Science 30 Project Pesticide Resistance. Student Booklet

Transcription

1 Science 30 Project Pesticide Resistance Student Booklet

2 Pesticide Resistance Table of Contents Page Project Overview 1 Equipment and Materials 1 Part 1: Defining Resistance and Designing A Spreadsheet to Model Resistance 2 Part 2: Analyzing a Spreadsheet Model for Pesticide Resistance 6 Part 3: Data Manipulation to Study Resistance Management Strategy 10 Extension A: Determining the LD 50 Rate 13 Extension B: The Effect of Kill Rate on the LD Rate 17 Copyright 2007, the Crown in Right of Alberta, as represented by the Minister of Education, Alberta Education, Learner Assessment, 44 Capital Boulevard, Street NW, Edmonton, Alberta T5J 5E6, and its licensors. All rights reserved. Duplication of this test in any manner or its use for purposes other than those authorized and scheduled by Alberta Education is strictly prohibited.

3 Project Overview: For thousands of years humans have attempted to control the size of insect and other pest populations. Within the last 50 years, development of technologies to control pest populations has involved the use of chemical substances. Early applications of the chemical pesticides dichlorodiphenyltrichloroethane (DDT) and malathion initially resulted in a rapid reduction in the number of pests such as mosquitoes, flies, and lice. However, continued applications of these pesticides resulted in a decline in their effectiveness. To counter this problem, people began to increase the concentration of the pesticides and the frequency with which they were applied. This did not have the desired effect of bringing pest populations under control. In fact, pest populations developed resistance to pesticides. In this project, you will investigate pesticide resistance. You will analyze data in a spreadsheet that simulates the changes to the population affected by the application of a pesticide. You will be asked to interpret the data generated, which is often shown as a graph, and to demonstrate your level of understanding of the relationships between pesticide application, the characteristics of a pesticide, pest population size, and the development of pesticide resistance. Equipment and materials for each group Spreadsheet template Computer, printer, and Internet access MS Excel installed MS Word installed Calculator Science 30 Project Pesticide Resistance Page 1

4 Part 1 : Defining Resistance and Designing a Spreadsheet to Model Resistance Defining Resistance Use your text, notes, the Internet, or other reference information to explain the meaning of the term pesticide resistance. Designing A Model and Spreadsheet to Demonstrate Change in Population Size Over Time Use the axes below to sketch a representation of the change in population that you predict would occur over time if a breeding pair of insects were introduced to a new ecosystem with enough resources to ensure their survival. Label the axes and write an appropriate title for the sketch you prepare. A spreadsheet can be used to model the growth of a particular population. The formulas used to format the spreadsheet are determined by observations, or predictions made from observations by scientists studying the organism in question, a related species, or a related situation. Science 30 Project Pesticide Resistance Page 2

5 Directions 1. Open the Excel application. 2. In the spreadsheet you have opened, enter the value 0 into cell A2. Enter the value 1 into cell A3, the value 2 into cell A4, and so on until you reach cell A12, into which you will enter the value 10. These values represent 10 generations of insects. 3. Select cell B1, and type the heading Theoretical Population. 4. Enter the value 2 into cell B2. This value represents the two insects (breeding pair) introduced into the area. Parameters for Model of Change in Insect Population A. A breeding pair of insects results in the production of many eggs. This particular species lays 100 eggs in each generation. B. Only half the eggs laid will hatch and result in adults. C. No predators prey on the insects. D. The insects live only one generation. E. Adults breed and lay eggs only once. The following formula which relates the total number of insects at the end of the first generation to the parameters mentioned above and the starting population size: (B2/2) ( ) 5. Enter the following formula into cell B3: =(B2/2)*(100*0.5) This will also appear in the formula bar at the top of the sheet. Press enter and record the value that appears in cell B3. Account for the significance of this value. (Note When entering a formula into a spreadsheet, you must enter the equal sign and ensure that both opening and closing brackets are used.) 6. Select cell B3 by clicking on the button on the mouse when the cursor appears in cell B3, and hold down the button on the mouse and drag to select the other cells in column B up to B Select Edit from the upper toolbar, and select the Fill and Down commands. This pastes the formula into the set of cells selected in step 6. The use of the fill down feature ensures that the calculation for a cell uses the answer from the cell immediately above it. Cells can also be filled by clicking on the bottom right corner of a cell and dragging. The Excel application will continue to fill cells for as far as you drag. 8. Select the data in the first two columns for generations 0 to 4 by clicking in cell A1 and holding down the mouse button and dragging the cursor to cell B6. 9. Graph the data in the selected cells by selecting Chart Wizard from the icon toolbar at the top of the spreadsheet. The Chart Wizard is the small bar-graph icon at the top of the page. 10. Follow the steps in the Chart Wizard to construct a graph of the data. In the first box (step 1), select Line, and then select the box showing a graph that contains data points connected by lines. Select the Next button at the bottom of the box to move on to the next step. In step 3, label your axes and title your graph. In step 4, save your graph as an object in your sheet by selecting the second of the two options. 11. Print your table and graph to hand in to your teacher OR save them to the folder designated by your teacher. Science 30 Project Pesticide Resistance Page 3

