G9-Biology-STB-2023-web.pdf

Biology Biology Biology Student Textbook Student Textbook Grade 9 Student Textbook...

Biology Biology Biology Student Textbook Student Textbook Grade 9 Student Textbook Grade 9 Grade 9 Federal Democratic Republic of Ethiopia FDRE Federal Democratic Republic of Ethiopia Ministry of Education MOE Ministry of Education  Biology Student Textbook Grade 9 Writers: Zufan Bedewi, Ph.D. Zelalem G/mariam, Ph.D. Editors: Kedir Woliy, Ph.D. (Content Editor) Girma Moti, MA (Curriculum Editor) Temesgen Daniel, Ph.D. (Language Editor) Illustrator: Simachew Ayenew, MSc Designer: Tesfamichael Getu, Ph.D. Evaluators: Berhanu Tesfaye, MA, MEd GebreHana Zeleke, MSc FDRE Ministry of Education Hawassa University First Published August 2023 by the Federal Democratic Republic of Ethiopia, Ministry of Education, under the General Education Quality Improvement Program for Equity (GEQIP-E) supported by the World Bank, UK’s Department for International Develop- ment/ DFID-now merged with the Foreign, Common wealth and Development Office/FCDO, Finland Ministry for Foreign Affairs, the Royal Norwegian Embassy, United Nations Children’s Fund/UNICEF), the Global Partnership for Education (GPE), and Danish Ministry of Foreign Affairs, through a Multi Donor Trust Fund. © 2023 by the Federal Democratic Republic of Ethiopia, Ministry of Education. All rights reserved. The moral rights of the author have been asserted. No part of this textbook reproduced, copied in a retrieval system or transmitted in any form or by any means including electronic, mechanical, magnetic, photocopying, recording or otherwise, without the prior written permission of the Ministry of Education or licensing in accordance with the Federal Democratic Republic of Ethiopia as expressed in the Federal Negarit Gazeta, Proclamation No. 410/2004 - Copyright and Neighboring Rights Protection. The Ministry of Education wishes to thank the many individuals, groups and other bodies involved – directly or indirectly – in pub- lishing this Textbook. Special thanks are due to Hawassa University for their huge contribution in the development of this textbook in collaboration with Addis Ababa University, Bahir Dar University and Jimma University. Copyrighted materials used by permission of their owners. If you are the owner of copyrighted material not cited or improperly cited, please contact the Ministry of Education, Head Office, Arat Kilo, (P.O.Box 1367), Addis Ababa Ethiopia. Photo credit: cover page, p.1,, 19, 44, 74, 103, 137 Unsplash, 2022 Printed by: GRAVITY GROUP IND LLC P.O. Box 13TH Industrial Area, Sharjjah UNITED ARAB EMIRATES Under Ministry of Education Contract no. MOE/GEQIP-E/LICB/G-01/23 ISBN:978-99990-0-008-6 Table of Contents Unit 1: Introduction to Biology 1 1.1 Definition of Biology 1 1.2 Why do we study Biology? 2 1.3. The Scientific Method 2 1.4. Tools of a Biologist 5 1.4.1. Laboratory tools of biologist 5 1.4.2. Field tools 10 1.5. The Light Microscope 10 1.5.1. The parts and function of the light microscope 11 1.5.2 Handling and using a light microscope 13 1.6. General Laboratory Safety Rules 14 Unit 2: Characteristics and Classification of Organisms 19 2.1 Characteristics of living things 19 2.2 Taxonomy of living things 21 2.2.1 Principles of classification 21 2.2.2. Taxonomic hierarchies in biological classification 22 2.3 Relevance of classification 24 2.4 Linnaean system of nomenclature 25 2.5 Common Ethiopian animals and plants 26 2.6 The five-kingdom system of classification 28 2.6.1. Kingdom Monera 30 2.6.2. Kingdom Protista 31 2.6.3. Kingdom Fungi 33 2.6.4. Kingdom Plantae 35 2.6.5 Kingdom Animalia 36 2.7 Renowned Taxonomists in Ethiopia 39 Unit 3: Cells 44 3.2. Cell theory 45 3.3. Cell structure and function 46 3.4 Types of cells 53 3.5. Animal and plant cells 54 3.6 Observing cells under a microscope 56 3.7 The cell and its environment 59 3.7.1 Passive transport 59 3.7.2 Active transport 68 3.8. Levels of Biological Organization 68 Unit 4: Reproduction 74 4.1 Introduction to reproduction 74 4.2 Asexual reproduction 75 4.3 Types of asexual reproduction 76 4.3.1 Fission 76 4.3.2 Fragmentation 76 4.3.3 Budding 77 4.3.4 Vegetative propagation 78 4.4 Sexual reproduction in Humans 81 4.5 Primary and secondary sexual characteristics 81 4. 6 Male reproductive structures 84 4.7. Female reproductive structures 86 4.8 The Menstrual cycle 88 4.9 Fertilization and pregnancy 90 4.10 Methods of birth control 92 4.11 Sexually transmitted infections (STIs): Transmission and prevention 97 Unit 5: Human Health, Nutrition, and Disease 105 5.1 What is food? 105 5.2 Nutrition 106 5.3 Nutrients 106 5.4 Balanced diets 110 5.5 Deficiency diseases 112 5.6 Malnutrition 115 5.7. Substance abuse 117 5.8. Infectious and noninfectious diseases 127 5.8. 1. Infectious diseases 127 5.8. 2 Non-infectious diseases 136 5.9 Renowned Nutritionists in Ethiopia 136 Unit 6: Ecology 139 6.1 Ecology 139 6.1.1 Definitions of Ecological Terms 139 6.1.2. Biotic and abiotic components 140 6.1.3.Ecological levels 143 6.1.4. Ecosystems 144 6.1.5 Biomes 145 6.1.6 Ecological succession 155 6.2. Ecological relationships 157 Unit 1: Introduction to Biology Sections Learning competencies 1.1 Definition of Biology Define Biology 1.2 Why do we study Biology? Explain why Biology is studied? 1.3 The scientific method Plan a biological investigation using the scientific 1.4 Tools of a Biologist method 1.4.1 Laboratory tools Identify some common tools of a Biologist 1.4.2 Field tools Utilize a microscope 1.5. Handling and using of light Microscope Execute general laboratory safety rules 1.5.1 Parts and function of light microscope 1.5.2 Handling and using microscope 1.6. General Laboratory Safety Rules 1.1 Definition of Biology Objectives Key Terms At the end of this section, the student will be able to: Biology: came from two define Biology Greek words bios means life, explain the relation of biology and other subjects and logos meaning study. Biology is the scientific study of life or living things. What does it mean to be “alive”? It seems very difficult to objectively define life in a simple sentence. Activity 1.1: THINK-PAIR- But, we recognize life mainly by common characteristics shared by SHARE living systems. Write down the common properties of living things Living things are composed of one or more cells, they can grow, that distinguish them from reproduce, they transmit genetic information to their offspring, they non-living things and need the energy to accomplish work, they can maintain relatively compare your answer with constant internal conditions (homeostasis) and they are capable of other students. evolutionary adaptation to the environment etc. What is a scientific study? Biologists study about living things using a scientific method that involves asking questions, suggesting possible answers; and testing for the validity of the answers through experimentation. This scientific study follows the study of structures and processes that we can verify observe and measure, either directly or indirectly with the help of tools and technology, such as microscopes. Grade 9 Biology 1 Unit One: Introduction to Biology Activity 1.2: Group What relationships does Biology have with other fields of natural work sciences? Make a group of students and discuss how the The study of biology is a point of merging information and tools knowledge of biology from all natural sciences. For example information about naturally can be applied in the fields occurring elements in living organisms, chemical bonding, molecules, of agriculture, medicine, acids ,bases and other related things can be studied using the tools and food processing, food principles of chemistry. Other scientific concept like conversion of preparation, preparation of radiant energy into organic molecules by photo-synthesis is studied beverage etc. and present it with the knowledge of chemistry and Physics. to your class. 