Page:Darwinism by Alfred Wallace 1889.djvu/15

 

CONTENTS

CHAPTER I

WHAT ARE "SPECIES" AND WHAT IS MEANT BY THEIR "ORIGIN"

Definition of species—Special creation—The early transmutationists—Scientific opinion before Darwin—The problem before Darwin—The change of opinion effected by Darwin—The Darwinian theory—Proposed mode of treatment of the subject .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .

Pages 1-13

CHAPTER II

THE STRUGGLE FOR EXISTENCE

Its importance—The struggle among plants—Among animals—Illustrative cases—Succession of trees in forests of Denmark—The struggle for existence on the Pampas—Increase of organisms in a geometrical ratio—Examples of rapid increase of animals—Rapid increase and wide spread of plants—Great fertility not essential to rapid increase—Struggle between closely allied species most severe—The ethical aspect of the struggle for existence .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .          .

13-40

CHAPTER III

THE VARIABILITY OF SPECIES IN A STATE OF NATURE

Importance of variability—Popular ideas regarding it—Variability of the lower animals—The variability of insects—Variation among lizards–