Standard I: Students will understand that living organisms interact with one another and their environment.

Transcription

1 Course: Biology Agricultural Science & Technology Unit: Energy in Living Systems Unit Home Utah State Core Biology Curriculum Standards and Objectives: Standard I: Students will understand that living organisms interact with one another and their environment. Objective 1: Summarize how energy flows through an ecosystem. a. Arrange components of a food chain according to energy flow. b. Compare the quantity of energy in the steps of an energy pyramid. c. Describe strategies used by organisms to balance the energy expended to obtain food to the energy gained from the food (e.g., migration to areas of seasonal abundance, switching type of prey based upon availability, hibernation or dormancy). d. Compare the relative energy output expended by an organism in obtaining food to the energy gained from the food (e.g., hummingbird - energy expended hovering at a flower compared to the amount of energy gained from the nectar, coyote - chasing mice to the energy gained from catching one, energy expended in migration of birds to a location with seasonal abundance compared to energy gained by staying in a cold climate with limited food). e. Research food production in various parts of the world (e.g., industrialized societies greater use of fossil fuel in food production, human health related to food product). Standard II: Students will understand that all organisms are composed of one or more cells that are made of molecules, come from preexisting cells, and perform life functions. Objective 2: Describe the flow of energy and matter in cellular function. a. Distinguish between autotrophic and heterotrophic cells. b. Illustrate the cycling of matter and the flow of energy through photosynthesis (e.g., by using light energy to combine CO 2 and H 2 O to produce oxygen and sugars) and respiration (e.g., by releasing energy from sugar and O 2 to produce CO 2 and H 2 O). c. Measure the production of one or more of the products of either photosynthesis or respiration. Unit Objectives: At the conclusion of this unit, students will be able to: A. Describe the conversion of energy from one form to another; B. Describe how living organisms obtain energy; C. Distinguish between autotrophic and heterotrophic organisms; D. Illustrate the cycling of matter and the flow of energy through photosynthesis and respiration; E. Arrange components of a food chain according to energy flow; and, F. Compare the quantity of energy in the steps of an energy pyramid.

2 Materials Needed (Equipment): 1. Roasted Marshmallows (or peanuts): Calorimetry lab a. goggles b. ring stand c. wire ring d. large cork e. matches f. balance g. water h. 200ml beaker i. 12-oz. soda can j. Celsius thermometer k. compass or scissors l. gloves or forceps m. marshmallow, shelled peanut, or other high-fat food such as a potato chip 2. Deadly Links a. white and colored drinking straws, pipe cleaners, poker chips, yarn, or other material students can easily pick up 30 pieces per student in a proportion of two-thirds white to one-third colored pieces; b. one brown lunch bag per grasshopper 3. Photosynthesis Hieroglyphics a. Unlined paper one sheet per student Facilities: Classroom PowerPoint Projector (if available); slides may also be printed onto overhead transparencies Large area for Deadly Links Lab area for calorimetry lab

3 Interest Approach: Why do we need to eat? What happens if we don t? Why do we need to breathe? What happens if we don t? In this unit, we will discuss why we need to eat, why we need to breathe, and our dependence upon plants for food and oxygen. We will also discuss things directly related to agriculture in the form of food production. Objective A: Describe the conversion of energy from one form to another What is energy? Where does energy come from? A1. Energy Capacity to perform work Kinetic energy = motion Potential energy = stored energy Energy is always conserved It cannot be created nor destroyed Can be converted from one form to another Ex: gasoline movement and heat Available in different forms Light energy Heat energy Chemical energy Mechanical energy When converting energy, some is always lost as heat Solar energy hitting earth daily = energy of 100 million atomic bombs Less than 1% is converted to chemical energy by photosynthesis A1. PowerPoint Slides 1-6 Use the analogy of a motor vehicle converting chemical energy (gasoline and battery) into other forms of energy (heat, electrical, mechanical). Emphasize the loss of heat in the process (need for cooling system, etc). Activity: Roasted Marshmallows Marshmallow Calorimetry Lab

4 Activity: ACTIVITY: MARSHMALLOW CALORIMETRY LAB The evening before a marathon, runners are advised to eat a huge plate of pasta. Why? Because pasta, a carbohydrate, is a terrific source of energy, or fuel for the body. Different foods contain varying amounts of energy, which is calculated as calories or kilocalories. In other words, calories are a way to measure the energy you get from the food you eat. In this activity, you will demonstrate how calories are measured. First, you need to build an inexpensive calorimeter. A calorimeter is a device that measures the transfer of heat energy during a chemical or physical change. One type of calorimeter contains a combustion chamber surrounded by water. When matter is placed in the chamber and physically or chemically changed (usually by burning), the temperature change of the surrounding water is measured and used to determine the energy (calorie) content of the sample. This lab indirectly measures food Calories (kilocalories) using a homemade calorimeter. MATERIALS: goggles ring stand wire ring large cork matches balance water 200ml beaker 12-oz. soda can Celsius thermometer compass or scissors gloves or forceps marshmallow, shelled peanut or other high-fat food such as a potato chip CAUTION: Be sure the room is well-ventilated. Use gloves or forceps to handle hot equipment and burned marshmallow. PROCEDURE 1. Punch four holes evenly around a soda can, 2 to 3cm from the top (use a compass or scissors). Place two straightened paper clips (or pieces of a wire hanger) into opposing holes. Hang the can in the wire ring on the ring stand and adjust the height accordingly. Add 200ml of water to the soda can. This apparatus is your calorimeter. 2. Straighten part of the third paper clip and leave one end bent. Turn the cork upside down and poke the straight end into the cork. The bent or looped end of the clip (it should be flat) is the platform for the marshmallow or peanut.