1.2 Why do we study Biology? Objectives At the end of this section, the student will be able to: explain why biology is studied give examples of biological application Attention Human beings have an inborn curiosity about the natural world Application of Biology in our that leads them to study about living organisms and their habitats. day to day life: Studying biology helps to understand how living things work, how Wine-making, the they function and interact with the environment. Biology touches our brewing, the baking of bread and the production everyday life in many ways. For example, biologists have discovered of cheese all depend on drugs that are used to treat different human diseases. Many biologists fermentation processes are working on problems that critically affect our lives, such as how brought about by yeasts, our animals and plants body work, how ecosystems work, how other fungi and bacteria, advancements in genetics and cell biology are transforming to medicine or enzymes from these and agriculture, as well as the use of forensics biology to investigate organisms. crime, Furthermore, studies how ecology is helping societies evaluate Antibiotics, such as environmental issues, such as global warming, how fermentation is penicillin, are produced by used to produce alcoholic drinks such as beer and wine. In addition, mould fungi or bacteria. biological studies are used in treating patients suffering from AIDS, The production of tuberculosis, and some types of cancer. industrial chemicals such as citric acid or lactic acid 1.3. The Scientific Method needs bacteria or fungi to bring about essential Objectives chemical changes. At the end of this section, the student will be able to: Sewage disposal depends on bacteria in the filter explain about scientific method beds to form the basis explain about the meaning of hypothesis of the food chain that practice about formulating hypothesis purifies the effluent. practice doing scientific experiment and drawing a bar graph Discovery of the structure Biology is a science of inquiry. of DNA and forensic analysis of DNA samples What comes to your mind when you hear the word science? from crime scenes. Biologists are always curious about why things happen or how things 2 Grade 9 Biology  Unit One: Introduction to Biology happen. By asking questions and seeking science-based responses known as the scientific method, they come up with new theories to explain new findings. The scientific method involves a series of steps that guide scientists through such scientific investigations. Biologists study the living world by posing questions about it. The general steps of the Scientific methods are: Observation The scientific study begins with careful observations (often a problem to solve) that leads to a question. The observations can be made either directly (e.g. using your sense organs) or indirectly using scientific tools such as microscopes. Asking Questions The observations usually lead the scientist to ask questions (inquiry). Forming of a hypothesis A hypothesis is proposed scientific explanations (possible answers) for a set of question (s).To solve a problem, one can propose several hypotheses. Scientific hypotheses should be testable. Testing the hypothesis Hypothesis can be tested through experimentation. Any scientific experiment must have the ability to be duplicated because the “answer” the scientist comes up with (whether it supports or rejects the original hypothesis) can’t become part of the scientific knowledge unless other scientists can perform the same experiment and achieve the similar results. If a hypothesis is not supported by experimental data, one can propose a new hypothesis. Making conclusions about the findings Scientists consider their original hypotheses and ask whether they could still be right in light of the new information gathered during the experiment. If so, the hypotheses can remain as possible explanations for how things work. If not, scientists reject the hypotheses and try to come up with alternate explanations (new hypotheses) that can explain what they’ve seen. Communicating the findings When scientists complete some work, they write a paper that explains exactly what they did and the results they obtained. Then, they submit the paper to a scientific journal in their field. In addition, the findings will be printed in scientific journals and assist teachers and students Key Terms in the field. Hypothesis: a proposed Example of a hypothesis testing in everyday life scientific explanation Suppose you want to use your torch (hand lamp) to find a missing pen Grade 9 Biology 3 Unit One: Introduction to Biology in your bedroom. When you switch the torch on, it is not working. The following flow chart will illustrate hypothesis testing for a torch that doesn’t work. Figure 1.1. Application of the scientific method to common problems in our surroundings Activity 1.3: Application of Scientific Method Objective: To determine the importance of temperature for seed germination, 1. Form a group 2. Germinate bean seeds at different temperatures like: Group one in room temperature; Group two in colder place like outside your room or in refrigerator; Group three in hotter place like inside the kitchen; and 3. Then give your possible hypothesis for the differences in germination. 4. Measure the times of germination and length of the seedlings for the different groups 5. Draw a bar graph based on the result of your experiment using X axis for measurement of time /hour of germination (1st day of germination, 2nd day of germination, 3rd day of germination etc.) and at Y axis indicate the length of the germinated plants. (You can measure the length of your germinating plants using ruler). 6. Interpret the results and conclude the result. 7. Report your result to your friend in your class. 4 Grade 9 Biology  Unit One: Introduction to Biology 1.4. Tools of a Biologist Objectives Activity 1.4. Class work At the end of this section, the student will be able to: Recall what you learn in your grade seven general identify the major tools of biologists science lesson and write describe the functions of the identified biologist tools down the names of the tools used by biologists Biologists use different types of tools in the laboratory and field for and compare your answer with your partners. scientific investigations. Some of the tools are used for measuring, some are used for observation and some are used for culturing micro- organisms. 1.4.1. Laboratory tools of biologist Hand lens Most cells cannot be seen with the naked eye. A hand lens has a higher magnification than our naked eye. It consists of a convex lens fixed within a circular metallic loop and is attached to a metallic or wooden handle. The main function of hand lens is to provide an enlarged image of the object placed under it. But hand lens is not sufficient to observe the detail in cells. There is a need for providing high magnifications tools such as microscope. Figure 1.2 Hand lens Activity 1.5: Laboratory Activity Attention Objective: To study the magnification and focusing of radiation The important function of using hand lens microscope is magnification Materials hand lens, Pieces of paper and resolution. 1. Draw a dot on the piece of the paper. Magnification is the number 2. Observe the dot using a hand lens. of times larger an image is, than the real size of the 3. What happened? Did the dot get bigger than the original size? object. Resolution can be Why? defined as the ability to 4. Bring the hand lens to where the sun light is available. distinguish between two 5. Put the piece of paper under the hand lens and stay for some separate points. minute. 