6 Note: You may use the Internet or other reference material indicated by your teacher to complete the questions in this part of the activity. 1.1 Comment on the shape of the graph showing the population size for the insects over four generations that you plotted using the spreadsheet. Is the change in the size of the insect population realistic? Support your answer with specific examples. 1.2 State two factors that act to decrease the size of a population. Describe how you might alter the calculation used in the spreadsheet to reflect the influence of one of these factors on the size of the insect population being modelled. State the changes you have made to the formula. Science 30 Project Pesticide Resistance Page 4

7 1.3 Revise the formula used in cell B2 which calculates the population size. Use the fill down feature described in direction 7 to copy the revised formula into the remainder of the cells in column B. Describe the effect that your revision to the formula has on the shape of your graph. Print the graph that shows the effect of the change you made to the formula. 1.4 Define carrying capacity. Prepare a sketch of a population time graph that depicts the carrying capacity for a population. State some factors that determine the carrying capacity for a population in an ecosystem. Science 30 Project Pesticide Resistance Page 5

8 Part 2: Analyzing a Spreadsheet Model for Pesticide Resistance Question: If genes for pesticide resistance are present in an insect population, what will happen to the population as it is sprayed over a number of applications? Hypothesis 1: After a number of sprayings, the frequency of the resistant gene will increase/decrease (circle one) because Hypothesis 2: The percentage of insects killed by each spraying will increase/decrease (circle one) over time because Open the file Student Spreadsheet Starting Template. Use the Save As feature under the File menu to save a copy of this file in your own name to a proper location on the computer, computer network, or external storage device. This copy will be the one you make changes to and submit to your teacher for marking. 1. Study the data under each column heading for the first generation and answer the following questions, keeping in mind that 1 hectare of land has a carrying capacity of insects. (The initial population at the beginning of each pesticide application is ): a. How many of the insects are non-resistant before the spraying of the pesticide? b. What is the kill rate of the non-resistant population? c. How many non-resistant insects remain after the spraying? 2. a. Identify the formula used to determine the number of non-resistant insects killed in the first generation. b. Explain why the formula identified in 2a can be used to calculate the number of non-resistant insects killed in the first generation. c. Using your calculator and the values in the appropriate cells of your spreadsheet, calculate a value that should appear in cell H2. Compare the value calculated to the one shown in cell H2 of the spreadsheet. Science 30 Project Pesticide Resistance Page 6

9 You will be required to submit: 1. A completed spreadsheet to your teacher (to complete the spreadsheet, use the instructions below) and 2. A completed response to the questions below Completing the spreadsheet To generate data for the remaining generations on the spreadsheet, select cell D3 and fill down to cell D13, then select E3 and fill down to cell E13 select H2 and fill down, then do the same for all columns I2 through M2 Graph 1 Using the spreadsheet, prepare a graph that displays the data from the following columns: A, which represents the Number of Generations, and L, the Total Population After Spraying. Place this appropriately titled graph on your spreadsheet. (To select multiple columns to appear on a graph, hold down the control key and use the mouse to select the appropriate columns). Graph 2 Prepare a second graph that displays the data from the following columns: Number of Generations, Total Population After Spraying, and Number of Resistant Insects After Spraying, Place this appropriately titled graph as a chart on your spreadsheet. Use the Save as function to save the table and graphs under your name. You will use the saved file in the other parts of this project. Use the two graphs that you have constructed to answer the following questions. Question 2.1 Describe what happens to the effect of the pesticide on the population of insects. Are the changes to the populations of insects shown on the graphs consistent with your hypothesis? You may continue your response on the next page. Science 30 Project Pesticide Resistance Page 7

