Honors Biology Lab Manual Unit 2: Feedback & Homeostasis

Transcription

1 Honors Biology Lab Manual Unit 2: Feedback & Homeostasis Name: Teacher: Period:

2 Unit 2 Portfolio: Grading Rubric (100 points) Item(s) Score Weight Total Points Labs/Activities, Unit Reflection, Article & Reflection, Personal Choice Item Student has all labs/activities complete and all other components completed. Student is missing 1 lab data, or 1 of the other 4 components Student is missing 2 lab data, or 2 of the other 4 components Student is missing 2 lab data, and 2 or more of the other 4 components 2 /8 Format/ Completion Conventions 1 or fewer errors in spelling, punctuation & grammar, complete sentences 2-3 errors in spelling, punctuation & grammar, complete sentences 4-5 spelling, punctuation, &/or grammar errors, complete sentences Inclusions are sloppy: crossouts, tears, &/or creases or >4 errors in spelling punctuation &/or grammar, complete sentences 2 /8 Labs/Activities ** (first 3 will be graded if none marked) All data/calculati ons/analysis questions for labs are complete & correct 1-2 Missing/Incor rect data/calculati ons/analysis questions 3-4 Missing/Incorr ect data/calculatio ns/analysis questions >4 Missing/Incorrec t data/calculation s/analysis questions 6 /24 Unit Reflection Reflection answers all 5 guiding questions and thoroughly shows areas of increased knowledge Reflection answers all 5 guiding questions and shows areas of increased knowledge Reflection answers all 3-4 guiding questions and thoroughly shows areas of increased knowledge Reflection answers less than 3 guiding questions and shows little gained knowledge 5 /20 Content Article & Reflection Article chosen relates to unit, is summarized, & rationale includes 3 examples of connections Article chosen relates to unit, is summarized & rationale includes 1-2 examples of connections Article chosen relates to unit, is summarized & rationale includes only 1 example of a connection Article chosen barely relates to unit (is summarized) and no or weak connections shown in rationale 5 /20 Personal Choice Item is complete with a complete explanation of concept included. Item/explanati on illustrates an accurate and thorough understandin g of every key idea within the concept(s) chosen. Item is complete with a mostly complete explanation of concept included. Item/explana tion illustrates an accurate understandin g of most key ideas within the concept(s) chosen. Item is complete with some explanation of concept included. Item/explanati on illustrates an accurate understanding of a few to no key ideas within the concept(s) chosen. Item is sloppy or incomplete. No explanation of the concept/key ideas is included or item/explanation of concept/key ideas is inaccurate. 5 /20 1

3 Unit 2: Feedback & Homeostasis Learning Targets 1. Explain feedback systems a. Positive feedback b. Negative feedback c. Identify stimuli, receptor, effector, and response d. Connect different body systems with response to a stimulus. 2. Plan and conduct an investigation that provides evidence of system feedback in the body from cellular level to organism level in order to maintain homeostasis. 3. Analyze data related to carbon to make the claim that one change to Earth s surface (biosphere, atmosphere, hydrosphere, cryosphere and geosphere) can create feedbacks that cause changes to other Earth systems. 4. Use a computational representation (such as a simulation or model) to illustrate the the relationships among Earth s systems (biosphere, atmosphere, hydrosphere, cryosphere and geosphere) and how those relationships are being modified by human activity, such as: a. Climate change b. Invasive species c. Greenhouse gases d. Biomagnification e. Habitat destruction 5. Analyze a major global problem by: a. Describing the challenge with a rationale for why it is a major global challenge; b. Describing, qualitatively and quantitatively, the extent and depth of the problem and its major consequences to society and/or the natural world on both global and local scales if it remains unsolved; c. Identifying the physical system in which the problem is embedded, including the major elements and relationships in the system and boundaries so as to clarify what is and is not part of the problem; d. Describing societal needs and wants that are relative to the problem. 2

4 Observing Feedback & Homeostasis in Yeast Cells Background: Cells have to control what atoms, molecules, and ions are allowed inside in order to maintain homeostasis. Nutrients need to be allowed in, while toxins need to be kept out. Organisms need to be able to maintain nearly constant internal environments in order to survive, grow and function effectively. Homeostatic mechanisms resist changes to the organism's internal environment. These complex mechanisms are specific to each individual factor, and act via one of two distinct pathways: positive and negative feedback. Yeast are unicellular fungi that can be economically important in the baking and brewing industries and the production of food supplements, cheeses, vaccines, fuels, and many other products. Like other organisms, yeasts have various physiological requirements to permit normal growth and survival. Yeast are small, round cells that can be observed under a microscope using a high-powered objective lens. Oftentimes, a dye known as methyl blue is used to help scientists identify intracellular structures of yeast. Methyl blue is a small molecule capable of moving easily through the yeast cell membrane; in high doses, it is toxic to living cells. Objective: In this activity, you will test to see how boiling affects the yeast s ability to maintain homeostasis by preventing the entry of a toxic chemical. Materials: Microscope Microscope slide and coverslip Dropper 0.1% methyl blue solution Boiled and unboiled yeast solutions Methods: 1. Place a drop of active yeast (unboiled) suspension on a glass slide. Add a coverslip and observe the yeast cells under low and high power. Make sketches of several cells under high power and observe the size, shape, color, and movement. This is your control slide. 2. Place about 1.0ml of yeast suspension in each of two small test tubes. 3. Heat one test tube using a boiling water bath for 90 seconds. This will be your boiled sample. Allow the tube and contents to cool for a few minutes. 4. Add 5 drops of methyl blue dye solution to the boiled yeast suspension and 5 drops to the unboiled suspension. 5. Prepare a slide for a sample of each for a sample of each solution and view under the microscope. Use 40x magnification to look at the slides. Observe and note any differences between the appearances of the two solutions of yeast cells. Look at the size, shape, color and movement of each. 3

