals. 2) What do you know about ecosystems? (An ecosystem is a group of living things and the environment in which they live.) 3) How do you think that a food web in an ecosystem is linked to how energy flows between organisms? Why? (When an animal eats a plant, it is eating food molecules. During cellular respiration, these food molecules provide energy to the cells.)

MODELING CARBON TRANSFER ACTIVITY Answer Questions 1–4 in the Procedure section for the organism. After you have answered the questions, make a model in your notebook of how carbon flows through your organisms. (Use your answers from 1-4 to help you draw the movement of carbon-containing molecules through their organism on their sheet of paper.) AQUATIC PLANTS

ON ONE SIDE OF BIG SHEET OF PAPER: DRAW THIS

BRAINSTORM WITH PARTNER 1) In what form do carbon atoms enter these organisms—carbon dioxide or food molecules? Why? Can these organisms eat other organisms? (These organisms get carbon atoms in the form of carbon dioxide when they photosynthesize. They do not eat other organisms, so they cannot get carbon atoms in the form of food molecules.) 2) Which of the other organisms can give aquatic plants carbon dioxide? How do they produce carbon dioxide? (All of the other organisms can give plants carbon dioxide. They produce carbon dioxide during cellular respiration. Students often do not think that plants can also produce carbon dioxide.) 3) Draw all arrows on your model that you suggest, and draw them on the activity sheet. Make a key for the model. For example, carbon dioxide is a solid blue line. 4) Can plants produce carbon dioxide for other plants? Does algae also use photosynthesis? Are the arrows going to be similar for algae and aquatic plants? Which arrows should we draw?

BRAINSTORM CONTINUES 5) How do mice, foxes, or insects get carbon atoms? (They eat other organisms.) 6) What organisms do mice eat? Foxes? Insects? (Mice eat plants. Foxes eat mice. Insects eat algae.) 7) Draw all arrows that students suggest. Add to the key for the model. Use the same color as you did for carbon dioxide, yet with dashed lines. For example, food molecules are represented by a dashed blue line. 8) Can a single carbon atom move through all of the organisms on this web? Provide an example. (Carbon atoms constantly cycle through the environment. For example, carbon in carbon dioxide can go through photosynthesis to become a food molecule in an aquatic plant, and then it gets eaten by a mouse, where it goes through cellular respiration to become carbon dioxide again, and so on.)

9) In what form do carbon atoms enter these organisms—carbon dioxide or food molecules? Why? Can these organisms eat other organisms? (These organisms get carbon atoms in the form of carbon dioxide when they photosynthesize. They do not eat other organisms, so they cannot get carbon atoms in the form of food molecules.) 10) Which of the other organisms can give aquatic plants carbon dioxide? How do they produce carbon dioxide? (All of the other organisms can give plants carbon dioxide. They produce carbon dioxide during cellular respiration. Students often do not think that plants can also produce carbon dioxide.) 11) Draw them on the activity sheet. Make a key for the model. Carbon dioxide is a solid blue line. 12) Can plants produce carbon dioxide for other plants? 13) Does algae also use photosynthesis? Are the arrows going to be similar for algae and aquatic plants? Which arrows should we draw?

CARBON TRANSFER BETWEEN ORGANISMS

BRAINSTORM ENERGY FLOW 1) What is the original source of all energy on Earth? What does this mean? 2)What kind of organisms can convert this type of energy? (The sun is the original source of energy. This means that all the energy in all the food molecules they eat originally came from light energy. Plants are able to use this light to make food molecules.) 3) In what form do aquatic plants get energy? What chemical reaction needs this energy? (Plants use light energy from the sun to make food molecules during photosynthesis.) 4) Draw arrows with a different color than carbon, and copy these onto the lower model on the activity sheets. Add this to the key. For example, energy is a solid red line. Label the different forms of energy on the model.

CONTINUED BRAINSTORM 5) How can energy flow between organisms (e.g., plant and mouse)? 6) Draw arrows. (Mice can eat aquatic plants. These aquatic plants are made of food molecules that can provide energy during cellular respiration.) 7) What other ways can energy be transferred between organisms in the model? Draw arrows that students suggest. (foxes can eat mice, and aquatic insects can eat algae.)

