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Brenda Walpole,Ashby Merson-Daviesand Leighton Dann

Biology for the IB Diploma

Biology for the IB Diplom

aBrenda W

alpole, Ashby Merson-Davies

and Leighton Dann

Biology for the IB Diploma Brenda Walpole, Ashby Merson-Daviesand Leighton Dann

This lively coursebook offers complete and thorough coverage of the Biology syllabus for the International Baccalaureate (IB) Diploma Programme, including the Standard and Higher Level topics and all eight Options.

The book clearly links to the syllabus by following the same division into topics and prominently displaying the assessment statements associated with each section. Students’ interest is stimulated by extra snippets of information displayed alongside the core text, offering deeper understanding and links with everyday life. Clear, simple language makes the text accessible to students of all abilities. Easy navigation is ensured with Standard and Higher Level material clearly marked in all chapters.

The coursebook contains:• short-answer questions throughout the chapters to test

knowledge, incorporating command terms as used in IB examinations to cultivate familiarity with the terms and develop skill in answering questions appropriately

• exam-style questions at the end of each chapter, offering thorough practice for the examination

• defi nitions of key terms displayed alongside the text for easy reference

• links to Theory of Knowledge concepts alongside appropriate topics, to stimulate thought and discussion

• clear, well-labelled illustrations and photos to help make concepts easy to understand.

Brenda Walpole has 20 years’ experience of teaching IB Biology and has written over 30 science books. She is currently an independent consultant in science education.

Ashby Merson-Davies has taught IB Biology for over 20 years. He was part of the IB Biology syllabus review team and has written a series of books which support the programme.

Leighton Dann has taught Biology at school and has been instrumental in developing new practical work for GCSE and post-16 courses in schools and colleges.

Course consultant: Peter Hoeben has been a deputy chief examiner and workshop leader for IB Biology, as well as a teacher for the subject.

Teacher support material and information on our full IB range are available at: ibdiploma.cambridge.org

Other titles available: ISBN 978-0-521-18294-2

ISBN 978-0-521-13821-5

Cambridge University Press’s mission is to advance learning, knowledge and research worldwide.

Our IB Diploma resources aim to:

topics that have local and global significance

for higher education

critical-thinking skills and forming reasoned answers.

cambridge un ive r s i ty p re s sCambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo, Delhi, Mexico City

Cambridge University PressThe Edinburgh Building, Cambridge CB2 8RU, UK

www.cambridge.orgInformation on this title: www.cambridge.org/9780521171786

© Cambridge University Press 2011

This publication is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press.

First published 2011 201

Printed in India by Replika Press Pvt. Ltd

A catalogue record for this publication is available from the British Library

ISBN 978-0-521-17178-6 Paperback

The publisher would like to thank the following teachers for reviewing the content:Jennifer ClarkeImpington Village College, ImpingtonSarah JinksSt. Clare’s, Oxford

Cambridge University Press has no responsibility for the persistence or accuracy of URLs for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate.

This material has been developed independently by the publisher and the content is in no way connected with nor endorsed by the International Baccalaureate Organisation.

�3rd printing 3

Introduction 11.1 Mean and distribution 11.2 The t-test 41.3 Correlation and cause 8

Introduction 122.1 Cell theory 122.2 Prokaryotic cells 202.3 Eukaryotic cells 222.4 Membranes 282.5 Cell division 34

Introduction 403.1 Chemical elements and water 403.2 Carbohydrates, lipids and proteins 423.3 DNA structure 463.4 DNA replication 483.5 Transcription and translation 493.6 Enzymes 533.7 Cell respiration 583.8 Photosynthesis 60

Introduction 674.1 Chromosomes, genes, alleles and mutation 674.2 Meiosis 714.3 Theoretical genetics 774.4 Genetic engineering and biotechnology 87

Introduction 1005.1 Communities and ecosystems 1005.2 The greenhouse e! ect 1055.3 Populations 1115.4 Evolution 1135.5 Classi" cation 119

Introduction 1306.1 Digestion 1306.2 The transport system 1346.3 Defence against infectious disease 1406.4 Gas exchange 1466.5 Nerves, hormones and homeostasis 1496.6 Reproduction 157

Introduction 1707.1 DNA structure 1707.2 DNA replication 1737.3 Transcription 1757.4 Translation 1777.5 Proteins 1827.6 Enzymes 185

Introduction 1948.1 Cell respiration 1948.2 Photosynthesis 201

Introduction 2149.1 Plant structure and growth 2149.2 Transport in angiospermophytes 2209.3 Reproduction in angiospermophytes 228

Introduction 23610.1 Meiosis 23610.2 Dihybrid crosses and gene linkage 24010.3 Polygenic inheritance 248

Introduction 25311.1 Defence against infectious disease 25311.2 Muscles and movement 26011.3 The kidney 26711.4 Reproduction 274

Introduction 288A1 Components of the human diet 288A2 Energy in human diets 297A3 Special issues in human nutrition 301

