Modern Concept Science and Technology 8 New

Modern Concept Science and Technology – 8 47 i. Nucleoplasm Nucleoplasm is a transparent semi-fluid substance containing nucleolus, chromatin network and various enzymes. It is made of water, protein, minerals, nucleic acid and enzymes. It helps in DNA replication, RNA transcription and balance the amount of water. ii. Chromatin network The chromatin network is a long thread like structure that is found in nucleoplasm. It contains hereditary information because it is made of genes, DNA and protein. They become short and thick during cell division and are called chromosomes. There are 23 pairs of chromosomes in a human cell. The split chromosome is called chromatid. iii. Nucleolus Nucleolus is a dense and round structure made of RNA and protein. It helps in the formation of spindle fibre during cell division. It disappears during cell divison and reappears when the new nucleus are formed at the end of cell division. Functions i. Nucleus controls the metabolic activities in the cell. So, it is also called the control centre. ii. Nucleus synthesis proteins. iii. It helps in cell division which is necessary for the growth and development of living body. iv. The DNA present in the nucleus helps to transfer the hereditary information from the parents to the offspring. f. Vacuoles Vacuoles are the membrane bound structure present in the cytoplasm. The fluid inside the vacuole is called cell sap. Cell sap is made up of mostly water with various dissolved substances like sugar, salts and other chemicals. The outer covering of vacuole is called tonoplast. Plant cell has a large central vacuole while an animal cell has many smaller vacuoles. Functions i. Vacuole stores water, sugar, salts and other waste materials of the cell. ii. The space inside the vacuole helps to maintain the turgidity of the cell. Fig 3.8 : Vacoule

48 The Cell g. Plastids Plastids are the disc shaped double layered cell organelles found only in the plant cells, few bacteria and euglena. There are three kinds of plastids. They are chloroplast, chromoplast and leucoplast. Chloroplasts contain chlorophyll. They are the site of photosynthesis. Chromoplasts contain colour pigments. They give colour to the different parts of the plants like fruits and flowers. Leucoplasts do not contain any pigments and are colourless. They are found in roots and other storage organs. Fig 3.9 : Chloroplast Fig 3.10 : Chromoplast Fig 3.11 : Leucoplast Functions i. Chloroplast helps to trap sunlight for photosynthesis. It helps to form fatty acid and amino acid. Chloroplast also stores DNA and genetic characteristics. ii. Chromoplast helps to ripen fruits and provides colour to the flowers. It helps in dispersal of seed. iii. Leucoplast is involved in the synthesis of starch, oils and proteins. FACTS WITH REASONS Chloroplast is called the kitchen of the cell. Chloroplast is called the kitchen of the cell because it prepares the food needed for the plant. h. Endoplasmic reticulum Endoplasmic reticulum is the branching tubules and flattened sacs that extend throughout the cytoplasm. They act as skeleton of the cell and provide mechanical support. They form pathways inside the cell for the transportation of essential chemicals and wastes. There are two types of Endoplasmic Reticulum (ER). They are Rough ER and Smooth ER. Rough ER has ribosomes attached to it and smooth ER does not. Rough ER is the site for protein synthesis. Fig 3.12 : Endoplasmic reticulum

Modern Concept Science and Technology – 8 49 Function i. Endoplasmic reticulum transports molecules to specific destination. ii. Rough ER transports proteins to various parts of the cell. iii. Smooth ER helps in lipid formation. iv. Endoplasmic reticulum also provides mechanical support to the cell. i. Golgi bodies or Golgi apparatus Golgi bodies or Golgi apparatus are the network of flattened layers of membrane-bound sacs. They are located near the nucleus. They were discovered by Camilo Golgi in 1898. Function i. They store, package, and distribute the proteins and lipids made in the endoplasmic reticulum. ii. They also manufacture substances like cellulose and pectin. j. Ribosomes Ribosomes are the small granular structures that float freely in the cytoplasm or are bound to the endoplasmic reticulum. They are the site of protein synthesis. Function Ribosomes synthesis proteins. They are called protein factory. They help in gene expression. k. Lysosomes Lysosomes are membrane-bound sacs that contain digestive enzymes. These enzymes are manufactured in the rough endoplasmic reticulum. If the lysosome breaks open, the enzymes can destroy the cell by digesting the cellular organelles. So, it is also called suicidal bag. Function i) Lysosomes help in intra-cellular digestion. ii) They engulf viruses or bacteria and protect the cell organelles from foreign bodies. iiii) It supplies nutrition during germination of seed. Vacuole Cisternae Secretory vesicle Fig 3.13 : Golgi complex Fig 3.14 : Spherical structures in the diagram are ribosomes MEMORY TIPS Lysosomes are called suicidal bags because if lysosome breaks open, the enzymes can destroy the cell by digesting the cellular organelles with their digestive enzymes.

50 The Cell ACTIVITY 1 To observe onion cells under a compound microscope. Take an onion and remove its outer dry scales. Cut a small section of it or take its fleshy layer out from the onion bulb. Peel a thin transparent layer carefully with forceps which can be seen on the bulb layers. Place it in a watch glass containing water. Transfer the slice of thin layer into the glass slide. Add a drop of saffron for colour and wash it with distilled water. Observe the slide under a compound microscope. Draw the diagram you observe and list some features of the cell including the parts of the cell you can distinguish and their functions. Project Work Demonstrate different types of cell organelles of animal and plant cells using card board or chart paper and coloured pencil. Differences between plant cell and animal cell S.N. Plant cell S.N. Animal cell 1 Plant cell is usually larger than an animal cell. 1 Animal cell is comparatively smaller in size. 2 It has cell wall. 2 It does not have cell wall. 3 Plastids are present in plant cell. 3 Plastids are absent in animal cell. 4 It contains a large central vacuole. 4 It contains many small vacuoles. 5 Nucleus lies on one side in the peripheral cytoplasm. 5 Nucleus lies at the centre. 6 Centrioles are usually absent. 6 Centrioles are present. 7 Reserve food is in the form of starch. 7 Reserve food is in the form of glycogen. 8 Lysosomes are rare. 8 Lysosomes are always present. Unicellular and Multicellular Organisms Unicellular organisms are those microscopic organisms which are composed of a single cell. Examples: amoeba, euglena, paramecium, etc. In these organisms, respiration occurs through general body surface. They have different structures like flagella (euglena), pseudopodia

Modern Concept Science and Technology – 8 51 (amoeba), cilia (paramecium), etc. for their movement. Multicellular organisms are those organisms which are made up of two or more cells. Examples: most plants and animals like cow, man, ant, fly, mosquito, banyan tree, grass, etc. Based on the development of multicellular animals, they have tissues, organs and systems for specific activities to support life processes. FACTS WITH REASONS Euglena is a unicellular organism. Euglena is a unicellular organism because its body is made up of only one cell. Hydra is called a multicellular organism. Hydra is called a multicellular organism because its body is made up of many cells. 3.1.2 Interrelationship between Cell, Tissue and Organ in Human Body Cell Each and every living thing has cells. A unicellular organism consists of only one cell whereas multicellular organisms contain many cells. Cell is the basic structural and functional unit of life. They perform many important functions without which we would not be able to continue living activities. While breathing, the cells exchange the deoxygenated air with oxygenated air. The cells produce enzymes that help in the digestion of food. There are no other smaller components than the cell which perform all those important functions. That is why the cell is the “fundamental unit of life.” Tissue A unicellular organism performs all the living activities such as respiration, digestion, excretion, reproduction, etc. within a single cell. But in case of multicellular organisms, there are separate groups of cells which are responsible for various activities. The body of the multicellular organisms contains several different types of cells, such as blood cells, nerve cells, muscle cells, etc. The group of large number of specialized cells with a common origin, similar structure and function is called tissue. Four major types of tissue in human body are epithelial tissue, connective tissue, muscular tissue and nerve tissue. Organs, for the specific function of the body are formed through the combination of these tissues. Organ Organ is a group of tissues working together for a particular function. An organ is a part of the body which has characteristics function, shape and structure. It is specialized for a particular physiologic function. For example, the stomach contains epithelial tissue, muscular tissue, Cells Muscle tissue cell Nerve cell Epithelial cell Connective cell Tissues Organ Fig 3.15 : Interrelationship between cell, tissue and organ

52 The Cell nerve tissue and connective tissue. Stomach has the specific physiologic function for breaking down of food. Similarly, lung is involved for the exchange of gases, kidneys are involved for the purification of blood, heart is involved for the blood circulation, etc. All the organs work accordingly to keep the whole body functioning well. System Brain Nervous system Excretory system Immune system Respiratory system Muscular system Endocrine system Circulatory system Skeletal system Digestive system Integumentary system Reproductive system Spinal cord Nasal passage Peripheral nerves Lungs Trachea Heart Blood vessels Stomach Hair Skin Joints Nails Bones Cartilage Kidneys Tendons Skeletal muscles Urinary bladder Thymus Lymph nodes Spleen Lymphatic vessels Pituitary gland Thyroid gland Adrenal glands Testes Testes Epididymis Uterus Ovaries Mammary glands Ovaries Pancreas Liver Gall bladder Large intestine Small intestine Fig 3.16 A system is a group of specialized organs working together to achieve a major physiological function. There are eleven systems in human body. All these system combine to form a complete human body. For example, the mouth, oesophagus, stomach, small intestine, large intestine, etc. are the organs of the digestive system. The digestive system is an organ system responsible for breaking down of the foods into nutrients. These nutrients are transported through the bloodstream. Similarly, heart and blood vessels make circulatory system which is responsible for the circulation of the blood. Thus, there is a close relationship among cells, tissues and organs. It can be summarized as:

Modern Concept Science and Technology – 8 53 Cells + Cells Tissue Tissue + Tissue Organ Organ + Organ System System + System Living Body The various systems, major organs and their tissues along with their main functions in human body are summarized in the table below: S.N Systems Major organs Types of tissues Functions 1. Integumentary System Skin, Hair and Nails Stratified epithelium To cover and protect the body 2. Skeletal System Bones and cartilage Connective tissues Production of blood cells, body support, body movement, protection for internal organs, etc. 3. Muscular System Various types of muscles Voluntary and involuntary muscles, connective tissues, cardiac muscles Body movement, facial expression, contraction and relaxation of the heart, etc. 4. Excretory System Kidneys, ureters, urinary bladder, urethra, skin, liver, lungs Pavement and cubical epithelium To excrete waste products from the body 5. Glandular System Different kinds of endocrine and exocrine glands Glandular epithelium To produce different kinds of hormones, enzymes, etc. 6. Nervous System Brain, spinal cord, nerves, sensory structures, etc. Nerve tissue To receive and conduct the sensory functions. 7. Respiratory System Nose, wind pipe, trachea, lungs, bronchi, alveoli, diaphragm, etc. Pavement and cubical epithelium To exchange oxygen and carbon dioxide 8. Circulatory System Heart, blood, arteries, veins, capillaries Pavement epithelium, smooth and cardiac muscle, connective tissue To transport nutrients and oxygen to the cells, transport of wastes away from the cells 9. Digestive System Mouth, stomach, intestine, liver, gall bladder, pancreas Columnar epithelium, involuntary muscle Digestion, absorption and elimination

