Crossing Over docx

Compiled by the Social Cohesion and Identity Research Programme of the

Human Sciences Research Council in association with the Africa Genome Education Institute

Published by HSRC Press

Private Bag X9182, Cape Town, 8000, South Africa

www.hsrcpress.ac.za

© 2006 Human Sciences Research Council

First published 2006

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HSRC Workbook

Preface

The Crossing Over Pilot Teacher Trainer Research Programme (a project of the Human

Sciences Research Council) was a week-long course held in Cape Town and attended

by 33 teachers with representivity from all nine provinces and from rural, urban,

private and state schools. We chose the name Crossing Over as it suggests not only

the transmission of knowledge from one to another, but the shift from one state of

knowledge to another too. It is also the act that chromosomes perform in the event of

meiosis. Crossing over is fundamental to change.

Crossing Over was designed to cover the basic content necessary for teaching the key

concepts of comparative functioning, relationships and the development of change,

otherwise known as evolution, in molecular biology. There was a special emphasis

on lesson planning skills and a series of exciting visits to appropriate environments.

The teachers had access to the best that is available in the country both in terms of

facilitators and sites (a glance at the Acknowledgements reveals this).

This book is a compilation of the material that was developed for the Crossing Over

Pilot Course for the GET (General Education and Training) curriculum and the FET

(Further Education and Training) curriculum. A further book, Reading Scientific Images:

The Iconography of Evolution, has also been produced by the project for educators

interested in the cusp between art and science and more specifically in reading

scientific images.

We hope that through this publication, Crossing Over is able to add value and bring

satisfaction to educators beyond the team of the course facilitators, the group of

participants and their learners. We thank the Royal Netherlands Embassy and the

Human Sciences Research Council for the financial support and the research resources

that they respectively contributed to the project.

Sandra Prosalendis

Project Coordinator: School Curriculum and Scientific Literacy Project

Social Cohesion and Identity Research Programme

Human Sciences Research Council

Acknowledgements

Putting together the Crossing Over initiative was a collaborative effort and

required the expertise and the imagination of the team named here. Thank

you to Mr Utando Baduza (HSRC), Ms Pam Barron (HSRC), Ms Colleen Dawson

(Consultant HSRC), Dr Edith Dempster (UKZN), Dr Helen De Pinho (UCT), Mr

Luvuyo Dondolo (HSRC), Mr Adrian Hadland (HSRC), Ms Cathy Hastie (SABC),

Dr Wim Hoppers (RNE), Professor Wilmot James (HSRC), Mr Richard Mason

(UCT), Professor Tony Morphet (UCT), Mr Kanthan Naidoo (Gauteng Education

Department), Professor John Parkington (UCT), Ms Sandra Prosalendis (HSRC), Dr

Jaishree Raman (MRC), Mr Trevor Samson, Ms Gillian Warren Brown, Ms Lynne

Wilson (HSRC) and Ms Jean Witten (HSRC).

The contributions of the UCT MicroBiology Department, Kirstenbosch Gardens,

Central Methodist Mission in Cape Town, the MTN Science Centre, the South

African Museum, the Fossil Park, Sivuyile Tourism and Information Centre and

Sivuyile Teacher Training College in Gugulethu, and Women Unite are also

acknowledged.

We thank the teachers listed below for their enthusiastic and considered

participation: Mr Thabo Msutu (Mzontsudu S.S. School, King William’s Town), Ms

Kuzeka Gecelo (Lingelethu J.S. School, Cala), Mr Anthony Pandaram (Westville

Boys High, Wandsbeck), Mr Barry Booysen (Ebenhaeser School, Wepener), Mr

Ezekiel Moyaha (Tidimane Middle School, Mogwase), Ms Nandipha Mapukata

(Blorhweni J.S.S, Ntabankulu), Mr Setshwaro Mokgethi (SaHeso Intermediate

School, Roodepoort Farm), Mr Philemond Nkuna (Noto High, NW Province),

Mr John Visagie (Intermediate School Keimoes, Northern Cape), Mr Dumisani

Dlodlo (KwaDomba High, Nongoma), Mrs R. Ramgoolam (Greytown Sec. School,

Greytown), Mr Stephan le Roux (Stanford Lake College, Haenertsburg), Mr NP

Sebone (Marumofase H. School, Indemark), Mr Thomas Jafta (Newslands East Sec.

