Lecture notes on Biology

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Prescribed by the National Curriculum and Textbook Board for Class IX-X from the academic year of 1996. SECONDARY BIOLOGY Class IX-X Written by Dr. Iqubal Aziz Muttaqui Nasim Banu Dr. Md. Abul Hasan Gul Anar Ahmed Translated by Professor Md. Obaidur Rahman Sikder Raihana Begum National Curriculum And Textbook Board, DhakaCHAPTER ONE INTRODUCTION TO BIOLOGY Now a days we find contributions of Aristotle, Socrates, Theophrastus and many other scholars of the past age in different fields of knowledge. This is not possible for the scholars of the present time. A question may arise in your mind as to why it is not possible today. The reason is that in ages long past the extent of knowledge was limited. People engaged in achieving knowledge were also small in number. Today the dimension of knowledge has been increased many times. To contribute in more than one field is quite difficult at the present time. For convenience to know and understand things we have divided our world of knowledge in many branches. In this way Science, Literature, Arts, Social Science and many other branches have been created. As a whole, knowledge of human beings is undivided. But it has been divided into various branches for easy learning and understanding. You may have known that the knowledge of science is increasing rapidly. It is becoming possible because of the research of a large number of scientists in different fields of science. Many people think that knowledge of science is becoming double in every eight years. New subjects of science are being created. It is not possible to realize and understand this huge store of knowledge for an individual alone. As a result, scientists are engaged in research in particular subject or topic. At different times many scholars have divided the knowledge of science in various ways. The division and different branches of science are constantly spreading with the increase of knowledge in science. The two main branches of science are Physical science and Biological Science. Physical Science is otherwise called the Science of non-living things. In Physical science characteristics, actions-reactions, multiformaity and many similar other properties of non-living objects are examined and discussed.2 Secondary Biology Observation, examination and discussion of livings beings are included in Biology. Biology is the science of living beings. The term Biology comes from two Greek words (bios means life and logos means knowledge). Aristotle is regarded as the father of Biology. We find two types of life in nature. One is plant while the other is animal. Accordingly Biology has been divided into two branches: Botany and Zoology. Botany deals with theoretical discussion and research about characters and other features of plants, while Zoology is limited in subjects relating to animals. PRINCIPAL BRANCHES OF BIOLOGY Biology has been divided into Botany and Zoology on the basis of nature of living beings. Inspite of this, now-a-days extensive research has been done on Microorganism. They influence human life in various ways. So for discussion about them a new branch is made. This is known as Microbiology. Considering the subjects of living bodies on which discussion is made the whole range of Biology is divided into the following main branches. 1. Morphology: This branch deals with both the external and internal structures of organism. The subject concerning internal . structures is also known as Anatomy. 2. Cytology: Each living organism consists of one or more cells. Structures and functions of cells are treated in this branch of Biology. 3. Histology: In this branch discussion is made on structure, location and function of different tissues. 4. Physiology: This branch includes all the activities of living things e.g growth respiration, excretion, photosynthesis and other biological activities. 5. Taxonomy: In this branch discussion is made on identification nomenclature, and classification of plants and animals into groups and subgroups.Intorduction to Biology 3 6. Genetics: How different characters are inherited from parents to offsprings, and how the processes can be controlled and improved etc. are brought under study and research in this branch. 