Life Scientist, Conservation Scientist, Agricultural Manager

Transcription

1 Seventh Grade Lesson Reproduction in Agriculture Description: Students will learn the advantages and disadvantages between asexual and sexual reproduction. Students will chart the growth of plants produced both sexually and asexually. Students will apply their knowledge to create a presentation for farmers comparing the two methods. Agriculture Jobs: Life Scientist, Conservation Scientist, Agricultural Manager Essential Vocabulary: Asexual Reproduction: when an organism produces offspring without fertilization. Because offspring inherit all of their DNA from one parent, they are genetically identical to each other and to their parent Cloning: a type of propagation means of reproduction used to recreate an ideal plant specimen for a parent. Techniques used can include: cuttings, layering, division, and grafting or budding Genetic Variation: the variation in the DNA sequence for each of the genomes. It is what makes animals and plants unique Propagation: a process of creating new plants form a variety of sources including seeds, cuttings, and bulbs Mitosis: a type of cell division in which a cell divides and produces identical copies of itself 1

2 Meiosis: a form of cell division that produces reproductive cells. A single cell divides twice to produce four cells containing half the original amount of genetic information Sexual Reproduction: a type of reproduction in which the genetic materials from two different cells combine, producing an offspring Math Standards 7. SP. B. 4 Use measures of center and measures of variability for numerical data from random samples to draw informal comparative inferences about two populations. Standards for Math Practice MP1: Make sense of problems and persevere in solving them. MP2: Reason abstractly and quantitatively. MP3: Construct viable arguments and critique the reasoning of others. MP4: Model with mathematics. MP5: Use appropriate tools strategically. MP6: Attend to precision. MP7: Look for and make use of structure. MP8: Look for and express regularity in repeated reasoning. Science Standards Sci. & Eng. Practices Crosscutting Concepts 7. LS. 6 Develop an argument based on empirical evidence and scientific reasoning to explain how behavioral and structural adaptations in animals and plants affect the probability of survival and reproductive success. 7. LS. 7 Evaluate and communicate evidence that compares and contrasts the advantages and disadvantages of sexual and asexual reproduction. 7. LS. 8 Construct an explanation demonstrating that the function of Asking Questions/Designing Problems Developing & using models Controlled investigations Data analysis & interpretation Math & computational thinking Constructing explanations & designing solutions Engaging in argument from evidence. Obtaining, evaluating & communicating 2 Pattern Cause and effect Scale, proportion, and quantity Systems and system models Energy and matter Structure and function Stability and change

3 mitosis for multicellular organisms is for growth and repair through the production of genetically identical daughter cells. information Task Background Knowledge: 1. Students should understand that plants grow from seeds. 2. Students should know and be able to describe the functions of the parts of a flowering plant. 3. Students should know and be able to describe the functions of the parts of a cell. 4. Students should understand the processes of mitosis and meiosis. 5. Students should know how and why new organisms form for the continuation of a species. Student Misconceptions: As you teach the following task, keep in mind that students have common misconceptions that will need to be appropriately addressed: 1. Sexual reproduction only occurs among animals. 2. Sexual and asexual reproduction are similar processes producing the same results. Pre-Assessment: Teachers will use formative assessments to determine the students prior knowledge and skills related to the lesson. For example, a teacher can use a self-assessment probe to ask students to reflect and comment on their level of knowledge and skill across a range of items. 3

4 Engage: The Teacher will show a video of Dolly the Cloned Sheep. Possible questions: 1. There were three different sheep used in the process of creating Dolly. Which one does Dolly look like? Why? 2. Who do you look like: your mom, dad, or a combination of both? 3. Why do you not look exactly the same as your parents or your siblings? 4. What is the difference in the way most mammals are reproduced and the way the way that Dolly was reproduced? Explore: Background Review: Students and teachers discuss the following questions: 1. What organelles (nucleus, centrioles, etc) in the cell are vital to reproduction? 2. Why is it important for organisms to reproduce? 3. Do all organisms need to reproduce? Explain your reasoning. 4. Do all organisms reproduce in the same way? Explain your reasoning. Guiding Question: What is the difference in asexual and sexual reproduction? Activity: Students work in groups to compare aspects of an organism that reproduces sexually with one that reproduces asexually. Students will document evidence from the informational text into the Student Research chart using the informational text Investigating Reproductive Strategies. Students will participate in a roundtable discussion of their 4

5 findings and create a list of the advantages and disadvantages of asexual and sexual reproduction. Suggested Discussion Questions: 1. What are the differences and similarities between asexual and sexual reproduction? 2. What are the advantages and disadvantages of asexual and sexual reproduction? 3. Is one of the modes of reproduction better that the other? Why? Explain: Teachers explain the processes of asexual and sexual reproduction making sure to highlight the advantages and disadvantages of both through presentation, notes, etc. See handout with Teacher Notes on Reproduction Types. Teachers will also discuss the different forms of asexual reproduction in animals and plants. Teachers make a connection between reproduction through mitosis and meiosis. Essential Question: How can farmers use their knowledge of reproductive processes to increase their crop yield? Teacher and students can use the resource Ag in the Classroom: Plant Propagation. Review the Background Agricultural Connections section for information about sexual and asexual reproduction in crops such as corn. Teacher may choose to present the information as a PowerPoint, student handout, etc. Objective: Students will create offspring using sexual and asexual reproduction. 5

