Secondary LevelsBIOLOGY STUDYfor

Complete

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Complete Biology Study for Secondary Levels has been carefully written by a team of seasoned Biology experts who are educators and examiners with many years of teaching and marking experience.

The single-volume book is written primarily to provide students with a sound knowledge of terms, concepts and principles of Biology. The simplicity in concept presentation and explanation, adequate diagrammatic and pictorial illustrations with scientific approach will provide students with high quality contents to ensure excellent performance in their examinations.

The topics have been written under four broad themes, viz:

• Organisation of life

• The organism at work

• The organism and its environment

• Continuity of life

The book is developed in simple, lucid and logical ways to facilitate effective teaching/learning process and to enhance students’ performance in their examinations. It contains various experiments and activities for verification of concepts, principles, theories and laws.

The book also provides summary of the topics at the end of each chapter with multiple choice questions and answers, and past examination questions.

Finally, it is hoped that this book will solve the age-long problems encountered by teachers and learners of Biology in particular, and Science in general.

Preface

Part OneTheme 1: Organisation of LifeChapter 1: Recognising Living Things ......................................................................................... 2 1.1 Biology and Science ................................................................................................................ 2 1.2 Definition and Branches of Biology ................................................................................. 2 1.3 Usefulness of Science and Biology ................................................................................... 3 1.4 Scientific Method ..................................................................................................................... 4 1.5 Characteristics of Living Organisms ................................................................................ 5 1.6 Differences and Similarities Between Plants and Animals ................................... 7Chapter 2: Classification of Living Things ................................................................................. 9 2.1 Definition of Classification .................................................................................................. 9 2.2 Binomial Nomenclature ....................................................................................................... 9 2.3 Hierarchy of Classification Groups ................................................................................ 10 2.4 Classification System ........................................................................................................... 12 2.5 Kingdom Monera ................................................................................................................... 13 2.6 Kingdom Protista .................................................................................................................. 15 2.7 Kingdom Fungi ....................................................................................................................... 20 2.8 Kingdom Plantae ................................................................................................................... 22 2.9 Kingdom Animalia ................................................................................................................ 28 2.10 Classification of Invertebrata ........................................................................................... 30 2.11 Phylum Chordata ................................................................................................................... 43Chapter 3: Organisation of Life ..................................................................................................... 51 3.1 Levels of Organisation of Life ........................................................................................... 51 3.2 Complexity of Organisation in Higher Organisms ................................................... 53Chapter 4: The Cell ............................................................................................................................ 56 4.1 Cell as a Living Component of an Organism .............................................................. 56 4.2 Forms in Which Living Cells Exist .................................................................................. 57 4.3 Cell Structure .......................................................................................................................... 61

Contents

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4.4 Cell Structure and Functions of Cell Components ................................................... 63 4.5 Differences and Similarities Between Plant and Animal Cells ........................... 67Chapter 5: The Cell and Its Environment ................................................................................. 71 5.1 Diffusion .................................................................................................................................... 72 5.2 Osmosis ..................................................................................................................................... 74 5.3 Examples of Osmosis in Plants and Animals ............................................................. 76 5.4 Turgidity and Its Significance in Plant Cells .............................................................. 76 5.5 Plasmolysis .............................................................................................................................. 77 5.6 Living cell as Osmometer ................................................................................................... 78 5.7 Haemolysis ............................................................................................................................... 78 5.8 Biological Significance of Osmosis and Diffusion .................................................... 79 5.9 Flaccidity ................................................................................................................................... 79 5.10 Active transport ..................................................................................................................... 79Chapter 6: Some Properties and Functions of the Cell ....................................................... 82 6.1 Nutrition (Feeding) .............................................................................................................. 82 6.2 Nutritional Requirements of Organisms ..................................................................... 83 6.3 Metabolism—Anabolism and Catabolism .................................................................. 85 6.4 Role of Enzymes ..................................................................................................................... 85 6.5 Respiration ............................................................................................................................... 86 6.6 Excretion ................................................................................................................................... 92 6.7 Growth ....................................................................................................................................... 93 6.8 Factors Affecting Growth ................................................................................................... 97 6.9 Cell Reaction to Its Environment .................................................................................... 98 6.10 Movement .............................................................................................................................. 100 6.11 Reproduction ....................................................................................................................... 100 6.12 Structure and Function of Male and Female Gonads .......................................... 105 6.13 Meiosis .................................................................................................................................... 106

Theme 2: The Organism at WorkChapter 7: Plant Nutrition ........................................................................................................... 110 7.1 Photosynthesis .................................................................................................................... 110