7. Ecology: This branch considers the effects of environment on living organisms or living communities and also interaction between them. 8. Evolution: This branch deals with the origin and successive transformations of living organisms. The groups discussed above are the basic branches of Biology. Scientists gradually started to utilize the knowledge of these branches for human welfare, and as a result applied branches of Biology were created. Agriculture, Medical science, Breeding etc. are some of the important applied branches of Biology. Applied Biology also includes Forestry and Horticulture, Fishery, Pest Control. Animal Husbandry etc. There are numerous varieties of plants and animals on earth. Generally similar plants or animals are arranged in particular groups. Some special branches of Biology have been created on the basis of different types of living things are under discussion and research: for example. Phycology includes only members of algae; fungi are treated in Mycology; Virology deals with viruses only; bacteria are considered in Bacteriology; Helminthology is based on study of worms only; insects are discussed in Entomology. Each of the above mentioned divisions has been divided into subdivisions or branches. It has been mentioned earlier that research in Biological fields has greatly extended now-a-days. Biology, as it appears today, was not the same the past 50 years ago. It was believed that sweat-soaked warm clothing of men and some wheat, if kept together in a box for few days, rats would be produced. This wrong concept about the origin of life prevailed for a long time. Subsequently ideas about origin of life have changed by the research works of various scientists. Modern4 Secondary Biology Biology is the result of research and thinking of some great scientists. This chapter introduces you with some of these scientists. Aristotle (384-322 B.C): The great Greek scientist, Aristotle is regarded as the father of Zoology. He first established Zoology as a branch of Science. Aristotle was simultaneously a scientist, poet, thinker and philosopher. It is he who first mentioned about the basic similarities in the structure of plants and animals. He stayed in an island named Lesbos for five years continuously and made research on animals. He wrote a book on animals and named it "Historia animalium" which is full of information and knowledge. Theophrastus (370-285 B.C.): Little amount of works of the Greek philosopher Theophrastus is known to us. Of those available, nine volumes of "On the History of Plants" and six volumes of "On the causes of plants" are important. Theophrastus was the pupil of great philosopher Aristotle. He divided the plant community into four groups. For example: Trees shrubs, Undershrubs and Herbs. He is regarded as the Father of Botany. Al Biruni (973-1048): Known as an world famous scientist and educationist. Al Biruni was an Arabian citizen. His real name is Abu Raihan Mohammad Ibne Ahmed Al Biruni. He made contributions in different branches of science. He visited India during the reign of Sultan Mahmud of Ghazni and described the conditions prevailing in India in an attractive way. Ibne Sina (980-1037): He was a renowned Muslim philosopher and scientist. He had excellent skill in Chemistry, Medicine, Mathematics, Astronomy and Literature. His full name is Abu Ali Hussain Ibne Abdullah Ibne Sina. He composed more than hundred books on different subjects. Sixteen of which were written on Medicine. He had a fourteen volume compositions named Al- Kanun' on Medicine.5 Secondary Biology A1 Nafis: He was an Arabian scientist. He first (300 years before William Harvey) described correctly the system of blood circulation in human body. He was also a successful physician. His actual name was Abu Al Hasan Ali Ibne Al Nafis, He dedicated himself in the field of science for a long time, and died in Damascus at the age of eighty. William Harvey (1578-1657): William Harvey was a British scientist. He rediscovered the system of blood circulation in 1628 and as a result some of the previous ideas about it came to an end. In 1651 he pointed out that life starts from the egg cell. He is considered to be the father of Animal Physiology. He clearly described the systems of blood circulation and excretion in animals, and explained the relationship between the two processes. He published a book "On the motion of the heart and blood in animals". Anthony Von leenwenhoek (1632-1723): Dutch scientist leeuwenhoek first built the microscope. But his microscope was not like that of today. Descriptions of bacteria, nerve cell, Hydra, Volvax, etc. were written by him on observations through his microscope. They have been found to be precisely correct. Carolus Linnaeus (1707-1778): Swedish scientist Linnaeus introduced the system of Binomial Nomenclature for plants and animals. A physician by profession, he was the professor of physiology in Uppsala University, Sweden. Collecting numerous plants and animals he classified them and made their nomenclature. His "Systema Naturae" composed on classification of living beings is a famous research work. Besides this his other two famous Botanical books titled "Species Plantarum" and "Genera Plantarum" are based on research work. He is considered to be the father of modern Taxonomy. Charles Robert Darwin (1809-1882): English naturalist Darwin introduced the Theory of Natural Selection. He expressed his findings and ideas in his famous research publication, "Origin of Species by Means of Natural6 Secondary Biology Selection" in the year 1859, after observing the living communities of Galapagos Islands. Alfred Russel Wallace (1823-1913): English naturalist Wallace made observation and research works in the Amazon plateau for