6. What happened to the paper? Why? Grade 9 Biology 5 Unit One: Introduction to Biology The Microscope One of the most important tools of the biologist is a microscope. A microscope is an instrument used to study objects that are too small to be seen with a naked eye. The microscope magnifies the image of small objects making them visible to the human eye. For example, microscopes are used to observe the shape of bacteria, fungi and parasites. There are several kinds of microscopes. The major types are: light microscope and electron microscope A light microscope is called light microscope because it uses a beam Figure 1.3. Light microscope of light to view specimens. There are two types of light microscopes, Simple light microscope which consists of a single lens while a Key Terms compound light microscope consists of two or more glass lenses. Microscope: an instrument used to observe and study Activity 1.6 Classwork objects that are too small How many lens does hand lens have? to be seen by the naked Discuss with your friend next to you. eye. It magnifies the image of small objects Light microscope: the A compound light microscope is the most common microscope used microscope uses a beam of in biology. It consists of two lens systems (a combination of lenses) to light to view specimens magnify the image of an object up to 2000x. Each lens has a different Electron microscopes: the magnifying power. A compound light microscope with a single eye- microscope uses a beam of piece is called monocular; one with two eye-pieces is said to be electrons (instead of a beam binocular. of light) and electromagnets (instead of glass lenses) Electron microscopes on the other hand use a beam of electrons to enlarge the image of an (instead of a beam of light) and electromagnets (instead of glass lenses) object to enlarge the image of an object. These microscopes provide a higher magnification than light microscopes and are used for observing extremely small micro-organisms such as viruses. Glass slides and cover slips: The microscope slides are used to support an specimens being examined under the microscope. The cover slips are the small square or circle shaped thin glass sheets that are used to cover specimens on the glass slide to protect from further addition of any chemical or dirt and it is also used to protect the microscope and prevent the slide from drying by locking the moisture. Cover slides provide better view under the microscope. Figure 1.4. Glass slide and Although the tool most closely associated with a biologist is the cover slides microscope, there are several common tools used by biologists in the laboratory and on field. 6 Grade 9 Biology  Unit One: Introduction to Biology Autoclave: is the equipment used to sterilize (kill micro-organisms) different biological samples. An autoclave sterilizes contaminated materials including culture media, and bacterial spores by exposing them to high temperatures and highly pressurized steam. Attention Culturing is the procedure used to grow microorganisms in a controlled environment. Many microorganisms reproduce very quickly. Culturing of micro-organisms also have important function Figure 1.5. Autoclave like in medicine (Penicillin) and for food (beverage) preparation. Wine and beer making uses culturing on a large scale, as it does in cheese making, bio-fuel production, and many other endeavors. There are many ways of killing microorganisms, including chemical disinfectants, flame, dry or wet heat, ultraviolet light, and ionizing radiation such as X-rays or gamma rays. The problem is, some bacteria form spores, which are resistant to chemical disinfectants, including bleach. In these situations, it is very important to use autoclaving which kill microorganisms as well as their spores. Incubator: is a device used to maintain a specific environment for culturing. An incubator is an instrument that maintains the temperature best suited for the growth of different types of micro- Figure 1.6. A Bacteriological organisms. incubator Petri dishes: are flat dishes with a matching cover of a slightly larger diameter. They are available in glass and plastic form. Petri dishes are used with gelling culturing media, such as agar, and placed in the autoclave to sterilize it. Figure 1.7. Petri dishes Culture tubes: are available in a huge range of sizes, shapes, materials, and so on. They are used to culture micro-organisms. Culture tubes may be used with solid (gel) culturing media or with liquid (broth) culturing media, and then placed in the autoclave for sterilization. Figure 1.8. Test tubes Flasks: is an apparatus having a flat bottom and a long narrow neck, which allows easy mixing of the solution without spilling out the content. it is also used to gently heat the content inside with a gentle swirling motion of the flask. It is essentially a large-volume culture tube that is used only with broth media and flasks are used to produce large populations of micro-organisms. They are available in a variety of shapes and sizes. Figure 1.9. flasks Grade 9 Biology 7 Unit One: Introduction to Biology Balance: is useful for making up solutions accurately, weighing specimens, and so on. Figure 10. Balance Dropper: A dropper consists of a glass tube that has a small opening at one end and is attached to a vacuum rubber bulb at the other end. A dropper is used when it is required to control the amount of solution being added to a reaction. Figure 1.11. Dropper Tongs Tongs are metallic scissors-shaped laboratory instruments. It is used to Lifting or picking up hot objects such as heated crucible, beakers, dishes, or flasks. Figure 1.12. Tongs Dissecting Tool Kit Dissecting Tool Kit is used to dissect animals such as frogs, fetal pigs, mice, etc. It consists of all the necessary tools required to carry out the process of dissection such as a catheter, groove probe, scalpel, surgical scissors (straight and curved), mayo scissors (straight and curved), dissecting forceps (with and without teeth), dissecting pin, Figure 1.13 dissecting kit etc. Dissecting pan Dissecting pan is equipment is used as a pan on which the specimen is kept while it is being dissected to study its internal organs. Figure 1.14 dissecting pan 8 Grade 9 Biology  Unit One: Introduction to Biology Crucible Crucible is a small container made up of ceramic or metal which is able to withstand high temperatures, and therefore, it is generally used to melt elements. Figure 1.15. Crucible Beaker Beaker is a cylindrical glass container used for making up solutions, holding hot or cold water or ice baths, and so on. Figure 1.16. Beakers Hotplate Figure 1.17 Hot plate Hotplate is useful for heating solutions, making up an agar culturing medium, and so on. pH meter is used to measure the pH (acidity or basicity) of substances. Thermometer is an instrument that measures the temperature of substances. Figure 1.18. pH mete Figure 1.19. Thermometer Forceps are used to hold or pick up small objects. They are available in a variety of shapes and sizes. Figure 1.20. Forceps Spatula A spatula is used for mixing substances into a solution, stirring the Figure 1.21. Spatula solution, and scrapping objects. It is shaped like a spoon Wash Bottles Wash bottles which are mainly used to rinse various laboratory materials. Wash bottles are flexible in nature that allows the user to adjust the water pressure as per the need by squeezing the bottle accordingly. Figure 1.22. Wash bottles Grade 9 Biology 9 Unit One: Introduction to Biology Bunsen burner or alcohol burner This apparatus produces a single open flame and it is used for heating and sterilization purposes in the various experiments conducted in labs. Figure 1.23. Bunsen burner 1.4.2. Field tools Insect nets –It is insect collecting nets which is composed of some Figure 1.24. Insect net sort of net bag made of cloth or fine mesh that is attached to a wire loop, which is attached to a wooden or metal pole. Fishing net is a net used for fishing. Nets are devices made from fibres woven in a grid-like structure. Some fishing nets are also called fish traps. Fishing nets are usually meshes formed by tying a relatively thin thread. 1.5. The Light Microscope Figure 1.25. Fish net Objectives At the end of this section, the student will be able to: handling the microscope use the microscope Most microscopes have several different powerful lenses attached to them, allowing the viewer to inspect the content at more than 100 times its actual size. Biology as modern science would not exist without the microscope, and good microscopes are essential for day- to-day activities for most biologists. In addition to their importance, microscopes are extremely expensive, therefore it is very important to know the function of all structures of microscope and handle the device properly before we are using it in the laboratory. When we observe an image under light microscope, light rays are focused on to the image on a microscope slide. This Light which transmitted through the specimen is then focused by two types of lenses known as eye and objective lens. The enlarged produced by these two lenses. A compound light microscope magnification is the product of eye and objective lenses, ×10 eyepiece and ×40 objective, the total magnification is ×400. 