5 Observations: Draw your observations in the boxes provided. Control Unboiled with Methyl Blue Boiled with Methyl Blue 4

6 Data Analysis: Graph your results using a bar graph. (ask your instructor if you need help). Use control group, living cells with dye (unboiled), and dead cells with dye (boiled) as your independent variables and the number of blue cells as your dependent variable. Title: Key: control group unboiled with methyl blue boiled with methyl blue 5

7 Analysis Questions: 1. Describe what you observed in each slide control (warm yeast solution), unboiled with methyl blue, and boiled with methyl blue. 2. Which solutions contained live yeast and which contained dead yeast? How can you tell? 3. Why would the living yeast cells need to keep methyl blue from entering through the cell membrane? 4. Did killing the yeast cells by boiling disrupt the cell membrane s ability to maintain homeostasis? How can you tell? 5. If a living yeast cell was unable to maintain homeostasis, what would be the consequence? 6

8 Homeostasis of the Eye Introduction: Homeostasis is one of the fundamental characteristics of living things. It refers to the maintenance of the internal environment within tolerable limits. All sorts of factors affect the suitability of our body fluids to sustain life; these include properties like temperature, salinity, acidity, and the concentrations of nutrients and wastes. Because these properties affect the chemical reactions that keep us alive, we have built-in physiological mechanisms to maintain them at desirable levels. When a change occurs in the body, there are two general ways that the body can respond. In negative feedback, the body responds in such a way as to reverse the direction of change. Because this tends to keep things constant, it allows us to maintain homeostasis. On the other hand, positive feedback is also possible. This means that if a change occurs in some variable, the response is to change that variable even more in the same direction. This has a destabilizing effect, so it does not result in homeostasis. Positive feedback is used in certain situations where rapid change is desirable. Purpose: Conduct an investigation using the human eye to provide evidence that feedback mechanisms maintain homeostasis. Hypothesis: Materials: Small flashlight Paper Pencil Procedure: 1. Observe the pupil of the subject s eye. Record the color of the iris in the data table. 2. List three characteristics of the pupil in normal light. (size, etc.) 3. Turn out the lights for two minutes and repeat step With the lights still out, shine a flashlight in the subject s eye and observe the change in the pupil. List the changes that occur. 5. Turn the lights back on wait two minutes and shine a flashlight in the subject s eye and observe the change in the pupil. List the changes that occur. 6. Repeat procedure for each member of the group (or until you have observed a total of 3 subjects). Try to observe subjects with different color irises to increase the validity of your observations. 7

9 Results (Data): Color of Iris with LIGHTS ON 3 characteristics of pupil with NORMAL LIGHT Color of Iris with LIGHTS OFF 3 characteristics of pupil with FLASHLIGHT in DARK ROOM 3 characteristics of pupil with FLASHLIGHT in LIGHT ROOM Subject 1 Subject 2 Subject 3 Results (Questions): 1. Summarize the differences between the pupil with the overhead lights on and the lights off. 2. What are the differences between the pupil when the flashlight is shined in it with the light on and the light off? 3. Why is there a change in the pupil with different light levels? 8

10 4. Does eye color affect the response of the pupil to the light change? Explain. 5. How did this activity show homeostasis? 6. Was this an example of positive or negative feedback? Explain why. 7. What would be the results if your eye showed a POSITIVE FEEDBACK response to bright light? 8. Briefly explain another experiment that could demonstrate homeostasis of the human body. 9