four years. His renowned book `Travels on the Amazon and Rio Negro" was written on this experience. He wrote "The Malay Archipelago" on his eight years research experience in Malay Peninsula. The huge collection of insects he made has been kept preserved in the Hope collection centre of Oxford University. He is famous for the introduction of Natural Selection Theory along with Charles Darwin. Gregor Johann Mendel (1822-1884): Austrian Priest Mendel performed research work with pea plants in his church garden for a long time. Based on this research he established two laws concerning genetics, which are followed till today. He is regarded as the father of Genetics. George Bentham (1800-1884): The most notable work of this English Botanist is the composition of three volumes of "Genera Plantarum" along with Joseph Dalton Hooker.Other books written by him are `Handbook of the British Flora'. `Flora Hongkongensis', Flora `Australiensis' etc. Thomas Henly Huxley (1825-1895): Renowned British Zoologist T.H. Huxley did a lot of works on birds. He termed birds as `glorified reptiles' and proved that birds have been evolved from the reptilian ancestors. Besides, he made extensive research on Zoology. He was a notable supporter of Charles Darwin's theory of Natural Selection. Huxley described protoplasm as the physical basis of life.Introduction to Biology 7 Theophrastus Aristotle Anthony Von Leewenhoek Carolus Linnaeus Charles Darwin8 Secondary Biology Alexander Fleming Gregor johann Mendel Selim Ali Watson Alexander Fleming (1881-1955): Alexander Fleming was a Microbiologists He observed in 1918 that some bacterial growth stops in a culture media where Penicaillium is grown. He tried to find out the reason behind it. From his quest and research he subsequently discovered the drug penicillin that has saved millions of lives. He won Nobel Prize along with two other winners in the year 1945. David Prain: David Prain was an English physician. He obtained degree in medicine from Aberdin and Edinburgh. Joining Indian Medical Service he came to India in 1883. His first Place of Posting was Luxmipur in Noakhali. Later he started research with the plants of this region. He was the Director ofIntroduction to Biology 9 Calcutta Botanical Garden from 1887 to 1897. His famous book, "Bengal Plants", Published in two volumes, widely treats plants of Bangladesh and adjoining areas. "Flora of Sundribuns" is another notable book written by him. Salim Ali (1896-1987): Known as the Birdman of India, Salim Ali was a renowned ornithologist. He scientifically observed all birds of India and wrote an informative book. The title of the book is "The Indian Birds" In addition to this he composed many other books on birds. His autobiography is also a famous publication. In 1983 the Indian Government awarded him "Padmabhushan" title in recognition of his research work. Sir Hans Krebs (1900-1981): English scientist Krebs won Nobel Prize in 1953 along with F.A. Lipmann in medicine and physiology for his research work on metabolism of cells. He was appointed as the departmental head of Biochemistry in the Oxford University in 1954. Krebs cycle of respiration in living beings is his discovery. James Watson and Francis Crick: The two British scientists, Watson and Crick are famous for making the model of the molecular structure of DNA which bears the hereditary factors of human beings. While carrying out the research for PhD Degree in Cambridge University they discovered the molecular structure of DNA in 1953. They won Nobel Prize in the year 1963 for this work. Watson and Crick first noticed that DNA molecule is structurally a double helix and spiral. Melvin Calvin (Born in 1911): Calvin, a professor of California University U.S.A. is famous for his research concerning the pathway of carbon assimilation in green plants. In co-operation with other scientist Bassham, discovered the biochemical steps of Carbon assimilation known as Calvin Bassham pathway of photosynthesis. He obtained Nobel Prize in 1961.10 Secondary Biology CHARACTERISTICS OF PLANTS AND ANIMALS Taking a few main characteristics from many we shall now compare plants with animals. 1. Size and shape: Plants have no definite size and shape while animals have definite size and shape. 2. Life Time: Life time is not limited for plants and under suitable conditions they live for a long period. But animals live up to a certain length of time under suitable conditions. 3. Growth: In suitable environment growth of many plants continue for a long period. Growth in animals takes place up to a certain stage of life and growth ceases after that. 4. Movement: Most land plants remain fixed in soil with the help of roots as a result they cannot move. But some organs of plants may show some movement. A few animals (Such as Sponge) are not capable of movement. Most of the animals can move freely. 5. Nature of Food: Plants cannot take solid food Animals can take solid and liquid type of food. 6. Nutrition: Plants are autotrophic, it can prepare food through photosynthesis. Animals cannot prepare their own food. For foods they are to depend on plants and other animals. 