School, Marblerary), Mrs G.N Links (St. Boniface H. School, Kimberley), Mr Johnny

Witbooi (Bridgton Sec. School, Oudtshoorn), Mr Nicholas Smith (St Boniface

High, Kimberley), Ms Chairmaine Stalmeester (Bridgton H. School, Oudtshoorn),

Mrs Nozuko Phakela (Fezeka Sec. School, Cape Town), Mr Thomas Mathew

(Somavugha High, Mahwelereng), Mr Ashley Engelbrecht (Simunye High, Cape

Town), Mr NE Nyawose (Durban Natural Science Museum, Durban), Mr Retsisang

Moreku (Mhwayi Primary, Kabokweni), Mr Siyanda Mcwango (Gordon Memorial

High, Dundee), Mr Benjamin Chipulu (Janjo High, Gopano), Mr Lesetja Seopa

(Mapule Sec. School, Bakone), Mr Frans Bodigelo (Mmadikete Intermediate,

Brits), Mr Amos Rangata (Emadwaleni High, Soweto), Mr KW Kgopane (Sango

Combined School, Laersdrif) Mr N Kamteni (Sophumelele Sec. School, Cape

Town) Mr Thabo Tsunyana (Sinako Sec. School, Cape Town) Ms Alticia Klaasen

(Villiersdorp Sec. School, Villiersdorp).

The author and publishers would like to thank the following people and

organisations for photographs and micrographs used in the publication: The

University of KwaZulu-Natal Centre for Electron Microscopy; Mike van der Wolk;

Harcourt Education.

HSRC Workbook

Contents

Introduction vi

The Natural Sciences curriculum viii

Using the workbook xiii

Part 1: Understanding Genes

& Inheritance

Contents 1

Overview

3

1. The cell 4

2. Measuring very small structures 9

3. The cell cycle

1

4

4. The chromosomes and cell development

1

6

5. Mitosis 19

6. Inheritance 23

7. Selection 32

8. General principles of reproduction

3

6

9. Sexual reproduction

3

8

Solutions to activities 44

Part 2: Introducing evolution

Contents 51

The Life Sciences curriculum 52

Overview

5

5

1. Charles Darwin and the voyage of The Beagle 5

7

2. Darwin’s theory of evolution 6

0

3. What evidence supports Darwin’s theory? 6

2

4. Present day evidence of evolution 7

0

5. Genetics and evolution 7

5

Resources 9

4

Solutions to activities 9

5

Introduction

The Human Genome Project is one of the greatest scientific efforts of the current

age. As a result of the HSRC’s interest in this project, we ran a teacher-training

project to help teachers become aware of the importance of the Human Genome

Project and to increase their understanding of genetics and the ways in which

characteristics are transferred or inherited from one generation to the next.

This short course was developed to provide teachers with the knowledge and

understanding required to do so.

Part 1 of this workbook is designed for Senior Phase teachers. It forms the

basis for the more advanced concepts needed in the FET phase which are covered

in Part 2: Introducing Evolution. An understanding of evolution is very important

for teachers, particularly as this is a new topic in the school curriculum. We

believe that understanding the theory and examining some of the supporting

evidence, will lead you to agree with the famous evolutionary biologist,

Theodosius Dobzhansky, who said ‘Nothing in Biology makes sense except in the

light of evolution.’

When we first trialled this material, we ran a week-long course for 35

teachers from all over South Africa. We were very lucky to run the course in Cape

Town, which is within a famous centre of evolution, the Cape Floral Kingdom.

The itinerary below shows you how the course itself helped teachers to raise

questions and develop their own understanding of the evolutionary process.

Day 1

Kirstenbosch

Botanical Garden

experience the incredible variety of plants in the Cape Floral

Kingdom

University of

Cape Town

– MicroBiology

Laboratory

extract DNA from onions

use models to discover how hereditary information is stored in

DNA, and then translated into protein molecules

investigate simple hereditary characteristics such as blood groups,

widow’s peak, attached ear lobes, and hair on the middle finger

joints.

Some of the teachers were amazed to find out that each of us inherits an equal

number of genes from our mother and our father, and that our children inherit

equal numbers of genes from their mother and father. They asked questions

like this: ‘I have 7 brothers and sisters, and all of them inherited equal numbers

of genes from our mother and father. Why do we look different?’ It was quite a

challenge to answer all the questions!

Day 2

West Coast

Fossil Park

view 5-million year old fossils being excavated.

The fossils were of large, sturdy giraffe-like animals all lying where they had

been buried five million years earlier. For most of the teachers, it was the first

time they had seen fossils, and it made them aware of changes in the Earth’s

surface, and changes in the life forms that have existed on the Earth. It also made

them aware of the long history of life on Earth, because five million years ago is

just the other day in geological time.

Did you know?

The Human Genome Project

(1990 – 2003) was an international

effort which aimed to identify the

20 000 – 25 000 genes in human

DNA, find out more about the

chemical composition of DNA, store

the information in databases, and

investigate the ethical and legal

issues related to their findings.

Although the project is finished,

the information that scientists have

found will be analysed for many

years to come. You can find out

more about this project online at:

www.ornl.gov/sci/techresources/

HumanGenome/home.shtml

vi Introduction