Introduction 310B1 Muscles and movement 310B2 Training and the pulmonary system 317B3 Training and the cardiovascular system 319B4 Exercise and respiration 322B5 Fitness and training 325B6 Injuries 328

Introduction 333C1 Proteins 333C2 Enzymes 337C3 Cell respiration 341C4 Photosynthesis 348

Introduction 360D1 Origin of life on Earth 360D2 Species and speciation 366D3 Human evolution 377D4 The Hardy-Weinberg principle (HL) 383D5 Phylogeny and systematics (HL) 388

Introduction 402E1 Stimulus and response 402E2 Perception of stimuli 405E3 Innate and learned behaviour 412E4 Neurotransmitters and synapses 418E5 The human brain (HL) 422E6 Further studies of behaviour (HL) 428

Introduction 437F1 Diversity of microbes 437F2 Microbes and the environment 442F3 Microbes and biotechnology 448F4 Microbes and food production 452F5 Metabolism of microbes (HL) 455F6 Microbes and disease (HL) 457

Introduction 471G1 Community ecology 471G2 Ecosystems and biomes 481G3 Impacts of humans on ecosystems 490G4 Conservation of biodiversity (HL) 497G5 Population ecology (HL) 505

Introduction 515H1 Hormonal control 515H2 Digestion 519H3 Absorption of digested foods 524H4 Functions of the liver 526H5 The transport system 531H6 Gas exchange 537

The International Baccalaureate Diploma course is designed to provide a broad education for students who will become our future citizens. Unlike other courses, the programme of study requires the study of six academic subjects, one of which must be an experimental science.

Biology has advanced at a rapid rate over recent decades and is truly the science of the 21st century. Advances in genetics, biochemistry, medicine and cell biology have kept the subject in the forefront of international news. To keep pace with new developments, the IB Biology course is regularly updated so that IB students can understand not only the principles of modern science but also the processes and the ethical implications that go with them. Theory of Knowledge (TOK) provides a cross-curricular link between di! erent subjects and stimulates thought and consideration of these issues.

Biology may be studied at Standard Level (SL) or Higher Level (HL) and both share a common core of six compulsory topics, which are covered in Chapters 1–6. At HL the core is extended to include a further " ve topics, covered in Chapters 7–11. In addition, at both levels, students then chose two Options to complete their studies. Options A – C are additional topics for SL only, Options D – G can be studied at either level with extra material covered at HL, and Option H is for HL only.

All the topics required for the core at both SL and HL, as well as all eight Options, are included in this book. Throughout, the colour of the page border indicates the level of the material on the page. Standard Level material has a mid-green page border all the way round, while Higher Level has a darker green at the top of the page and red at the bottom.

Each chapter is divided into sections which include the syllabus assessment statements as starting and reference points. Short-answer questions appear throughout the text so students can check their progress and become familiar with the style and command terms used, and examination style questions appear at the end of each chapter. Answers to all questions are given at the back of the book.

The study of Biology has a vital part to play in the future of the world. It is crucial to understanding our planet, the e! ect human activities have on it and how the organisms which live on it will survive in the future. The IB Biology course provides opportunities for scienti" c study in this global context that will both challenge and stimulate students.

As you read, you will also see short-answer questions at various points in the text, usually at the end of a section. These will allow you to keep a check on your progress as you work through each chapter.

At the end of each chapter, examination style questions will give you the chance to check that you have understood each topic and help you prepare for your " nal examinations.

As you read this book you will see that certain features are shown in di! erent coloured boxes.

At the start of each section you will " nd a list of Assessment statements, which form the syllabus for the IB Biology course. They are the objectives for the section and give you the command terms such as ‘State’, ‘Describe’ and ‘Explain’ which will appear in the IB Biology examination papers. Command terms give an idea of the depth of knowledge that is required for a given Assessment statement.

Throughout the text, side boxes and de" nition boxes give additional information on various subjects related to the text. The content of the boxes is included to broaden your background knowledge of a topic and to help you remember key information.

Theory of Knowledge (TOK) boxes are also found throughout the text. These will provide food for thought and support the TOK you will be studying in your IB Diploma programme. You will be able to consider important questions about scienti" c knowledge, including ethical considerations and the development of new theories.

Photosynthesis means ‘making things with light’. Glucose is the molecule most commonly made.

Our own perception is a crucial source of knowledge. The way we see things depends on the interaction between our sense organs and our mind, and what we perceive is a selective interpretation.

When studying material that has been prepared for microscopic examination, we must always bear in mind that staining and cutting cells will alter their appearance. Interpreting images requires care, and what we perceive in a particular image is likely to be in# uenced by these techniques as well as our own expectations.

Consider the shape of mitochondria in Figure 2.9. Why do some mitochondria appear cylindrical and others circular?Plant cells have a single central vacuole. Examine the plant cell in Figure 2.11. How many vacuoles can you see? How can you explain this?

Evolution cumulative change in the heritable characteristics of a population

De" ne ‘polygenic inheritance’.Explain that polygenic inheritance can contribute to continuous variation, using two examples, one of which must be human skin colour.

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