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7.2 Mechanism of Photosynthesis ...................................................................................... 112 7.3 Raw Materials and Conditions Necessary for Photosynthesis ....................... 113 7.4 Experiments on Photosynthesis .................................................................................. 114Chapter 8: Animal Nutrition ....................................................................................................... 119 8.1 Food Substances ................................................................................................................. 119 8.2 Classification of Food ........................................................................................................ 119 8.3 Balanced Diet ....................................................................................................................... 124 8.4 Food Tests .............................................................................................................................. 125 8.5 Enzymes ................................................................................................................................. 126 8.6 Digestive Enzymes ............................................................................................................. 126Chapter 9: Modes of Nutrition ................................................................................................... 130 9.1 Modes of Nutrition ............................................................................................................. 130Chapter 10: Feeding Mechanisms in Holozoic Organisms ............................................ 136 10.1 Feeding Mechanisms ........................................................................................................ 136 10.2 Feeding Habits ..................................................................................................................... 138 10.3 Process of Feeding in Amoeba and Hydra ............................................................... 139 10.4 Mammalian Teeth ............................................................................................................... 140 10.5 Dental Care ............................................................................................................................ 142Chapter 11: Supporting Tissues and Systems ..................................................................... 145 11.1 Skeleton and Supporting System in Animals .......................................................... 145 11.2 Biological Significance of Skeleton ............................................................................. 145 11.3 Forms of Skeleton ............................................................................................................... 145 11.4 Types of Skeleton ............................................................................................................... 147 11.5 Vertebrate Skeleton ........................................................................................................... 148 11.6 Appendicular Skeleton ..................................................................................................... 15311.7 Joints ........................................................................................................................................ 15711.8 Functions of Skeleton in Animals ................................................................................ 15911.9 Muscles ................................................................................................................................... 15911.10 Supporting Tissues in Plants ......................................................................................... 16311.11 Mechanism of Supporting System in Plants ........................................................... 16511.12 Secondary Growth in Dicot Stem ................................................................................. 168

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Theme 3: The Organism and Its EnvironmentChapter 12: Basic Ecological Concepts .................................................................................. 171 12.1 Ecological Concepts ........................................................................................................... 172 12.2 Components of An Ecosystem ...................................................................................... 173 12.3 Local Biotic Communities or Biomes in Nigeria ................................................... 175 12.4 Major Biomes of the World ............................................................................................ 177 12.5 Population Studies ............................................................................................................. 181 12.6 Characteristics of Population ........................................................................................ 181 12.7 Methods Used for Population Studies ....................................................................... 182 12.8 Techniques for Collection of Samples ........................................................................ 183 12.9 Determination of Population Size and Density ..................................................... 184 12.10 Ecological Factors .............................................................................................................. 185 12.11 Soil Studies ............................................................................................................................ 189Chapter 13: Functioning Ecosystem ....................................................................................... 196 13.1 Autotrophy and Heterotrophy ...................................................................................... 196 13.2 Producers .............................................................................................................................. 196 13.3 Consumers ............................................................................................................................ 197Chapter 14: Food Chains, Food Webs and Trophic Levels ............................................. 200 14.1 Food Chain ............................................................................................................................. 200 14.2 Food Web ............................................................................................................................... 201 14.3 Trophic Levels ..................................................................................................................... 202 14.4 Non-cyclic Nature of Chemical Energy Transfer ................................................... 203 14.5 Nutrient Movement ........................................................................................................... 204 14.6 Decompostion and Its Importance ............................................................................. 209Chapter 15: Energy Transformation in Nature .................................................................. 213 15.1 Energy Loss in the Ecosytem ......................................................................................... 213 15.2 Laws of Thermodynamics .............................................................................................. 214 15.3 Application of Both Laws to Ecological Phenomena ........................................... 214Chapter 16: Relevance of Biology to Agriculture ............................................................... 217 16.1 Effects of Agricultural Activities on Ecological Systems .................................... 217

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16.2 Effects of Different Types of Farming Methods on Ecological Systems ...... 219 16.3 Pests and Diseases of Agricultural Importance .................................................... 221 16.4 Pests of Farm Animals ...................................................................................................... 226 16.5 Food Production and Storage ........................................................................................ 229 16.6 Relationship Between Availability of Food and Human Population ............ 231 16.7 Government Effort to Increase Food Production ................................................. 232Chapter 17: Micro-organisms Around Us ............................................................................. 235 17.1 Micro-organisms in Air and Water ............................................................................. 235 17.2 Concepts of Culturing ....................................................................................................... 237 17.3 Process of Culturing .......................................................................................................... 238 17.4 Identification of Micro-organisms in Air and Water ........................................... 239 17.5 Micro-organisms in Our Body and Food .................................................................. 241 17.6 Carriers of Micro-organisms ......................................................................................... 242Chapter 18: Micro-organisms in Action ................................................................................ 246 18.1 Methods Used to Measure Growth in Micro-organisms .................................... 246 18.2 Beneficial Effects of Micro-organisms ....................................................................... 248 18.3 Harmful Effects of Microbes .......................................................................................... 249 18.4 Spread of Disease-causing Micro-organisms ......................................................... 252Chapter 19: Towards Better Health ......................................................................................... 256 19.1 Control of Harmful Micro-organisms ........................................................................ 256 19.2 Vectors and their Control ................................................................................................ 258 19.3 Public Health ........................................................................................................................ 260 19.4 Health Status and Community Issues ........................................................................ 261 19.5 Community or Public Health ......................................................................................... 263Chapter 20: Aquatic Habitat—Marine Habitat ................................................................... 269 20.1 Marine Habitat ..................................................................................................................... 26920.2 Major Zones of Marine Habitat ..................................................................................... 27020.3 Distribution of Organisms and their Adaptive Features in Marine Habitat .................................................................................................................................... 27320.4 The Marine Food Chain .................................................................................................... 274Chapter 21: Aquatic Habitat—Estuarine Habitat .............................................................. 276 21.1 Estuarine Habitat ............................................................................................................... 27621.2 Distribution of Plants and Animals in Estuarine Habitat .................................. 277

