PHYSICAL GEOGRAPHY Made Simple The Made Simple series has been created especially for self-education but can equally well be used as an aid to group study. However complex the subject, the reader is taken step by step, clearly and methodically, through the course. Each volume has been prepared by experts, taking account of modern educational requirements, to ensure the most effective way of acquiring knowledge. In the same series Accounting Italian Administration in Business Latin Advertising Law Auditing Management Biology Marketing Book-keeping Mathematics British Constitution Modelling and Beauty Care Business Calculations Modern European History Business Communication Modern World History Business and Enterprise MSX Studies Music Business Law Office Practice Calculus Personnel Management Chemistry Philosophy Child Development Photography Commerce Physical Geography Computer Programming Physics Cost and Management Accounting Politics Economic and Social Geography Practical Typewriting Economics Psychology Education Russian Electricity Salesmanship Electronics Secretarial Practice Elements of Banking Social Services English Sociology Financial Management Spanish French Statistics German Teeline Shorthand Graphic Communication Typing PHYSICAL GEOGRAPHY Made Simple Richard H. Bryant, BA, PhD MAI« SIMPLE BOO K S Made Simple Books An imprint of Heinemann Professional Publishing Ltd Halley Court, Jordan Hill, Oxford OX2 8EJ OXFORD LONDON MELBOURNE AUCKLAND SINGAPORE IBADAN NAIROBI GABORONE KINGSTON First edition 1976 Second edition 1979 Reprinted (with revisions) 1980 Reprinted 1982 JRLeprinted 1984 Reprinted 1986 Reprinted 1987 Reprinted 1989 Reprinted 1990 © Richard H. Bryant 1986 This book is sold subject to the condition that it shall not, by way of trade or otherwise, be lent, re-sold, hired out, or otherwise circulated without the publisher's prior consent in any form of binding or cover other than that in which it is published and without a similar condition including this condition being imposed on the subsequent purchaser British Library Cataloguing in Publication Data Bryant, Richard H. Physical geography made simple.—2nd ed. (Made simple books, ISSN 0265-0541) 1. Physical geography I. Title II. Series 910'.02 GB54.5 ISBN 0 434 98520 1 Printed and bound in Great Britain by Richard Clay Ltd, Bungay, Suffolk Preface Many new and stimulating developments have been apparent in recent years in the study of physical geography. These are not just a question of new information, but reflect the introduction of fresh concepts and frameworks in the subject. Almost inevitably, this has produced an increasing diversity of specialist textbooks that make it difficult for the generalist to keep abreast of all aspects of the discipline. There has also been a tendency for the main parts of physical geography—namely the study of landforms, weather and climate, water, and soils, plants and animals—to evolve their own approaches and objectives. This book makes an attempt to offer some redress to these trends. It tries to bring together within one volume much of the modern thinking in the subject, and to express these ideas in a simple and concise manner. It adopts the view that physical geography is concerned with the natural environment as a whole, in which its physical and biological components are linked within one vast system. The book also gives more prominence to some of the rather neglected parts of the subject, particularly biogeography, thus modifying the traditional imbalance within physical geography towards the study of landforms. Students of geography in schools or in colleges should find this book a valuable introduction to modern physical geography. However, no specialist knowledge is assumed on the part of the reader, and the book should therefore be of particular interest to the layman. It is hoped that this book, together with its companion volume, Economic and Social Geography Made Simple; will encourage readers to dig deeper into the subject of geography, and some guidance has been given in this respect in the lists of suggested further reading at the end of each chapter. Many friends and colleagues have given freely of their time and advice during the writing of this book, and it is a pleasure to take this opportunity of thanking them, particularly: George and Eileen Booth, Elizabeth Dawlings, Hazel Faulkner, Martin Harris, and Peter White; Dr Ian Baillie and Dr Kevin O'Reilly; and Dr Jean Emberlin for her help with the biogeography section. RICHARD H. BRYANT, Department of Geography, The Polytechnic of North London. Revisions have been made to parts of the text to incorporate recent evidence and ideas, particularly in respect of Chapters Two and Eighteen. Similarly, some of the diagrams and tables have been amended. All lists of Suggested Further Reading have been brought up to date. CHAPTER ONB INTRODUCTION TO PHYSICAL GEOGRAPHY Physical geography may be defined as the integrated study of the natural environment on or close to the Earth's surface. Human geography, on the other