11 Leaf Stomata & Homeostasis Lab Background: Transpiration is the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere. During transpiration, water evaporating from the spaces within leaves escapes through small pores called stomata. Although evaporation of water through open stomata is a major route of water loss in plants, the stomata must open to allow for the entry of CO 2 used in photosynthesis. In addition, O 2 produced in photosynthesis exits through open stomata. Consequently, a balance must be maintained between the transport of CO 2 and O 2 and the loss of water. Specialized cells called guard cells help regulate the opening and closing of stomata. To maintain homeostasis, plants must adjust their rates of transpiration in response to environmental conditions. Artist Depiction of Stomata (open and closed) Microscope View of Stomata Methods: Part 1: Using the microscope 1. Obtain a leaf. 2. On the underside where stomata are located, apply a thin layer of nail polish at least 1 cm 2. Let the patch dry for 5 min. You can work on part 1B while you are waiting for the nail polish to dry. 3. After the nail polish is dry, firmly apply one piece of clear tape to the nail polished area of the leaf. 4. Gently peel the tape off of the leaf so that the nail polish adheres to the tape. You now have an impression of the underside of the leaf. 5. Place the tape on a blank microscope slide face down. 6. Scan the slide on low power until to find a good area with a few stomata. Move to medium power and draw what you see in the 1 st circle. Count the number of stomata you can view on medium power and record how many are open or closed. 7. Increase the magnification to high power on the compound microscope and draw ONE stoma that you can see clearly in the 2 nd circle. 8. Each stoma is bordered by two sausage-shaped cells that are usually smaller than surrounding epidermal cells. These small cells are called guard cells and, unlike other cells in the epidermis, contain chloroplasts. 9. Label one stoma, the guard cells, and one of the epidermal cells. 10

12 Results: Leaf surface (whole) Single stoma number of open stomata present: number of closed stomata present: Analysis Questions USE COMPLETE SENTENCES: 1. What is the formula for photosynthesis? 2. What is the function of the stomata? How do they help the plant maintain homeostasis? (Think about the formula you just wrote) 3. Provide an explanation for the results of Part 1 with respect to the stomata being open or closed. 4. At what time of day would you expect the stomata to be closed and why? 11

13 Part 2: Homeostasis and Stomata 1. Develop an appropriate hypothesis to test the effects of darkness on stomata functioning. 2. Repeat the procedure from part 1 and record your results in the data table. Light Plant Dark Plant Number of open stomata Number of closed stomata Total number of stomata/leaf 3. Create a bar graph to illustrate the data table below. Title: 12

14 Analysis Questions USE COMPLETE SENTENCES: 1. Provide an explanation for the results of Part 2 with respect to homeostasis & the environment. 2. Considering the lab that you just completed, summarize how stomata are responsible for helping plants maintain homeostasis. Be thorough in your explanation and be sure to include the terms: guard cells, stomata, carbon dioxide, oxygen, water, dark, light, photosynthesis, open, closed, transpiration, and homeostasis. 13

15 Homeostasis Webquest Ben s Bad Day! (DO NOT FORGET THE NON-NEGOTIABLES!) Go to: Go thru Ben s day starting at 8:00 am. Q1. Why did Ben feel dizzy and faint when he jumped out of his chair? Q2. Draw the homeostasis for blood pressure here: (be sure to include all parts) Q3. What stimulus did Ben s body have to deal with at 8:30? Q4. Draw the homeostasis for temperature here: (be sure to include all parts) Q5. What did Ben s muscles produce when he ran after his paper at 11:50 am? Q6. What did the lactic acid cause in his body? Q7. Draw the homeostasis for blood ph here: (be sure to include all parts) Q8. At 5:00 pm what is Ben doing? 14

16 Q9. THINK: Ben s brain needs more glucose. Why would Ben s brain need more glucose? Q10. THINK: What process is taking place in the cells of Ben s brain? Q11. Click on the pancreas. Explain how the pancreas is involved in glucose levels. Q12. Click on the adrenal glands. Explain how the adrenal glands are involved in maintaining glucose levels. Q13. Click on the liver. Explain how the liver is involved in glucose levels. Q14. Click on the muscle. Explain how the muscles are involved in glucose levels. Q15. Draw the homeostasis for blood glucose here: (be sure to include all parts) Q16. At 8:30 Ben eats some pretzels. What does this make worse? Q17. What part of the body must first sense that Ben is dehydrated? 15

17 Q18. What part of the body must respond first in order to change the osmolarity (amount of water) in his body? How does it respond? Q19. Draw the homeostasis for blood osmolarity (water) here: (be sure to include all parts) Q20. What made Ben so hyper at 12:00 a.m.? Q21. Which part of Ben s body is stimulated? Q22. What does this part of the body release into the blood? Q23. List the other parts of Ben s body work to maintain blood sugar levels. Q24. THINK: Why would this be? Q25. Draw the homeostasis for blood glucose here: (Be sure to include all parts) Q26. Explain how the body uses feedback to maintain homeostasis (use one of the examples from this simulation to explain). 16