5 3. Place the thermometer into the mouth of the can. Remember to suspend the thermometer in the water when taking a temperature reading. Before going any further, check the apparatus to make sure that everything is secured. 4. Choose a marshmallow (or peanut), measure its initial mass and record in the data table (below). 5. Take an initial temperature reading of the water in the can and record in the data table. 6. Place the marshmallow (or peanut) on its stand. Use a match to set the marshmallow (or peanut) on fire. This may take several tries. Closely observe the nut as it burns. If the peanut falls off the stand, start over immediately. 7. As soon as the marshmallow (or peanut) stops burning, immediately take a final water temperature reading and record it in the data table. 8. As soon as the marshmallow (or peanut) has cooled, use forceps to lift the burned remains onto the balance. Take a final marshmallow (or peanut) mass and record in the data table. DATA TABLE Volume of water in can (in liters): Initital reading: 0.200L (1/5 of liter) Final reading: 0.200L Mass of marshmallow (peanut): Initial reading: Final Reading: Water temperature: Intial reading: Final reading: CALCULATIONS 1. Change in mass of marshmallow (peanut) equals (initial mass minus final mass). 2. Change in water temperature equals (final temperature minus initial temperature).

6 3. Marshmallow (Peanut) energy in kcal (for.200l of water) equals change in water temperature times volume of water or 0.200L. 4. Kcal per gram of food burned equals peanut energy in kcal divided by change in mass of the nut. ACTIVITY EXTENSIONS Discuss the sources of heat loss during this experiment. Can you suggest a better design? Discuss the pros and cons of eating marshmallows (peanuts) as a staple in the average American diet. Create a diet for an athlete, taking into consideration metabolism of fats, proteins and carbohydrates. Note: Expect the kcal for the peanut to range between 2 and 8. This activity is an adaptation of a classic calorimeter lab. The idea for using a soda can originally appeared in Science Teacher, September 1992 (p. 54), contributed by Peter Markow of Saint Joseph College in West Hartford, Connecticut. Objective B: Describe how living organisms obtain energy Where do we get energy? B1. How do we get our energy? B1. PowerPoint Slides 7-9 The Environment and Energy Energy the ABILITY to do WORK All LVING ORGANISMS use energy for life processes. Producers Green Plants They capture light energy from the sun and convert it into food energy Consumers Animals that depend upon green plants and other animals for food.

7 Objective C: Distinguish between autotrophic and heterotrophic organisms. Do plants eat? How do they get their energy? C1. Different organisms get energy in different ways Autotrophs -- organisms that can make their own food (green plants) Heterotrophs -- organisms that cannot make their own food and have to feed on autotrophs or other heterotrophs (cows) Autotrophs = producers Heterotrophs = consumers C1. PowerPoint Slides Objective D: Illustrate the cycling of matter and the flow of energy through photosynthesis and respiration. What do you think of when you hear the word respiration? D1. Converting energy in living organisms Respiration?? D1. PowerPoint Slides Although breathing is part of respiration, the real meaning of the word has to do with converting stored energy into usable energy. ATP (Adenosine Triphosphate) The form of energy used by cells for cell activities Energy stored in ATP is BROKEN DOWN by ATPase, an ENZYME, to a molecule of ADP. When that chemical bond is broken, energy is released. Without ATP all living organisms will The usable energy for living things is in the form of a chemical called ATP.

8 DIE. All organisms get their ENERGY from ATP. D2. Photosynthesis & Respiration PHOTOSYNTHESIS Production Harvests sunlight energy Converts to chemical energy Stores energy in form of organic molecules (glucose) D2. Power Point Slides The two key processes for converting and releasing usable energy are photosynthesis and respiration. Together they form a cycle. RESPIRATION Consumption Breaks down organic molecules into chemical energy Photosynthesis and Respiration Form a Cycle Photosynthesis converts light energy into chemical energy (ATP, NADPH) Chemical energy and CO 2 made into sugars Requires H 2 O, CO 2, and sunlight It is important to note that both plants and animals undergo respiration. D3. Photosynthesis 6CO 2 + 6H 2 O C 6 H 12 O 6 + O 2 D3. PowerPoint Slides CARBON DIOXIDE +WATER + SUNLIGHT SUGAR + OXYGEN Three Phases Light absorption by CHLOROPHYLL Light Dependent reactions water is SPLIT into HYDROGEN and OXYGEN. OXYGEN is released and energy is transferred to the next phase. Light Independent reactions carbon dioxide and WATER are combined to form CARBOHYDRATES Factors affecting Photosynthesis Amount of LIGHT Intensity of the LIGHT Amount of WATER DIRECTION of the light Temperature Hieroglyphics Moment: Photosynthesis the formula