10 Grade 9 Biology  Unit One: Introduction to Biology Activity 1.7: Classwork Fill the following table by calculating the exact magnification. Eye lens magnification Objective lens magnification Total lens magnification X5 X500 X10 X40 X100 X1000 Activity 1.8: Practical Activities In this section, you will learn how light microscope magnifies objects by eyepiece and objective microscope. Objective: To study focusing of a light microscope Materials needed for this activity: a microscope, microscope slides, cover slips A. Take a piece of paper and make sure it is transparent B. Write letter C or P on the paper C. Put the paper on the stage of microscope D. Use low power objective move the paper from side to side till you get a clear focus/image E. Draw the letter that you observe. What difference have you seen between the letter on the paper and the image under the microscope? Why? F. Replace/move the low power objective with middle power objective G. What do you see? What makes this difference? 1.5.1. The parts and function of the light microscope Microscopes are generally made up of structural parts for holding and supporting the microscope and its components and the optical parts which are used for magnification and viewing of the specimen images. This section define the parts of a microscope and the functions they perform to enable the visualization of specimens. Eyepiece Eyepiece is the part found at the top of the microscope and is used to look through the microscope. It is also named as the ocular. Its standard magnification is 10x with an optional eyepiece having magnifications from 5X to 30X. Eyepiece tube Eyepiece tube is the eyepiece holder. It carries the eyepiece just above the objective lens. In some microscopes such as the binoculars, the eyepiece tube is flexible and can be rotated for maximum visualization. Grade 9 Biology 11  Unit One: Introduction to Biology Activity 1.9: Group Objective lenses work Objective lenses are major lenses that further magnify the specimen at Look at the picture on the different intensities with multiple objective lenses. Mostly they have a figure 1.26. magnification power of 4X-100X. Write the parts of the microscope parallel to the Arm number and discuss in Arm is a holder connected to all components that function as a support groups about the function of for the microscope so that the microscope can be used properly. each parts. Body tube Body tube connects the eyepiece to the objective lenses. Nose piece Nose piece is rotating mount that holds many objective lenses.. It is movable hence it allows to change the magnification. The Adjustment knobs The Adjustment knobs are knobs that are used to focus the microscope. There are two types of adjustment knobs i.e. fine adjustment knobs and coarse adjustment knobs. Fine adjustment: regulate the distance between object and objective, to achieve the necessary sharpness. The fine focus moves the stage only minimally. Coarse adjustment: Brings specimen into general focus. Coarse adjustment also moves the stage to adjust the difference between the object and the objective. The function of the coarse focus is to Figure 1.26. The parts of the capture the exact distance roughly and quickly. light microscope Stage Stage is the section in which the specimen is placed for viewing. Stage clip Stage clip acts as a holder for the object plate and ensures that it doesn’t fall out of place accidentally. Aperture Aperture is a hole on the microscope stage, through which the transmitted light from the source reaches the stage. Microscopic illuminator Microscopic illuminator is the microscopes light source, located at the base. It is used instead of a mirror. It captures light from an external source of a low voltage of about 100v. Condensers Condensers are lenses that are used to collect and focus light from the illuminator into the specimen. They are found under the stage next to the diaphragm of the microscope. They play a major role in ensuring 12 Grade 9 Biology  Unit One: Introduction to Biology clear sharp images are produced with a high magnification of 400X and above. Diaphragm Diaphragm is also known as the iris. It is found under the stage of the microscope and its primary role is to control the amount of light that reaches the specimen. It’s an adjustable apparatus, hence controlling the light intensity and the size of the beam of light that gets to the specimen. Base Base is the very bottom part. Base serves to accommodate all parts of the light microscope. 1.5.2 Handling and using a light microscope Be very careful when removing the Microscope from the cabinet. Carry the microscope properly, always grip the microscope by the arm and put your hand beneath its base. Hold the microscope upright at all times. Do not bump it against anything. Make sure that the slide is clean and dry before putting it on the stage. Put the slide on the stage, with the most promising region exactly in the middle of the hole in the stage that the light comes through. Always focus on low power (4X objective) first even if eventually you need high power magnification. Focus with the larger coarse-focusing knobs first, then when you have nearly got the image in focus make it really sharp using the smaller fine-focusing knobs. If you want to increase the magnification, move the slide so the most promising region is exactly in the middle of the field of view and then change to a higher magnification lens. Use immersion oil only with the 100X objective (oil immersion lens) in place. Use only one drop of oil. Always focus by moving the lens and the specimen further apart, never closer to each other. Never touch the surfaces of the lenses with your fingers or anything else. Lower the stage and then remove the slide when you are done. Always clean the microscope when you are done. (use a lens paper and the alcohol) Always place the 4X objective over the stage and be sure the stage is at its lowest position before putting the microscope away. Grade 9 Biology 13 Unit One: Introduction to Biology Always turn off the light before putting the microscope away. Always return the microscope to the correct cabinet. Always place the oculars toward the back of the cabinet Always wrap the cord correctly before putting the microscope away. 1.6. General Laboratory Safety Rules Objectives At the end of this section, the student will be able to: explain about laboratory safety rules identify the major laboratory safety rules Safety is the condition of being protected from harm or other danger. Safety can also refer to the control of recognized hazards in order to achieve an acceptable level of risk. Laboratory safety is important before we do any activities in the laboratory: working carefully in the laboratory, dealing with minor problems before they become major problems, keeping safety constantly in mind are some of the safety rules. Activity 1.10 Figure 1.27. Dress and safety for the laboratory Look at the picture on the figure 1.27 and Important general laboratory safety rules are recall what you learned in 1. Following the instructions your grade seven general science subject to answer It is critical to read and listen the laboratory procedure and be familiar the following questions. with all the steps, from start to finish. It is very important to know Discuss in groups. how to use all of the lab equipment before you begin. 1. Why goggles and 2. Knowing the location of safety equipment laboratory coats used? It is mandatory to have a fire extinguisher and first-aid kit readily 2. Why is hair tied back? in the laboratory. It’s important to know the location of the safety 3. List some safety rules equipment and how to use it. It’s a good idea to periodically check 14 Grade 9 Biology  Unit One: Introduction to Biology equipment to make sure it is in working order. Review lab safety signs and look for them before starting an experiment. 