MORE THOUGHTS ON THE ENERGY CYCLE 8) From where do algae originally get their energy? 9) Which of the organisms in the model use cellular respiration? 10) What types of energy are released because of this chemical reaction? How should we represent that on this model? (All organisms perform cellular respiration and release kinetic and thermal energy.) 11) Can energy flow from the fox to another organism? From the aquatic insects? Can energy continue cycling the same way that carbon can? Why? (Because no organism eats the fox in this model, energy cannot flow from it to another organism [although students might know that decomposers “eat” dead animals]. Once energy is released as kinetic and thermal energy because of cellular respiration, it cannot be used by other organisms to do things. Energy cannot continue cycling like carbon molecules can. The environment needs a constant supply of light energy from the sun.)

ON OTHER SIDE OF PAPER DRAW THIS FOR MODELING ENERGY FLOW Draw as many arrows as you think you can connecting energy between the organisms. Remember to use arrows for energy going to the organism and energy going out of the organism. On the arrow, please say what type of energy it is transferring. Use a different color marker for this part. Light, Thermal (Kinetic), Chemical

ENERGY FLOW BETWEEN ORGANISMS

COMPARING THE TWO MODELS 1) How is the flow of carbon atoms and energy similar in this ecosystem? Why? (Carbon and energy flow overlap when carbon is in the form of food molecules. Food molecules can provide energy.) 2) How is the flow of carbon atoms and energy different in this ecosystem? Why? (When carbon dioxide is being transferred between organisms, energy is not flowing as well. Carbon dioxide cannot provide energy to cells.) 3) Why can carbon flow between all organisms, but energy can flow only from plant to animal and animal to animal? (Carbon can be transferred between all organisms because it exists as both food molecules and carbon dioxide. Energy cannot flow between two plants or from an animal to a plant. During these transfers, carbon is in the form of carbon dioxide, and it does not provide energy to cells.)

CREATING A NEW MODEL 1) Return to the models of the cycling between cellular respiration and photosynthesis in the last activity. 2) Generalize about the organisms that perform cellular respiration (from plant and mouse to all plants and animals) in this model based on the number of different organisms performing this chemical reaction in their activity today. 3) Add the flow of energy to this model based on what you learned today. In the models, you must link the flow of energy to the chemical reactions that they already drew. Use the following labels: light energy food molecules (that can provide energy) kinetic and thermal energy You must show the following: 1.Plants use light energy during photosynthesis. 2.Food molecules can provide energy. 3.Organisms release kinetic and thermal energy after cellular respiration that cannot be used by other organisms.

CREATING THE MODEL PART 2 1) Add the flow of energy to this model based on what you learned today. In the models, link the flow of energy to the chemical reactions that they already drew. Use the following labels: light energy food molecules (that can provide energy) kinetic and thermal energy You must show the following: 1.Plants use light energy during photosynthesis. 2.Food molecules can provide energy. 3.Organisms release kinetic and thermal energy after cellular respiration that cannot be used by other organisms

EXAMPLE OF A MODEL The top part of the model shows how carbon in the environment can cycle from food molecules to carbon dioxide through photosynthesis and cellular respiration. The bottom part of the model shows the same cycle and adds how energy flows through an ecosystem. You first saw the model in Reading 10.1, and you will see the second in Reading 10.2.

WRAPPING UP 1) What can you understand from this model about the flow of carbon?  (During photosynthesis, plants rearrange the carbon atoms in carbon dioxide into carbon- containing food molecules. Then during cellular respiration, plants and animals rearrange the carbon in food molecules back into carbon dioxide.) 2) What can you understand from this model about the flow of energy?  (Light energy enters the environment, and then plants use this for photosynthesis to create food molecules. These food molecules are then used by plants and animals in cellular respiration to provide energy to cells. This energy is released as kinetic and thermal energy. From this model, you can also see the similarities and differences between the flow of energy and carbon. The flow of energy does not overlap the flow of carbon when carbon is in the form of carbon dioxide.)

ONE MORE THOUGHT 3) Do you think that this model shows that energy is created before photosynthesis or is destroyed after cellular respiration? How do you explain what the model shows about the flow of energy?  (Students might respond that energy cannot be created or destroyed. Light energy enters the environment, but it is not being created. After cellular respiration, energy is kinetic, thermal, and so on. These types of energy are not destroyed, but organisms can no longer use them to do things.)

GREAT LAKES FOOD WEB

SUMMING IT UP 1) How did learning about the connection between cellular respiration and photosynthesis help you to answer the Driving Question?  (Humans are dependent on plants to use the light energy from the sun to make food molecules. Humans are also dependent on plants to make the oxygen they need for cellular respiration. Humans could not get the energy they need to do things without an organism performing photosynthesis. Plants are also dependent on plants and animals that perform cellular respiration because of their need for carbon dioxide