7. Structure of Cell: A Plant cell has dead cell wall. Most of the mature cells have a large vacuole and plastids. The animal cell has no cell wall and it contains small vacuoles and centrioles. 8. Reproduction: Plants reproduce by vegetative, asexual and sexual methods. Reproduction in animals mainly takes place by sexual method.Vegetative and asexual reproduction may be found in some animals. 9. There are different systems in animal body. But plants have no body system.Introduction to Biology 11 ROLE OF BIOLOGY IN SOCIAL, ECONOMIC AND ENVIRONMENTAL DEVELOPMENT The two main branches of Biology are Botany and Zoology. In addition to these, there are other branches and sub-branches of Biology. You have come across some of those in the preceding parts of this chapter. Now let us discuss the importance of Biology on the basis of knowledge you have already attained. Agricultural science has many branches of which Agronomy, Horticulture, Plant breeding, plant pathology, Fishery, Animal husbandry, Poultry, Honeybee culture (Apiculture), Sericulture etc. are important. With the application of knowledge of these branches economic development is possible. Both plants and animals are the essential components of natural environment. It is known to you that plants and animals are interdependent in many ways. Ecology makes us alert about the importance of plants and animals and also the necessity of their presence in nature, Educated and conscious citizens can play important role in conservation and development of environment. Economic development sometimes produces adverse effects on natural environment. Environmental degradation and hazards can be encountered through proper application of our knowledge in ecology, Economic solvency and good environment help social development. NATURE AND ORIGIN OF LIFE You know what nature is. We live in nature. We have soil, water, air different plants, animals, insects and worms etc. all around us. All these together constitute nature. Millions of years ago nature was not as we see it today. Nor will it remain the same after millions of years. This indicates that nature is always changing. Nature undergoes changes due to various natural forces such as river-currents, earthquakes, volcanic eruptions etc. Different human12 Secondary Biology activities, such as destruction of forests, construction of dams etc. also bring about changes in nature. Scientists have been thinking about the origin of nature. There are different theories about the origin of the Earth. Among these the commonly acceptable theory explains that a part of the Sun or a similar star got detached as a result of the attraction of another star. The planets including the Earth and then satellites have been created from the detached part of the sun. According to this theory at the beginning the Earth was in a hot, gaseous state Subsequently the Earth gradually cooled and condensed to form the Earth as it is now. The core of the Earth is still in an extremely hot liquid and gaseous state. Nature of the Earth at the primary stage was not at all suitable for inhabitation of life. Gradually it became favourable for the existence of living forms. Now a question may arise in your mind as to how life originates in nature. Did plants and animals exist in nature from the very beginning? There are different theories regarding the origin of life on the Earth. In the beginning of this chapter we have described an old concept of the origin of life But the theory presented by Oparin, a Russian scientist, about the origin of life is still accepted. According to the theory of Oparin nature was quite hot when life was created Different gases such as ammonia (NH3), hydrogen (H2), methane (CH4) hydrogen cyanine (HCN) etc. were present in the atmosphere. During that period there was heavy rainfall and thunderstorm. Under such environmental condition amino acids were formed by the interaction of various gases and these amino acids are considered by scientists to be the first molecule of life The first cell or life came into being through incorporation of amino acids. It is also believed that life was created first in the primitive aquatic environment.14 Secondary Biology 3. According to the Oparin's theory and established scientific reasons which one of the following is correct if arranged chronologically from origin of life to the recent? a. Amino acid Unicellular Algae Bacteria Unicellular Amoeba. b. Amino acid Unicellular Amoeba Bacteria Unicellular Algae. c. Amino acid Bacteria Unicellular Algae Unicellular Amoeba. d. Amino acid Bacteria Unicellular Amoeba. Unicellular Algae 4. According to the Oparin's theory and established scientific reasons which one of the following animals came into being at the last in the terrestrial environment? a. Bird b. Man c. Buffalo d. Banyan tree Creative questions 1. Kalidas became curious about plants and animals when he was