3. Dressing for the laboratory It is important to wear protective cloths including a laboratory coat, safety goggles, gloves, hearing protection, long pants, a long-sleeve shirt, and leather shoes or boots that fully cover your feet(NO sandals). Wear a disposable respirator mask when you handle chemicals that are toxic. The dressing procedure should be based on the nature of the experiment. 4. Never eat or drink in the laboratory. Don’t eat or drink in the science laboratory. It is forbidden to store food or beverages in the same refrigerator that contains experiments, chemicals, or cultures. 5. Never taste or sniff chemicals. Avoid tasting or smelling chemicals or biological cultures. Tasting or smelling some chemicals can be dangerous or even deadly. The best way to know what’s in a container is to label it and read before use, so get in the habit of making a label for glassware before adding the chemical. 6. Act responsibly in the laboratory. Never randomly mixing chemicals to see what happens. It may result an explosion, fire, or release of toxic gases. 7. Cleaning the experiment area in the laboratory and storing the waste properly. Every laboratory session should begin and end with your glassware, chemicals, and laboratory equipment clean and stored properly. Figure 1.28. Signs for general laboratory safety rules 8. Handling chemicals properly Wear a disposable respirator mask when handle chemicals that are toxic. Never allow laboratory chemicals to contact your bare skin. 9. Knowing what to do with laboratory accidents If someone burn or if he exposed to chemical immediately flood the burned area with cold tap water for several minutes to minimize the damage done by the burn. 10. All laboratory personnel should place emphasis on safety and chemical hygiene at all times. Never leave containers of chemicals open. All containers must have appropriate labels. Unlabelled chemicals should never be used. Grade 9 Biology 15 Unit One: Introduction to Biology Unit Summary Biology is the scientific study of living things. Living organisms interact with themselves and the environment at all levels of biological organizations. Biological inquiry depends on a scientific method. Scientists follow a method while performing scientific experiments and writing up the results. By following the scientific method carefully, scientists make sure that their conclusions are based on observations and that other scientists can repeat their experiments. The steps for scientific method includes: observations, questions, hypothesis, experiment, conclusion (result) and communication with other Scientists. Biologists use different types of tools in the laboratory and field. Some of the tools are used for measuring, some are used for observation and some are used for culturing micro-organisms. Of all the tools, the most important scientific tools of the biologist is a microscope. A microscope is an instrument that is used to see very small objects by a process called magnification. Laboratory safety is mainly important before we do any activities of the laboratory. Working carefully in the laboratory, dealing with minor problems before they become major problems, keep safety constantly in mind, and chances of any problems you have will be very minor ones. 16 Grade 9 Biology  Unit One: Introduction to Biology Review Questions I. Choose the correct answer for the following questions. 1. Which of the following is not a property of life? a. Populations of organisms rarely change over time. b. Living things exhibit complex but ordered organization. c. Organisms take in energy and use it to perform all of life’s activities. d. Organisms reproduce their own kind. 2. Which of the following is the correct procedure of scientific method? a. Experiment conclusion application Question observation b. Question observation experiment analysis prediction result c. Observation question hypothesis prediction, experiment results conclusion d. Observation question opinion conclusion hypothesis 3. Hypothesis in biology is best described as... a. possible explanation of an observation. b. an observation that supports a theory. c. a general principle that explains some aspect of life. d. an unchanging statement that correctly predicts some aspect of life. 4. Which of the following is not the correct method of handling chemicals? a. wearing a disposable respirator mask when handling chemicals that are toxic b. never allow laboratory chemicals to contact your bare skin c. never put chemicals open d. return and pour the unused (left over) chemicals to its original container II. Write short answer for the following questions 5. Write the main difference between light and Electron microscope. 6. Write the function of the following common laboratory tools. Types of tools Function Flasks Test tubes Wash bottle Dropper Test tube rack Spatula Dissecting Pan Wash bottle Mortar and pestle Grade 9 Biology 17 Unit One: Introduction to Biology 7. Look at the following laboratory safety signs and write their meaning. 8. Why does a microscope have several objective lenses? 9. What will happen to the field of view in a microscope as you close the diaphragm? Explain your answer. 10. Why should you always focus a microscope by moving the objective lens away from the specimen? 11. Explain the importance of adding oil immersion when using high power objective? How? 12. List at least three field tools used by biologists. 18 Grade 9 Biology  Unit 2: Characteristics and Classification of Organisms Content Learning competencies 2.1. Characteristics of living things State the characteristics of living things 2.2. Taxonomy of living things Classify living things based on taxonomic prin- 2.2.1. Principles of classification ciples 2.2.2. Taxonomic hierarchies in biological classification Argue for or against the importance of classifi- 2.3. Relevance of classification cation 2.4. Linnaean system of nomenclature Describe the system of Linnaean nomenclature 2.5. Common Ethiopian animals and plants Classify common Ethiopian animals and plants 2.6. The five-kingdom system of classification based on the taxonomic categories. 2.6.1. Kingdom Monera 2.6.2. Kingdom Protista List the characteristic features of the five king- 2.6.3. Kingdom Fungi doms 2.6.4. Kingdom Plantae Appreciate the works of renowned taxonomists 2.6.5 Kingdom Animalia in Ethiopia 2.7. Renowned taxonomists in Ethiopia 2.1 Characteristics of living things Objectives Activity 2.1: Reflective At the end of this section, the student will be able to: Discussion state the characteristics of living things. If somebody places an object in front of you and asks you whether it is alive, what would you do? Living things have variety of shapes and forms. Thus, biologists study Would you poke it to see if it life in many different ways. Biologists often live with wildlife, collect reacts? fossils, or listen to whales. For example, they count how many times Would you watch it closely a hummingbird’s wings beat per second. What makes something to see if it moves or breathes? “alive”? Anyone could deduce that a galloping horse is alive and a car Would you dissect it to look is not, but why? We cannot say, “If it moves, it’s alive” because a car at its parts? can move, and gelatin can wiggle in a bowl. They certainly are not alive. Although we cannot define life with a single sentence, we can come up with a series of characteristics shared by living systems. Grade 9 Biology 19 Unit Two: Characteristics and Classification of Organisms What are the characteristics of living things? Activity 2.2: Field Observation Some of the properties that are shared by all living things are listed below: Discuss what makes living All living things are made up of one or more cells: Those made up of things different from non- living. Go outside your one cell, such as bacteria are termed ‘unicellular’ and those made up village or your school of more than one cell, such as plants