10 Question 2.2 Assume that the gene for resistance is recessive. Draw a Punnet square for a homozygous resistant (rr) insect crossed with a heterozygous insect. Question 2.3 Explain the mechanism of natural selection and relate it to what happens when insects develop resistance to pesticides. Science 30 Project Pesticide Resistance Page

11 Spreadsheet and Graphs Scoring Guide Questions Scoring Guide Score 4 of Excellence 3 2 Acceptable 1 0 Scoring Descriptions An appropriate and practical spreadsheet is presented. The data are accurately entered and the instructions to complete the formatting of the spreadsheet are thoroughly and correctly followed. Two graphs are presented, including correctly labeled axes, title. Presentation of the graphs lends itself to easy and thorough interpretation of the data. An appropriate and practical spreadsheet is presented. The data are accurately entered and the instructions to complete the formatting of the spreadsheet are thoroughly and correctly followed. Two graphs are presented, including adequately labeled axes, title. Presentation of the graphs lends itself to successful interpretation of the data. A practical spreadsheet is presented. The data are accurately entered and the instructions to complete the formatting of the spreadsheet are correctly followed. Two graphs are presented, including adequately labeled axes, title. Presentation of the graphs lends itself to generally successful interpretation of the data. A poorly designed and functioning spreadsheet is presented. The data are incompletely entered and the instructions to complete the formatting of the spreadsheet are incorrectly followed. The graphs presented, may contain inaccuracies, or demonstrate inappropriate format. Presentation of the graphs lends itself to poor or unsuccessful interpretation of the data. The response does not address any of the major points of the question at an appropriate level for a 30-level course. Score 4 of Excellence 3 2 Acceptable 1 0 Questions Scoring Guide Scoring Descriptions The response is well organized and addresses all the major points of the question using appropriate and clear communication strategies. The descriptions/diagrams of the interaction of pesticides, genetics, and their relationship to natural selection reflect a thorough understanding of the concepts. Responses relate closely to the hypothesis and an accurate interpretation of the graphs. The response is organized and addresses most of the major points of the question using appropriate communication strategies. The descriptions/diagrams of the interaction of pesticides, genetics, and their relationship to natural selection reflect a sound understanding of the concepts. Responses relate closely to the hypothesis and an accurate interpretation of the graphs. The response is organized and addresses the major points of the question using adequate communication strategies. The descriptions/diagrams of the interaction of pesticides, genetics, and their relationship to natural selection are reflect a adequate understanding of the concepts. Responses relate to the hypothesis and an interpretation of the graphs. The response is not well organized and addresses few the major points of the question using inappropriate communication strategies. The descriptions/diagrams of the interaction of pesticides, genetics, and their relationship to natural selection do not reflect an adequate understanding of the concepts. Responses do not relate to the hypothesis and an interpretation of the graphs. The response does not address any of the major points of the question at an appropriate level for a 30-level course. Science 30 Project Pesticide Resistance Page

12 Part 3: Data Manipulation to Study Resistance Management Strategy As demonstrated by the spreadsheet simulation, the management of insect populations may not involve a simple solution, such as using more pesticide or developing a new pesticide. There are a number of ways in which insect control is managed to achieve maximum effectiveness. In this activity you will compare the results of the application of various amounts of a particular pesticide over an extended period of time. Comparing the amount of pesticide applied with the kill rate of non-resistant insects after a number of generations will allow you to determine the point in time at which the pesticide is no longer effective. Question: How does the dosage rate of a pesticide affect the development of pesticide resistance? Hypothesis: A high dose of pesticide will create resistance sooner / later (circle one) because Dosage of a Particular Pesticide and the Resulting Kill Rate Dosage of a Particular Pesticide Kill Rate of Non-Resistant Insects (%) Saturation 95 Moderate amount of pesticide 70 Low amount of pesticide 50 Directions Open the copy of the spreadsheet you made in Part 2, that you saved using your name. 1. You already have the graph for the 70% kill rate. Keep it for comparison purposes. 2. Revise the Excel table to represent a change in the kill rate (dosage of pesticide) a. Enter 95 in the appropriate cell (F2). b. Form a graph as you did in Part I, using columns A, K, and L. c. Save the graph for comparison purposes. d. Repeat steps a to c using a 50% kill rate. 3. Print the three graphs so that you can compare them. Science 30 Project Pesticide Resistance Page 10