54 The Cell 10. Reproductive System Ovaries, testes, vagina, penis, etc. Cubical epithelium and columnar epithelium Sexual reproduction 11. Immune and Lymphatic system Lymph, lymph nodes, thymus, spleen, lymphatic vessels Lymphatic tissue To defend the body against infection and cancer, supports circulatory system by returning fluid from tissues to the circulatory system HOT SKILL HIGHER ORDER THINKING SKILL 1. Our body is flesh, bones and blood. But it is said that our body is made of cells. What are cells? How do we know that our body is made up of cells? What is it like? Our body is made of flesh, bone and blood. But it is said that it is made of cells. The statement is really true. We know that our body is made of cells because many scientists and doctors have observed flesh, bones and blood through the microscope and discovered cells. We ourselves can observe blood cells, skin and cheek cells through the microscope. The cells are like tiny building blocks. They are usually oval. Red blood cells are biconcave and do not have nucleus. Most cells have dense and dark nucleus at the core. All of the cell organelles are found floating in the cytoplasm which is bound by cell membrane. There are numerous tiny vacuoles. Mitochondria is bean shaped cell organelle. Centrosome are found closer to the nucleus. Endoplasmic reticulum runs through out the cell and transports protein. 2. Are every cells in our body alike? Do we and plants have same type of cells? How is our cell different from the plants? Explain. No, every cells of our body are not same because their shape, size, structure and colour differs based on their location and function. No, we do not have cells similar to the plants. There are some fundamental differences between our cells and the plant cells. Our cells are different from cells in the following ways: i. Our cells have numerous tiny vacuoles but plant cells possess one or two large vacuoles. ii. Our cells do not have cell wall but plant cells have cell walls. iii. Our cells are removed from the body when they die but plant cells are stored in the body for ever. iv. Nucleus of human cells are centrally located but nucleus of plant cells are located to the edge of the cell. v. Our cells cannot synthesize food but plant cells can do photosynthesis due to presence of chloroplast. 3. Nucleus is called control centre of the cell? What does it do to earn the title? Nucleus is called control centre of the cell because it controls every metabollic activities of the cells, duplication of DNA and activation of various genes to produce proteins.

Modern Concept Science and Technology – 8 55 4. How do nutrients change into energy in mitochondria? When the food is digested, nutrients mix into the blood stream and reach the cell. Similarly oxygen reach the cell from lungs. Mitochondria collects nutrients and oxygen. These fuel oxidizes in the cristae to release usable energy in the form of adenosine triphosphate. 5. Plants are colourful. Various parts have various colours. What might be the reason? Discuss. Plants are colourful. Their leaves, stems, flowers and fruits are colourful. The cell organelles called plastids are responsible for the colourful parts of the plants. There are three types of plastids. The leucoplast is colourless or white. The chloroplast gives green colour to the leaf and other parts. The chromoplast however contains pigments of many different colours. They are usually found in fruits and flowers. 6. What is the relation among cell, tissue, organ and system? Cell is the basic unit of life. A group of similar cells working together for a particular function is called tissue. A group of tissues specialized for a particular function is called organ. Different organs performing a related function make a system. One system has one specific function. The group of systems such as respiratory system, digestive system, reproductive system, skeletal system, muscular system, nervous system, etc. work together make a living body. In this way, cell, tissue, organ and system are related. 7. How do multiple systems keeps us alive? Write in brief. System is a combination of multiple organs that has particular functions. For example, respiratory system helps in breathing. Similarly there are multiple systems in our body that keeps us alive. Some of them are skeletal system which makes our body frame and produces blood. Muscular systems helps in body movement. Digestive system helps in digestion of food. Excretory system removes waste from the body. Circulatory system transports nutrients, water, oxygen and hormones to various parts of the body. Nervous system helps to know the surrounding, process information and make decisions. The function of one system is linked with the other system. Complete coordination between multiple system keeps us alive. 3 4 STEPS STEPS EXERCISE EXERCISE STEP1 1. Select the best answer from the given alternatives. a) What makes the cell wall of a plant? i. chitin ii. cellulose iii. peptidoglycan iv. protein b) Which cell organelle is capable of digesting even the cell organelles? i. ribosome ii. lysosome iii. DNA iv. nucleus c) Which one of the given cell organelles is a non-living? i. mitochondria ii. cell wall

56 The Cell iii. nucleus iv. plastids d) Why is vacuole necessary for a cell? i. for photosynthesis ii. store waste iii. protein synthesis iv. DNA replication e) Why is lysosome called sucidal bags? i. it can synthesize protein ii. it's chemical can digest waste iii. it's chemical can digest other cell organelles iv. it controls every activities of the cell 2. Write True for the correct and False for the incorrect statements. a) A single cell contains all the vital structures and substances for its independent function. b) The main material of the cell wall is wax. c) Lysosomes are called suicidal bags of the cell. d) Vacuoles synthesize proteins. e) Nucleus is the power house of the cell. 3. Fill in the blanks with appropriate words. a) Bacteria and archaea are made of ............ cells. b) Energy is produced by ............ in the cell. c) The control centre of the cell is ............ d) Colour is given to different parts of the plants by ............ e) Cell membrane is made of ............ and proteins. 4. Answer the following questions in one word. a) Which material makes the cell wall? b) Which cell organelle produces energy for the cell? c) Which cell organelle controls the cell? d) Which plastid is colourless? e) Which plastid helps in photosynthesis? f) What is the outermost layer of plant cell called? g) Name the site for the production of energy in the cell. STEP2 5. Give reasons. a) Cell is the structural and functional unit of life. b) Bacteria are called prokaryotes. c) Euglena is a unicellular organism. d) Hydra is called a multicellular organism. e) Lysosome is called suicidal bag. f) Mitochondria are the powerhouse of the cell.

Modern Concept Science and Technology – 8 57 g) Chloroplast is the kitchen of a plant cell. 6. Differentiate between: a) Cell wall and cell membrane b) Unicellular organisms and multicellular organisms c) Eukaryotic cell and prokaryotic cell 7. Answer the following in short. a) What is a cell? b) What is nucleus? Write its function. c) Define mitochondria. In what form mitochondria produces energy? d) What are unicellular and multicellular organisms? Give any two examples of each. e) What is a tissue? f) Define organs. Give few examples. g) What is system? Give few examples. STEP3 8. Answer the following questions. a) Mention the major functions of the following: i) Cell wall ii) Cell membrane iii) Mitochondria iv) Plastid v) Nucleus vi) Cytoplasm b) Identify the cell organelles and write their major functions. i. ii. iii. iv. c) Draw the well labelled diagram of plant cell and animal cell. d) Study the given diagram and answer the following questions. i. What is shown in the diagram? ii. Write the name of A and B. iii. What is the function of C. iv. Which one of them is called power house of the cell? Why? e) Compare the plant cell with animal cell. f) Describe the interrelationship among cells, organs and tissues. A C B

58 Classification of Living Beings Key terms and terminologies of the unit Classification of organisms : Classification is the act of grouping of organisms on the basis of their similarities and dissimilarities. Taxonomy : Taxonomy is the branch of biology which deals with identification, classification and nomenclature of organisms. Taxon : A taxon is a generally accepted category under which the organisms having similar characteristics are grouped. e.g. kingdom, phylum etc. Genus : Genus represents the group of those organisms that have similar physiology, anatomy and feeding habit. Species : Species represents the organisms that are completely similar to each other and can interbreed to produce a fertile offspring. Epithet : Epithet is the second word of the scientific name of the organism, i.e., species. Microscopic organisms : The organisms that are too small to be seen through unaided eyes (naked eyes) are called microscopic organisms. Two kingdom system : The system of classification of living organisms into two kingdoms of plants and animals is called two kingdom system of classification. Five kingdom system : The system of classification of living organisms into five kingdoms of monera, protista, fungi, plantae and animalia is called five kingdom system. Sequence of Curriculum Issued by CDC  Introduction to two kingdom system of classification and five kingdom system of classification  Introduction to microorganisms  Positive effects of microbes such as decomposition of organic materials, uses of yeast, curd formation, production of antibiotics, antibodies and antivirals.  Negative effects of microbes such as food spoilage, wound infection and infectious diseases  Methods to prevent diseases and infection caused by germs  Methods to prevent food spoilage. UNIT Classification of Living Beings 3.2 Estimated teaching periods Theory Practical 5 1 Robert Harding Whittaker is an American Plant ecologist known for introducing five kingdoms taxonomic classification. He was born on 27th December 1920 and died on 20th October 1980. His work five kingdom system of classification was better to explain the evolutionary relations among the organisms than the two kingdom systems of classifications. He has contributed to the classification of Biome. He obtained his B.A. from Washburn Municipal University and PhD in biology at the University of Illinois. About the Scientist Robert Harding Whittaker

Modern Concept Science and Technology – 8 59 Monera : The group of unicellular and prokaryotic organisms is called Monera kingdom. Protista : The group of unicellular and eukaryotic organisms is called Protista kingdom. Fungi : The group of multicellular, eukaryotic and saprophytic organisms is called fungi kingdom. Plantae : The group of green, eukaryotic and autotrophic organisms is called plantae kingdom. Animalia : The group of non-green, eukaryotic and heterotrophic organisms is called animalia kingdom. Bacteria : Bacteria are the smallest, single-cellular, prokaryotic organisms. Virus : Viruses are the smallest microscopic, acellular, non-protoplasmic bodies that are considered to be the connecting link between living and non-living things. Introduction Millions of plants and animals are found on the earth. The research shows that there are about 5,500 mammals, 10,000 reptiles, 40,000 fishes, 15,000 amphibians, 10,000 birds and 6,755,830 invertebrates in the world. If we examine the names and characteristics of all these species, the variation is so huge that it becomes impossible to study each of them. There is also difficulty of language for the study of these organisms around the world. This problem is solved by grouping the plants and animals on the basis of their similarities and differences into certain types. This process is called classification of living beings. Classification of organisms is the act of grouping organisms on the basis of their similarities and dissimilarities. It was first done by Swedish biologist Carolus von Linneaus in the 1750s. Carolus introduced a system known as the Binomial system of Nomenclature in which the plants and animals were given a unique name called the scientific name. The scientific name consists of two Latin words: the first word is called the genus or the generic name and the second one is called the species or specific name or epithet. Today, all known organisms in the world have a universal scientific name that every biologist understands irrespective of his language and country. The system Carolus started is well developed into a branch of biology known as the Taxonomy. Carolus von Linnaeus is known as the father of taxonomy. FACTS WITH REASONS Carolus von Linnaeus is known as the father of taxonomy. Carolus von Linnaeus started the systematization in the classification process through Binomial system for the first time. So, Carolus von Linnaeus is known as the father of taxonomy. Hierarchy in Classification Commonly, there are two kinds of organisms: plants and animals. These plants and animals have further types and sub-types. Look at the simple classification of a bird parrot: Hen falls under the 5th common level of animals’ type. The types in which parrot is classified forms a hierarchy. In this example, there are five groups forming a hierarchy. Each group level of hierarchy is known as a taxon. A taxon is a generally accepted category under which the organisms having similar characteristics are grouped. There are various taxa (pl. of taxon)

60 Classification of Living Beings which form a hierarchy of classification. The classification hierarchy is shown below: Kingdom Phylum Sub-phylum Class Type Animalia Chordata Vertebrata Aves Hen Importance of Classification When a new species of an organism is discovered, its characteristics are studied and the kind of organism is identified. Identification is the process of distinguishing the type of organism on the basis of its characteristics. Then, the discovered organism is classified under a proper taxon. After that, the organism is given a binomial name which completes the process of the systematic classification. The advantages of classification of organisms are as follows: i) It helps us to learn about the characteristics of large number of plants and animals in a group. ii) It is systematic and scientific. Hence, it is an easy and understandable method of studying the characteristics of organisms. iii) It projects a basic idea about the inter-relationship between similar and dissimilar species. iv) Classification helps to study trend of diseases, evolution, growth and decline in the population of creatures. FACTS WITH REASONS Classification of organisms is necessary. Classification of organisms is necessary to identify, group, and properly name the organisms with the help of a standardized system based on similarities found in the organisms. Common name and Scientific name An organism can have several names depending on the country or its native region. These multiple names are not universal, and they make communication in biology difficult. These names are called common names. To avoid the confusion of common names, every organism under the Binomial System is given a scientific name. Every single organism on this earth has a scientific name that every biologist understands. Some of the plants and animals and their scientific names are given in the table alongside. The genus or generic name The genus is the first word of the scientific name. Genus represents the group of those organisms that have similar Kingdom Phylum or Division Sub-phylum or Sub-division Class Order Family Genus Species MEMORY TIPS Phylum and sub-phylum: for animals Division and sub-division: for plants Common name Scientific name Human Homo sapiens Tiger Panthera tigris Lion Panthera leo Cat Felis catus Pea Pisum sativum Rice Oryza sativa Apple Malus domestica Potato Solanum tubersum Maize Zea mays MEMORY TIPS The scientific name consists of two Latin or Greek words. The first word is called the genus or the generic name and the second one is called the species or specific name or epithet.

