Essays Upon Heredity and Kindred Biological Problems

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Weismann August. Essays Upon Heredity and Kindred Biological Problems

Essays Upon Heredity and Kindred Biological Problems

Table of Contents

THE DURATION OF LIFE

PREFACE

I. THE DURATION OF LIFE

APPENDIX. Note 1. The Duration of Life among Birds

Note 2. The Duration of Life among Mammals

Note 3. The Duration of Life among Mature Insects

Note 4. The Duration of Life of the Lower Marine Animals

Note 5. The Duration of Life in. Indigenous Terrestrial and Fresh-water Mollusca

Note 6. Unequal Length of Life in the two Sexes

Note 7. Bees

Note 8. Death of the Cells in higher Organisms

Note 9. Death by Sudden Shock

Note 10. Intermingling during the Fission of Unicellular Organisms[30]

Note 11. Regeneration

Note 12. The Duration of Life in Plants

Note 13

Footnotes for the Appendix to Essay I

ON HEREDITY

PREFACE

II. ON HEREDITY

Footnotes for Essay II

LIFE AND DEATH

PREFACE

III. LIFE AND DEATH

Footnotes for Chapter III

CONTINUITY OF THE GERM-PLASM, &c

PREFACE

CONTINUITY OF THE GERM-PLASM, &c

CONTENTS

IV. THE CONTINUITY OF THE GERM-PLASM AS THE. FOUNDATION OF A THEORY OF HEREDITY

Introduction

I. The Germ-plasm

II. The Significance of the Polar Bodies

III. On the Nature of Parthenogenesis

Footnote

Footnotes for Essay IV

SIGNIFICANCE OF SEXUAL REPRODUCTION, ETC

PREFACE

SIGNIFICANCE OF SEXUAL REPRODUCTION, etc

CONTENTS

APPENDICES

V. THE SIGNIFICANCE OF SEXUAL REPRODUCTION. IN THE THEORY OF NATURAL SELECTION

Footnotes for Essay V

APPENDICES

Footnotes for Appendices for Essay V

ON THE NUMBER OF POLAR BODIES AND THEIR SIGNIFICANCE IN HEREDITY

PREFACE

ON THE NUMBER OF POLAR BODIES, &c

CONTENTS

VI. ON THE NUMBER OF POLAR BODIES AND THEIR. SIGNIFICANCE IN HEREDITY

I. Parthenogenetic and Sexual Egg

II. The Significance of the Second Polar Body

III. The Foregoing Considerations Applied To the Male Germ-Cells

IV. The Foregoing Considerations applied To Plants

V. Conclusions with regard to Heredity

VI. Recapitulation

Footnotes for Essay VI

VII

Footnotes for Essay VII

VIII. THE SUPPOSED TRANSMISSION OF. MUTILATIONS

Footnotes for Essay VIII

INDEX

THE END

Отрывок из книги

August Weismann

Authorised Translation

.....

In answering the question as to the means by which the lengthening or shortening of life is brought about, our first appeal must be to the process of natural selection. Duration of life, like every other characteristic of an organism, is subject to individual fluctuations. From our experience with the human species we know that long life is hereditary. As soon as the long-lived individuals in a species obtain some advantage in the struggle for existence, they will gradually become dominant, and those with the shortest lives will be exterminated.

So far everything is quite simple; but hitherto we have only considered the external mechanism, and we must now further inquire as to the concomitant internal means by which such processes are rendered possible.

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