6 Sexual: 1. Prior to the lesson, lima beans should be soaked in water for 12 hours to increase germination rate. For better germination rate, a location with ample sunlight is highly recommended. 2. Students read Seed to Seed 101 handout to review the process of pollination. 3. In teams, students will be given a lima bean seed and research the flower structure of the specific plant from which the seed came. 4. Students will diagram and describe the structures involved in the reproduction of the plant. 5. Students will plant their seeds to observe how the seed develops into a plant using the following steps: a. Dip a cotton ball in water, and squeeze the excess water out. b. Place the wet cotton ball inside of a Ziploc snack or sandwich bag. c. Place two seeds in the plastic bag, one on each side of the cotton ball. d. Label the bag with group names. e. Without sealing bags (they need air!), place the bag in an area of the room where the seeds can be observed for the next three days. 6. Students should record observations of the seeds in a journal for the next 3-5 days. See student handout Seeds Data Table and Calculations. 7. When one seed has germinated, remove the other seed from the bag. 8. The seed can be transplanted into the soil by cutting the bottom of the bag and placing the seed and cotton ball into a container with soil. 6

7 Asexual: 1. Suggested plants: tomato, basil, rosemary, geranium, rose, African violet 2. Teacher will explain that plants are able to generate a new plant from a small piece of stem, leaf, or other plant tissue. 3. Review the similarities and differences in sexual and asexual reproduction. 4. Students will create new plants that are genetically identical to a parent plant. a. Fill a small cup with holes in the bottom with potting soil. b. Find a section of the plant that is at least four inches long and has at least four leaves. c. Find a node (where the leaf attaches to the stem) on this section of stem. d. Cut the stem about half an inch below the node at an approximate 45-degree angle. e. Place the cutting in the container with soil. Be sure the node is below the surface of the soil and the leaves are above the surface of the soil. f. Water the soil immediately. Apply water until you see it flow out the holes in the bottom of the container. g. Place the container with the cutting in bright, indirect sunlight. h. Monitor the cutting daily. Make sure the soil is moist and not soaking wet. 5. Students should record their observations of the plant in their journal for a minimum of five days. See student handout Stem Cuttings Data Table and Calculations. 6. Students should compare the development of the seed and the plant cuttings. An extended period of time, up to 20 days, is recommended for better comparison between the populations. See Student Handout:Comparing the Growth of Two Populations. 7

8 Elaborate: Student Project: Task: A farmer has had his crop almost entirely destroyed by a catastrophic event. He had forgotten to make his insurance payments and will not be able to recoup the cost of the crops. It is imperative that he grows a new crop as quickly as possible so that he has an income for the year and does not lose his farm. Your task is to provide the farmer with a plan to produce a new crop quickly. Compare the growth rates of plants produced sexually and asexually, using the class grown plants data. Be sure to include the advantages and disadvantages that the farmer will face by using each method. To deliver your plan to the farmer, prepare a presentation using PowerPoint, Prezi, three-sided poster board, or typed report. Your mathematical evidence should be included using tables and graphs. See Student Task handout. Evaluate: Teacher may choose to administer a standard-based assessment and determine the student s mastery level after completing the Task. Resources: Chart: Student Research: How do organisms reproduce? (attached) Handout: Comparing the Growth of Two Populations (attached) Handout: Investigating Reproductive Strategies Activity (p ) kdxxsyxvyzw5zy2hlcmzmcg9ydgzvbglvfgd4ojzmzwezyza 3ZDU2Y2FkNmM Handout: Seed to Seed Handout: Seeds Data Table and Calculations (attached) 8

9 Handout: Stem Cuttings Data Table and Calculations (attached) Handout: Student Task - What are the best methods for plant reproduction and growth? (attached) Teacher Notes: How do organisms reproduce? (attached) Video: ABC News: Dolly the Sheep: References: Genetic Science Learning Center. (2008). Investigating Reproductive Strategies. Retrieved September 30, 2017, from kdxxsyxvyzw5zy2hlcmzmcg9ydgzvbglvfgd4ojzmzwezyza 3ZDU2Y2FkNmM National Agricultural Literacy Curriculum Matrix. (2013). Plant Propagation. Retrieved September 30, 2017, from =80&grade=6&lesson_states=TN&author_state=0&content=SCI ENCE&search_term_lp=asexual National Gardening Association. (2002). Seed to Seed 101. Retrieved September 30, 2017, from 9