studying at Shingua High School. Seeing his curiosity the teachers of that school advised him to study biology when he will be grown up. According to that advise Kalidash studied on Botany in the University. The subjects he studied included both pure and applied branches of Biology. But afterwards he started working on applied branch and invented many high yielding fruits & crops. He is still engaged in this works. a) What is Biology? b) Why is physiology called the pure branch of Biology? c) Explain that why is the works of Kalidash included in the applied branch of Biology. d) Analyse the importance of pure branch in the success of Kalidash.Introduction to Biology 13 The first cell had protoplasm, amino acid and later on DNA molecules are formed by union of amino acid molecules, But the cells did not have any nucleus. This non-nucleated cell successively gave rise to nucleated cell and multicultural organism. Exercise Multiple choice questions 1) Why is Gregor Johann Mendel famous for? a. For Natural Selection theory. b. For the invention of blood circulation mechanism. c. For the invention of penicillin. d. For the law of heredity. 2) Which scientist contributed much for detail description of plants in Bangladesh? i. Aristotle ii. Theophrastus iii. David Prain Which of the following is correct? a. i. b. ii. c. iii. d. ii & iii Give answer to the question no. 4 and 5 according to the following paragraph. The theory presented by Oparin about the origin of life in nature is more accepted. According to the theory at the beginning of life amino acids, the first molecule of life were formed by the interaction of various gases. Then the first cell or life came into being through incorporation of amino acids in the aquatic environment. The first cell did not have any nucleus. This non-nucleated cell gave rise to a nucleated cell and successively multicellular organisms.CHAPTER-TWO Structure and Nature of Living Cell Those who have life are living beings. Microorganisms, Plants and Animals have life, so they all are living beings. Living world is composed of microorganisms plants and animals. One or more cells make every living being. Cell is the structural and functional unit of living body. All sorts of reaction and anti- reaction in living body are cell centered. So to know about any living beings one should know about the living cell at first. All living cells are not alike. As they are, different in structure, they are different in size, shape and functions. Different types of cell are described below in brief. All the cells of Plants and Animals are eukaryotic but they have differences as well. Difference between Plant cell and Animal cell are shown in a tabular form at the end of this chapter. However the main difference between them is the Plant cells have a non-living cell wall, which is absent in the Animal cells. Smooth Endoplasmic reticulum Microvilus Cell wall Golgibody Chloroplast Cell membrane Vacuole Centrosome Centriol Nuclear wall Cytoplasm Nucleolus Chromatin fiber Nuclear pore Mitochondrion Animal cell Rough Endoplasmic reticulum Plant cell Fig : 2.1 :- Generalised Plant and Animal Cells (Seen under Electron Microscope)16 Secondary Biology A. On the basis of Nuclear Structure Prokaryotie cell or Proto cell : Nucleus is not well organized in these cells; nuclear membrane and nucleolus are absent here. In these cells Chromosome contains only DNA. Generally no other organelles are present except Ribosome. Cell division happens here through Amitosis process. Eukaryotic cell or Eucell : There are well-organised nucleus in these cells with membrane and nucleolus. Chromosome contains DNA, proteins Chloroplasts, Mitochondria and other organelles. Cell division happens through mitosis process. B. On the basis of Function Somatic cell : These cells construct the living body but do not take part in reproduction. In the lower group of living objects they are haploid i.e. only one set of chromosomes are present, but in higher groups they are diploid i.e. there are two sets of chromosome in the nucleus. Reproductive cell: These cells take part in sexual reproduction but do not construct the main body. These cells are also haploid. Sperm and ovum are examples of reproductive cell. Size, shape and Structure of Living cell : It is normal to have some diversity in size, shape and structure of cells. The size, shape and structure of a eukaryotic cell (eucell) are described below in brief. Size : A cell may be 0.1 ยต (micron) to 55cm (centimeter) or even more. 1 Millimeter = 1000 Micron Shape: Cells are of different shapes. Mainly they are spherical, oval, rectangular, barrel shaped or polygonal. Structure of typical cell : Structurally cells are of various types. For that in a certain cell all the organelles or structural ingredients may not be present. For that reason, considering the presence of all the organelles in a certain cell, it may be termed as a Generalized Cell. A generalized cell has mainly two parts- Cell wall and protoplasm.Structure to Nature