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21.3 Adaptive Features of Plants and Animals in Estuarine Habitat ..................... 27721.4 Food Chains in Estuarine Habitat ................................................................................ 278Chapter 22: Aquatic Habitat—Freshwater Habitat .......................................................... 280 22.1 Freshwater Habitat ............................................................................................................ 28022.2 Types of Freshwater Habitat ......................................................................................... 28122.3 Characteristics of Freshwater Habitat ....................................................................... 28122.4 Factors Affecting Freshwater Habitat ........................................................................ 28222.5 Adaptive Features of Freshwater Organisms ......................................................... 28322.6 Food Chains and Energy Flow in Freshwater Habitat ........................................ 283Chapter 23: Terrestrial Habitat—Marsh ............................................................................... 286 23.1 Marsh ....................................................................................................................................... 28623.2 Plants and Animals that Live in Marshes ................................................................. 28823.3 Adaptive Features of Organisms in the Marsh ....................................................... 28923.4 Food Chains in the Marshes ........................................................................................... 289Chapter 24: Terrestrial Habitat—Forest ............................................................................... 291 24.1 A Forest ................................................................................................................................... 29124.2 Tropical Rainforest ............................................................................................................ 29124.3 Climatic Factors of Tropical Rainforests .................................................................. 29224.4 Distribution of Plants and Animals in a Forest Habitat ..................................... 29324.5 Adaptive Features of Plants and Animals in a Forest Habitat ......................... 29424.6 Food Chains in Tropical Rainforest Habitats .......................................................... 295Chapter 25: Terrestrial Habitat—Grassland ....................................................................... 297 25.1 Grassland ............................................................................................................................... 29725.2 Distribution of Plants and Animals in Grassland .................................................. 29825.3 Some Adaptations of Grassland Communities ...................................................... 29825.4 Food Chains in Grasslands .............................................................................................. 299Chapter 26: Terrestrial Habitat—Arid Lands ..................................................................... 301 26.1 Arid Lands ............................................................................................................................. 30126.2 Distribution of Organisms in Arid Habitat .............................................................. 30226.3 Some Adaptations of Organisms of Arid Lands ..................................................... 30226.4 Food Chains in Arid Habitat ........................................................................................... 304

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Chapter 27: Reproduction in Unicellular Organisms and Invertebrates ................. 306 27.1 Reproduction ....................................................................................................................... 30627.2 Asexual Reproduction in Amoeba ............................................................................... 30727.3 Reproduction in Paramecium ....................................................................................... 30827.4 Reproduction in Spirogyra ............................................................................................. 30827.5 Reproduction in Earthworm ......................................................................................... 30927.6 Metamorphosis ................................................................................................................... 30927.7 Reproduction in Cockroach .......................................................................................... 31027.8 Reproduction in Housefly ............................................................................................... 31027.9 Reproduction in Snail ....................................................................................................... 311

Part TwoTheme 1: Organisation of LifeChapter 28: Classification of Plants ......................................................................................... 315 28.1 Botanical Classification .................................................................................................... 31528.2 Agricultural Classification .............................................................................................. 31528.3 Classification of Plants Based on Life Cycle ............................................................ 317Theme 2: The Organism at WorkChapter 29: Digestive System .................................................................................................... 319 29.1 Parts of the Alimentary Canal ....................................................................................... 319 29.2 Types of Alimentary Canals ........................................................................................... 320 29.3 Similarities and Differences Between the Alimentary Canals of

Grasshopper and Bird ...................................................................................................... 323 29.4 Alimentary Canal of Mammals ..................................................................................... 324 29.5 Absorption of Digested Food ......................................................................................... 326 29.6 Assimilation of Digested Food ...................................................................................... 326 29.7 Categories of Mechanisms and Modifications in Some Animals .................... 328 29.8 Feeding Habits ..................................................................................................................... 331 29.9 Feeding in Protozoa, Hydra and Mammals .............................................................. 332Chapter 30: Transport System ................................................................................................... 335 30.1 Need for Transportation ................................................................................................. 335

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30.2 Materials for Transportation in Organisms ............................................................ 336 30.3 Media of Transportation ................................................................................................. 336 30.4 Similarities and Differences Between Transportation of Substances in