Modern Concept Science and Technology – 8 61 physiology, anatomy and feeding habit. For example, tiger and lion belong to the similar genus called Panthera. The organisms of the same genus but different species generally do not interbreed with each other. The species or specific name or epithet The species forms the second word of the scientific name. Species represents the organisms that are completely similar to each other and can interbreed to produce a fertile offspring. For example, a male cat and a female cat belong to the same species. They can interbreed with each other to produce the same species type. 3.2.1 Introduction of Two Kingdom System and Five Kingdom System of Classification The Two Kingdom System The two kingdom system of classification was introduced by Sir Carlous Von Linnaeus in 1758. He broadly divided living organism into two groups. They are plants and animals. Plant kingdom was named Regnum Vegetable and animal kingdom was named Regnum Animale. The kingdoms were further divided into sub-kingdoms, divisions, phyla and classes. Two kingdom system was first scientific system of classification and it made study of organisms easier. However it is discarded now because it could not classify microorganisms, prokarytoic organisms and fungi. Features of two-kingdom system of classification i. It is divided into two kingdoms. They are plant kingdom and animal kingdom. ii. It is simple, clear and easy to understand. iii. It is first scientific classification of organisms. Demerits of two-kingdom system of classification i. Autotrophs and heterotrophs are kept together. ii. Multicellular and unicellular are kept together. iii. Plants and fungi are kept together. iv. Prokaryotes and eukaryotes are kept together. v. It does not includes lichens. FACTS WITH REASONS The two kingdom classification system is inadequate. On the basis of two kingdom classification system, grouping of diverse organisms into only two kingdoms is not satisfactory. This system puts together Eukaryotes and Prokaryotes. It also groups together nonphotosynthetic fungi with photosynthetic green plants. The Five Kingdom System The two kingdom system (Plantae and Animalia) could not distinguish between prokaryotes/ eukaryotes, autotrophs/heterotrophs and unicellular/multicellular. There were many MEMORY TIPS In some organisms, interbreeding between different species of same genus is also possible. Example: i. Male tiger + female lion = tigon ii. Male lion + female tiger = liger iii. Female horse + male donkey = mule iv. Male horse + female donkey = hinny These animals are called hybrids. They have selected qualities of their parents.

62 Classification of Living Beings organisms that did not fit in the two kingdom system satisfactorily. Therefore, American Biologist Robert H. Whittaker proposed the five kingdom system, adding three more kingdoms: Monera, Protista and Fungi, in addition to the earlier two kingdoms: plantae and Animalia. The five kingdom system is explained in brief below: 5 Kingdom System Monera Unicellular prokaryotes Plantae Multicellular autotrophic eukaryotes Animalia Multicellular heterotrophic eukaryotics Fungi Non-green uni/ multicellular eukaryotes Protista Unicellular eukaryotes Bases for five kingdom system of classification Organisms are grouped into five kingdoms in the five-kingdom classification system. This grouping is based on the following aspects: i. The complexity of cell Structure (Prokaryote or Eukaryote) ii. The complexity of the organism’s Body (Unicellular or Multicellular and Complex). iii. Mode of their Nutrition (autotrophs and heterotrophs). Features of five-kingdom system of classification i. Prokaryotes and eukaryotes are separated. ii. Unicellular and multicellular organisms are separated. iii. Green plants and non-green plants like algae and fungi are kept in separate groups. iv. This system of classification is related to evolution of organisms. So, it helps to get clear concept of lifestyle of living beings. 1. Monera This kingdom includes all types of bacteria (e.g. cyanobacteria or blue-green algae, coccus, bacillus, etc.). They are single-celled microscopic prokaryotes having no nuclear membranes. They are both autotrophic and heterotrophic. Fig 3.17 : Bacteria Fig 3.18 : Coccus Fig 3.19 : Blue-green algae MEMORY TIPS Kingdom monera consists of onecelled organisms, both autotrophs and heterotrophs that are extremely simple in structure.

Modern Concept Science and Technology – 8 63 2. Protista This kingdom includes single-celled microscopic eukaryotes. i.e. they contain a well-defined nucleus with membrane bound cellular structures. They have a nuclear membrane and are both autotrophic and heterotrophic. For example, amoeba, paramecium, euglena, dinoflagellates, etc. Their locomotory organs are primitive. 3. Fungi Fungi is the kingdom of non-green eukaryotes. They may be single or multi-celled. They cannot prepare food by themselves and are heterotrophic. Hence, they have to depend upon dead and decayed matter for food. Most of the fungi are filamentous and thread-like in structure. Mushroom Yeast Mucor Fig 3.23 :Fungi 4. Plantae These are well-developed multicellular organisms. They have a eukaryotic cell and can prepare food by themselves (autotrophic). Plants lying in this kingdom are both higher and lower type. The herbs, shrubs and trees are parts of this kingdom. 5. Animalia The organisms lying in this kingdom are multicellular, eukaryotic and heterotrophic. They have different forms of habitats. Most of them have well developed tissue, organ and body systems. They swallow their food as a whole and have a digesting column in the body (holozoic in nature). Their cells do not have a cell wall. Fig 3.20 : (a)Amoeba (b) Paramecium (c) Euglena MEMORY TIPS Fungi are useful in our daily life too. The fungus called yeast is used to prepare beer and bread. Similarly, antibiotics are extracted from a fungus called penicillium. Mushroom is a fungus which has several medicinal values. But, some fungus are parasitic too e.g. puccinia, yarshagumba etc. Mango Moss Fern Fig 3.24 : Plants

64 Classification of Living Beings Dolphin Frog Starfish Fig 3.25 : Animalia FACTS WITH REASONS The five kingdom classification system is most accepted. In five kingdom classification system, grouping of diverse organisms is done into five kingdoms. This system groups organisms on the basis of complexity of Cell Structure (Prokaryote or Eukaryote), Complexity of the Organism’s Body (Unicellular or Multicellular and Complex) and Mode of their Nutrition (Photosynthesis, Absorption or Ingestion). So, five kingdom classification is the most accepted system of classification. 3.4 Some Microorganisms A large variety of organisms are present on the earth surface. Among them some are very small and some are very big. To make our study easy, all these organisms are broadly classified into two groups. They are microorganisms and macro-organisms. Those organisms which cannot be seen by our naked eyes are called microorganisms. Microscope is used to observe these microorganisms. So, microorganisms are also called microscopic organisms. The body of microorganism may be unicellular or multicellular. The group of microorganisms is very diverse. It includes all virus, bacteria and some algae and fungi. Bacteria Bacteria are the smallest, single-cellular, prokaryotic organisms.They were the first life forms to appear on the earth. Bacteria are universal organisms. Therefore, they can be found in wide range of habitats including air, water, soil, body of animals and plants, food, oceans, hot springs, etc. They were first discovered by Antonie Van Leeuwenhoek in 1676 AD and the term bacteria was coined by Christian Gottfried Ehrenberg in 1828 AD. Characteristics of bacteria i) Bacteria have prokaryotic cell. ii) They do not have membrane bound nucleus and other cell organelles. iii) They have a rigid cell wall outside the cell membrane. iv) They occur alone or make a colony. v) Except bacilli and spirilla, most of the bacteria are immotile, i.e. cannot move. vi) They reproduce asexually by means of fission. Bacteria Virus Protozoa Fungi Fig 3.26 : Microorganisms Fig 3.27 : Bacteria MEMORY TIPS 1. Earwax has antimicrobial properties. It reduces the growth of bacteria and fungi in the human ear. 2. Honey is a natural reservoir for the Botulism bacteria. Adults can normally digest it and infants cannot. This is why we should not give honey to the babies.

Modern Concept Science and Technology – 8 65 vii) They are found everywhere in air, water, soil, food, inside the living beings, etc. viii) They show autotrophic as well as heterotrophic nutrition. Economic importance of bacteria Bacteria have both harmful as well as useful effects. Some of the harmful and useful effects of bacteria are mentioned below: a) Useful effects of bacteria i) Bacteria are used to produce antibiotics which are used to cure or prevent diseases. ii) They are used as a source of enzymes in laboratories and industrial processes. iii) They are widely used in biotechnology like production of foods, genetically modified animals, etc. iv) They help in digestion of food in humans and other animals. v) They degrade and decompose the dead bodies of animals and plants and recycle the nutrients back in the environment. vi) The nitrifying bacteria maintain the concentration of nitrogen in the soil. So, they help in production of crops. vii) Bacteria are used for manufacturing alcohols, leathers, cheese, etc. viii) Bacteria are used in manufacture of jute fibres because bacteria can decompose flesh of jute and hemp, leaving the fibre behind. ix) Bacteria are used to treat dirty water because they can decompose organic waste. x) Bacteria decompose organic waste into compost manure. xi) Bacteria are used to treat dirty water because they can decompose organic waste. xii) Lactobacillus is a genus of bacteria which can degrade sugars into lactic acid through fermentation. As a result, milk will change into curd. It is also used to make cheese. b) Harmful effects of bacteria i) Pathogenic bacteria cause different kinds of diseases to human beings, animals and plants. ii) Some bacteria produce toxins which are fatal to human beings, animals and plants. iii) Some bacteria spoil foods and food products like cooked food, fish, meat, dairy products, etc. iv) Denitrifying bacteria decrease the productivity of land by decreasing the nitrogen content in the soil. v) Bacteria produce bad smell as a result of decomposition. Virus The word virus has been derived from the Greek word venom which means poison or poisonous fluid. Viruses are the smallest microscopic, acellular, non-protoplasmic bodies that are considered to be the connecting link between living and non-living things. Virus is a small infectious agent that shows living characteristics only inside the living cell. So, it is also known as obligatory parasite. MEMORY TIPS The first discovered virus was Tobacco Mosaic Virus (TMV). It was discovered by a Russian Microbiologist, Dmitry Ivanovsky in 1892 AD. Fig 3.28 : Structure of bacteriophage virus Capsid Head DNA Tail Tail fibres