are termed ‘multi-cellular’. compound and sort the things you observe into All living things require energy: All organisms use a source of energy living and non-living. Based for their metabolic activities. For example, every muscle in your body on your observations, write is powered by the energy you obtain from your diet. Some organisms a short report and present to use energy from the sunlight to make their foods through the process your classmates. of photosynthesis. Such organisms, for example plants, are known as producers or autotrophs. Other organisms cannot make their own food but consume others. Such organisms are known as consumers or heterotrophs. All living organisms respond to stimuli: organisms can detect or sense stimuli (change) in the internal or external environment and make appropriate responses. All living things can grow: Growth is a permanent increase in size and mass due to an increase in cell number or cell size or both. Even bacteria and single-celled creatures show an increase in size. Multicellular organisms which increase the number of cells in their bodies become more complicated and change their shape and size. All living things can reproduce: Reproduction is the process that makes more of the same kind of organism. Single-celled organisms may simply keep dividing into two. However, multicellular plants and animals may reproduce sexually or asexually. All living things can excrete: Excretion is the removal of the metabolic wastes produced in cells as a result of chemical reactions (metabolism). For example, respiration and other chemical reactions in the cells produce waste products such as carbon dioxide. Living organisms expel such substances from their bodies in various ways. All living things display ordered complexity: All living things are both complex and highly ordered. The levels of organization in biological systems begin with atoms and molecules and increase in complexity. Your body is composed of many different kinds of cells each containing many complex molecular structures. Many non- living things may also be complex, but they do not exhibit this degree of ordered complexity. Most living things maintain homeostasis: Most organisms maintain relatively constant internal conditions that are different from their environment. Homeostasis is the regulation of an organism’s internal 20 Grade 9 Biology  Unit Two: Characteristics and Classification of Organisms conditions to maintain stability. For example, your body temperature remains stable despite changes in outside temperatures. All living things possess adaptations that evolve overtime: All organisms interact with other organisms and their environment in ways that influence their survival, and as a result, organisms evolve adaptations to their environments (Fig.2.1). Self Assessment 2.1 1. Is it possible to define life in a simple sentence? If your answer is no, why not? Give a short explanation. Figure 2.1. Characteristics of life 2. How are living things different from the non-living things? 2.2 Taxonomy of living things 2.2.1 Principles of classification Activity 2.3: Reflective Discussion Objectives This section explains how At the end of this section, the student will be able to: biologists have organized the study of living things. This classify living things based on taxonomic principles, organization makes it easy to tell which organisms share Why do biologists classify living things? characteristics and which are related to each other. Organizing items not only makes them easier to find but can also 1. How organized are you? make them easier to understand. One tool biologists use to organize 2. Do you organize your and understand living organisms is classification. Classification is the clothes or books in some process of grouping things based on their similarities. The science of way? naming, identifying and classifying organisms is known as taxonomy. 3. Discuss the advantages Scientists who study taxonomy are called taxonomists. Biologists of being organized. classify organisms into different categories mostly by judging the degrees of their apparent similarities and differences. These include the external and internal structures of the organism as well as where Key Terms the organism lives. Taxonomists also consider the genetic makeup of organisms to reveal their evolutionary relationships to other Identification: identifying organisms using organisms. The assumption is that the greater the degree of physical characteristic feature similarity between them, the closer their biological relationship is. Nomenclature: Aspect They try to identify and classify organisms based on a number of of taxonomy that deals features (e.g., morphological, physiological, molecular, behavioural, specifically with the naming and/or ecological characters). of organisms Taxonomy: The science of naming and classifying species. Grade 9 Biology 21 Unit Two: Characteristics and Classification of Organisms 2.2.2. Taxonomic hierarchies in biological classification Activity 2.4: Problem Objectives solving At the end of this section, the student will be able to: Read a book or search in describe taxonomic hierarchies the Internet on biological classification. Why do biologists need to organize living things in hierarchies? Thousands of years ago, the Greek philosopher Aristotle (384-322 BC) developed the first widely accepted biological classification systems. He used simple morphological characters to classify plants into trees, shrubs and herbs. He also divided animals into two groups -those which had red blood and those that did not have. Though it was useful for a while, Aristotle grouped some organisms that had very little in common. For example, he grouped birds, bats, and flying insects because they could fly. Later on in the 1700s, a Swedish Botanist Carolus Linnaeus (1707–1778), who is also known as the father of taxonomy, introduced a taxonomic hierarchy of classification. He was the first person to propose an orderly system for classifying organisms. Taxonomic hierarchy is the process of arranging various organisms into successive levels of the biological classification either in a decreasing or an increasing order. In the Linnaean classification system, all organisms are placed in a ranked hierarchy. The kingdom is ranked the highest followed by Phylum (division), class, order, family, genus, and species (Fig. 2.2). Each rank in a taxonomic hierarchy is termed taxon (plural, taxa). Linnaeus’ developed a two Kingdom system of classification. He classified all living organisms under kingdoms Plantae and Animalia that included all plants and animals, respectively. This system did not distinguish between the eukaryotes and prokaryotes, unicellular and multicellular organisms; and photosynthetic (green algae) and non-photosynthetic (fungi) organisms. At the broadest level, biologists divide the diversity of life into three domains: Bacteria, Archaea, and Eukarya. Domain is the rank above kingdom. Every organism on Earth belongs to one of these three domains. The first two domains, Bacteria and Archaea, identify two very different groups of organisms that have prokaryotic cells, relatively small and simple cells that lack a nucleus or other compartments bounded by internal membranes. Archaea are prokaryotic as their cells have no nucleus and membrane bounded organelles. Their range of size is similar to that of bacteria. Many Archaea inhabit extreme environments. Bacteria are prokaryotic as their cells have no nucleus. They are all small organisms that vary in size between that of the largest virus and the smallest single-celled eukaryote. The major differences 22 Grade 9 Biology  Unit Two: Characteristics and Classification of Organisms of bacteria and archaea includes the chemical composition of the cell wall and cell membrane; the use chlorophyll for photosynthesis by Key Terms bacteria but not by archaea, methane generation, and sensitivity to Bacteria: is the most diverse some antibiotics. Eukaryotes have relatively large and complex cells and well-known group of that contain a nucleus and other membrane-enclosed compartments. single-celled