10 Student Research: How do organisms reproduce? You are a biologist scientist learning about how organisms reproduce. Research five different organisms (plants, animals, fungi, or bacteria), compare their method of reproduction, and analyze the advantages and disadvantages of their reproductive methods. Organism s Name Offspring Appearance Advantages Disadvantages 1 Sexual or Asexual Reproduction Number of Parents Involved

11 Teacher Notes: How do organisms reproduce? Description of the process Sexual Reproduction A type of reproduction in which the genetic materials from two different cells combine producing an offspring. Number of parents two involved Type of cells Sexual cells known as gametes involved (egg and sperm) Method of Meiosis producing cells involved in reproduction Offspring A combination of both parent appearance cells involved Advantages Genetic variations may increase the organism s chance of survival. Disadvantages Organisms need to reach maturity in order to produce sexual cells. Two different sexual cells must be present to combine into one organism. Offspring may display undesirable traits Slower population growth May be subjected to environmental conditions unfavorable for pollination Organism Examples Leech, dog, meadow garlic, corn Asexual Reproduction A type of reproduction when an organism produces offspring without fertilization. The offspring inherits all of the DNA from one parent. one Somatic cells from the organism s body Mitosis Exactly identical to only parent cell involved (clone) One only organism needs to be present to produce new offspring. Rapid population growth Get desired characteristics Lack of genetic variations may reduce the organism s chance of survival. Can t adapt to changing environment More risk of disease Amoeba, starfish, strawberries, potatoes 11

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13 Seeds Data Table and Calculations Part I: How do they seeds grow over time? Record observations after placing the seeds in a wet cotton ball inside a plastic bag. s of Seed Bags A Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 9 Day 10 Additional Days B C D E Part II: How long did it take the seeds to germinate? Calculate the mean, median and mode for the number of days that it took the seeds to germinate. Mean (average number of days for germination) Median (middle number of days in an ascending list recorded for germination) Mode (number of days that occurs most often for germination) 13

14 Stem Cuttings Data Table and Calculations Part I: How do the stem cuttings grow over time? Record observations after placing the stem cuttings in soil. Stem Cutting s Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 9 Day 10 Additional Days A B C D E Part II: How long did it take the stem cuttings to show any sign of growth? Calculate the mean, median and mode for the number of days that it took the stem cuttings to show any sign of growth. Mean (average number of days for new growth) Median (middle number of days in an ascending list recorded for new growth) Mode (number of days that occurs most often for new growth) 14

15 Comparing the Growth of Two Populations Inference: How long will it take for seeds to germinate and show some sign of growth? How long will it take stem cuttings to show some sign of growth? Data Table: Complete data table using the data collected during the class experiments. Document the number of days it took for seeds and stem cuttings to show any sign of growth: Seeds A B C D E F G H I J Stem Cuttings Calculations: Calculate the mean for each population (seeds vs. stem cuttings) and the difference between the two population means. 1. Seeds mean is 2. Stem cuttings mean is 3. The difference between the two means is Analysis: Based on the mean, compare the growth rate of each reproduction type. Is the mean about the same for each of the populations? Does one of the populations show a greater or lesser variability? Explain. Recommendation: What is the significance of the variability between the two populations of plants for a farmer that is trying to grow plants? Explain. 15

16 What are the best methods for plant reproduction and growth? Task: A farmer has had his crop almost entirely destroyed by a catastrophic event. He had forgotten to make his insurance payments and will not be able to recoup the cost of the crops. It is imperative that he grows a new crop as quickly as possible so that he has an income for the year and does not lose his farm. Your task is to provide the farmer with a plan to produce a new crop quickly. Compare the growth rates of plants produced sexually and asexually using the class grown plants data. Be sure to include the advantages and disadvantages that the farmer will face by using each method. To deliver your plan to the farmer, prepare a presentation using PowerPoint, Prezi, 3-sided poster board, or typed report. Your mathematical evidence should be included using tables and graphs. Parts I and II will help you get organized. Part I: Today s farmers have the opportunity to improve their farming practices and increase their crop yields by incorporating new technologies and reproductive practices. However, new technologies and procedures can bring challenges and new problems to farmers. Your first task is to research two-four new technologies and reproductive practices and identify the possible advantages and disadvantages for a farmer. Based on your findings, you will be making a recommendation for a farmer on how to best reproduce plants. 16

17 Complete Data Table with research findings Method Sexual or Asexual Reproduction Advantages Disadvantages Part II: Summarize your class findings while growing plants from seeds and stem cuttings. What results did your class obtain? Based on these results, what are the advantages and disadvantages for each process, sexual vs. asexual plant reproduction? 17

18 As a group, construct an argument based on your research and class experimental evidence explaining the best growing practices that the farmer should incorporate when trying to recuperate the lost crops. Support your argument by explaining the advantages and disadvantages of sexual and asexual plant reproduction and the trends observed in the experimental data collected. Finally, make a recommendation based on your findings for the farmer to reproduce, grow plants and recuperate the lost investment in the least possible time. 18