66 Classification of Living Beings It was first discovered by Dmitri Ivanovsky in 1892 AD. Virus is too small to observe under the light microscope. So, we need an electron microscope to observe them. The size of virus ranges from 25 nanometers to 250 nanometers. FACTS WITH REASONS Viruses are called obligatory parasites. Viruses show living characteristics and multiply inside the living host only. Outside of a living cell, viruses show non-living characteristics. So, viruses are called obligatory parasites. Viruses are called the connecting link between living and non-living things. Inside the body of the living host cell, virus behave like a living parasite. They are inactive and like a dust particle outside the living cell. Therefore, they are kept on the boundary of living and non-living things. Due to this reason virus are called connecting links between living and non-living things. Occurrence of viruses Viruses are present in different habitats like food, water, air, soil and even in rocks. They can infect all types of life forms, from animals and plants to microorganisms, including bacteria. In humans, viruses cause different diseases like rabies, HIV/AIDS, polio (or poliomyelitis), measles, common cold, etc. Viruses enter into the human body through air, water, food, soil, wounds, pores, openings, etc. Living properties of virus i) Viruses contain genetic materials like DNA or RNA. ii) They are capable of rapid multiplication (reproduction) in a host cell. iii) They are capable of transferring geneic materials from parent cells to their offspring. iv) They eat and digest living cells of bacteria, infect them and cause diseases to plants and animals. Non-living properties of virus i) Viruses do not have definite cellular structures. ii) They remain inert and inactive outside the living cell. iii) They do not perform metabolic activities. iv) They can be crystallized in laboratory like crystalline solids. Differences between bacteria and viruses. SN Bacteria SN Viruses 1 Bacteria are very small microorganisms which can be seen under a compound microscope. 1 Viruses are smaller than bacteria. They can be seen only under the electron microscope. 2 Bacteria are living organisms. 2 Viruses are the borderline between living and non-living organisms. 3 They show metabolic activities. 3 They do not show metabolic activities. 4 Bacterial cell has cell organelles. 4 Viruses do not have cell organelles.

Modern Concept Science and Technology – 8 67 ACTIVITY 1 Take two chart papers and draw the well labelled diagrams of bacteriophage and bacteria separately in each chart paper. Compare the characteristics between them and discuss with your friends in the classroom. The positive effect of virus i. Genes or certain parts of virus are used to make vaccines and antidotes. ii. The protein of virus can be used to produce antigens and antibodies. It is used to treat diseases. iii. Bacteriophages can kill e-coli bacteria and protect us from dysentery and other diseases. iv. Bacteriophages are used to sterilize water because they can kill bacteria. v. Viruses are used to treat genetic disorders by using gene therapy. vi. Some viruses can be used as an anti-cancer agent. Negative effects of virus i. Viruses are responsible for common cold, viral influenza, polio, AIDS and many other diseases. ii. Coronavirus pandemic forced the entire earth to go on lockdown. iii. Plant viruses such as potato mosaic viruses can destroy crops. iv. Animal viruses such as bird flu can kill chickens, ducks and sometimes humans. v. A virus can attack our nervous system causing serious illness. vii. Viral infections spread so fast that it causes a pandemic. Fungi Fungi are unicellular or multicellular eukaryotic organisms without chlorophyll. The cell wall of fungi is composed of chitin. The fungal cells are multinucleated. They are found mainly in soil or on the plant material rather than in freshwater and sea water. Most fungi grow in an acidic medium with a pH value of about 5. They grow at about 25°C temperature, except for pathogens, which grow at 37°C. Yeast is a unicellular fungus while mucor, rhizopus, mushroom, etc. are multicellular fungi. The main body of the most fungi is made up of fine, branching and usually colourless threads called hyphae. Each multicellular fungus has vast numbers of hyphae. All these hyphae interlock to make a twisted web called mycelium. Fig 3.29 : Mushroom Fig 3.30 :Yeast Fig 3.31 :Bread mold

68 Classification of Living Beings Since fungi lack photosynthetic pigments, they depend upon other organisms to derive their nutrition. Therefore, they are called heterotrophs. Most of the fungi are saprophytes which derive nutrition from dead organic matter. Saprophytes are also called decomposers as they decompose complex dead organic materials into simpler forms and cycle nutrients in nature. Few fungi are parasites which absorb food from the host body. Parasites cause various diseases in animals and plants. Mildews, rusts, scabs or canker, etc. are most common fungal diseases in plants. Skin diseases, hair disease, ear disease, eye diseases, etc. are most common fungal diseases in animals. Few fungi are also symbiotic. They live in association with other organism without hampering them. Lichen is an example of mutual association of algae and fungi. Fungi reproduce through both sexual and asexual reproductions. Asexual reproduction involves fragmentation, budding, sporulation and fission. Similarly, sexual reproduction occurs by the union of opposite cells within a single or different mycelium. Characteristics of fungi i) Fungi are eukaryotic organisms without chlorophyll. ii) They may be unicellular or multicellular. iii) The body of fungi is thallus. It means that they are not differentiated into root, shoot and leaves. iv) The cell wall of fungi is made up of fungal cellulose. v) The fungal body is made up of hyphae. vi) They mostly reproduce by asexual reproduction involving fragmentation, budding, sporulation and fission. Economic importance of fungi a) Useful effects of fungi i) Fungi are very useful in different industries like, bakeries, wine industries, making cheese, commercial production of citric acid, etc. ii) Antibiotics like Penicillin can be extracted from penicillium. iii) Fungi contain a number of alkaloids which are utilized in medicine and useful in controlling haemorrhage during child birth. iv) Fungi like mushrooms, morels, truffles, etc. are used as food. v) Fungi decompose the dead bodies of the organisms and help in recycling the nutrients. vi) Yeasts are used in the fermentation of fruits, grains and cereals to produce beer and wine. vii) Fungi such as mushroom helps to supply minerals and vitamins. They also supply medicinal chemicals that help to improve our immunity system. viii) Shiitake mushroom is used to make antivirals which are used to treat viral infections. ix) Some fungi occasionally work with bacteria to change milk into curd. MEMORY TIPS 1. In order to prevent food from all types of fungal decay, it should be in temperature lower than -18°C, as they remain active even at 0°C. 2. Yeast is a unicellular fungus which is mostly used in fermentation.

Modern Concept Science and Technology – 8 69 b) Harmful effects of fungi i) Fungi cause various diseases in animals and plants. Examples: Late blight of potato, black stem rust of wheat, brown spot of rice, mycosis, skin disease, vaginal yeast infection, hair disease, etc. ii) They spoil food, fruits, vegetables, etc. iii) Fungi are responsible for decaying wooden furniture, textiles and paper. iv) It can also damage woollen clothes and cotton clothes. v) Moulds such as aspergillus can destroy tons of stored food such as pickles, bread and dairy products. vi) Fungi cause diseases in crops, livestock and humans. vii) Amanita species of mushrooms are poisonous that can kill us. viii) Parasitic fungi such as Puccinia and Taphrina can kill plants. Amoeba Amoeba is a species of protista kingdom. It is unicellular, eukaryotic and aquatic organism. It is found in water, moist soil, food and as a parasite too. Entamoeba histolytica is a parasitic amoeba which causes amoebic dysentries (amoebiasis) in humans. Nagaleria fowleri is a free living amoeba but can cause diseases to humans if enters our body. Amoeba is irregular in shape. It locomotes by the help of pseudopodia. Pseudopodia also helps to trap food. Food is digested at food vacuole and waste is removed by contractile vaculoe. How to be safe from diseases and infection caused by germs? Germs cause too many infections and diseases that it kills millions of people each year. We should always try to be safe from germs. Some methods to be safe from the diseases and infections from germs are: i. We should keep the surrounding clean. ii. We should not consume stale food, spoilt food or any food from floor. iii. We should get vaccinated in time. iv. We should use antiseptic in wounds. v. Antibiotics, antibodies and antivirals also keeps us safe from diseases by killing germs. vi. We should avoid getting contaminated. For example wear mask to avoid corona. Methods of food preservation Food is very important for us all. Millions of tons of food are spoiled each day. According to Food and Agriculture Organization, 25,000 people die each day due to starvation and Fig 3.32: amoeba

70 Classification of Living Beings malnutrition-related diseases. So, it is our primary concern to use food wisely. We should never waste food. Tons of food are spoilt due to germs, bacteria, yeast, fungi, mould, light, temperature, moisture, etc. We can practice multiple methods to prevent food spoilage. Some common ways to prevent food spoilage are dehydration, freezing, salting, sweetening, boiling, canning and using vinegar, glycerol or oil. A. Dry preservation (dehydration) Dehydration is the act of removing water from the food. It is usually done by spreading food in the sunlight. A solar food dryer can be used to trap solar heat and make a food dry. Otherwise, food such as grains, seeds, mustards etc are dried in the sunlight. Vegetables such as radish, carrot, squash etc are sliced and dried in the sunlight to remove moisture. The green leafy vegetables such as spinach, lettuce etc also can be dried. Sometimes fish and meat are also dried and stored. The drying removes moisture from the food. Bacteria and fungi cannot multiply in dry food. So, they cannot spoil food. FACTS WITH REASONS Grains are dried in sunshine before storing. Grains are dried in sunshine before storing to remove moisture so that bacteria and fungi won’t damage it. ACTIVITY 2 When its time to harvest rice or other food from fields, collect some. Store some without drying and some after drying. See the difference after a week. B. Cold preservation(freezing) Freezing is a very popular method to prevent food spoilage. People usually use a refrigerator in their kitchen to preserve food. It is widely used in restaurants, shops, groceries etc. to prevent food spoilage. The freezing process can greatly prevent food spoilage because the bacteria do not reproduce well in cold temperatures. So, the food in the fridge remains almost unspoiled. C. Wet preservation Using oil, vinegar or glycerine The oil, vinegar and glycerol can control microbial activity. The oil prevents moisture. Vinegar has low pH which kills germs. Glycerine is sweet, viscous liquid with an antimicrobial property. So, oil, vinegar and glycerine can prevent food spoilage. MEMORY TIPS Dehydration of food is the act of removing water or moisture from the food. It decreases microbial activities. MEMORY TIPS Vinegar is acid. It has low pH. Bacteria do not grow well in it. So, it can be used to preserve food.

Modern Concept Science and Technology – 8 71 FACTS WITH REASONS Oil is used as preservative. Oil is used as preservative because it does not allow food to absorb moisture. So, it slows down the microbial activity. ACTIVITY 3 Get some radish and make pickles. One or many of the above-mentioned techniques can be used to prevent food spoilage. For example, to store radish, it is cut, dried and mixed with salt and oil. Then it is canned and dried in sunlight. It is pickled. Food can also be preserved by following ways Salting Salt is a water-soluble substance. When we mix salt in food such as pickles, it absorbs moisture from the food. A decrease in the moisture is unfavourable for bacteria so they cannot reproduce. Since the number of bacteria is less food won’t spoil. Therefore, adding salt to food prevents food spoilage. Sweetening Sweetening is the process of preserving food by adding sugar to the food. The sugar controls the moisture level in food and reduces microbial activity. It prevents or slows the growth of bacteria, moulds and yeast in food like jam and jelly. However, some moulds are tough. They can grow on jam too. FACTS WITH REASONS Even though sugar is mixed in jam some moulds still grow in it. Even though sugar is mixed in jam some moulds still grow in it because moulds are tough. If there is low sugar concentration the moulds will grow. ACTIVITY 4 Find some fruits and cut it into small slices. Boil a cup of water and dissolve lots of sugar in it. Add fruits in sugar syrup and stir it. When the fruit is covered with sugar. Let it dry. Store some for a week and observe. Does it decay or not? Boiling Boiling food kills germs in it. It can prevent food spoilage for a certain short duration. Sometimes the food such as tomato, fruits etc. is boiled and canned. Since there are no germs, food is preserved. The mushroom is boiled and dried before storing to prevent spoilage. Similarly, milk can be boiled to kill germs. Boiled milk lasts longer. MEMORY TIPS Foods may be stored in a sugar syrup or cooked in sugar until they crystalise.

