Ethnobotany What types of plants can be used as medicine? Course: Biology Length of Lesson: Two Day Lesson (60 minutes per day) Author: Kristin Do Lesson overview: This lesson is an introduction to the field of ethnobotany to students. They will learn about medicinal plants and the uses of these plants. In addition, this lesson will complete the lesson part of the final project using medicinal plants to try to find the cure for cancer. Lesson Bibliography: http://volcano.oregonstate.edu/education/livingwmsh/cs/gbt.html Conway, David. The Magic of Herbs. EP Dutton & Co., Inc. New York: 1973. Plant Based Drugs and Medicines : http://www.rain-tree.com/plantdrugs.htm Chevallier, Andrew. The Encyclopedia of Medicinal Plants. Dorling Kindersley Limited. London: 1996. 1 st day overview: Students will be introduced to ethnobotany, first with a short movie, and later with a short direct teaching on herbs that are used as vitamin supplements and the history of plant derived modern medicines. Performance objectives students will be able to: - Identify different species of plants and their uses in medicine. - Explain the historical background of ethnobotany. 1
TEKS Addressed: Plants: 10C analyze and identify characteristics of plant systems and subsystems 13A evaluate the significance of structural and physiological adaptations of plants to their environments 13B survey and identify methods of reproduction, growth, and development of various types of plants Evolution: 6C identify and illustrate how changes in DNA cause mutations and evaluate the significance of these changes 6D compare genetic variations observed in plants and animals 13A evaluate the significance of structural and physiological adaptations of plants to their environments Materials: - Various herbal medicines with the list of ingredients - Pictures of various plants that are used in current medicines Engagement The teacher will show the students a movie which addresses the field of ethnobotany. The students are expected to write a reflection on the movie i.e. what they think ethnobotany is and if they think plants can be used to treat diseases, and etc. http://www.youtube.com/watch?v=zy8toxeci8w 5-7 minutes After the movie, the teacher will take out vitamins that are made from herbs and ask the students various questions regarding it. 1. What do you think these vitamins are made from? 2. Where are these vitamins made? 3. Where do you think 1. Made from chemicals. 2. Made from factories. Pharmaceutical companies. 3. From scientists, from 2
companies get their ingredients from? factories that make chemicals. Exploration Each student will be given a specific plant that the teacher researched on. Based on what they learned about evolution and extinction, they will try to identify the given plant brought to class by following a dichotomous key. 30 minutes Each of you is given five different pictures of plants. Some of chemicals in our modern medicine are derived from these plants. What you will do today is to find the genus, species and the common name of these plants by using a dichotomous key. Chinese Rhubarb (Rheum palmatum) Thyme (Thymus vulgaris) Aloe Vera (Aloe vera) Visnaga (Ammi visnaga) Celery (Apium graveolens) Astragalus (Astragalus membranaceus) Gotu Kola (Centella asiatica) Eucalyptus (Eucalyptus globulus) Ginkgo (Ginkgo biloba) Witch Hazel (Hamamelis virginiana) As you have already learned, almost every living thing in the world have either evolved or become extinct. While going through the dichotomous key, you will try to identify some of the family members of the plants and the different species under the family. In addition to 1. What is a dichotomous key? 2. Where did this plant most likely found today? 3. What are some other usages of this plant? 1. A system of identifying objects (such as plants,) in which a succession of paired choices leads progressively to identification of the object (the only remaining correct choice). 2. Africa, Asia, Europe, etc. 3. It can help in burns / help with constipation, etc. 3
identifying the plant, you will research where the plant is found and what other uses these plants have. You will be given about 30 minutes to complete. Explanation The students will do a presentation on the plants that they have researched on. There will be question and answer session after each group s presentation. After the presentation, the teacher will address misconceptions, mistakes, and omissions. The Chinese rhubarb is native to China and it is still found here. It is eases constipation and is used as a laxative. Thyme is native to southern Europe but is grown worldwide today. It relieves muscle spasms currently is used to treat infections, especially fungal. Aloe vera is native to eastern and southern Africa, but cultivated worldwide. It heals wounds, and helps in burns. It is also widely used for skin