Animals and Plants ............................................................................................................ 337 30.5 Mechanisms of Transportation .................................................................................... 338 30.6 Transportation in Higher Organisms ......................................................................... 33830.7 Circulatory System ............................................................................................................. 34230.8 Human Circulatory System ............................................................................................ 34330.9 Double Circulation of Blood in Human Beings ...................................................... 34730.10 Lymphatic System .............................................................................................................. 34830.11 Mechanism of Transportation in Higher Plants .................................................... 34830.12 Transpiration ....................................................................................................................... 352Chapter 31: Gas Exchange System (Respiratory System) .............................................. 36031.1 What is Gas Exchange? ..................................................................................................... 360 31.2 Characteristics of Gas Exchange Organ or Surface .............................................. 36031.3 Types of Respiratory System ......................................................................................... 36131.4 Mechanisms of Gas Exchange System in Lower Organisms ............................. 36231.5 Mechanisms of Gas Exchange System in Higher Organisms ............................ 36231.6 Human Gas Exchange System ....................................................................................... 36431.7 Breathing ............................................................................................................................... 36631.8 Gas Exchange in Plants .................................................................................................... 36831.9 Photosynthesis Versus Respiration ............................................................................ 370Chapter 32: Excretory System ................................................................................................... 37332.1 Excretion ................................................................................................................................ 373 32.2 Diffetent Types of Excretory Organs or Systems .................................................. 37432.3 Excretory Mechanisms in Some Organisms ............................................................ 37632.4 Structure of Urinary System in Mammals (Man) .................................................. 37732.5 Mechanism of Excretion Through Nephron ............................................................ 37932.6 Urine ........................................................................................................................................ 38032.7 Excretion In Plants ............................................................................................................. 381

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Theme 3: The Organism and Its EnvironmentChapter 33: Nutrient Cycling in Nature ................................................................................. 384 33.1 Aspects of Nutrient Cycling in Nature ....................................................................... 384 33.2 Nutrient Cycling in Nature ............................................................................................. 385 33.3 Decompostion in Nature ................................................................................................. 391Chapter 34: Ecological Management—Association ......................................................... 395 34.1 Biological Association ...................................................................................................... 39534.2 Types of Association ......................................................................................................... 395Chapter 35: Ecological Management—Tolerance ............................................................. 40135.1 Tolerance ............................................................................................................................... 401Chapter 36: Ecological Management—Adaptation .......................................................... 40536.1 Adaptation ............................................................................................................................. 40536.2 Adaptation in Plants Due to Environmental Conditions ................................... 40636.3 Adaptation in Animals Due to Environmental Conditions ............................... 40936.4 Structural Adaptation of Fish and Tadpoles to Live in Water ......................... 41036.5 Structural Adaptation of Birds ..................................................................................... 411Chapter 37: Ecological Management—Pollution .............................................................. 415 37.1 Pollution ................................................................................................................................. 415 37.2 Atmospheric (Air) Pollution .......................................................................................... 416 37.3 Radiation Pollution ............................................................................................................ 421 37.4 Noise Pollution .................................................................................................................... 423 37.5 Water Pollution ................................................................................................................... 425 37.6 Soil Pollution ........................................................................................................................ 429Chapter 38: Conservation of Natural Resources ................................................................ 43238.1 Natural Resources .............................................................................................................. 43238.2 Conservation ........................................................................................................................ 43338.3 Conservation of Natural Resources ............................................................................ 43338.4 Ways to Ensure Conservation of Natural Resources ........................................... 435Chapter 39: Pests and Diseases of Crops .............................................................................. 44039.1 Pests ......................................................................................................................................... 44039.2 Diseases Caused by Pests ................................................................................................ 445

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Theme 4: Continuity of LifeChapter 40: Reproductive Systems in Vertebrates ........................................................... 44940.1 Reproduction ....................................................................................................................... 44940.2 Basis of Reproduction in Vertebrates ........................................................................ 45040.3 Reproductive System in Fish ......................................................................................... 45040.4 Reproductive System in Reptiles ................................................................................. 45140.5 Reproductive System in Birds ....................................................................................... 45140.6 Reproductive System in Mammals .............................................................................. 45240.7 Menstrual Cycle ................................................................................................................... 45540.8 Structures of Mammalian Gametes (Sperm and Ovum) .................................... 456Chapter 41: Reproductive Systems in Plants ...................................................................... 46341.1 Flower ..................................................................................................................................... 46341.2 Calyx ......................................................................................................................................... 46441.3 Corolla ..................................................................................................................................... 46541.4 Androecium .......................................................................................................................... 46541.5 Gynoecium ............................................................................................................................. 46741.6 Placentation .......................................................................................................................... 46941.7 Inflorescence ........................................................................................................................ 47041.8 Fertilisation ........................................................................................................................... 470Chapter 42: Pollination in Plants .............................................................................................. 474 42.1 Pollination ............................................................................................................................. 474 42.2 Types of Pollination ........................................................................................................... 474 42.3 Agents of Pollination ......................................................................................................... 477

