Biology
for the IB Diploma
SECOND EDITION
Brenda Walpole
with additional
online material
,Biology
for the IB Diploma
Second edition
Brenda Walpole
with
Ashby Merson-Davies
Leighton Dann
Cambridge University Press’s mission is to advance learning,
knowledge and research worldwide.
Our IB Diploma resources aim to:
• encourage learners to explore concepts, ideas and
topics that have local and global significance
• help students develop a positive attitude to learning in preparation
for higher education
• assist students in approaching complex questions, applying
critical-thinking skills and forming reasoned answers.
,University Printing House, Cambridge cb2 8bs, United Kingdom
Cambridge University Press is part of the University of Cambridge.
It furthers the University’s mission by disseminating knowledge in the pursuit of
education, learning and research at the highest international levels of excellence.
www.cambridge.org
Information on this title: www.cambridge.org/9781107654600
© Cambridge University Press 2011, 2014
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
Second edition 2014
Printed in the United Kingdom by Latimer Trend
A catalogue record for this publication is available from the British Library
isbn 978-1-107-65460-0 Paperback
Additional resources for this publication at education.cambridge.org/ibsciences
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. Information regarding prices, travel timetables, and other
factual information given in this work is correct at the time of first printing but
Cambridge University Press does not guarantee the accuracy of such information
thereafter.
The material has been developed independently by the publisher and the content
is in no way connected with nor endorsed by the International Baccalaureate
Organization.
notice to teachers in the uk
It is illegal to reproduce any part of this book in material form (including
photocopying and electronic storage) except under the following circumstances:
(i) where you are abiding by a licence granted to your school or institution by the
Copyright Licensing Agency;
(ii) where no such licence exists, or where you wish to exceed the terms of a licence,
and you have gained the written permission of Cambridge University Press;
(iii) where you are allowed to reproduce without permission under the provisions
of Chapter 3 of the Copyright, Designs and Patents Act 1988, which covers, for
example, the reproduction of short passages within certain types of educational
anthology and reproduction for the purposes of setting examination questions.
The website accompanying this book contains further resources to support your IB Biology
studies.Visit education.cambridge.org/ibsciences and register for access.
Separate website terms and conditions apply.
, Contents
Introduction v 5 Evolution and biodiversity 159
Introduction 159
1 Cell biology 1 5.1 Evidence for evolution 159
Introduction 1 5.2 Natural selection 164
1.1 Introduction to cells 1 5.3 Classification of biodiversity 169
1.2 Ultrastructure of cells 12 5.4 Cladistics 178
1.3 Membrane structure 19 Exam-style questions 185
1.4 Membrane transport 23
1.5 The origin of cells 30 6 Human physiology 187
1.6 Cell division 33 Introduction 187
Exam-style questions 41 6.1 Digestion and absorption 187
6.2 The blood system 193
2 Molecular biology 43 6.3 Defence against infectious disease 202
Introduction 43 6.4 Gas exchange 209
2.1 Molecules to metabolism 43 6.5 Neurons and synapses 215
2.2 Water 49 6.6 Hormones, homeostasis and reproduction 220
2.3 Carbohydrates and lipids 54 Exam-style questions 232
2.4 Proteins 59
2.5 Enzymes 62 7 Nucleic acids (HL) 235
2.6 Structure of DNA and RNA 68 Introduction 235
2.7 DNA replication, transcription and 7.1 DNA structure and replication 235
translation 71 7.2 Transcription and gene expression 245
2.8 Cell respiration 78 7.3 Translation 251
2.9 Photosynthesis 82 Exam-style questions 259
Exam-style questions 89
8 Metabolism, cell respiration
3 Genetics 93 and photosynthesis (HL) 262
Introduction 93 Introduction 262
3.1 Genes 93 8.1 Metabolism 262
3.2 Chromosomes 99 8.2 Cell respiration 268
3.3 Meiosis 103 8.3 Photosynthesis 276
3.4 Inheritance 110 Exam-style questions 283
3.5 Genetic modification and biotechnology 124
Exam-style questions 133 9 Plant biology (HL) 285
Introduction 285
4 Ecology 136 9.1 Transport in the xylem of plants 285
Introduction 136 9.2 Transport in the phloem of plants 293
4.1 Species, communities and ecosystems 136 9.3 Growth in plants 297
4.2 Energy flow 141 9.4 Reproduction in plants 300
4.3 Carbon recycling 147 Exam-style questions 305
4.4 Climate change 151
Exam-style questions 157
iii
, 10 Genetics and evolution (HL) 308 Answers to test yourself questions380
Introduction 308
10.1 Meiosis 308 Glossary 386
10.2 Inheritance 313
10.3 Gene pools and speciation 327
Index 401
Exam-style questions 335 Acknowledgements 407
11 Animal physiology (HL) 337
Introduction 337
11.1 Antibody production and vaccination 337
11.2 Movement 346
11.3 The kidney and osmoregulation 353
11.4 Sexual reproduction 365
Exam-style questions 377
Free online material
The website accompanying this book contains further resources to support your IB Biology
studies. Visit education.cambridge.org/ibsciences and register to access these resources:
Options Self-test questions
Option A Neurobiology and behaviour Assessment guidance
Option B Biotechnology and bioinformatics Model exam papers
Option C Ecology and conservation Nature of Science
Option D Human physiology Answers to exam-style questions
Answers to Options questions
iv
, Introduction
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. The latest revision of the IB Biology syllabus will be examined
in the years 2016–2022, and this second edition of Biology for the IB Diploma
is fully updated to cover the content of that syllabus.