treatment and for constipation. Visnaga is native to North Africa and is grown in the Middle East and around Mediterranean. It is currently known to treat kidney stones and asthma remedy. Celery is native to Britain and other European countries but it is grown worldwide. It helps lower blood pressure and as a diuretic. Astragalus if native to Mongolia and China and is cultivated worldwide. It s currently used to control fluids in the body and as a diuretic. Gotu kola is native to India and southern United States. It grows in tropical and subtropical parts. It is used to treat wounds and for skin disorders. Eucalyptus is native to Australia, but is grown worldwide. It is used as an antiseptic and for pain relief. Ginkgo is native to China and is grown on large plantations in China. They are used to help in circulation. Witch Hazel is indigenous to Canada and eastern parts of US. It is used for skin problems and to treat damaged veins. 1. What type of medical effect does Chinese rhubarb have? What other plant that we talked about have the same effect? 10 minutes 1. It can help people with constipation. Aloe vera. 4
Elaboration 15 minutes The teacher will give them a short description on the development of modern medicine. As discussed at the beginning of class, herbalism is the earliest from of medicine. As you know, even animals seek out the appropriate herb whenever they are ill. For thousands of years medicine depended almost exclusively on flowers, barks, and leaves; only recently have synthetic drugs come into use and in many cases these carbon copies of chemicals identified in plants. So as you know, plants are the most important type of medicine. Medicines such as pills and IVs were not always there. Aborigines and people centuries of years ago used plants as their basic medicinal purposes. In ancient China, doctors made medicines by mixing different types of herbs and boiling them in water. It is difficult to know when the first pills were made, but it made it a lot easier for people to take medicine. Before, many pharmaceutical companies sent voyages to different parts of the world to find medicinal plants and I am not sure if you guys still remember but remember the launch day? Well you guys are going to do the same thing, except in the classroom. All of you be an ethnobotanist and will examine different areas of the world to find a medicinal plant that you could possibly use to cure cancer. As I have already told you, these plants that you used today are actually incorporated in daily medicine. So please think or find a plant of your interest and start researching about them. 1. Were pills always there for people to take when they get sick? 2. How did they get made? 1. Yes/ No. 2. Made by people who first mixed herbal medicine in a round shape. 5
Evaluation Student will turn in a worksheet that they completed throughout class. If not done, they need to complete it as homework. 0 minutes Homework for today is to continue reading Plotkin s Tales of a Shaman's Apprentice: An Ethnobotanist Searches for New Medicines in the Amazon Rain Forest. Assessment: Gallery walk Artifacts for day 1: -Worksheet that they completed in class. 2 nd day overview: Continued lesson from day one. Students will be do a case study on Performance objectives students will be able to: TEKS Addressed: Same as day one. Materials: Computer Internet Ethnobotany books Engagement 15-20 minutes Teacher Probing Questions Student Reponses 6
The teacher will finish discussing about the short background of ethnobotany and herbal medicine. The teacher will also review the materials learned on Thursday. 1. What is ethnobotany? 2. Why is learning about ethnobotany important? 1. The study of how people of a particular culture and region make of use of indigenous plants. 2. Ethnobotany is important because most of our medicines today are derived from plants and also informs us about the different plants that could be used for medicinal purposes. Exploration 40 minutes Teacher Probing Questions Student Responses The teacher will give the students about 30 minutes to research on a modern medicine that is derived from plants. The students will research about plant derived modern medicine and do a case study on it. 1. What type of plant did you choose? 1. Aloe Vera, etc. 2. Where can you go to find information about this plant? 2. In a book, on the website, on Google, etc. 3. What type of medicine are these plants used in? 3. For skin problems. 7
Evaluation Teacher Probing Questions Student Responses At the end of class, each group will turn in their case study. 1 minute Homework for today is to continue and finish reading Plotkin s Tales of a Shaman's Apprentice: An Ethnobotanist Searches for New Medicines in the Amazon Rain Forest. Assessment: Case study paper. Artifacts for day 1: -Worksheet that they completed in class. 8