Part ThreeTheme 2: The Organism at WorkChapter 43: Regulation of Internal Environment .............................................................. 48343.1 Homeostasis ......................................................................................................................... 48343.2 Kidneys ................................................................................................................................... 48443.3 Liver ......................................................................................................................................... 48843.4 Skin ........................................................................................................................................... 49043.5 Care of Mammalian Skin ................................................................................................. 494

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Chapter 44: Hormonal Co-ordination .................................................................................... 49744.1 Hormones .............................................................................................................................. 49744.2 Glands—Exocrine and Endocrine ............................................................................... 49844.3 Animal Hormones .............................................................................................................. 49844.4 Plant Hormones .................................................................................................................. 50544.5 Auxins ...................................................................................................................................... 50644.6 Other Types of Plant Hormones and their Functions ......................................... 507Chapter 45: Nervous Co-ordination ........................................................................................ 51145.1 Organisation of Nervous System in Vertebrates ................................................... 51245.2 Central Nervous System (CNS) ..................................................................................... 51245.3 The Brain ............................................................................................................................... 51345.4 Spinal Cord ............................................................................................................................ 51645.5 Peripheral Nervous System (PNS) .............................................................................. 51645.6 Autonomic Nervous System (ANS) ............................................................................. 51845.7 Neurons .................................................................................................................................. 51945.8 Conduction of Nerve Impulse ....................................................................................... 52145.9 Reflex Action ......................................................................................................................... 52345.10 Conditioned Reflexes ........................................................................................................ 524Chapter 46: Sense Organs ............................................................................................................ 52946.1 Sense Organs ........................................................................................................................ 52946.2 Eye—Organ of Sight .......................................................................................................... 52946.3 Ears—Organs of Hearing ................................................................................................ 53546.4 Nose—Sense of Smell ....................................................................................................... 53846.5 Tongue—Sense of Taste ................................................................................................... 53846.6 Skin—Sense of Feeling ..................................................................................................... 539Theme 3: The Organism and Its EnvironmentChapter 47: Ecology of Population .......................................................................................... 54247.1 Ecological Succession ....................................................................................................... 54247.2 Primary Succession ........................................................................................................... 54447.3 Secondary Succession ...................................................................................................... 54647.4 Succession Versus Competition ................................................................................... 547

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47.5 Ecological Climax ............................................................................................................... 54747.6 Overcrowding ...................................................................................................................... 54847.7 Food Shortage ...................................................................................................................... 549Chapter 48: Balance in Nature .................................................................................................. 55248.1 Factors Affecting a Population ...................................................................................... 55248.2 Dynamic Equilibrium in Nature and Factors that Maintain It ........................ 55348.3 Family Planning .................................................................................................................. 554Theme 4: Continuity of LifeChapter 49: Reproductive Behaviours—Courtship Behaviours in Animals .......... 55849.1 Courtship Behaviours in Animals ............................................................................... 55849.2 Different Types of Courtship Behaviours in Animals ......................................... 559Chapter 50: Reproductive System and Reproduction in Humans .............................. 56350.1 Reproductive Systems in Male and Female (Human) ......................................... 56350.2 Menstrual Cycle ................................................................................................................... 57150.3 Fertilisation and Birth in Humans .............................................................................. 57250.4 Development of Embryo ................................................................................................. 57350.5 Parturition ............................................................................................................................. 575Chapter 51: Development of New Seeds ............................................................................... 57951.1 Flower—A Reproductive Unit of Plant ...................................................................... 57951.2 Fertilisation ........................................................................................................................... 58051.3 Seeds ........................................................................................................................................ 58251.4 Germination of Seeds ....................................................................................................... 58351.5 Conditions Necessary for Seed Germination .......................................................... 585Chapter 52: Fruits ........................................................................................................................... 58952.1 Fruit .......................................................................................................................................... 58952.2 Classification of Fruits ...................................................................................................... 59052.3 Dispersal of Fruits and Seeds ........................................................................................ 59252.4 Similarities and Differences Between Seeds and Fruits .................................... 594Chapter 53: Variation in Population ....................................................................................... 59653.1 Variation ................................................................................................................................. 596

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53.2 Types of Variations ............................................................................................................ 59753.3 Application of Variation ................................................................................................... 599Chapter 54: Biology of Heredity ............................................................................................... 60254.1 Heredity .................................................................................................................................. 60354.2 Transmission and Expression of Characters in Organisms .............................. 60354.3 Terminologies used in Heredity ................................................................................... 60454.4 Mendelism in Genetics ..................................................................................................... 60554.5 Mendel’s Laws of Inheritance ....................................................................................... 60654.6 Test Cross and Back Cross .............................................................................................. 60754.7 Principle of Incomplete Dominance ........................................................................... 60854.8 Sex Determination in Human Beings ......................................................................... 60854.9 Chromosomes—Carriers of Heredity ........................................................................ 60854.10 Probability in Genetics ..................................................................................................... 61054.11 Sex Linkage in Human Beings ....................................................................................... 61154.12 Application of the Principles of Heredity ................................................................. 612Chapter 55: Evolution ................................................................................................................... 61755.1 Adaptation ............................................................................................................................. 61755.2 Competition .......................................................................................................................... 61755.3 Structural Adaptation ....................................................................................................... 61855.4 Evolution ................................................................................................................................ 62155.5 Theories of Evolution ....................................................................................................... 62255.6 Evidences of Biological Evolution ............................................................................... 62455.7 Forces Responsible for Evolution ................................................................................ 625Answers to Multiple Choice Questions (MCQs) ................................................................... 628Glossary ................................................................................................................................................. 635Index ....................................................................................................................................................... 658