13 Part 3 You will be required to submit the following: 1. Three graphs that compare the dosages (kill rates) of a particular pesticide 2. Responses to questions 3.1 and 3.2 below 3. A brief report related to Question 3.3 Question 3.1 Identify two characteristics on the table and graphs you have generated that indicate that the insects are becoming resistant to the pesticide. Question 3.2 State the general trend that exists between the kill rate of non-resistant insects and the number of generations required for the insect population to demonstrate resistance to a pesticide. How does this result compare with your hypothesis? Question 3.3 Research two methods of insect control and briefly outline the advantages and disadvantages of each method. Science 30 Project Pesticide Resistance Page 11

14 Question Scoring Guide Score 4 of Excellence 3 2 Acceptable 1 0 Scoring Descriptions The response is well organized and addresses all the major points of the question using appropriate and clear communication strategies. Accurate interpretations and conclusions are made, based on an analysis of the graphs. Methods of pest control are well presented along with a sophisticated explanation of their advantages and disadvantages. The response is organized and addresses most of the major points of the question using appropriate communication strategies. Accurate interpretations and conclusions are made, based on an analysis of the graphs. Methods of pest control are well presented along with a sound explanation of their advantages and disadvantages. The response is organized and addresses the major points of the question using adequate communication strategies. Adequate interpretations and conclusions are made, based on an analysis of the graphs. Methods of pest control are presented along with an explanation of their advantages and disadvantages. The response is not well organized and doesn t address the major points of the question using inappropriate communication strategies. Few interpretations and conclusions are made, based on an analysis of the graphs. Methods of pest control along with a explanation of their advantages and disadvantages are not well presented. The response does not address any of the major points of the question at an appropriate level for a 30-level course. Science 30 Project Pesticide Resistance Page 12

15 Extension A: Determining the LD 50 Rate LD means lethal dose. LD 50 is defined as the amount of substance that kills half (50%) of the test population of animals. The LD 50 is a standardized measure for expressing and comparing the toxicity of pesticides. The animals involved in an LD 50 test are often rats or mice, although other organisms, even aquatic invertebrates are used. (For humane reasons, members of the Organization for Economic Cooperation and Development (OECD) recently agreed to phase out the LD 50 test in favour of alternative testing methods that greatly reduce (or even eliminate) deaths of test animals. ) Currently LD 50 values are one of the most important ways of describing the toxicity of a pesticide. LD 50 is calculated relative to the size of the animal, with the most common units being milligrams of chemical per kilogram of test animal (mg/kg) or parts per million (ppm). The following table shows some common pesticides and their LD 50 values. Chemical Pesticide Oral LD 50 in Rats (mg/kg) Aldicarb ( Temik ) 1 Carbaryl ( Sevin ) 307 DDT 87 Dieldrin 40 Diflubenzuron ( Dimilin ) Malathion 885 Methoprene Methoxychlor 5000 Parathion 3 Piperonyl butoxide 7500 Pyrethrins 200 Rotenone 60 Science 30 Project Pesticide Resistance Page 13

16 Extension A continued Report on Particular Pesticides Select one of the pesticides listed in the table on the previous page or another of your choice. Complete a table like the one below by using the Internet to find the additional information on the pesticide you have selected. An electronic version of this form may be supplied to you by your teacher. Pesticide Report: Name of pesticide: Category or classification Target organism Mode of action LD 50 values for mammals tested (from research) Number of LD 50 tests performed Is there agreement between the studies to determine LD 50 for mammals? List of organisms other than mammals tested in toxicity tests Environmental and other concerns associated with the use of this substance References Description of Strategy Used to Find References Science 30 Project Pesticide Resistance Page 14

