B50. 001- Access Biology Course Developers Dr. S. J. Oniye ABU, Zaria Mr. Peter Tunku ABU, Zaria Unit Writers Dr. S. J. Oniye ABU, Zaria Mr. Peter Tunku ABU, Zaria Course Co-ordinator M. K. Olubiyi NOUN, Lagos Edited by Prof. C. O. Akueshi University opos National Open University of Nigeria ■ National Open University of Nigeria Headquarters 14/16 Ahmadu Bello Way Victoria Island Lagos Abuja Anner Office 245 Samuel Adesujo Ademulegun Street, Central Business District OppositeArewa Suites Abuja e-mail: [email protected] url: wwwnou.edu.ng C) National Open University of Nigeria 2004 First published 2004 ISBN 978 058 384 X All Rights Reserved Published by Folubee Prints for National Open University of Nigeria Programme: B.Sc Science and Technology Course: Access Biology Duration: First Semester Programme Leader: Dr. M. A. Wasagu iii Contents Volume 1 Basic Concepts in Biology 1 Unit 1 Biology as a Science 1 Unit 2 , Classification of Living Organisms II Unit 3 Viruses 18 Unit 4 Bacteria 25 Unit 5 Protozoa 35 Unit 6 • Paramecium, Biological and Economic Importances-of Protozoa 43 Unit 7 Fungi 53 Unit 8 Algae 63 Unit 9 Mosses 70 Unit 10 Ferns 77 Volume 2 Flowering Plants 83 Unit 1 Characteristics of Flowering Plants - Differences between Gymnosperms and Angiosperms 83 Unit 2 Differences between Monocotyledons and Dicotyledons — Morphology of Angiosperms — Root System 89 Unit 3 Shoot System - Stems, leaves, flower and fruits 101 Unit 4 Important Definitions - Herbs, Shrubs, Trees, Ephemeral, Annual, Biennial, Perenial Plants 124 Unit-5 Nutrition in Plants 129 Unit 6 Co-ordination and Control in Plants 138 Unit 7 Transport and Transpiration in Plants 144 Unit 8 Respiration in Plants 155 Unit 9 Reproduction in Plants 165 Unit 10 Growth and Development in Plants 185 Volume 3 Regulatory Systems and Mechanisms in Animals 201 Unit 1 Regulatory Processes 201 Unit 2 The Mammalian liver 206 Unit 3 The Mammalian kidney '12 Unit 4 The Mammalian skin 218 Unit 5 Hormones in Animals 222 Unit 6 Nervous Coordination and Sense Organs in Animals 228 Unit 7 Locomotion in Animals 243 Unit 8 Respiration (Gaseous Exchange) in Animals 256 Unit 9 Nutrition and Transport System inAnimals 264 Unit 10 Reproduction in Animals 285 iv Volume 4 Evolution and Genetics 303 Unit 1 Evolutionary Theories, Evidence of Evolution and Modern view on Evolution 303 Unit 2 Modem Examples of Evolution (Microevolution); classification and evolution 316 Unit 3 Common Terms in Genetics Transmission and Expression of Characters — Hereditary Variation 322 Unit 4 Mendels work in Genetics — Chromosomes as a Basic of Inheritance Heredity and Environment — Probability in Genetics 331 Unit 5 Application of Genetics 347 Volume 5 Ecology 155 Unit 1 Basic Concepts and Principles in Ecology 55 Unit 2 Feeding Relationships in Ecology 1160 Unit 3 Interactions in an Ecosystem 166 Unit 4 Adaptation by Animals to different Environments 37C Unit 5 Adaptations by Plants to Different Environments 1 7-1 Unit 6 Habitat Studies 1 79 Unit 7 Population Studies Unit 8 Nutrient Cycles 392 Unit 9 Pollution and En% ronmental Health problems 399 Unit 10 Conservation of Natural resources 405 . Volume 1: Basic Concepts ineBiology Page 1.0 Introduction 2 2.0 Objectives 2 3.0 Definition of Biology 2 3.1 Characteristics of Living Things 2 3.2 Differences between Plants and Animals 2 3.3 Microscope 3 3.4 Plant and Animal Cell 3.4.1 Plant Cell 4 3.4.2 Animal Cell 3.5 Differences between Plant and Animal Cells 6 3.6 Similarities between Plant and Animal Cells 6 3.7 Cell Division 6 3.7.1 Meiosis 6 3.7.2 Mitosis 8 3.8 The Cell and Exchange of Materials 9 3.8.1. Diffusion 9 3.8.2. Osmosis 9 3.8.3. Plasmolysis 10 4.0 Conclusion 10 5.0 Summary 10 6.0 Tutor MarkedAssignment 10 7.0. Further Reading and Other Resources 10 1 2 Access Biology Biology is a science that deals with the living world. Its methods of i 1)::tiry are similar to those employed in all natural sciences. It is a fascinating study that ranges from microscopic cellular molecules to the multicellular macro forms of life, encompassing the earth's surface and its living organisms. The unit examines the characteristics of living things which distinguish them from non-living things, plant and animal cells, cell division and the exchange of materials within a cell. By the end of this unit, you should be able to: (a) define what Biology is; (b) distiguish between living things and non-living things; (c) show diagrammatically plant and animal cell; (d) describe the two types of cell division; (e) describe the process involved in the exchange of materials within a cell. Biology is the branch of science that involve the study of living things (Plant and animals) 3.1 Characteristics of Living Things Living things can be distinguished from non-living