18 Introduction: Homeostasis in the Human Circulatory System Lab Homeostasis means maintaining a relatively constant state of the body s internal environment. The term used to describe a pattern of response to restore the body to normal stable level is termed negative feedback. When a stimulus (environment change) is met by a response that reverses (negates) the trend of the stimulus, it is negative feedback. As a result the internal environment is returned to normal. Pulse rate is constantly checked by receptors (sensors) throughout your body. A stimulus such as elevated pulse rate leads to a reaction by an organ making the response. An appropriate response will return the pulse rate to normal. Exercise causes many factors of homeostasis to kick in to maintain internal equilibrium. How exercise affects some of these factors can be determined by measuring and observing certain conditions of the human body. Some of these conditions are: change in skin color on arms and face perspiration level external body temperature breathing rate heart rate blood pressure Purpose: To observe an example of homeostasis working to control your body s pulse rate (heart rate). Materials: stopwatch Procedure: 1. Start by determining which person in your group will exercise and which person in your group will watch the stopwatch and record data. 2. Have you OR your partner sit down and measure their pulse rate in their radial artery (wrist). 3. Take three separate measurements, each for thirty seconds. Calculate the beats per minute by multiplying the values obtained by 2. Record each in Data Table Find an average for the three values of your resting heart rate. Record this in Data Table Observe any other physical characteristics such as skin color on arms and face, perspiration level, and breathing rate. Record this in Data Table You OR your partner will exercise vigorously for three minutes by jogging in place or doing jumping jacks. Start your stopwatch when you start exercising. Measure the pulse rate immediately on finishing the three minutes of activity; measure the same as before (count for 30 seconds then multiply by 2). Record the value in Data Table Observe any other physical characteristics such as skin color on arms and face, perspiration level, and breathing rate. Record this in Data Table Let your stop watch continue as you rest for 5 minutes. Measure your pulse rate again after you rest for 5 minutes the same way. Record your pulse rate after this 5 minute rest period in Data Table Observe any other physical characteristics such as skin color on arms and face, perspiration level, and breathing rate. Record this in Data Table Repeat steps 6-9 two more times for a 2 nd and 3 rd trial. Record the value in Data Table 3 & Create a bar graph that shows the results of each trial. Remember each trial has 2 different values that need to be graphed, as well as the resting pulse. Make sure you include all necessary graph components! 17

19 Data: Data Table 1: Resting Pulse Rate Resting Pulse Rate 1 Resting Pulse Rate 2 Resting Pulse Rate 3 Average Resting Pulse Rate Physical Characteristics Data Table 2: Pulse Rate After Exercise Trial 1 ACTIVITY PULSE RATE Physical Characteristics After 3 minutes vigorous activity After 5 minutes of rest Data Table 3: Pulse Rate After Exercise Trial 2 ACTIVITY PULSE RATE Physical Characteristics After 3 minutes vigorous activity After 5 minutes of rest Data Table 4: Pulse Rate After Exercise Trial 3 ACTIVITY PULSE RATE Physical Characteristics After 3 minutes vigorous activity After 5 minutes of rest 18

20 Graph: Title: Key: resting pulse after 3 minutes of vigorous activity after 5 minutes of rest 19

21 Questions: 1. What is your average resting pulse rate? Most adults are between beats/min. How do your values compare? 2. What happens to your pulse rate with vigorous exercise? 3. Every cell in the body requires oxygen for respiration so that sufficient energy can be produced. Carbon dioxide, a waste product, is also produced and needs to be removed. Therefore, the levels of both gases must be regulated. How does this explain the changes in your pulse rate? 4. How did your body respond during the resting period after each activity? 5. Explain why your body responded this way during the resting period after each activity? 6. How do you think the results from this lab would compare for a trained athlete and an average person? Explain. 7. What are some ways your body regulates the increase of body temperature that also occurs when exercising? 8. Explain what happened to your respiratory rate (breaths per minute) during exercise. 9. Explain what happened to your respiratory rate during the resting period after exercise. 10. Summarize how this activity demonstrates feedback and homeostasis in the human body. 20

22 Organism Homeostasis Lab: Diabetes Part 1: What You Should Know About Diabetes and the Glucose Tolerance Test 1. Read the paragraphs below referring to What You Should Know About Diabetes and the Glucose Tolerance Test. For each paragraph, select the graphic from the last page of this lab (p. 28) that illustrates the information. Cut and paste the graphics in the appropriate boxes on the information sheet. Information about Diabetes and the Glucose Tolerance Test Graphic that illustrates the information 1. Key to the Diagrams 2. Most of the food you eat is turned into glucose, or sugar, for your body to use for energy. Your blood carries the glucose to all the cells in your body. Your blood always has some glucose in it because your body needs glucose for energy to keep you going. But too much glucose in the blood isn t good for your health. To maintain homeostasis, you need to keep a normal level of glucose in your blood. 3. Healthy people have a feedback (control) mechanism that maintains homeostasis by keeping blood glucose levels relatively constant and within a normal range. A high blood glucose level acts as a stimulus for the pancreas. The pancreas responds to this stimulus by secreting insulin, a chemical messenger (hormone). Insulin helps the glucose from food diffuse out of the blood and into your cells. This lowers blood sugar levels. 4. Most of the cells in the body carry receptors for the insulin hormone on their cell membranes. Once the insulin binds to one of these receptors, the receptor gives a signal to the cell s interior. This signal causes glucose transport proteins in the cell membrane to open and allow glucose to diffuse out of the blood and into body cells 21