72 Classification of Living Beings Canning The food such as fish, seafood, fruits, dairy products etc are dried, heated or ‘boiled and dried’, then oil or preservatives is mixed in it. Air is removed from the container and food is stored in it. It is called canning. FACTS WITH REASONS Canned food is dried and sterilized. Canned food is dried and sterilized to remove moisture and kill bacteria. It prevents decaying. HOT SKILL HIGHER ORDER THINKING SKILL 1. Five kingdom system is introduced to eliminate shortcomings of two kingdom system. Five kingdom system is introduced to eliminate shortcomings of two kingdom system. Following points will help to justify the sentences. i. Two kingdom system does not separate unicellular organisms from multicellular organisms but five kingdom system does. ii. Mushroom are kept under plant kingdom system even though they do not have chlorophyll but all fungus are classified as separate kingdom in five kingdom system. iii. Prokaryotes are not separated from eukaryotes in two kingdom system of classification but well described in five kingdom system of classification. iv. Two kingdom system has not properly described the position of autotrophs and heterotrophs but five kingdom system does. 2. Fungi was called non-green plant for so many years but now the five kingdom system classifies it as a separate kingdom. Fungi was classified as non-green plants since ages. It was kept under thallophyta division in two kingdom system of classification. But now it is removed from the plant kingdom because its cell wall is not similar to the cell wall of plant. More significantly it does not have chloroplast to do photosynthesis. It is not autotrophic. Therefore in five kingdom system of classification it is declared as a separate kingdom. Its main features as a separate kingdom is, it is a group of saprophytic organisms. 3. Chandrakala lost her lunch. She found her lunch box after 3 days in the shoe rack. When she opened it, it smelled very bad. It was covered with cotton-like coating. What happened to the food and why? Is it edible? What happens if it is consumed? When Chandrakala found her lost tiffin box and opened it, she saw a cotton-like coating and it smelled very bad. It is probably fungus and moulds.

Modern Concept Science and Technology – 8 73 The food might have contained moisture. Under suitable condition the spores of fungus germinated into hyphae and multiplied. The bad smell is from decomposing food due to bacteria and fungus. It is not edible anymore. If we consume this kind of food, we will be poisoned. We will suffer from vomiting, fever, diarrhoea and liver diseases. 4. Can life continue in the earth without bacteria? Think and comment. Life cannot continue in the earth without the bacteria because of the following reasons: i. Without bacteria we cannot digest our food properly, suffer from diarrhoea and intestine will be underdeveloped. ii. Without bacteria no minerals collected in the body of living things will ever return to the earth. They help to decompose dead matters and recycle minerals. Without them bio-geochemical cycles will stop and life will end in earth. iii. Lots of food product are made by the help of bacteria, without them there would be food scarcity. iv. Without bacteria soil would be infertile and no crops would grow. Therefore life cannot continue in the earth without the bacteria or any other microbes. 5. Once Mr. Khania picked up a food dropped on the restaurant floor and ate. He suffered from diarrhoea for three days. What might be the reason? How can we stay safe from bacterial infections and diseases? Picking up food dropped in the restaurant floor and eating it was a huge mistake on Khania's part because restaurants floor could be dirty and could contain billions of bacteria from visitors shoes. So eating that food obviously make him sick. Catching diarrhoea is to be expected. Bacterial diseases and infection could cost life. We can be safe from them by following certain habits. Some of them are: i. Proper cleanliness is the first way to prevent bacterial infections and diseases. ii. Using sanitizers, soap and water to wash hand keeps germs away. iii. Cuts and wounds should be cleaned with antiseptics. iv. Using antibiotics is an option to treat diseases. v. Boil foods to kill germs. 6. Mom cut mushroom, boiled it and spread in the sunlight. How does it prevent spoilage? Food spoilage can be prevented in multiple ways. Boiling, cutting and drying is one of them. Mom cut and boiled the mushroom first. It helps to kill the germs. When all the germs are dead, it won't spoil. She then sun dried it. It removed the moisture from the mushroom. When moisture is removed microbial activities will be reduced. As a result food won't decay.

74 Classification of Living Beings 7. Pistia caught common cold. She has a mild fever. She wants to go to school because she has exam. What precautions should she take so that she won't infect others? Since Pistia caught common cold and has mild fever, it is wise not to go to school because virus might have caused common cold to her. Her friends can be infected with virus if proper healthy habits is not maintained by herself and her friends. However, if she is not suffered severely and confident enough to go for exam, she should strictly follow some safety measures: i. Use mask all time at any cost. ii. Use hand sanitizer frequently. iii. Do not open masks, even if she is alone. iv. Do not share lunch with others. v. Do not share any things with other. vi. Do not stay close to anyone. Following above measures could prevent infecting others. 3 STEPS 3 STEPS EXERCISE EXERCISE STEP1 1. Select the best answers from the given alternatives. a. What does genus mean? i. closely related individuals ii. closely related species iii. identical organisms iv. organisms living in same ecosystem b. Why do coccus belong to Monera? i. it is prokaryotic unicellular organism ii. it is eukaryotic unicellular organism iii. it is primitive multicelular organism iv. it is eukaryotic multicellular organism c. Why cannot we see virus through light microscope? i. virus is colourless ii. virus is 25 nanometer to 250 nanometer iii. microscope is useless iv. virus cannot be kept in microscopic slide d. What are the colourless thread of the fungi called? i. gills ii. basidium iii. spores iv. hyphae e. Why is salt added in pickles? i. to keep food moist ii. to control the population of bacteria iii. to make food dry iv. to keep food oily

Modern Concept Science and Technology – 8 75 2. Write True for the correct and False for the incorrect statements. a. The two kingdom system of classification was introduced by Sir Carlous Von Linnaeus in 1758. b. Fungi is the kingdom of non-green eukaryotes. c. The herbs, shrubs and trees are parts of Monera kingdom d. Plants swallow their food as a whole and have a digesting column in the body e. Fungi were the first life forms to appear on the earth. 3. Fill in the blanks with suitable words. a. Virus do not have definite ............ structure. b. Genes of virus are used to make ............ c. Fungi lack ............ pigments. d. Freezing is effective in preventing food spoilage because ............ do not reproduce well in cold temperatures. e. Sweetening is the process of preserving food by adding ............ to the food. 4. Answer the following in very short. a. Who introduced binomial system of nomenclature? b. Which organism is called Solanum tubersum? c. Which kingdom do blue green algae belong to? d. Who and when was discovered bacteria? e. Which living organisms do not have cells? STEP2 5. Give reasons a. Five kingdom system of classification of organisms is better than two kingdom system of classification of organisms. b. Dogs and wolves belong to same genus. c. Cyanobacteria belongs to the kingdom monera. d. Bacteria are very important part of the ecosystem. e. Dettol is used in cuts and wounds. f. Bacteria are very important for food industries. g. Some bacteria decreases the fertility of soil. h. Bacteriophages are used to sterilize water. i. Bacteria are used to treat sewages. j. Canning can prevent food spoilage. 6. Differentiate between the following. a. Two kingdom system of classification and five kingdom system of classification b. Monera and protista c. Fungi and plantae d. Genus and species

76 Classification of Living Beings 7. Answer the following in short. a. Define classification of organisms. b. Write any two features of Monera, protista and fungi. c. What do you mean by bacteria? Give two examples. d. Define a virus. Give two examples. e. What is fungi? Give two examples. f. How do sweetening and salting prevent food spoilage? g. Freezing and boiling can prevent food spoilage. Explain. STEP3 8. Answer the following questions. a. Many scientists have tried to classify the living organisms. Is classification of organisms really necessary? What are the advantages of classifying organisms? Discuss. b. Five kingdom system is said to be better than two kingdom system of classification. Enlist any three features of five kingdom system of classification that makes it better than the two kingdom system of classification. c. Explain the five kingdom system of classification of living things in brief. d. Bacteria is harmful in many ways but very useful as well. Discuss the usefulness and harmful effects of bacteria. e. Miss Arya of grade 5 fall down and cut her ankle. What should she do immediately to prevent infection? What causes infection? How can we avoid infection? f. Mr. Arjun has a potato farm. He harvested tons of potatoes this year but unfortunately he could not sell it this month. What should he do so that he can sell it after few months? g. Tons of food products are spoilt each year. What can be done to reduce food spoilage? Write in brief on every method you can think of. h. Aunt cut the radish into tiny pieces, dried it, added spices, salt and oil. What might be the reason to do so to the pickles? i. Can humans survive without bacteria? Think and comment.

Modern Concept Science and Technology – 8 77 Key terms and terminologies of the unit 1. Biodiversity : Biodiversity means the enormous variety and variability of life on the earth. 2. Variation : The clear differences that can be observed between two individuals of the same or different species is called variation. 3. Genetic diversity : The clear and distinct variations between individuals of same species is called genetic diversity. 4. Specific diversity : The presence of multiple species of organism and their respective population in a particular area is called species diversity. 5. Ecosystem diversity : The clear physical differences among the ecosystem of multiple places is called ecosystem diversity. 6. Loss of biodiversity : The decrease in the population of any species in a particular area, so that they are either threatened, endangered or extinct is called loss of biodiversity. 7. Development : Development is the process of transforming the surrounding environment to achieve human needs for easier livelihood. Sequence of Curriculum Issued by CDC  Introduction and importance of biodiversity  Status of biodiversity in Nepal  Causes of biodiversity declination and control measures of biodiversity declination  Introduction and importance of sustainable development  Principles of sustainable development  Objectives of sustainable development.  National efforts for sustainable development. UNIT Biodiversity and Environment 4 Estimated teaching periods Theory Practical 6 2 Raymond Fredric Dasmann is well known for his idea of sustainable development. He was born in San Francisco on May 27, 1919, and died on November 5, 2002. He was an American biologist and environment conservationist. He helped to develop the concept of eco-development and biodiversity and identified the importance of recognizing indigenous people and their culture in conserving natural landscapes. About the Scientist Raymond Fredric Dasmann

78 Biodiversity and Environment 8. Sustainable development : Development that meet the needs of present generation without compromising the ability for future generation to meet their own needs is called sustainable development. 9. Nature friendly development Carrying out the development activities with less impact to the environment is called nature friendly development. Introduction Numerous species of living organisms live in the earth including humans. Our environment is rich in biodiversity. Humans utilize available natural resources from the environment and survive. The developmental activities are degrading the quality of environment each day. So it is now essential to practice eco-friendly and sustainable developmental activities. 4.1 Biodiversity The environment is a collection of living things and non-living things around us. There are various types of plants and animals around us. Two individuals of the same species are also different from each other. One species of organism is different from the other. All of these living things live and interact in the environment. Such a dynamic inter-relation between living things and non-living things forms an ecosystem. Ecosystems are also different from place to place. As discussed above, there are so many different types of ecosystems on the earth. Each ecosystem contains varieties of species of plants, animals, protists, fungi and bacteria. Each individual of a species also has variations. Such a variety of life in a place as a whole is called biodiversity. Biodiversity means the enormous variety and variability of life on the earth. Biodiversity is very important for life to continue on the earth. According to convention on Biological Diversity (CBD) Biodiversity is the degree of variation of life. It is a measure of the variety of organisms present in different ecosystems. FACTS WITH REASONS Nepal is rich in biodiversity. Nepal is rich in biodiversity because it has many different types of land with unique climate, land, water resources and temperature supports different genus, species and ecosystems. ACTIVITY 1 Visit a botanical garden or national park with your parents. Observe the richness of biodiversity. Types of biodiversity Broadly biodiversity is divided as floral diversity and faunal diversity. Floral diversity means the presence of diverse species of plants in a particular ecosystem. Faunal diversity means presence of diverse species of animals in a particular ecosystem. MEMORY TIPS There are 8 million total estimated animal and plant species on Earth.