Biology may be studied at Standard Level (SL) or Higher Level (HL).
Both share a common core, which is covered in Topics 1–6. At HL the
core is extended to include Topics 7–11. In addition, at both levels,
students then choose one Option to complete their studies. Each option
consists of common core and additional Higher Level material.You can
identify the HL content in this book by ‘HL’ included in the topic title
(or section title in the Options), and by the red page border. The Options
are included in the free online material that is accessible with the code
available in this book.
The structure of this book follows the structure of the IB Biology
syllabus. Each topic in the book matches a syllabus topic, and the sections
within each topic mirror the sections in the syllabus. Each section begins
with learning objectives as starting and reference points. Test yourself
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 topic.
Theory of Knowledge (TOK) provides a cross-curricular link between
different subjects. It stimulates thought about critical thinking and how
we can say we know what we claim to know. Throughout this book, TOK
features highlight concepts in Biology that can be considered from a TOK
perspective. These are indicated by the ‘TOK’ logo, shown here.
Science is a truly international endeavour, being practised across all
continents, frequently in international or even global partnerships. Many
problems that science aims to solve are international, and will require
globally implemented solutions. Throughout this book, International-
Mindedness features highlight international concerns in Biology. These are
indicated by the ‘International-Mindedness’ logo, shown here.
Nature of Science is an overarching theme of the Biology course.
The theme examines the processes and concepts that are central to
scientific endeavour, and how science serves and connects with the wider
community. At the end of each section in this book, there is a ‘Nature of
Science’ paragraph that discusses a particular concept or discovery from
the point of view of one or more aspects of Nature of Science. A chapter
giving a general introduction to the Nature of Science theme is available
in the free online material.
INTRODUCTION v
for the IB Diploma
SECOND EDITION
Brenda Walpole
with additional
online material
,Biology
for the IB Diploma
Second edition
Brenda Walpole
with
Ashby Merson-Davies
Leighton Dann
Cambridge University Press’s mission is to advance learning,
knowledge and research worldwide.
Our IB Diploma resources aim to:
• encourage learners to explore concepts, ideas and
topics that have local and global significance
• help students develop a positive attitude to learning in preparation
for higher education
• assist students in approaching complex questions, applying
critical-thinking skills and forming reasoned answers.
,University Printing House, Cambridge cb2 8bs, United Kingdom
Cambridge University Press is part of the University of Cambridge.
It furthers the University’s mission by disseminating knowledge in the pursuit of
education, learning and research at the highest international levels of excellence.
www.cambridge.org
Information on this title: www.cambridge.org/9781107654600
© Cambridge University Press 2011, 2014
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
Second edition 2014
Printed in the United Kingdom by Latimer Trend
A catalogue record for this publication is available from the British Library
isbn 978-1-107-65460-0 Paperback
Additional resources for this publication at education.cambridge.org/ibsciences
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. Information regarding prices, travel timetables, and other
factual information given in this work is correct at the time of first printing but
Cambridge University Press does not guarantee the accuracy of such information
thereafter.
The material has been developed independently by the publisher and the content
is in no way connected with nor endorsed by the International Baccalaureate
Organization.
notice to teachers in the uk
It is illegal to reproduce any part of this book in material form (including
photocopying and electronic storage) except under the following circumstances:
(i) where you are abiding by a licence granted to your school or institution by the
Copyright Licensing Agency;
(ii) where no such licence exists, or where you wish to exceed the terms of a licence,
and you have gained the written permission of Cambridge University Press;
(iii) where you are allowed to reproduce without permission under the provisions
of Chapter 3 of the Copyright, Designs and Patents Act 1988, which covers, for
example, the reproduction of short passages within certain types of educational
anthology and reproduction for the purposes of setting examination questions.
The website accompanying this book contains further resources to support your IB Biology
studies.Visit education.cambridge.org/ibsciences and register for access.
Separate website terms and conditions apply.