Chapter 1Recognising Living Things

PERFORMANCE OBJECTIVESAfter completing this chapter, students should be able to: • State various branches of biology• State the characteristics of living things• Statetheimportanceofscientificmethod

• Statethedifferencesandsimilaritiesbetweenplantsandanimals

1.1 BIOLOGY AND SCIENCETheword‘Science’originatesfromtheLatinisedword‘scientia’meaningknowledge.Itcanbedefinedas thestudyofstructureandbehaviourof thephysicalandnaturalworldthroughobservationandexplanation.Generally,scienceisdividedasshownbelow.

Human beings have always been curiousaboutthethingsintheirenvironment,especiallythingsthathavelife.Thiscuriosityhasledthemto explore and study nature. Changingweather,movementoflivingorganisms,formationofplantsfrom seeds and much more have always madehuman eager to learnmore about the universe.Biologyistherefore,thebranchofsciencewhichisconcernedwiththestudyoflivingthings.

1.2 DEFINITION AND BRANCHES OF BIOLOGYDefinition: The term ‘Biology’ (Greek. bios meaning life and logos meaning to study) iscoined by Lamarck and Treviranus in 1802.

Biology is the science devoted to the study oflivingorganisms.

Why studying Biology?Thestudyofbiologyisimportantbecause:• Biology helps us to understand ourselvesbetter and to realise the meaning of beingalive.

• It enables us to meet our needs throughjudicioususeofresources,eradicatediseasesandcheckdegradationofourenvironment.

• Itteachesushowtopractisescience.• It makes us aware of the fundamentals ofnutrition,healthandpopulationcontrol.

SCIENCE

PHYSICS CHEMISTRY BIOLOGY

Studyofcompositionofmatterandtheirproperties

Studyofmatterandenergy

Studyoflife

Studyofanimalsincludinghumanbeings

Studyofplants

4 Recognising Living Things

7.Transportation:Theknowledgeof sciencein transportation has helped man to builddifferent means of transportation such ascars, buses, trains, aeroplanes and rockets.These means of transportation help in the movement of people and goodswithin andacrossthenationspossible.

Important biological researches in science include: • Invitrofertilisation(IVF)thathelps infertilecoupletohaveachild.

• Production of hybrid crop plants and farmanimalswithdesirablequalities.

• Useofbiologicalpesticides tominimisesoilpollution.

• Production of single cell protein (SCP) tocontrol the mass death of people due toproteindeficiency.

• Use of hybridoma technology to produceantibiotics.

Inspiteofthese,scientistsarealsoworkingonsome other important issues that affect our life suchasworld’sexponentialpopulationgrowthand cure for AIDS, Ebola virus disease, LassaFeverandCOVID-19.

1.4 SCIENTIFIC METHODScience describes the area of knowledge thatcanbeexplainedintermsofscientificprocessesormethods.With thehelpof scientificmethod,scientists try to investigate, verify an accurateandreliableversionofanynaturalphenomena.It creates an objective framework for thepurpose of scientific inquiry and analyses theresults to establish a conclusion which eithersupportsorcontradictstheobservationmadeatthebeginning.

The scientific method is a systematicapproachthatarisesfrom: • Observation and identification: This is

the first step of a scientific method that

involvescarefulobservationsandidentifyingaprocessorproblemwiththeuseofsensesofsight, touch, feeling,hearingandtaste toidentifywhatonehasseenorfeltabouttheobjectorprocess.

• Hypothesis:Itisbasedonobservation.Itisaproposedexplanationthatcanbeverified.

• Experimentation: It is a process carriedout in order to test a hypothesis. Whileconducting an experiment, the followingpatternmustbefollowed:

Title: Topic of the experiment Aim:Itstatesthepurposeofexperiment Materials required: It includes the

apparatus that will be used in theexperiment.

Method: It describes step by stepprocedures required for performing theexperiment.

Observation: It records what one hascarefullyviewedwithattentiontodetailsduringandaftertheexperiment.

Result:Ananalysisofdatacollectedfromtheexperimentprovidesaprecisepictureof the outcomes which are collectivelyknown as result. If the result confirmsthe hypothesis, then the hypothesis isconsidered likely to be correct. If theresult does not support the hypothesis,thenthehypothesisisquestioned.Inthiscase, another hypothesis should then beformulated.