organisms that They are grouped into the domain Eukarya. The domaineukarya lack a nucleus. includes groups such as protists, fungi, plants and animals. Have a great Classes: is a taxon of similar diversity of forms: there are unicellular, colonial and multicellular orders. organisms. Eukaryotic cells: cells with a nucleus and membrane- bound organelles. Attention Family: is a taxon of similar genera. Archaea Bacteria Eukarya Genera: is a taxon of similar species. Cells with no Cells with no nucleus Cells with a nucleus and membrane-bound DNA exists as a circular membrane-bound organelles. Kingdoms: is a taxon of organelles. ‘chromosome’. DNA in the nucleus arranged similar phyla (plural for DNA exists as a circular as linear chromosomes with No membrane-bound histone proteins phylum). ‘chromosome’ organelles are present Ribosomes are similar to Ribosomes are different from Orders: is a taxon of similar Ribosomes are similar both bacteria and archaea bacteria. families. to archaea There are unicellular , Cell wall does not Cell wall contains colonial and multicellular Phylum: is a taxon of contain peptidoglycans peptidoglycans organisms Cells divide by binary Cell division is by mitosis similar classes. (Plant fission Cells divide by binary Are unicellular/ colonial fission, Many different ways of taxonomists use the taxon Are unicellular/ colonial reproducing – asexually and division instead of phylum). sexually. Prokaryotic cells: are unicellular organisms without a separate nucleus. Species: unique type of organism Taxon: is a group of organisms that share a unique set of traits. Self Assessment 2.2 1. What is taxonomic hierarchy? 2. List some of the taxonomic hierarchies that you know. Figure 2.2. Taxonomic hierarchy Grade 9 Biology 23 Unit Two: Characteristics and Classification of Organisms Attention Have you ever asked yourself what a species is? What are the characteristic features of a species? The smallest natural group of organisms is the species. A species can be defined as a group of organisms that can reproduce to produce fertile offspring. Members of a species also often resemble each other very closely in appearance, unless humans have taken a hand in the breeding programs. All cats belong to the same species but there are wide variations in the appearance of different breeds. There are many other definitions of species; for example, phylogenetic species, morphological species, evolutionary species, systematic species, recognition species etc. However, for a biological species, members could reproduce to produce fertile offspring. Members of a species also often resemble each other very closely in appearance. 2.3 Relevance of classification Objectives Activity 2.5: Investigating At the end of this section, the student will be able to: 1. Why and how do describe the relevance of classification human beings classify organisms? 2. Visit a library in your What are the relevancies of biological classification? school or public library The applications of classification are manifold: identification of in your village, and write harmful and beneficial organisms, reduce energy and time to on the importance of biological classification study organisms, and help us understand the relationship between and present your results organisms, etc. Classification gives biologists a framework that allows to your classmates. them to study the relationships between organisms. For example, this framework allows biologists to study the relationship between birds and dinosaurs. Biologists have found that the bones of some dinosaurs have large internal spaces. So do the bones of birds. Because of these findings, some biologists believe that dinosaurs are more closely related to birds than to reptiles. Taxonomy can also be a useful tool for scientists who work in such areas as agriculture, forestry, and medicine. Taxonomy can also help the economy. For example, taxonomists can discover new sources of lumber, foods, medicines, and energy. For example, a taxonomist might know that a certain species of tree contains chemicals that make good disinfectants (e.g., Shiferaw/ Moringa- Moringa stenopetala). It is possible that a closely related plant species could have the same useful substances. So instead of having one source of chemicals, there may be two or more sources. Self Assessment 2.3 1. For which of the following purposes could taxonomy be used? a. to determine whether a plant is safe to be planted in a schoolyard b. to find a new source for medicine that comes from plants c. to determine how closely related two species animals d. all of the above 24 Grade 9 Biology  Unit Two: Characteristics and Classification of Organisms 2.4 Linnaean system of nomenclature Objectives Activity 2.6: Inquiring and researching At the end of this section, the student will be able to: Did you know Carl describe the system of Linnaean nomenclature Linnaeus? explain how organisms are given scientific names. List the major contributions write scientific names properly and give examples. of Carl Linnaeus to the Science of taxonomy. How did Carl Linnaeus classify living organisms? Linnaeus was a Swedish naturalist who initially graduated in medicine but became interested in plants. He travelled in Scandinavia, England and Eastern Europe, discovering and naming new plant species. In 1735 he published his Systema Naturae, in which he accurately described 7700 plant species and classified them. He further grouped species into genera, genera into classes, and classes into orders. He also classified over 4000 animals, but rather less successfully into mammals, birds, insects and worms. Linnaeus refined and popularized the binomial system of naming organisms, in which the first name represents the genus and the second name the specific epithet. This system is still the official starting point for naming or revising the names of organisms. Binomial nomenclature Species must be named in such a way that the name is recognized all over the world. For example, maize is named Bekolo in Amharic, Boqqollo (Badallaa) in Afan Oromo and Baddela in Sidaamu Afoo and corn in American English etc. If you are not aware of these names, it could lead to confusion. If the botanical name, Zea mays, is used, however, there is no chance of error. As you all might know our country is endowed with cultural and linguistic diversities and each would have different names for the same species. As a result, it would be difficult for a person to know the names given by the 80 plus ethnolinguistic groups in Ethiopia. Similarly, there are over thousands of languages in the African continent and beyond. Therefore, the Latin form of the name allows it to be used in all over the world irrespective of language barriers. The similarity in size, shape, behaviour and colour makes it difficult to differentiate one species from the other. Again, the use of the scientific name avoids such confusion. The binomial system of naming species (introduced by Linnaeus) is an internationally agreed system in which the scientific name of an organism is made up of two parts showing the genus and the species. Grade 9 Biology 25 Unit Two: Characteristics and Classification of Organisms Binomial means ‘two names’; the first name gives the genus and the Self Assessment 2.4 second gives the specific epithet. A genus (plural, genera) consists of a group of similar species. The specific epithet sometimes describes 1. What is a binomial a characteristic of the organism. For example, Enset, false banana, nomenclature? Ensete ventricosum and Banana, Musa acuminate, belong to the same 2. Write the scientific family (Musaceae).In writing a scientific name, the first letter of name names of the following of the genus is a capitalized letter and the specific epithet always starts organisms: house fly, with a small letter, for example, the scientific name of human beings is mouse, dog, cat & goat. Homo sapiens. The scientific names are underlined when handwritten or italicized when printed. 