, Contents
Introduction v 5 Evolution and biodiversity 159
Introduction 159
1 Cell biology 1 5.1 Evidence for evolution 159
Introduction 1 5.2 Natural selection 164
1.1 Introduction to cells 1 5.3 Classification of biodiversity 169
1.2 Ultrastructure of cells 12 5.4 Cladistics 178
1.3 Membrane structure 19 Exam-style questions 185
1.4 Membrane transport 23
1.5 The origin of cells 30 6 Human physiology 187
1.6 Cell division 33 Introduction 187
Exam-style questions 41 6.1 Digestion and absorption 187
6.2 The blood system 193
2 Molecular biology 43 6.3 Defence against infectious disease 202
Introduction 43 6.4 Gas exchange 209
2.1 Molecules to metabolism 43 6.5 Neurons and synapses 215
2.2 Water 49 6.6 Hormones, homeostasis and reproduction 220
2.3 Carbohydrates and lipids 54 Exam-style questions 232
2.4 Proteins 59
2.5 Enzymes 62 7 Nucleic acids (HL) 235
2.6 Structure of DNA and RNA 68 Introduction 235
2.7 DNA replication, transcription and 7.1 DNA structure and replication 235
translation 71 7.2 Transcription and gene expression 245
2.8 Cell respiration 78 7.3 Translation 251
2.9 Photosynthesis 82 Exam-style questions 259
Exam-style questions 89
8 Metabolism, cell respiration
3 Genetics 93 and photosynthesis (HL) 262
Introduction 93 Introduction 262
3.1 Genes 93 8.1 Metabolism 262
3.2 Chromosomes 99 8.2 Cell respiration 268
3.3 Meiosis 103 8.3 Photosynthesis 276
3.4 Inheritance 110 Exam-style questions 283
3.5 Genetic modification and biotechnology 124
Exam-style questions 133 9 Plant biology (HL) 285
Introduction 285
4 Ecology 136 9.1 Transport in the xylem of plants 285
Introduction 136 9.2 Transport in the phloem of plants 293
4.1 Species, communities and ecosystems 136 9.3 Growth in plants 297
4.2 Energy flow 141 9.4 Reproduction in plants 300
4.3 Carbon recycling 147 Exam-style questions 305
4.4 Climate change 151
Exam-style questions 157
iii
, 10 Genetics and evolution (HL) 308 Answers to test yourself questions380
Introduction 308
10.1 Meiosis 308 Glossary 386
10.2 Inheritance 313
10.3 Gene pools and speciation 327
Index 401
Exam-style questions 335 Acknowledgements 407
11 Animal physiology (HL) 337
Introduction 337
11.1 Antibody production and vaccination 337
11.2 Movement 346
11.3 The kidney and osmoregulation 353
11.4 Sexual reproduction 365
Exam-style questions 377
Free online material
The website accompanying this book contains further resources to support your IB Biology
studies. Visit education.cambridge.org/ibsciences and register to access these resources:
Options Self-test questions
Option A Neurobiology and behaviour Assessment guidance
Option B Biotechnology and bioinformatics Model exam papers
Option C Ecology and conservation Nature of Science
Option D Human physiology Answers to exam-style questions
Answers to Options questions
iv
, Introduction
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. The latest revision of the IB Biology syllabus will be examined
in the years 2016–2022, and this second edition of Biology for the IB Diploma
is fully updated to cover the content of that syllabus.
Biology may be studied at Standard Level (SL) or Higher Level (HL).
Both share a common core, which is covered in Topics 1–6. At HL the
core is extended to include Topics 7–11. In addition, at both levels,
students then choose one Option to complete their studies. Each option
consists of common core and additional Higher Level material.You can
identify the HL content in this book by ‘HL’ included in the topic title
(or section title in the Options), and by the red page border. The Options
are included in the free online material that is accessible with the code
available in this book.
The structure of this book follows the structure of the IB Biology
syllabus. Each topic in the book matches a syllabus topic, and the sections
within each topic mirror the sections in the syllabus. Each section begins
with learning objectives as starting and reference points. Test yourself
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 topic.
Theory of Knowledge (TOK) provides a cross-curricular link between
different subjects. It stimulates thought about critical thinking and how
we can say we know what we claim to know. Throughout this book, TOK
features highlight concepts in Biology that can be considered from a TOK
perspective. These are indicated by the ‘TOK’ logo, shown here.
Science is a truly international endeavour, being practised across all
continents, frequently in international or even global partnerships. Many
problems that science aims to solve are international, and will require
globally implemented solutions. Throughout this book, International-
Mindedness features highlight international concerns in Biology. These are
indicated by the ‘International-Mindedness’ logo, shown here.
Nature of Science is an overarching theme of the Biology course.
The theme examines the processes and concepts that are central to
scientific endeavour, and how science serves and connects with the wider
community. At the end of each section in this book, there is a ‘Nature of
Science’ paragraph that discusses a particular concept or discovery from
the point of view of one or more aspects of Nature of Science. A chapter
giving a general introduction to the Nature of Science theme is available
in the free online material.
INTRODUCTION v