Conclusion:Itistheinferencedrawnfromtheexperiment.Itsummarisestheoverallresults of an experimental procedure,whether the proposed hypothesis at thebeginningof theexperimentwas correctornot.

TheuseofscientificmethodcanbeexplainedbyconsideringtheExperiment 1.1.

E xperiment1.1Title:Photosynthesis(PlantNutrition)Aim:TotestthehypothesisthatoxygenisgivenoutduringphotosynthesisMaterials required:Abeakercontainingwater,testtube,support,twigsofElodeaplantandfunnel

5Recognising Living Things

Procedure:1. ThetwigsofElodeaplantandfunnelwereobtainedandkeptinthecentreofabeaker.2. AglassfunnelwasinvertedoveritonthesupportasshowninFig. 1.1.3. Thesetupwasfilledwithwater.4. A test tube full of water was taken and the mouthclosedwith the thumb. Thiswas then inverted overthestemoftheglassfunnelinthewater.

5. The thumbwas removed and the test tubemade torestontheinvertedfunnel.

6. The set-up so fixedwas kept in the sunlight for 3-4hours.

Observation:Afterashorttime,agasintheformofairbubblesarisesfromtheElodeaplantandgetscollectedin the test tube by downward displacement of water.Thegasinsidethetesttubemaybetestedforoxygenbyremovingitandthenbyinsertingaglowingsplinter.Result:Theglowingsplinterburstsintoflamewheninsertedinthetesttube.Conclusion:Thegaspresentinthetesttubesupportstheburningofsplinter,soitisconcludedthatthegasevolvedisoxygenwhichisgivenoutduringtheprocessofphotosynthesis.

Gas

Fig. 1.1 Experimenttoshowthatoxygenisgivenoutbygreenplantsduringphotosynthesis

AirbubblesTest tube

Beaker

WaterFunnelElodeaplantSupport

Sunlight

1.5 CHARACTERISTICS OF LIVING ORGANISMSThereisagreatvarietyofthingsaroundus.Someof themare living thingswhile others arenon-living things. You can identify the examples oflivingthingsandnon-livingthingsintheFig. 1.2 andFig. 1.3,respectively.

Byconsideringtheabovegivenexamples,wecanfindthatthesun,mountain,tableandchairs,and theriverhaveno lifebut the tree,dog,girlandbutterflyhavelife inthem.Hence, itcanbeconcludedthatthethingsthathavelifearecalledliving things and the thingswhichhaveno lifeare called non-living things. All living things

Fig. 1.2 Examplesoflivingthings

Fig. 1.3 Examplesofnon-livingthings

show certain characteristics. On the basis ofthese characteristics, they canbedifferentiatedfrom the non-living things. Such characteristicsoflivingthingsinclude:

1.5.1 NutritionTheprocessoftakinginnutrientandusingittoperformvariouslifeactivitiesiscallednutrition.Plants make their own food using simpleinorganic substances (water and carbon IVoxide)andenergyofthesunbyaprocesscalledphotosynthesis.Generally,animalsobtainready-made food from their surroundings. Livingthings need food to get energy for performingvarious life activities. Non-living things do notneedfoodtogetenergy.

1.5.2 RespirationLivingthingsreleaseenergyfromthebreakdownof food substances within their bodies. Theprocessofreleaseofenergybythebreakingdownof food inside the body is called respiration.Non-livingthingsdonotneedfoodtogetenergy.

1.5.3 Movement Movementisacharacteristicfeatureofalllivingorganisms.Organismscanmovetheirbodyparts

7Recognising Living Things

Living things and non-living things are inter-related in the following ways:• Living things respire by taking in oxygenwhichisanon-livingthing.

• Plants make their food by the process of

photosynthesis by using carbon (IV) oxide,waterandsolarenergy.Thesearenon-livingthings.

• Plantsabsorbwaterfromthesoilwhichisanon-livingthing.

1.6 DIFFERENCES AND SIMILARITIES BETWEEN PLANTS AND ANIMALSBothplantsandanimalsarelivingthings,yettheyexhibitsomesimilaritiesanddifferencesbetweenthem.YoucanlearnaboutthembyconsideringtheTables 1.1and1.2,respectively.

Table 1.1Similaritiesbetweenplantsandanimals

Characteristics Similarities

Cellularorganisation Bothplantsandanimalsaremadeupofcells. Respiration Bothplantsandanimals requireenergy for lifeactivities.Theenergy isobtainedby

oxidisingsimplesugarsinthecell. Nutrition Bothplantsandanimalsneedfoodtogetenergy. Reproduction Bothplantsandanimalsreproducesexuallyandasexuallytocontinuetheirspecies. Growth Bothplantsandanimalsgrow.Animalsgrowtosomeextentinlifewhiletheplantscan

growthroughouttheirlife. Movement Plantsdonotmovebutshowmovementthroughtheirparts.Animalsmovefromone

placetotheotherinsearchoffood.Liketheplants,theyalsoexhibitmovementthroughtheirbodypartssuchaslegsandhandstoperformvariousactivities.