2.5 Common Ethiopian animals and plants Objectives At the end of this section, the student will be able to: classify common Ethiopian animals and plants based on the taxonomic categories. write the scientific names of common Ethiopian plant and animals species use dichotomous keys to identify unknown organism Ethiopia is endowed with high biological diversity (biodiversity) due to its geographical location, topographical diversity and diverse climatic features. The country is a hot spot for a diversity of wild plant and animal species with a high degree of endemicity. Furthermore, Ethiopia is a primary centre of diversity for field crops such as noug (Guizotia abyssinica), tef (Eragrostis tef) and the Ethiopian mustard (Brassica carinata). Besides, field crops such as barley, sorghum, durum wheat, finger millet, faba bean, chickpea, lentil, and cowpea have wide diversity in Ethiopia. Also Ethiopia has served as a gateway to domestic animals from Asia to Africa and its diverse ecology favoured diversification of these resources. The scientific and common names of some plants and animals in Ethiopia are presented in table 1. Activity 2.7:Inquiring and Researching Read books and/or search in the Internet for the scientific and the local names common Ethiopian plants and animals species. Present your report to your classmates. 26 Grade 9 Biology  Unit Two: Characteristics and Classification of Organisms Table 1: Scientific names of some common plants and animals in Ethiopia Common Taxon name Kingdom Phylum/ Class Order Family Genus Scientific Division Name Elephant Animalia Chordate Mammalia Proboscidea Elephanti- Loxodonta Loxodonta dae africana Ethiopian Animalia Chordate Mammalia Carivora Canidae Canis Canissimensis Wolf Gelada Animalia Chordate Mammalia Primate Cercopithe- Thero- Theropithecus cidae pithecus gelada Lion Animalia Chordate Mammalia Carivora Felidae Panthera Panthera leo Walia Animalia Chordate Mammalia Artiodactyla Bovida Capra Capra walie Ostrich Animalia Chordate Ave Struthioni- Struthion- Struthio Struthio formes idae camelus Watled Animalia Chordate Ave Pelecani- Threskior- Bostrychia Bostrychia Ibis formes nithidae carunculata Enset Plantae Angio- Monocylo- Zingiberales Mussaseae Ensete Ensete ventri- spermata doneae cosum Maize Plantae Angio- Lilospida Cyperales Poacea Zea Zea mays spermata Noug Plantae Angio- Eudicots Asterales Asteraceae Guizotia Guizotia ab- spermata yssinica Tef Plantae Angio- Lilospida Cyperales Poacea Eragrotes Eragrstos tef spermata Wheat Plantae Angio- Lilospida Cyperales Poacea Triticum Triticum aes- spermata tivum Dichotomous keys Activity 2.8: Inquiring and Researching How do biologists use dichotomous keys? You may have come across Dichotomous keys are used to identify unfamiliar organisms. They organisms that you did not simplify the process of identification. Each key is made up of pairs of recognize and could not contrasting features (dichotomous means two branches), starting with classify. How do you solve quite general characteristics and progressing to more specific ones. this problem? By following the key and making appropriate choices it is possible to identify the organism correctly. Figure 2.3 shows an example of a Self Assessment 2.5 dichotomous key that could be used to place an unknown vertebrate 1. Make a field visit in and unknown invertebrate in the correct class. Item 1 gives you a your village and or your choice between two alternatives. If the animal is poikilothermic school compound and (cold-blooded), you move to item 2 and make a further choice. If it is ask the names of twenty a homoiothermic (warm-blooded), you move to item 4 for your next common Ethiopian choice. The same technique may be used for assigning an organism to animals and plants. Write its class, genus or species. However, the important features may not their scientific names always be easy to see and you have to make use of less fundamental (species names) along characteristics. with their local names. Grade 9 Biology 27 Unit Two: Characteristics and Classification of Organisms Figure 2.3. Vertebrate (left) and invertebrate(right) keys 2.6 The five-kingdom system of classification Objectives At the end of this section, the student will be able to: list the characteristic feature of the five kingdoms, describe the kingdoms of the Monera, Protista and Fungi and give examples of organisms from each one. describe the kingdom Plantae and explain its major taxa, giving examples. discuss features the kingdom Animalia and explain its major taxa, giving examples. group animals into vertebrates and invertebrates and explain the differences between them. Why did we come up with the five kingdoms? Classification of organisms into plants and animals was easily done and understood, but a large number of organisms did not fall into either category. Hence the two kingdom classification used for a long time was found inadequate. Besides, gross morphology a need was Activity 2.9: Cooperative also felt for including other characteristics like cell structure, nature Learning of cell wall, mode of nutrition, habitat, methods of reproduction, What is the largest group evolutionary relationships, etc. of organisms recognized by biologists? How many such Whittaker (1969) proposed a five kingdom classification to solve groups should there be? the pitfalls of the two kingdom system of classification. The main Most biologists used to favor criteria for classification used by him include cell structure, body the adoption of two groups. organization, mode of nutrition, reproduction and phylogenetic What are these two groups? relationships. Whittaker’s five-kingdom scheme consists of animals, plants, fungi, monera and protists(Fig.2.4). It is still not easy to fit all 28 Grade 9 Biology  Unit Two: Characteristics and Classification of Organisms organisms into the five-kingdom scheme. For example, many protista with chlorophyll (the protophyta) show important resemblances to Attention some members of the algae, but the algae are classified into the plant kingdom. Viruses are not included in any kingdom – they are not considered to be living organisms because they lack key characteristics of living things. Viruses are particles that are not alive. They cause diseases and infections. Viruses are made up of nucleic acids, either DNA or RNA, surrounded by a protein coat. They are smaller than the tiniest bacterium. Most biologists agree that viruses are not alive because they don’t grow, develop, or carry out respiration. All viruses replicate, or make copies of themselves. However, viruses need the help of living cells to copy themselves. In order Figure 2. 4. The five kingdoms of life to copy itself, a virus must enter a living cell. The cell in which a virus replicates is Self Assessment 2.6 called the host cell. 1. Do you agree or disagree with the classification of algae as a plant? Explain. 2. Do you suggest an alternative category or group for organisms’ such as algae and the likes? Activity 2.10: Debate Debate on why it is difficult for biologists to develop a rigid classification scheme? Do you think the Whittaker’s five-kingdom scheme has solved the classification problems biologists are trying to answer for generations? Procedure: 1. Divide members of your classmates into three groups. 2. Members of group 1 support the idea that Whittaker’s five-kingdom scheme has solved the classification problems. 3. Members of group 2 are against the idea that Whittaker’s five-kingdom scheme has solved the classification problems. 4. The third group will be the audience. 5. Let members of group 1 and 2 present their position each in five minutes, and 6. Let students from group three ask questions both groups. Grade 9 Biology 29 Unit Two: Characteristics and Classification of Organisms Activity 2.11: Collaborative 2.6.1. Kingdom Monera Learning Objectives What do you think about At the end of this section, the student will be able to: when you hear the word bacteria? You probably think describe the kingdom Monera and give example of organisms about germs or something describe importance of Monera that is bad for you. Did you What are Monera? know that some bacteria are actually helpful? For Monera includes eubacteria and archaebacteria. Eubacteria (true example, some bacteria