23 5. Diabetes means that your blood glucose (often called blood sugar) is too high because glucose can t get into your cells. When glucose can t get into your cells, it stays in your blood. 6. Type 1 diabetes accounts for 5% to 10% of all diagnosed cases of diabetes. Type 1 diabetes is called an autoimmune disease, because the immune system attacks the person s own pancreas cells. The cells in the pancreas that produce insulin are destroyed. Most people with Type 1 diabetes produce no insulin at all. Without insulin, glucose cannot get into the cells and accumulates in the blood. 7. Type 2 diabetes accounts for about 90% to 95% of all diagnosed cases of diabetes. People can develop Type 2 diabetes at any age - even during childhood, although most people with Type 2 diabetes are adults. People with Type 2 diabetes produce insulin but the insulin receptors on their cells do not respond properly to the insulin message. Being overweight and inactive increases the chances of developing type 2 diabetes. 8. Treatments for both types of diabetes include making wise food choices, being physically active, and controlling blood pressure and cholesterol levels. People with Type 1 diabetes must take insulin injections. People with Type 2 diabetes use oral medicines to lower blood glucose levels. If diabetes is not properly treated, the high blood glucose levels can cause serious health complications including heart disease, blindness, kidney failure and leg amputation. Diabetes is the sixth leading cause of death in the United States. 9. A Glucose Tolerance Test is a diagnostic blood test for diabetes. After fasting (not eating) overnight, you are given a concentrated sugar solution (50 to 100 grams of glucose) to drink. Your blood is sampled periodically over the next several hours to test its glucose levels. Normally, blood glucose does not rise very much and returns to normal within two to three hours. If you have diabetes, the blood glucose level is usually higher after fasting, rises more after drinking the glucose solution and takes from four to six hours to come down to normal levels. 22

24 Answer the following questions. Refer to the information and diagrams in What You Should Know About Diabetes and the Glucose Tolerance Test. 1. What is insulin? What does it do in your body? 2. What do the insulin receptor molecules on the cells in your body do? 3. List two similarities between Type 1 and Type 2 diabetes. 4. List two differences between Type 1 and Type 2 diabetes. 5. What health problems may result if a patient s diabetes is not properly treated to maintain normal blood glucose levels? 23

25 Part 2: Analyzing Blood Glucose Levels Using the Glucose Tolerance Test To prepare for the glucose tolerance test, your patient fasted for 12 hours. To begin the test, she drank a solution that contained a measured amount of glucose. Blood samples were collected immediately before she drank the glucose solution and every half hour after she drank the glucose solution. The blood sample was centrifuged to separate it into blood cells and blood plasma (the liquid part of blood). You will test the concentration of glucose in the patient s blood plasma to determine if she has diabetes. Your lab kit has 5 samples of the patient s blood plasma that were collected at various time intervals during the patient s glucose tolerance test. 1. Use Column 1 on the Glucose Tolerance Testing Sheet. 2. Place 1 drop of the appropriate plasma samples to be tested in the appropriate circles in Column Place a strip of glucose test paper into each of the circles in Column 1 of the Glucose Tolerance Testing Sheet that contain the plasma samples that you are testing. Immediately compare the color of the test paper with the color on the Glucose Test Paper Color Chart. 4. Record the results of the glucose tests in Table 1. Time of Blood Collection Minutes After Drinking Glucose Solution Glucose Level in Blood (milligrams/deciliter) 0 (after fasting) The graph below shows the blood plasma glucose levels for a healthy person who does not have diabetes. Plot the data from the patient s glucose test results (from Table 1) on the graph. 24

26 Answer the following questions. Use the information in the What You Should Know About Diabetes and the Glucose Tolerance Test fact sheet to help you interpret the results of the patient s glucose tolerance test. 1. Explain why the blood glucose level for the healthy person was low (70 mg/dl) at the beginning of the glucose tolerance test. 2. Explain why the blood glucose level for the healthy person rises after drinking the glucose solution. 3. Explain what causes the healthy person s blood levels to decrease after 30 minutes. 4. Explain what might cause the patient s blood glucose levels remain high after 30 minutes. 5. Based on the information in the graph, do you think the patient has diabetes? Support your answer with evidence from the graph. 6. Do you have enough information to determine if the patient has Type 1 or Type 2 diabetes? If not, how would you go about figuring this out? 25