Modern Concept Science and Technology – 8 79 Genetic diversity The clear differences that can be observed between two individuals of the same or different species is called variation. Variation is important for the organism because it helps to increase gene pool so that organisms can survive better. Each organism has different genes. Even though two organisms belong to same species they can have different characteristics. For example, Achham cattle are small local cows of Nepal which is very different from big Holstein cows even though they are same species. Such variations in organisms of same species are called genetic diversity. The clear and distinct variations between individuals of same species is called genetic diversity. Species diversity A species is a group of similar individuals. One species is different from the other. For example, a cow is different from a buffalo or dog. A paddy plant is different from a spinach or banana plant. There are many different species of organisms dwelling in a particular area. Such presence is called species diversity. The presence of multiple species of organism and their respective population in a particular area is called species diversity. Ecosystem diversity An ecosystem is a dynamic interrelationship between living and non-living components of the environment. It is unique to a particular place and climatic belt. The ecosystem of a forest will be different from the ecosystem of a meadow or pond. The ecosystem of plain lands will be different from the ecosystem of hills or mountains. Such variations in the ecosystem of different places is called ecosystem diversity. The clear physical differences among the ecosystem of multiple places is called ecosystem diversity. FACTS WITH REASONS An ecosystem is delicate. An ecosystem is considered delicate because a change in the population of a single species can greatly change an entire ecosystem. Pollution, hunting, climate change and invasive species can sometimes collapse the ecosystem. ACTIVITY 2 Observe the organisms found in forest and those found in pond. Are they same? Discuss the reasons. Differences between Ecosystem diversity and species diversity Ecosystem diversity Species diversity 1. It is the variation on the self sustaining systems in which there is interaction between biotic and abiotic components. 1. It is the variation among the organisms of different species. 2. It refers to the diversity of a place at the level of an ecosystem. 2. It refers to the variation of different kinds of species in our surroundings. MEMORY TIPS An ecosystem can be as large as an entire forest or as small as a clump of moss.

80 Biodiversity and Environment Differences between Species diversity and Genetic diversity Species diversity Genetic diversity 1. It is the variation among the organisms of different species. 1. It is the variation in the hereditary units that transfer parental characteristics to their offspring. 2. It refers to the variation of different kinds of species of our surroundings. 2. It refers to the variation among the members of the same species. ACTIVITY 3 Visit a nearby ecosystem with your science teacher. Identify various kinds of species found in that ecosystem. Prepare a short report on it and submit to your science teacher. Importance of biodiversity i. Biodiversity at the genetic level results in slight variations among the members of the same species. It helps organisms to survive well in their environment. ii. Presence of multiple diverse species helps to continue the food chain in the ecosystem. iii. Presence of microscopic bacteria and yeast helps to decompose dead organisms and return minerals to the earth. iv. Most of the medicine we use comes from different species of plants and animals. v. Trees, bushes and wetlands store water and prevent the flood. It purifies water. vi. Insects and birds pollinate crops. vii. Biodiversity is the source of food, shelter and oxygen for all life forms. viii. Biodiversity develops job opportunities for local people. It is a source of revenue for a country. FACTS WITH REASONS Biodiversity is a source of food. Biodiversity is a source of food in the earth because we obtain food from plants or animals that lives within the ecosystem and the ecosystem is composed of diverse life forms. ACTIVITY 4 Is there any ecotourism centre nearby you? How can biodiversity be used to attract tourists? Discuss. Present status of biodiversity in Nepal Nepal is very rich in ecosystem diversity. The altitude of Nepal ranges from 60 meters to 8848 meters. As a result, there are 118 different types of ecosystems in Nepal. Tall grasslands, marshlands and evergreen tropical forests are observed in the Terai region. Deciduous forests, sub-tropical forests, and conifers are found from hills to middle mountains. MEMORY TIPS Another advantage of biodiversity is recreation. Many people enjoy unique biodiversities, such as birdwatching, hiking, camping and fishing. MEMORY TIPS There are over 22,000 species reported from Nepal i.e., 1.3% of the global biodiversity.

Modern Concept Science and Technology – 8 81 Conifer forests and alpine meadows are found in high mountains. Nepalese wetlands harbour many threatened species of flora and fauna. It is also a resting place for many migratory and globally threatened birds. Nine of the country’s wetlands have been listed as Ramsar sites. Since there are 118 unique ecosystems, Nepal is very rich in species diversity. Nepal is a tiny country but it contains 3.2 % of the world's known plant species and 1.1% of animal species. There are 11,971 species of plants and 11,861 species of animals in Nepal. A total of 284 species of flowering plants, 160 animal species including one mammal, 1 species of bird, and 14 species of herpetofauna (reptiles) are found only in Nepal. 54 species of wild mammals and 18 species of trees found in the mountains are threatened. Nine species of plants, 55 mammals, 149 birds, 64 herpeto-fauna and 21 fish are included in the IUCN Red List. Several species of plants and animals, including 27 mammals, 9 birds, 14 angiosperms, and 4 gymnosperms have been declared protected species by the government. The same species of plants and animals show variations based on the geological region they are found. Achhami cattle (Bosindicus) and lampuchhre sheep (Ovisaries) are near endangered species. Pure siri cattle have become extinct in Nepal. Sakini is the most adapted indigenous breed of poultry of Nepal. Ajingara marsh in Kapilvastu harbours three species of wild rice, namely Oryzarufipogon, Oryzaminutaand Oryzanivara. Hygroryzaaristatais a wild relative of many rice varieties found in the Terai. Algae, Fungi and Plants diversity in Nepal and the world Group of Plants Found in the world Found in Nepal Percentage in Nepal Lichen More than 17,000 850 5 Algae 56,579 1,001 1.76 Fungi 98,998 2,467 2.45 Bryophytes 16,236 1,213 7.47 Pteridophytes 12,000 580 4.83 Gymnosperms 1,021 41 4 Angiosperms 369,400 6,973 1.87 Source: Adhikari (2016), Shrestha (2018), Chaudhary ( 1996), Pradhan(2016), Mieche (2015) et.all. Animals diversity in Nepal and the world Group of animal Found in the world Found in Nepal Percentage in Nepal Mammals More than 4,765 185 3.96 Aves 9,799 886 8.90 Reptiles 7,870 78 0.99 Amphibia 4,780 118 2.47 Fish 10,000 187 1.87 Butterfly 17,500 651 3.27 Spider 39,490 175 0.44 Source: Nepal Government, Department of National park & wildlife conservation (2019), Bird-life International (2006), IUCN (2003) et.all.

82 Biodiversity and Environment FACTS WITH REASONS The Nepal government has enlisted one-horned rhinoceros as a protected animal. The Nepal government has enlisted one-horned rhinoceros as a protected animal because its population is too low. It's almost extinct. ACTIVITY 5 Make a list of a few trees, animals and birds that are found in Nepal only. Loss of biodiversity Each organism has a very special role in the ecosystem. However, most species are endangered, threatened or gone extinct because of human activities. The decrease in the population of any species in a particular area, so that they are either threatened, endangered or extinct is called loss of biodiversity. Human activities are the main reasons for declining biodiversity. Causes of loss of biodiversity i. Poaching and illegal wildlife trade is threat to biodiversity. Weak laws, ignorance, poverty and black markets encourages poaching. Poaching is the illegal hunting of wild animals or the illegal gathering of plants. People are found hunting rare wild animals or gathering rare species of plants and selling them to earn a livelihood. It is a serious threat to biodiversity. ii. Human-wildlife conflict decrease population of wild animals. Many people live nearby forest areas. They collect firewood, grass and fruits from the forest to survive. Sometimes the wild animals enter the village and harm people, crops and infrastructure. Sometimes people hunt animals in the forest to survive. It has negative effect on biodiversity. iii. Invasion by alien species disturbs local ecosystem. Sometimes foreign or genetically modified plants and animals knowingly or unknowingly introduced into the agriculture land, river, forest etc. They invade another ecosystem and multiply so much that the ecosystem will collapse. iv. Poisonous substance used in agriculture kills hundreds of animals. The rainwater dissolves chemical fertilizer from fields and flows into the river. The algae will grow so much that there will be oxygen deficiency in water at nights. It can kill aquatic animals. Chemical insecticides and pesticides are poisonous chemical substances used to control insects. They not only kill harmful but good insects either. They can even kill birds, rodents and mammals. So, there will be a disturbance in the ecosystem. MEMORY TIPS A biodiversity hotspot is an area of rich biodiversity that faces serious threats to its existence.

Modern Concept Science and Technology – 8 83 v. Over-harvesting resources and mining disturbs local ecosystem. Humans collect timbers and medicinal plants from forest, catches fished from rivers and seas. Similarly, construction materials like gravels, sand, rocks and fossil fuels are mined degrading soil, rivers, forests, ponds etc. Excessive collection of such natural resources is a major cause of declining biodiversity. vi. Deforestation destroys habitat of wild animals. Urbanization and industrialization are major causes of deforestation. Forest is cut for agricultural land, residence, furniture, papers and herbs. The loss of a huge area of forest is called deforestation. Deforestation, over-grazing and forest fire are major causes of loss of habitat of wild animals. Hundreds of species of plants and animals will be lost due to loss of habitat vii. Climate change makes its harder for organism to survive. Climate change changes the weather and season of the place. The average temperature of a place rises. The water cycle will be irregular. As a result, it will be very difficult for organisms to survive in their natural habitat. FACTS WITH REASONS Deforestation is the main cause of declination of biodiversity. Deforestation is the main cause of declination of biodiversity because when the trees are cut, wild animals lose their shelter, food and fresh water. The ecosystem will be disturbed. Their population will decline. ACTIVITY 6 Many villagers collected firewood from the forest. They also collect grass from the forest to feed their cows. If the population of the village is doubled, how will it affect the ecosystem? Discuss. Measures to conserve biodiversity Since biodiversity is the reason that every organism can survive, it must be conserved. The Interim Constitution of Nepal (2007), asks the government to make special arrangements for the conservation of biodiversity. Ways to conserve biodiversity i. Enabling policies, strategies and regulatory framework. Strict and practicable rules and regulations, and well-planned strategies are necessary to prevent poaching, illegal timber smuggling and over-gathering of herbs etc. ii. International participation and negotiations Government should participate in international conventions and negotiate for conservation of biodiversity. They will provide, knowledge, plans and sometimes funding to protect biodiversity. MEMORY TIPS The Amazon has already lost 17% of its forest cover and an additional 17 % of its rainforests have been degraded.