hand, is concerned with man's activities over the surface of the Earth. The nature of the relationship between man and the natural environment is inevitably a complicated one; it varies from place to place, and it has changed through time. In the context of our present awareness of the need to conserve the environment for the best use of all life, including man, the traditional division between the two parts of geography has frequently become one of emphasis rather than of substance. If physical geography deals with the natural environment, what is meant by this expression? First, we should note that, strictly speaking, environment means 'that which surrounds': in its broadest sense this includes all energy and matter capable of influencing man, from the astronomic to the subatomic level. But in practical terms, such subjects as astronomy and nuclear physics are beyond the immediate concern of the physical geographer. He is primarily interested in the visible natural environment, although the basic principles of physics and chemistry are fundamental in explaining how the environment operates. Second, we should be aware that large parts of the Earth's surface cannot now be described as truly natural, because of widespread interference by man. In many cases the apparently wild parts of the countryside of Britain and other heavily populated parts of the globe are only semi-natural, and in others, they are highly artificial. An evaluation of man's impact on the natural environment is a theme we shall return to at the end of the book. Nevertheless, in whatever setting, it is important that we make the attempt to understand how natural processes operate in order to appreciate our environment more completely. Physical geography has been described not so much as a basic science, but as an integration or overview of a number of earth and life sciences which give insight into the nature of man's environment. The question then is, what sciences should be selected to achieve this objective? First, we need to consider the form of the Earth's relief features. The scientific study of landforms is known as geomorphology: this concerns itself not only with the analysis of the shape of landforms, but also with the erosional and depositional processes at work on them and their evolution through time. These aspects of the environment are examined in Part One of the book. Some of the major physiographic features of the Earth, such as mountain chains, continental plains and ocean basins, are a result of internal Earth forces. Hence, certain aspects of geology, the study of rocks, are relevant to physical geography. Rock type and structure are also important as variables which influence the effectiveness of wind, rain and weathering processes on landforms. Chapter Two outlines the essential geological background to landform study. 1 2 Physical Geography Made Simple A second major concern of the physical geographer is the atmospheric environment. Meteorology, the study of weather processes, together with climatology, the analysis of climate or average weather, make up Part Two of this book. The distinction between these two atmospheric sciences is largely arbitrary: the climate of any particular place can only be understood through a knowledge of atmospheric processes. A third component of physical geography is the study of plant and animal distributions, normally called biogeography. The physical geographer needs to be conversant with the basic principles of botany and zoology, and particularly of ecology, which studies the relationships between plants and animals and their environment. This is dealt with in Part Three. These three aspects determine the basic framework of the book, but there are also other disciplines which make significant contributions to the subject. The more important of these include pedology, the study of soils, which form an important environmental link between landforms, climate, and plants and animals; hydrology, the study of water on the Earth's land areas; and oceanography, which covers the study of waves, tides and currents, as well as the biological characteristics of oceans. The subject clearly embraces a wide range of specialisms and the physical geographer cannot hope to be an expert in them all. But it would be very wrong to imagine that physical geography is simply of potpourri of mappable subjects. It is worth recording that many of the above specialisms, now sciences in their own right, grew out of an original physical geography of a century or more ago. The inevitable trend towards specialism has in no way altered the realities of nature. On the Earth's surface, land, air, water, soils, plants and animals all exist together, and the physical reality of any one place is made up of all these elements. Matter and energy pass continually from one to the other. Although the combination of features may vary from one place to the next, everywhere there exists a tendency towards dynamic balance or equilibrium, in which a change in one of the elements leads to adjustment in the others.