27 Part 3: Blood Insulin Levels There are two types of diabetes that result in higher than normal blood glucose levels- Type I and Type 2. A person with Type I diabetes does not produce insulin. A person with Type 2 diabetes does produce insulin but their cells are unable to respond to the insulin message. To determine whether a patient has Type 1 or Type 2 diabetes, you need to test the concentration of insulin in the patient s blood plasma. 1. Use column 2 on the Glucose Tolerance Testing Sheet. Place 1 drop of the appropriate plasma sample to be tested in the appropriate circles in Column 2- Insulin Level in Blood. 2. Add one drop of the Insulin Indicator Solution to the plasma in each of the circles. 3. After 10 seconds, compare the color of the fluid in each circle with the Insulin Test Indicator Color Chart. 4. Record the results of the insulin tests in Table 2. Time of Blood Collection Minutes After Drinking Glucose Solution Insulin Level in Blood (picomole/liter) 0 (after fasting) The graph below shows the blood plasma levels for a healthy person who does not have diabetes. Plot the data from the patient s insulin test results on the graph. 26

28 Answer the following questions. Use the information in the What You Should Know About Diabetes and the Glucose Tolerance Test fact sheet to help you interpret the results of the patient s glucose tolerance test. 1. Compare the insulin levels in a healthy person with the insulin levels in the patient. 2. Based on the information in the graph, do you think the patient has Type 1 or Type 2 diabetes? 3. Support your answer to question 2 with information from the graph. 4. Why would insulin injections typically not be used to treat the patient s diabetes? 5. What treatment plan would you suggest to keep the patient s glucose levels within normal range? 6. What health problems may result if the patient does not follow the treatment plan suggested to keep her blood glucose levels within normal range? 7. Why could diabetes be classified as a disease that interferes with the body s normal homeostatic mechanisms? 27

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31 Part I: Earth s Feedback Loops Earth s Feedback Loops Webquest Go to the site below, watch the video and answer the following questions: 1. What types of positive (reinforcing) feedbacks occur on Earth? 2. What types of negative (balancing) feedbacks occur on Earth? 3. What type of feedbacks shift ecosystems from destabilized states to stabilized states? Part II: Feedback Loops in the Arctic Go to the site below, watch the video and answer the following questions: 4. Describe a positive (reinforcing) feedback operating in the Arctic. 5. Describe a negative (balancing) feedback operating in the Arctic. 6. Think about the changes happening in the Arctic. Predict how might these changes might cause other changes in the Arctic biosphere. Part III: Feedback Loops in Rainforests Go to the site: and use the information on the site to complete the following questions. 30

32 Background Information on Rainforests 7. What are the 3 characteristics shared by rainforest ecosystems? 8. Where are the majority of the world s tropical rainforests located? Why are they located there? 9. What significance to rainforests play in the Earth s carbon cycle? 10. How are humans interfering with rainforests (and ultimately, the carbon cycle)? About Rainforests (Summary) 11. Summarize the ecosystems services that rainforests provide to Earth. 12. Summarize why rainforests are so diverse. Why is this diversity important to humans? (see Background Information on Rainforests if you need to) 13. Provide 3 reasons humans are cutting down and destroying rainforests. How much area is being destroyed each year? 14. How is climate change impacting rainforests? 31

33 15. Summarize how rainforests help stabilize the world s climate. 16. In addition to rainforests impact on the carbon cycle, how do rainforests help maintain the water cycle? How does this impact us in the United States? Part IV: PUT IT ALL TOGETHER! When you took your carbon journey through the carbon cycle (The Carbon Cycle Game) in Unit 1, you moved through a complex system of carbon processes and reservoirs with many changes along the way. Understanding the carbon cycle and how it behaves requires that we think of it as a complex dynamic system with components of the system interacting with each other in often unpredictable and emergent ways. A change in one part of a complex system can often cause a myriad of changes in other parts of the system. The Amazon rainforest ecosystem is a good example of a complex ecosystem currently undergoing changes. Examine the image of the Amazon Rainforest Die-Off pictured below. Use the image to answer the following questions. You can also read more about the Amazon Rainforest Die-Off at: 32

34 17. Identify at least 5 environmental variables (biotic or abiotic factors) in this diagram. 18. What do you think the arrows mean in this diagram? 19. What cause and effect relationships between parts of a system can you identify in this environmental story of the Amazon Rainforest Die-Off? In other words, what changes in one part of a complex system caused changes in other parts of the system? 20. One environmental variable initiated this cascade of changes. What variable do you think it is? Explain your reasoning. HINT: Temperature might seem the most obvious, but what caused the temperature to rise? 21. Why do you think the changes illustrated in the Amazon Rainforest Die-Off diagram are drawn in a circle? 22. Is the Amazon Rainforest Die-Off an example of a negative or positive feedback loop? Justify your response. 33