of Living Cell 17 Cell Wall: Cell wall is the unique characteristics of a plant cell. The non-living and hard wall, which constructs the plant cell, is called the cell wall. At first Robert Hook observed it in 1665 AD. There is no cell wall in Animal cells. Chemical composition of cell wall: The cell wall is mainly composed of cellulose, hemicellulose, pectose, lignin, suberine etc. Those are made by different carbohydrate compound. The cell wall of fungi is made of a carbohydrate called chitin. The cell wall of bacteria made of protein, lipid and polymer. Function of cell wall: The functions of cell wall are to give a definite shape to the cell. It protects the Cell from external injury and gives necessary rigidity and to regulate the flow fluid between external and internal side of the cell. Protoplasm: Protoplasm is made by the mixture of different complex compounds. It is jelly like, translucent, viscous, colourless semi solid-living substance. All the pro perties of life are present in it. Protoplasm is divided into three parts: Plasma membrane, Cytoplasm and Nucleus. 1. Plasma membrane or Cell membrane: Just beneath the cell wall there is a soft living membrane surrounding the whole protoplasm. This is called cytoplasmic membrane or cell membrane. Stucture: Plasma membrane is bi-layered. Under electron microscope there revealed a light layer between two dark layers. In the cell membrane of some epithelial cell there found some finger like out growth-these are called Microvilli (Singular : Microvillus). They increase the absorption surface of the cell. The membrane between two adjacent cells modified in various forms to make the18 Secondary Biology Connection between two cells rigid. They also make the movement of different substances between the cells easier. In many cells spaces in the cell membrane may be broader. Functions of Cell membrane : (a) Transportaion of different materials inside and outside the cell, (b) Absorption of different substances (mainly nutrients) from outside the cell, (c) protection of the cell body and giving the cell a definite shape. 2. Cytoplasm : Outside the nucleus, the part of protoplasm, which is surrounded by the cell membrane, is known as cytoplasm. It is composed of different organic and inorganic compounds Microvilli like water. different nucleic acid and enzymes. The outer area of cytoplasm is more concentrate. less granular and hard, which is called Ectoplasm, and the central area, Which is less concentrated, called Endoplasm. Different organelles like plastids, mitochondria, endoplasmic reticulum, ribosome, golgi bodies, lysosome, centrosome and different nonliving substances are present in the cytoplasm. Function of Cytoplasm : (a) to hold different organelles and (b) to perform some organic functions. Description of organelles present in cytoplasm is given below : Plastid : Plastids are largest in size among the organelles present in cytoplasm. They can be seen clearly under microscope. Plastids are not present in Fungi, Bacteria and Animal cells.Structure to Nature of Living Cell 19 Plastids are mainly of two types: Leucoplastid or Leucoplast and Chromoplastid or Chromoplast. Leucoplastids are colourless and Chromoplastids are coloured. Chromoplastid again is of two types Chromoplast and Chloroplast. Leucoplast: They are colourless, as they have no pigment. Leucoplast may be converted into Chromoplast or mainly chloroplast in contact with sunlight. In absence of light the case may be reversed. Position: Leucoplasts are present in the cells of organs like root. underground stem etc. which do not come in contact with sunlight. Shape: Leucoplast may be semicircular or tubular in shape Function: Their function is to store food. Chromatoplast: Chromatoplasts are green or other colour; when green, it is called chloroplast and when they are other colour it is called Chromoplast. Chromoplast: They are variously coloured, other than green, mostly yellow and red in colour. They are also variable in shape. Chromoplast occurred in coloured part of plants. e.g. petals, coloured fruit and seeds, roots of carrot etc. Function: Flowers are coloured and beautiful due to their presence. Chloroplast: They possesses green pigments named chlorophyll in excess as a result they are green. Other pigments are also present to some extent. Every cell may contain one or more chloroplast. In higher plants the shapes of chloroplast is lenceolate. In Algal cells their shapes are of various types, e.g. cup shaped, spiral, reticulate, star shaped. semicircular etc. Structure of chloroplast: The following parts make Chloroplast : 1. A bi-layered semipermiable membrane surrounds the whole chloroplast. It is composed of protein and lipid. This is called lipoprotein. 2. A hygroscopic matrix surrounded by a membrane is there. This matrix is called stroma. 3. In the stroma, 40-80 well-arranged barrel shaped grana (sing: granum) are present. In one granum there are 5-25 granum disc. Inside

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