17 Question Extension A Explain why organisms other than the target organisms are used in LD 50 studies. Describe another test, other than LD 50, that could be performed on a pesticide to obtain information about its toxicity or its behaviour in the environment. Describe what information this test could provide. Science 30 Project Pesticide Resistance Page 15

18 Extension A: Determining the LD Rate continued Extension A: Pesticide Report Scoring Guide Score 4 of Excellence 3 2 Acceptable 1 0 Scoring Descriptions The response is well organized and addresses all the major points of the question using appropriate and clear communication strategies. The student was able to find the appropriate information about the pesticide in an efficient manner using sophisticated search strategies. The response is organized and addresses most of the major points of the question using appropriate communication strategies. The student was able to find the appropriate information about the pesticide in an efficient manner using practical search strategies. The response is organized and addresses the major points of the question using adequate communication strategies. The student was able to find the appropriate information about the pesticide with some help using practical search strategies. The response is not well organized and addresses few of the major points of the question using inappropriate communication strategies. The student was not able to find the appropriate information about the pesticide in an efficient manner. The response does not address any of the major points of the question at an appropriate level for a 30-level course. Extension A: Question Scoring Guide Score 4 of Excellence 3 2 Acceptable 1 0 Scoring Descriptions The response is well organized and addresses all the major points of the question using appropriate and clear communication strategies. The response reflects a sophisticated understanding of the use of LD 50 and other pesticide tests. The response is organized and addresses most of the major points of the question using appropriate communication strategies. The response reflects a good understanding of the use of LD 50 and other pesticide tests. The response is organized and addresses the major points of the question using appropriate communication strategies. The response reflects an adequate understanding of the use of LD 50 and other pesticide tests. The response is not well organized and addresses few of the major points of the question using inappropriate communication strategies. The response does not reflect an adequate understanding of the use of LD 50 and other pesticide tests. The response does not address any of the major points of the question at an appropriate level for a 30-level course. Science 30 Project Pesticide Resistance Page 16

19 Extension B: The Effect of the Kill Rate on the LD Rate In this part of the project, you will investigate the effect of altering the kill rate (using the percentages 95, 70, 50, and 25) on the LD rate. Directions: Open the copy of the spreadsheet you made in Part 3 that you saved using your name. 1. You already have the graph for the 95%, 70%, and 50% kill rates. 2. Alter the table to represent a change in the kill rate and its affect on the LD rate by following the steps below. a. Enter 95 in the appropriate cell (F2). b. Form a graph as you did in Part 3, using columns A, K, L, and M. c. Save the graph for comparison purposes. d. Repeat steps a to c using the 70%, 50%, and 25% kill rates. 3. After you have prepared a graph, use the following steps to display LD rate as a second y-axis. a. Double click on the LD rate line of data on your graph. b. In the Format Data Series window that appears, select the Axis tab. c. Select the button Secondary Axis. To label all axes, go back to Chart Options. You may find it necessary to print each graph as you formulate it, since each graph will change with new data entry. Science 30 Project Pesticide Resistance Page 17

20 Question Extension B Describe the pattern shown by the line depicting the LD rate on your graph. Explain why the line depicting LD rate differs from the line depicting the number of resistant insects after spraying. Explain the significance of the location where the line depicting the LD rate crosses the lines depicting the total population after spraying. Science 30 Project Pesticide Resistance Page 18

21 Extension B: Question Scoring Guide Score 4 of Excellence 3 2 Acceptable 1 0 Scoring Descriptions The response is well organized and addresses all the major points of the question using appropriate and clear communication strategies. The response reflects a sophisticated interpretation of the graphs. The response is organized and addresses most of the major points of the question using appropriate communication strategies. The response reflects an accurate interpretation of the graphs. The response is organized and addresses the major points of the question using appropriate communication strategies. The response reflects an adequate interpretation of the graphs. The response is not well organized and addresses few of the major points of the question using inappropriate communication strategies. The response does not reflect an accurate interpretation of the graphs. The response does not address any of the major points of the question at an appropriate level for a 30-level course. Science 30 Project Pesticide Resistance Page 19