35 The Effect of Greenhouse Gases on Glaciers & Earth s Temperature Computer-Based Simulation Objectives Discover some causes and effects of increasing global temperature. Determine the environmental factors that affect the motion and size of glaciers. Explain how greenhouse gases influence the temperature of the Earth. PART A: Glaciers 1. Open up the PhET Glaciers simulation ( and play with the sim for five minutes. What do you find? 2. Observe what happens to the glacier as you adjust different parameters in the simulation. Record your observations in the table. 3. What claims can you make about the relationship between the amount of snowfall and the movement and thickness of glaciers? Provide evidence for your claims. 4. What claims can you make about the relationship between the average temperature and the movement and thickness of glaciers? Provide evidence for your claims. 34

36 PART B: The Greenhouse Effect 1. Open up the PhET Greenhouse Effect simulation ( and play with the sim for five minutes. What do you find? Greenhouse Effect Tab 1. Adjust the concentration of greenhouse gases in the atmosphere and observe what happens. Record your observations in the table below. Greenhouse Gas Concentration What happens to sunlight? What happens to infrared photons? What happens to the temperature? Today Ice Age None Photon Absorption Tab 2. Explore how the different molecules interact with visible and infrared light. Do you find any patterns? 3. Which gases are considered greenhouse gases? Provide evidence to support your answer. 35

37 4. Build an atmosphere with different compositions. Use the table below to record your observations. Composition of Atmosphere What happens to infrared photons? What happens to visible photons? Lots of greenhouse gases No greenhouse gases 5. Compare your observations for infrared photons in #1 and #4. Use this data to explain how greenhouse gases can affect global temperature. Use microscopic evidence to explain the difference in global temperatures during the ice age and present day. PART C: Reflection Use your observations on in The Greenhouse Effect simulation to explain your observations in the Glaciers simulation. What connections can you make? 36

38 Modeling the Greenhouse Effect Prelab: The picture below is the experiment we will be setting up. All jars will be exposed to bright light! Answer the questions below based on the picture. Experimenting with jars A and B: 1. What is the independent variable? 2. What is the dependent variable? Experimenting with jars B and C: 1. What is the independent variable? 2. What is the dependent variable? Predictions: 1. The temperature in Jar A will increase / decrease / stay the same (circle one) because 2. The temperature in Jar B will increase / decrease / stay the same (circle one) because 3. The temperature in Jar C will increase / decrease / stay the same (circle one) because 4. The temperature in the water of Jar C increase / decrease / stay the same (circle one) because 37

39 5. Using the textbook (section 4.1) and your prior knowledge of Earth s systems, fill in the chart below showing the connections between this model of the greenhouse effect and the actual greenhouse effect taking place in the biosphere. Part of Model Jar Cover Light Water Air within Jar Part of the Earth/ Sphere Represented Connection (Why?) Data: Location Temperature ( C) Time (min) Jar A Jar B Jar C Water Jar C 38

40 Graph the temperatures over time for each jar on the graph below. You will have 4 lines on one graph when you are finished. Title: Key: Jar A temperature Jar B temperature Jar C temperature Jar C water temperature 39

41 Analysis: 1. What was the difference in temperature from beginning to end for jar A? 2. On the picture at the beginning of this lab, draw an arrow showing the movement of the light and transformation into heat in model A. 3. Describe how model A is different than the actual earth as discussed in the reading. 4. What was the difference in temperature from beginning to end for jar B? 5. On the picture at the beginning of this lab, draw an arrow showing the movement of the light and transformation into heat in model B. 6. Describe how model B is similar to the actual earth as discussed in the reading. 7. Which jar (A or B) showed the greatest difference in temperature change? Explain why this jar had the largest change. 8. What was the difference in temperature from beginning to end for jar C? For the water in jar C? 9. What does the water in Jar C represent? 40

42 10. On the picture at the beginning of this lab, draw an arrow showing the movement of the light and transformation into heat in model C. Be sure to show this for the water and the jar. 11. Explain the difference in temperature for the water in jar C and the air in jar B? Why would this occur? Conclude: 12.Use the carbon cycle diagram below to explain the effect of deforestation and burning of coal on carbon cycling. How might these processes be contributing the greenhouse effect as modeled in the lab today? 41

43 Safe Water? Introduction: An infant is admitted to the hospital with serious symptoms. The infant s family recently moved to a house with a private well, not a public water supply. You will test water from the family s well and identify health risks associated with the contaminated well water. The family moves to a house with a public water supply and must consider whether to use tap water or bottled water. You will consider the safety, costs, health consequences, and ecological impact of using tap water versus bottled water. Part I: The Case of an Ailing Infant Patient: Joey Nash Age: 5 months Symptoms: Vomiting, diarrhea, bluish skin, weakness, and increased breathing rate Patient History: Joey s parents report that he was healthy until they moved several weeks ago into a home near a small farm. They water that the Nash family uses for drinking, cooking, and for preparing Joey s baby formula comes from their private well, not the town s public water supply. Recommendation: Well water testing should be done because several families who live near the Nash family have had health problems due to contaminated well water. You will test the water from the Nash s well for three potential contaminants that could be causing Joey s symptoms - coliform bacteria, nitrates, and arsenic. Procedure: 1. Place one drop of the well water sample into each of the circles on the Well Water Testing sheet. 2. Add one drop of each of the appropriate test solutions to the Well Water Testing circles: a. Add one drop of Coliform Bacteria Test Solution to the Coliform Bacteria Test circle. b. Add one drop of Nitrate Test Solution to the Nitrate Test circle. c. Add one drop of Arsenic Test Solution to the Arsenic Test circle. 3. Use the Water Testing Color Charts in your kit to determine whether the concentration of each contaminant is safe or unsafe (too high). Record the results of the water tests in the data table below. Potential Well Water Contaminant Safe or Unsafe Coliform Bacteria Nitrates Arsenic 42