9 What does it take to make a fire or to release heat and light energy from fuel? D4. Respiration What does it take to make a fire? The release of energy from sugar molecules C 6 H 12 O 6 + O 2 6CO 2 + 6H 2 O SUGAR + OXYGEN ENZYMES CARBON DIOXIDE +WATER D4. PowerPoint Slides Answers: oxygen, fuel, heat same is true in the mitochondria of our cells. To obtain energy for our cells, and ultimately our bodies, we need oxygen, fuel (carbohydrates) and a spark (enzymes)! Activity: Hieroglyphics Moment: Photosynthesis the formula from Engaging Strategies for Agriculture Classrooms, 2006, National FFA Organization. For each compound in the photosynthesis equation, students draw an icon for instance, for Carbon dioxide, the student might sketch a car with CO2 drawn on the car, for water, the student might sketch and label a couple of drops of water; for oxygen, might sketch an Ox; and might draw a bottle of glue for glucose. Steps are as follows: 1. Present the formula: Sometimes it s difficult to remember the formula because it s a jumble of numbers and letters. To help us remember the compounds in photosynthesis, we ll substitute an icon for each. Ask students: What pictures or icons will help us remember the component parts of the photosynthetic formula? 2. Brainstorm icons (may be done in groups). Generate a bank of ideas on the board or overhead. Let s create a couple of icons we could use for each of the compounds carbon dioxide, water, oxygen, and glucose. 3. Have students draw representations. Using unlined paper divided into four or six squares, write each compound and draw a hieroglyphic that helps you remember the compound and its meaning. Now re-write the formula, substituting the compound names with the icons. Take the next 3-5 minutes. 4. Share. After a specified amount of time, have students compare with one another and explain their creations. With the person next to you, explain and compare your new icon formula for photosynthesis. Extension: have students use icons to represent the formula for respiration.

10 Objective E: Arrange components of a food chain according to energy flow. What does a mouse eat? What eats a mouse? How do you know? E1. Types of Consumers E1. PowerPoint Slide Primary Consumer (Herbivores) eat PLANTS to get energy Secondary Consumers (Carnivores, omnivores) eat ANIMALS to get energy Tertiary Consumers (Carnivores, omnivores) eat ANIMALS to get energy Decomposers - Break down and DECOMPOSE DEAD ORGANISMS getting energy and releasing nutrients back into the environment. E2. You Are What You Eat Food Chains a simple LINEAR drawing showing which organisms feed upon which others Food Web A NUMBER OF INTER- CONNECTING FOOD CHAINS E3. How organisms obtain energy ECOSYSTEMS are powered by energy from the SUN Energy only enters living things at the PRODUCER level. As energy is passed along the FOOD chain, much of it is lost as HEAT. E2. PowerPoint Slides Activity: Deadly Links E3. PowerPoint Slides Activity: Deadly Links To emphasize principles of food chains and the flow of energy, conduct the Project Wild activity Deadly Links. This is a fun tag-like simulation of the interaction between producers and consumers. It also introduces issues related to overuse of pesticides and the effects on the food chain. This activity is found on page 270 of the Project Wild K-12 Activity Guide and can be obtained by attending one of the Project Wild training sessions. This is highly encouraged. For more information on training sessions, go to

11 Objective F: Compare the quantity of energy in the steps of an energy pyramid. Which of the following would provide the most energy for you to run a race? 1 cup pasta or 1 cup roasted mountain lion? F1. How organisms obtain energy ECOSYSTEMS are powered by energy from the SUN Energy only enters living things at the PRODUCER level. As energy is passed along the FOOD chain, much of it is lost as HEAT. Energy flows ONE way through the food chain, from PRODUCERS through CONSUMERS. Each level of the food chain has LESS available energy in it. F1. PowerPoint Slides F2. Pyramids of Numbers Numbers decrease as we go from one food level to the next. Numbers that decrease are BIOMASS, AVAILABLE ENERGY, and organism population size. All Unit Files Evaluation: Energy Test and Key References: Prentice Hall Biology by Kenneth R, Miller and Joseph S. Levine. 2002, Pearson Education, Upper Saddle River, New Jersey. Strategies for Great Teaching by Mark Reardon and Seth Derner, 2004, Zeyphry Press, Chicago, Illinois Engaging Strategies for Agriculture Classrooms, National FFA Organization, ProjectWILD K-12 Activity Guide, by the Council for Environmental Education, ProjectWILD, Bethesda, MD. Unit Home