things by a number of characteristics. (a) Movement:- All living things move. Movement means a change in position which could be total one location to another) as in the case of animals or limited to one part of the body as in plant,. (b) Nutrition:- A Living organism needs food to supply the energy and materials for life pt c, sses. Nutrition involves the total process of taking in, and the utilisation of foods in animals; as well as taking in of mineral substances and their utilisation in plants. (c) Respiration:- This is the break down of food substances taken in by the organism to release energy. (d) Irritability (Sensitivity):- This is the ability of a living organism to receive an external stimulus and respond to it. (e) Excretion:- This is the removal of waste products of metabolism from'the body of a living organism. (f) Reproduction:- This is the process of giving rise to new individuals of the same kind for the continuation of life. Reproduction may be sexual or asexual in nature. (g) Growth:- A living organism grows. This is an increase in size which is usually accompanied by development (a change in form and abilities). The materials used for growtlur derived from the food taken in by the organism. (i) Adaptation:- This is the posession of features (structures or functions) which enable organisms to live successfully and to survive in their respective environments. 3.2 Differences between Plants and Animals There are notable differences between plants and animals. These are shown in Table 1.1 Biology as a Science 3 Table .1.1 FEATURES PLANT ANIMALS 1. Nutrition Autotrophic nutrition, Heretotrophic Nutrition, obtain i.e. makes own food by complex organic food already Photosynthesis, since it made. is green and has clorophyll. 2. Support Depends on tugor and Many Possess an lignifield tissues. endoskeleton or an exoskeleton. 3. Movement Rooted on one spot. The whole animal can Movement is generally move about quickly. slow since usually is as a result of growth. 4. Sensitivity Responds slowly to Sensory system allows stimulus by means of rapid responses. hormones. 5. Growth May grow large with Body is compact, growth branching body. Growth stops at maturity in higher which is mostly at animals. meristems, is indefinite. 6. Cell Structure Cellulose cell wall and Cell wall is absent. vacuoles containing cell Vacuole and chloroplast, sap are present, may are absent. contain Chloroplasts. Source: Federal Government School Practical Book 3.3 Microscope Microscopes are instruments which magnify the size of objects. There are various types. Simple, Compound and Electron microscope. The diagram below (Fig. 1) shows a simple type. Eyepiece lens coarse adjusment Objective Knob Lenses S a cover slip mounting Iris needle Mirror Slide Fine Adjustment Kno specimen mounted in a drop of water bas Fig 1.1 a. A compound light Microscope Fig LI b. Making a wet-mount of a specimen 4 Access Biology 3.4 Plant and Animal Cells 3.4.1 Plant Cell Under the light microscope, the plant cell has two principal parts. These are the protoplasm and the cell wall. The protoplasm is a term used to describe all the constituents of a living cell. Protoplasmic materials in the nucleus are called nucleoplasm and those outside the nucleus are called cytoplasm. The generalised plant cell (Fig. 1.2) shows the cell wall enclosing a nucleus which is surrounded by cytoplasm. Within the cytoplasm, there are a variety of sub-cellular parts called organelles. The.organelles include the following: (a) Cell wall: This encloses the outer surface of the cell membrane in plants. It is rigid, made up of cellulose. It provides support in plants. (b) Plastids: These are spherical organelles in the cytoplasm of plants. The three types of plastids common in plants cells are leucoplasts, chromoplast and chloroplast. The chloroplasts contain the green pigment called chlolophyll used in the manufacture of organic food Each chloroplast is surrounded by a membrane. Leucoplasts are colourless plastids and they form sites for the storage of starch and lipids. ChromOplasts contain different colours, and the colour of flower petals is due to these plastids. (c) Nucleus: Spherical or disc-shaped body located in the centre of the cell. It controls all the activities of the cell. (d) Endoplasmic reticulum (E.R.): It is a network of channels which traverses the cytoplasm and also connects to the cell membrane and the nuclear membrane. Its functions are: (i) Transport of substances within the cytoplasm and across the cell to the nucleus and cell membrance (ii) It also helps in the formation of enzymes and proteins. (iii) It provides a surface for the atachment of ribosomes. (e) Mitochrondria: These are small bodies which are barely visible under the light microscope.