44 4. Based on the results of the well water tests, what conclusions can you draw about the safety of the water in the Nash s well? Base your answers to questions 5-9 on the information in the Fact Sheet: Well Water Safety. 5. Which of Joey s symptoms may be caused by unsafe nitrate levels in the well water? 6. Name the condition caused by unsafe nitrate levels and the treatment used for this condition. 7. Which of Joey s symptoms may be caused by unsafe coliform bacteria levels in the well water? 8. Name the condition caused by unsafe coliform levels and the treatment used for this condition. 9. List at least three likely sources of the contaminants that made Joey sick. Be specific. 10. List at least three actions that Joey s family could take to prevent well water contamination from affecting their health in the future. 43

45 Part II: Tap Water versus Bottled Water Joey recovered from his illnesses, and for a while the Nash family used bottled water for all of their drinking and cooking. However, bottled water was expensive and their landlord refused to take action to treat their water supply. The Nash family moved to an apartment in town so that they would have tap water from the town s public water supply. The town water supply came from a local lake and was treated and tested before it was distributed to the town. Town officials gave Mrs. Nash a copy of an official report that said the water had been tested and was safe. To be sure the town s water was safe, Mrs. Nash sent a sample of the town tap water to a state certified water testing laboratory. For comparison, she also sent a sample of Pure Spring Water sold by a local bottled water company. You will test samples of the bottled water and the town tap water for three potential contaminants coliform bacteria, nitrates, and arsenic. Procedure: 1. Place one drop of the bottled water sample into each of the Bottled Water Testing circles on the Bottled Water Testing sheet. 2. Place one drop of the tap water sample into each of the Tap Water Testing circles on the Tap Water Testing sheet. 3. Add one drop of each of the appropriate test solutions to the Bottled Water Testing cicrs and the Tap Water Testing circles: a. Add one drop of Coliform Bacteria Test Solution to the Coliform Bacteria Test circles. b. Add one drop of Nitrate Test Solution to the Nitrate Test circles. c. Add one drop of Arsenic Test Solution to the Arsenic Test circles. 4. Use the Water Testing Color Charts in your kit to determine whether the concentration of each contaminant is safe or unsafe (too high). Record the results of the water tests in the data table below. Potential Water Contaminant Coliform Bacteria Nitrates Arsenic Bottled Water Safe or Unsafe Tap Water Safe or Unsafe 5. Based on the results of the bottled water and tap water tests, what conclusions can you draw about the safety of each type of water? 6. Mrs. Nash would like to continue using bottled water for drinking and cooking. List one possible reason why she might prefer to use bottled water instead of tap water. 44

46 7. Mr. Nash would prefer using tap water for drinking and cooking. List one possible reason why he might prefer to use tap water instead of bottled water. 8. Use the information in The Facts about Bottled Water to make a list of at least eight evidences that support the use of tap water from a public water supply instead of bottled water. 9. On your list above, put X s in front of the three pieces of evidence that would most likely persuade you or a friend to use tap water from a public water supply instead of bottled water. 10. Write a paragraph to persuade people to use tap water from a public water supply instead of bottled water. Include at least the three evidences that you selected in question 9. 45

47 Unit 2 Reflection A. How does each lab/activity exemplify the learning targets for the unit? Be specific about each learning target and use the dos and don ts suggestions! 46

48 B. What were you able to learn by completing the labs/activities? Again, be specific about each learning target and use the dos and don ts suggestions! 47

49 C. How did the labs/activities compare and contrast to each other? Again, be specific about each learning target and use the dos and don ts suggestions! 48

50 D. In which labs did you experience trouble? Again, be specific and use the dos and don ts suggestions! 49

51 E. How does this unit of work relate to real life situations? Again, be specific and use the dos and don ts suggestions! 50

52 Article Rationale & Summary Article Title: Author(s): Source: Summary: Summarize the main points of the article in 4-6 sentences. Rationale for inclusion in this unit: How does the material in the article relate to what was learned/studied in this unit? Include a detailed description of at least 3 different specific examples. Again, be specific about each connection and use the dos and don ts suggestions! 51

53 (Copy of Article) 52

54 Personal Choice 53

55 Rationale for Personal Choice 54