84 Biodiversity and Environment iii. Establishment and management of protected areas National Park, wildlife reserves, hunting reserves, conservation areas are some protected areas. Such places prevent human encroachment in the forest. It protects, flora, fauna and ecosystem in the area. iv. Management of forest outside protected area. Local people should be allowed to use and protect the forest. Afforestation and reforestation of barren land help to protect the forest. Encroached forest areas must be reclaimed. When the forest area is protected biodiversity won’t decline. v. In-situ and Ex-situ Conservation of Biodiversity In-situ conservation means the effort to conserve biodiversity in its natural habitat. Insitu conservation can be practiced on particular species or an ecosystem as a whole. Protected areas, botanical gardens and national herbarium are good examples of in-situ conservation of biodiversity. The Central Zoo is an ex-situ conservation of biodiversity. Species are raised outside their natural habitat. They are protected by humans for a certain duration until they can be released into the wild. vi. Public participation Biodiversity can only be protected if local people are involved in it. Their daily livelihood is intertwined with the local environment. So we must generate awareness in them about the importance of biodiversity. We should teach them to utilize the forest and its resources without harming the forest. We should reduce the conflict between people, wildlife and government. Eco-tourism can be promoted which helps local people to earn a livelihood as well as conserve biodiversity. FACTS WITH REASONS Restricting people from collecting a bounty of forest does not help to conserve biodiversity. Restricting people from collecting a bounty of forest does not help to conserve biodiversity because when people are restricted from collecting bounty from the forest, their daily life will be harder. So they will steal timbers, collect medicinal herbs illegally and hunt animals. As a result,biodiversity will decline. ACTIVITY 7 What can we do as a member of society to conserve surrounding biodiversity? Discuss. 4.2 Environment We know that environment is composed of living beings and non-living things. Human beings utilize both these living and non-living components of the environment for their survival as well as the development of mankind. Humans are using their intelligence to invent newer tools and technology by depleting resources from the environment.

Modern Concept Science and Technology – 8 85 Concept of Development Development is the process of transforming the surrounding environment to achieve human needs for easier livelihood. Humans conduct various activities for development. Building houses, construction of roads and railways, setting up industries and factories to produce goods for human use, etc. are the some of the major development activities. Other development activities are use of tools, techniques and chemicals for food production, construction of irrigation canals, generating power from water, sunlight, wind, minerals etc. All these development activities use vast resources from the environment. This results in the degradation of the environment. Development and Environment There will be no physical development if there is no environment. All the resources that are needed for development come from the environment. Industries and factories use raw materials from plants and animals to produce different products. Fossil fuels from the environment are used for running industries, factories and vehicles. Metallic and non-metallic minerals are used for construction of infrastructures like roadways, railways, bridges, buildings, etc. Rapid and haphazard use of resources for development has led to environmental degradation. If the environment is degraded, it cannot produce more resources from which our future generation can take advantages. Degraded environment also disrupts development by causing floods, landslides, soil erosion etc. FACTS WITH REASONS Development and environment are interrelated. Development and environment are interrelated because humans live in the environment and uses raw materials from environment for development but which may hamper environment and human itself. Differences between development and environment S.N. Development S.N. Environment 1 Development is the process of transforming the surrounding environment to achieve human needs for easier livelihood. 1 Everything around us is called environment. 2 Development activities use vast resources from the environment resulting degradation of the environment. 2 Resources that are needed for development comes from the environment. 4.2.1 Concept of Sustainable Development The development activities that are carried out these days only focus on the short term benefits of the present generation. It is degrading the environment without taking care of the environment resources for future generation. To use the environment resources wisely and

86 Biodiversity and Environment conduct environment friendly development works, the concept of sustainable development is introduced. Development that meets the needs of the present without compromising the ability of future generations to meet their own needs is called sustainable development. It simply means while doing development works, we must consider using fewer resources from environment so that it provides its resources for a long time. The concept of sustainable development was recognized by international community in 1972 A.D. for the first time at the United Nations Conference on the Human Environment held in Stockholm, Sweden. FACTS WITH REASONS Sustainable development is the present need. Sustainable development is the present need because it conserves natural resources for future generation by relying on the renewing capacity of resources. Aspects of sustainable development Sustainable development is based on three major pillars; the environment, the economy and the society. a. Environmental aspect i. Developmental activities should not harm wild animals. ii. Developmental activities should conserve natural resources. iii. We should conserve environment while making roads, house etc. iv. We should focus on minimising deforestation, natural disasters etc. b. Social aspect i. Social harmony, equality and education helps to promote sustainable development. ii. Public participation, production of skilled manpower is important for sustainable development. iii. Poverty elimination helps to promote sustainable development. c. Economic aspect i. Sustainable development focus in stable economic growth. ii. It focus on equal distribution of natural resources for every community. iii. It helps to create job and benefits for us and for future generation. Importance of sustainable development i. Sustainable development helps in renewing the natural resources. ii. It is an environment friendly method of development. So, it does not harm the environment. iii. It helps to meet the essential needs for jobs, food, energy, water, and sanitation. MEMORY TIPS The concept of sustainable development was popularized by the Brundtl and Commission in 1987, on Environment and Development in its report "Our Common Future" that was published in 1987.

Modern Concept Science and Technology – 8 87 iv. It helps to conserve the natural resources. v. It ensures the ability of the future generation to meet the needs of development Sustainable development helps to conduct development activities with minimal effect to the environment. If we follow the principles of sustainable development, we can continue our development works without harming the environment. Principles of sustainable development Development activities benefits people by promoting livelihood and economic status of the people. Development activities also need natural resources. Overexploitation of resources from the environment can cause adverse effects. If we overuse the resources, they will finish or lose their ability to renew. So, future generations are sure to be affected by them. Therefore, there is a need of long term development with least impact to the environment. For this, a latest development concept called ‘Sustainable Development’ has been widespread. Sustainable development is a long term developmental activity that meets the need of present generation and also does not compromise the ability of the future generation to meet their demands. Hence, it is a planned development activity that keeps in mind, the well-being of not just the present generation but the future generation too. Sustainable development is based on three major pillars; the environment, the economy and the society. The main principles of sustainable development are discussed below: a) Conservation of ecosystem The principle of sustainable development aims at the conservation of ecosystems as it conserves all the biotic and abiotic components. Earth can only be sustainably conserved if all the types of terrestrial and aquatic ecosystems are conserved. b) Conservation of biodiversity We obtain food and other resources from the biodiversity. Each and every organism on this earth is special. They are the active part of the biodiversity. If one group of organisms are extinct, then it affects the whole structure of the ecosystem. So, biodiversity should be conserved. c) Development of sustainable society All people should get quality food, safe home, quality health services, quality education and jobs. If the society is healthy and prosperous, it can continue development activities sustainably. Sustainable society helps to achieve sustainable development easily. So, sustainable development also aims in the development of sustainable society. d) Control of population growth The population of the world is increasing day by day but the resources are limited. Therefore, population growth should be controlled for meeting the goals of sustainable development. If population growth is controlled, the consumption of natural resources also decreases. It results in environment conservation and availability of resources for future generations. e) Development of human resource Not only natural resources, but also the human resources are needed for sustainable

88 Biodiversity and Environment development. Well educated, trained and qualified human resources are necessary to implement sustainable development projects. They have better abilities to understand the problems of the nature and hence can achieve a higher degree of sustainability. f) Increase in public participation No programs or projects can be successful without public participation. Sustainable development is for general public. Public participation develops interest, positive attitude and commitment towards sustainable development. g) Conservation of cultural heritages Cultural heritages are also our resources preserved and left by ancestors. They should be preserved for future generation. Proper reconstruction of heritages for their protection, conservation of positive values and giving continuity to this practice are the steps for sustainable development. h) Limit of carrying capacity The earth is a reserve of limited resources. If the population and the development works demand more resources than the earth can generate, then the whole structure crashes. Development will be stopped and people will fail to progress. Therefore, population growth and development should be controlled to achieve sustainable development. Nature Friendly Development Nature friendly development is one of the most important aspects of sustainable development. Carrying out the development activities with less impact to the environment is called nature friendly development. Our development works surely affect the environment. Without any impact on the environment, no development activities can be done. For example, if we build a house, we need to extract sand, pebble, limestone (for cement), rocks, water, etc. Without these resources, building a house is not possible. But, we can ensure minimum and wise use of such resources by taking care of the nature. The impact on the environment should be minimum. This is nature friendly development. Let us take another example, if a road passes through a dense forest and large number of trees need to be cut, we can build underground roads in such areas. Also, we can build a bridge for animals to connect two forests if the road divides the forest. Following are some of the important points to be considered for nature friendly development. 1. Undertaking development works only after knowing the impact on the environment : Before starting the development work, the concerned body has to ensure what probable damage can the development work poses to the environment. It is called environmental screening. Environmental screening helps to identify whether development activities greatly impact environment or not. Based on the possible level of impacts, Brief Environment Study (BES), Initial Environment Examination (IEE) and Environment Impact Assessment (EIA) should be done. These studies and assessments provides different measures for environment friendly development based on development activities. 2. Making environment a priority in development works : When any development works is done, environment conservation should be on the first priority. If

Modern Concept Science and Technology – 8 89 any damage has to be done to the environment, the development work should include some part of the budget in reversing the damage. If the development work has some fund for environment, it can be used to mitigate or control the impact. For example : the project that destroys trees should have fund for plantation of trees. 3. Construction of many small projects than a large project: A large project like that of a large hydro-power dam creates many environmental problems. It demands destruction of environment to a larger extent. So, instead of building large power plants, the agencies have to focus on building small scale plants. This minimizes the environmental damage. 4. Proper use of natural resources: Natural resources like plants, animals, soil, rocks, water etc. should be wisely used. For example-packing of products from industries needs much more paper or plastic. If packaging is removed or reduced, then thousands of trees will be saved. Keeping some space open as garden in your home can save tiles or other metals needed for pavement. 5. Reducing release of pollutants in the environment during development works : We can reduce the amount of pollutants we produce every day. Construction works produce huge amount of solid wastes like cement debris. These can cause land and water pollution. Similarly, leftover harmful chemical after construction also pollute land and water. The chemical pesticides and fertilizers that are used in large scale agriculture also pollute land and water. Burning of fuels in construction machines, burning fire wood, etc. during development works release smoke and harmful gases in air. Therefore, we should use the resources wisely and reduce pollution. Sustainable Development Goal (SDG) The SDG focuses on people, the planet, prosperity, peace and partnership. The 15th goal of SDG focuses on the wise use, protection and promotion of terrestrial ecosystem. It tries to prevent desertification, conserve the forest, prevent soil erosion and conserve biodiversity. Some common objectives of SDG regarding environment and biodiversity are food security, clean drinking water for all, sanitation, infrastructure, climate change adaptation and mitigation and sustainable management of coastal and marine resources. According to the global circulation model, imbalance in the environment of one place will definitely hamper the environment of another place. So, every country must work together to meet the SDGs. The effort of Nepal to meet SDGs Nepal has committed to achieve sustainable development goals (SDGs) which are planned for 2016-2030. There are 17 major goals along with 169 targets in SDGs. The goals are no poverty; zero hunger; good health and wellbeing; quality education; gender equality; clean water and sanitation; affordable and clean energy; descent work and economic growth; industry,