Sensitivity Bothplantsandanimalsaresensitivetotheirenvironment.

Table 1.2Differencesbetweenplantsandanimals

Characteristics Plants Animals

Cellular Plantsarecomposedofcellswhichare Animalsarealsomadeofcellsinwhichthe organisation enclosedbyadeadandrigidcellwall.The cellwallisabsent.Theanimalcellis cellwallismadeupofcelluloseandprovides boundedbyalivingcellmembranewhich mechanicalsupporttotheplantcell. maintainstheexternalandinternal environmentofthecell. Nutrition Plantshaveautotrophicmodeofnutrition, Animalshaveheterotrophicmodeofnutrition. itmeanstheycanmaketheirownfoodby Theydependonplantsandotheranimal theprocessofphotosynthesis.Hence,they sourcesfortheirfood,henceareknownas arealsoknownasproducers. consumers. Movement Plantsarefixedtotheirlocations.However, Animalscanmovetheirbodypartsorthe theyshowmovementthroughtheirroots, wholeoftheirbodiestoacquirefoodor stemandleaves. escapefromdanger. Growth Inplants,growthisapical.Itshowsonlyin Inanimals,growthoccursequallyinallparts. thegrowingregionssuchastipsofroots andshoot. Responseto Plantsshowslowresponsestowardsthe Animalsshowrapidresponsestowards stimuli differentstimulisuchasheat,light,gravity thedifferentstimulisuchasheat,light, andtouch. gravityandtouch. Bodyplan Theplantbodyisasymmetrical,thatis,it Animalshavecompactsymmetricalbody hasunlimitedgrowthinalldirections. formwithlimitedgrowth. Excretion Plantsdonothaveaproperexcretorysystem. Animalshavewelldevelopedexcretory Theyexcreteintheformofgums,latexand system. resinsthroughtheirbodyparts.

8 Recognising Living Things

SUMMARY

• Science is defined as the study of structure andbehaviour of the physical and natural worldthroughobservationandexperimentation.

• Biology is considered as the branch of sciencewhichisconcernedwiththestudyoflivingthings.

• Biology is the science of living organisms thatinvolves the explanation of structure, growth,functionandevolutionoflife.

• Likeanyotherbranchofscience,biologyalsohasnumerous branches. Each branch deals with aparticular aspectoflife.

• The scientific method is a systematic approachto find out things around through observation,identification,hypothesisandexperimentation.

• Alllivingthingsarecharacterisedbytheprocessesof nutrition, growth, movement, reproduction,sensitivityandexcretion.

• Bothplantsandanimalsarelivingthings,yettheyexhibitsomesimilaritiesanddifferencesbetweenthem.

RACTICE TIMEP A. MULTIPLE CHOICE QUESTIONS (MCQs)

1. Whatisthelaststepofthescientificmethod? (a) Analysingdata (b) Formingaconclusion (c) Performinganexperiment (d) Makingobservation 2. The study of fossils and their distribution in

timeiscalled (a) Paleontology (b) Entomology (c) Physiology (d) Morphology 3. Alifeprocessperformedonlybytheplantis (a) Respiration (b) Photosynthesis (c) Reproduction (d) Movement 4. Thescienceoflifeiscalled (a) Physiology (b) Biology (c) Anatomy (d) Ecology 5. An analysis of data collected from the

experiment provides a precise picture of theoutcomeswhicharecollectivelyknownas

(a) Observation (b) Result (c) Hypothesis (d) Conclusion 6. Ametabolicwastewhichisexcretedbythebody

through respiration is (a) Oxygen (b) Carbon(IV)oxide (c) Nitrogen (d) Hydrogen 7. Aplantbodyhas (a) Symmetricalbodyplan (b) Asymmetricalbodyplan (c) Radialbodyplan (d) Noneofthem

8. Which of the following is a characteristic of anon-livingthing?

(a) Itisabletorespire. (b) Itdoesnotshowanygrowth. (c) Itcanmove. (d) Itneedsfoodtogrow. 9. A characteristic that can be shared by both

livingandnon-livingis (a) Locomotion (b) Irritability (c) Increaseinbiomass (d) Increaseinsize (UTME2008) 10. The irreversible life process by which new

protoplasm is added to increase the size andweightofanorganismcanbetermedas

(a) Anabolism (b) Catabolism (c) Growth (d) Development (UTME1989)

B. ANSWER THE FOLLOWING QUESTIONS

1. Design an experiment to show that plantsrelease oxygen gas during the process ofphotosynthesis.

2. Differentiatebetweenthefollowing: (a) Livingthingsandnon-livingthings (b) Plantsandanimals 3. Whatistheusefulnessofscienceandbiologyin

theareasofagricultureandmedicine? 4. Whatarethestepsinvolvedinscientificmethod? 5. Explainthefollowingterms: (a) Hypothesis (b) Observation