90 Biodiversity and Environment innovation and infrastructure; reduced inequalities; sustainable cities and communities; responsible consumption and production; climate action; life below water; life on land; peace and justice; and partnership for the goals. Nepal has formed multiple committees that are working to meet SDGs. The following activities are carried out for this purpose: i. Nepal has launched community development programs for poverty elimination, biodiversity conservation, education for all, sanitation etc. from 2016-2019 to meet SDGs. ii. Nepal formed a climate change council in 2009 to adapt and mitigate the impact of climate change. This council constructed a dam and a drain to prevent the bursting of Tsho Rolpa (altitude: 4,580 meters) glacial lake in 2020. They also conducted many cabinet meetings on Kalapatthar (altitude: 5550 m) and Rara lake (altitude: 2990 m) for public awareness about water resources and challenges. iii. Nepal launched a community forest in 1970. It is a successful model to protect the forest, wild lives and environment at the local level. It is observed that the forest area is increasing considerably after the local people were allowed to manage their forest based on the community forest act in 1993. iv. 15th plan of Nepal guarantees a clean, pure and green environment for all. It also deals with waste management and promotes greenery. v. The Environment Protection Act, 2019 (2076) was made by the government with the following objective: 1. Modify and use the current laws on the environment to protect the right of the people to live in a clean, green and healthy environment. 2. The person or company that pollutes the environment must pay compensation to the victim. 3. We must maintain a balance between the environment and development. 4. We must reduce the harmful impact on the environment and biodiversity. 5. We must adapt or mitigate the harmful impacts of climate change. Differences between development and sustainable development. S.N. Development S.N. Sustainable Development 1 Development is the process of transforming the surrounding environment to achieve human needs for easier livelihood. 1 The long term development that is conducted by protecting the environment in such a way that the resources of the environment can be used by the future generations too is called sustainable development. 2 Regular development does more damage to the environment. 2 Sustainable development does minimum damage to the environment.

Modern Concept Science and Technology – 8 91 HOT SKILL HIGHER ORDER THINKING SKILL 1. Biodiversity is richness of life. It is significant for well being of our planet. Biodiversity is richness of life. It is significant for well being of our planet because a healthy biodiversity offers numerous natural services to maker our planet living. Such as: i. Conservation of water resources, soil formation and maintenance of ecosystem. ii. It helps in pollution breakdown, climate stability and nutrient recycling. iii. It is source of food, medicine and timber. iv. It is source of plants and animals. 2. Nepal is rich in biodiversity but it is under threat. Support the statement. Nepal is rich in biodiversity but it is under threat because of human activities. Some of them are: i. Every year many people go to harvest yarshagumba risking their life, yarshagumba may go extinct. Locals should harvest them sustainably. ii. Varieties of birds are on the verge of extinction due to loss of habitat. iii. Wild buffalo (arna) are endangered species and in verge of extinction. iv. Lots of forest is lost to smuggling and forest fire. v. Poaching is increasing which is threat to endangered species. 3. Unplanned development is destruction. Unplanned development disturbs environment in many ways. So it can be called destruction of the environment. Some of the reasons are explained below: i. Unplanned cities can have problem of proper drainage system. It could result in flooding, overflow of sewage from drains, spread of bad smell and germs. ii. Unplanned cities sometimes do not have dumping sites. So, they could not dispose waste properly. iii. Forest could be cut randomly. iv. There could be scarcity of drinking of water. v. Biodiversity will be lost. vi. There could be industries and factories inside the cities which causes health issues. 4. Let's suppose you became president of your ward and conducting various infrastructural developmental activities. What factors should you consider so that you won't harm the environment and development would last long? If I became ward president and if I am supposed to do infrastructural developmental activities, I would put environment conservation as my first priority. i. I would not destroy forest while conducting development activities. ii. I would not destroy watersheds. iii. I would not allow people to occupy public places. iv. I would request farmers to use compost fertilizers and bio-insecticides over chemical fertilizers and chemical pesticides. v. I would displace industries and factories far away from human settlements. vi. I would install dust bin in public places.

92 Biodiversity and Environment 5. Mr. Harka and his friends are actively involved in making a water tank to supply water in their village but Mr. Hari says its government job. He will neither go to help nor donate for the construction of the water tank. How would you convince him that only the public participation can lead to sustainable development? Sustainable development means utilizing available resources to fill the demand of todays world but also making sure that the resources can be transferred to the future generations. Public participation plays major role in the success of sustainable development. In above case Mr. Hari is unwilling to provide any kind of help in making water tank for his village. He thinks it is the job of government only. I would convince him by making him aware of the below listed importance of public participation in sustainable development. i. Public participation encourages people to make decisions. ii. It allows people to examine there problem and find optimum solution. iii. There will be transparency among the local people about the activity. iv. People will protect the things made by themselves. v. It develops responsibility among the locals. vi. It save government expenses for fulfilling another needs of public. vii. It increases the feeling of brotherhood and sisterhood and dignity in society. 6. Let's suppose there is a tiny forest nearby your house. Many people claim it is theirs and cut trees frequently. Lots of people use it as dumping site. Many animals have already left the forest and birds have stopped coming there. Only the rodents, housefly and dogs are found there. How would you conserve the biodiversity in that forest? If there is a tiny forest near by my house and if many people are trying to cut it down. If the biodiversity of the forest is declining I would definitely do the following things to conserve the biodiversity of the forest: i. First, I would write a letter to the ward office to protect the forest. ii. I would collect my friends and clean the park. iii. I would use old buckets, or boxes or sacks in many places as dustbin. iv. I would make pamphlets against deforestation and littering. v. I would visit every neighbour and request not to cut trees. vi. I would protest if anyone tries to cut tree or inform forest department. 7. Development and environment should go hand in hand. For any kinds of development we need lots of resources. All of the resources are collected from the environment. Therefore development is impossible without the environment. Any developmental activities that destroys environment is not sustainable. Natural resources available in the surrounding can be collected for construction. It provides job and prosperity. But if the development is unplanned it will cause environmental pollution and eventually harm humans. On the other hand, polluted and degraded environment does not provide quality resources for development and development activities cannot be carried out regularly. Therefore, development and environment should go hand in hand.

Modern Concept Science and Technology – 8 93 3 STEPS 3 STEPS EXERCISE EXERCISE STEP1 1. Select the best answer from the given alternatives. a) What do development require? i) living resource ii) non-living resources iii) living and non-living resources iv) courage b) What do SDGs include? i) No poverty, zero hunger ii) Zero hunger, wood smuggling iii) Good health, deforestation iv) Collect any resources c) Which one is the most successful sustainable development programs of the government? i) Community forest programs ii) Water supply iii) Hydro-power iv) Urbanization d) When was the term sustainable development used first time? i) 1972 ii) 1938 iii) 2045 iv) 1927 e) What is the time period allocated for meeting sustainable development goals? i) 1972- 1998 ii) 1939 - 1938 iii) 2016-2030 iv) 2045 - 2073 2. Write True for the correct and False for the incorrect statements. a) Degraded environment does not support resources for further development and creates resource crisis. b) Environmental screening helps to identify whether the development works affect the environment or not. c) The chemical pesticides and fertilizers that are used in large scale agriculture also pollute land and water. d) There are 17 major goals along with their targets in SDGs. e) The term sustainable development was used for the first time in 1972. 3. Fill in the blanks with appropriate words. a) Human beings utilize both the living and non-living components of the …………. for their survival as well as the development of mankind. b) …………. activities uses huge amount of resources from the environment; resulting in the degradation of the environment. c) The concept of sustainable development was recognized by international community in …………. for the first time. d) Sustainable development helps to conduct development activities with minimal effect to the …………. e) All the resources that are needed for development come from the ………….

94 Biodiversity and Environment 4. Answer the following questions in one word. a) When was the term sustainable development introduced? b) What is the term used for “the process of transforming the surrounding environment to achieve human needs for easier livelihood”? c) Which concept includes long term development and protecting the ability of future generation to meet the demand? d) What kind of development puts nature in priority? e) Write one function of environment impact assessment in a word. STEP2 5. Give reasons. a) Development and environment are interrelated. b) Sustainable development is the present need of the world. c) Nature friendly development should be encouraged. d) Development is impossible without environment. 6. Write any two differences between: a) Development and environment b) Sustainable development and current development c) Development and nature friendly development. 7. Answer the following in short. a) What is biodiversity? Enlist its types. b) What do you mean by development? c) What do you mean by nature friendly development? d) Define sustainable development. e) What is an environment? f) Write the full forms for the following. i) IEE ii) EIA g) Identify the following pictures as developmental activity, sustainable development activity, unmanaged urbanization and industrialization. Then write the consequences of these activity in each picture. a) b) c)

Modern Concept Science and Technology – 8 95 d) e) STEP3 8. Answer the following in short. a) Define sustainable development. When did the concept of sustainable development arise? b) Write a short note on each type of biodiversity. c) Discuss the present status of biodiversity in Nepal? d) Biodiversity is lost to climate change and smuggling every year? What might be the major causes of loss of biodiversity e) Let's suppose we live in a semi-urban area. Urbanization, industrialization and deforestation is common in semi-urban area. Biodiversity will be lost significantly during the process of development. As a decent citizen what can we do to prevent loss of biodiversity in our places? f) Describe the efforts made by Nepal in the field of sustainable development. g) List some successful projects of Nepal in nature friendly/sustainable development. h) Enlist the measures that should be followed for nature friendly development. i) Villagers wants to construct the road right through the forest. They say that roads will benefit the village and it will cost less to construct the road through the forest. However making road around the forest will cost a lot of budget. As an educated member of society explain the harmful effects of making road through the forest and explain them the importance of sustainable developments. j) Discuss the principles of sustainable development. k) Nepal government is actively working to launch sustainable development activities. Enlist some of its activities on sustainable development.

96 Life Processes Key terms and terminologies of the unit 1. Life processes : Those activities which are carried out by living organisms and essential to continue life on the earth are called life processes. 2. Reproduction : The biological process in which living organisms produce their own kind by asexual or sexual method is called reproduction. 3. Asexual reproduction : The type of reproduction which takes place without the fusion of a male gamete and a female gamete is called asexual reproduction. 4. Fission : Fission is a method of asexual reproduction in which single parent body divides itself into two or more daughter organisms. 5. Binary fission : The method of asexual reproduction in which a unicellular organism divides into two daughter organisms is called binary fission. 6. Multiple fission : The method of asexual reproduction in which a unicellular organism divides into more than two daughter organisms is called multiple fission. 7. Budding : The method of asexual reproduction in which new offspring is reproduced by means of a small outgrowth or bud is called budding. Sequence of Curriculum Issued by CDC  Introduction to asexual reproduction in organisms  Introduction to sexual reproduction in organisms  Introduction to pollination  Introduction to fertilization  Vegetative propagation through stem, leaf and root  Structure of monocotyledonous and dicotyledonous seeds  Functions of parts of seeds  Dispersal of seeds  Effects of air, water and heat in the germination of seeds  Importance of germination of seeds UNIT Life Processes 5 Estimated teaching periods Theory Practical 12 3 Rudolf Jakob Camerarius is noted for his discovery of sexual reproduction in plants. He was born in the Roman empire on 12th February 1665 and died on 11th September 1721. He was a German botanist and physician. He experimented on Mulberry, castor oil plants and maize plant to discover that if male parts of the plant are removed then the fruits contain no seeds. Which meant no sexual reproduction. About the Scientist Rudolf JakobCamerarius