I will here give a brief sketch of the progress of opinion on the Origin of Species. Until recently the great majority of naturalists believed that species were immutable productions, and had been separately created. This view has been ably maintained by many authors. Some few naturalists, on the other hand, have believed that species undergo modification, and that the existing forms of life are the descendants by true generation of pre existing forms. Passing over allusions to the subject in the classical writers (Aristotle, in his "Physicae Auscultationes" (lib.2, cap.8, s.2), after remarking that rain does not fall in order to make the corn grow, any more than it falls to spoil the farmer's corn when threshed out of doors, applies the same argument to organisation; and adds (as translated by Mr. Clair Grece, who first pointed out the passage to me), "So what hinders the different parts (of the body) from having this merely accidental relation in nature? as the teeth, for example, grow by necessity, the front ones sharp, adapted for dividing, and the grinders flat, and serviceable for masticating the food; since they were not made for the sake of this, but it was the result of accident. And in like manner as to other parts in which there appears to exist an adaptation to an end. Wheresoever, therefore, all things together (that is all the parts of one whole) happened like as if they were made for the sake of something, these were preserved, having been appropriately constituted by an internal spontaneity; and whatsoever things were not thus constituted, perished and still perish." We here see the principle of natural selection shadowed forth, but how little Aristotle fully comprehended the principle, is shown by his remarks on the formation of the teeth.), the first author who in modern times has treated it in a scientific spirit was Buffon. But as his opinions fluctuated greatly at different periods, and as he does not enter on the causes or means of the transformation of species, I need not here enter on details.[...]
Table of Contents
Preface
Introduction
Chapter 1 - Variation Under Domestication
Chapter 2 - Variation Under Nature
Chapter 3 - Struggle For Existence
Chapter 4 - Natural Selection
Chapter 5 - Laws Of Variation
Chapter 6 - Difficulties Of The Theory
Chapter 7 - Miscellaneous Objections To The Theory Of Natural Selection
Chapter 8 - Instinct
Chapter 9 - Hybridism
Chapter 10 - On The Imperfection Of The Geological Record
Chapter 11 - On The Geological Succession Of Organic Beings
Chapter 12 - Geographical Distribution
Chapter 13 - Geographical Distribution--Continued
Chapter 14 - Mutual Affinities Of Organic Beings: Morphology -- Embryology -- Rudimentary Organs
Chapter 15 - Recapitulation And Conclusion
Glossary Of The Principal Scientific Terms Used In The Present Volume
Objectives & Core Themes
The primary objective of this seminal work is to provide a comprehensive scientific explanation for the origin and transformation of species, challenging the then-prevailing doctrine of their immutability. Through the observation of natural phenomena and selective breeding, the author proposes a mechanism by which organic beings adapt and evolve over geological time.
- The mechanics of natural selection and the struggle for existence.
- Variation under domestication and in the natural state.
- The role of instinct, hybridism, and geographical distribution in species formation.
- Evidence from the geological record, morphology, and embryology supporting descent with modification.
- Addressing and refuting potential objections to the proposed theory.
Excerpt from the Book
CAUSES OF VARIABILITY.
When we compare the individuals of the same variety or sub-variety of our older cultivated plants and animals, one of the first points which strikes us is, that they generally differ more from each other than do the individuals of any one species or variety in a state of nature. And if we reflect on the vast diversity of the plants and animals which have been cultivated, and which have varied during all ages under the most different climates and treatment, we are driven to conclude that this great variability is due to our domestic productions having been raised under conditions of life not so uniform as, and somewhat different from, those to which the parent species had been exposed under nature. There is, also, some probability in the view propounded by Andrew Knight, that this variability may be partly connected with excess of food. It seems clear that organic beings must be exposed during several generations to new conditions to cause any great amount of variation; and that, when the organisation has once begun to vary, it generally continues varying for many generations. No case is on record of a variable organism ceasing to vary under cultivation. Our oldest cultivated plants, such as wheat, still yield new varieties: our oldest domesticated animals are still capable of rapid improvement or modification.
As far as I am able to judge, after long attending to the subject, the conditions of life appear to act in two ways--directly on the whole organisation or on certain parts alone and in directly by affecting the reproductive system. With respect to the direct action, we must bear in mind that in every case, as Professor Weismann has lately insisted, and as I have incidently shown in my work on "Variation under Domestication," there are two factors: namely, the nature of the organism and the nature of the conditions. The former seems to be much the more important; for nearly similar variations sometimes arise under, as far as we can judge, dissimilar conditions; and, on the other hand, dissimilar variations arise under conditions which appear to be nearly uniform.
Summary of Chapters
Preface: An overview of the historical development of scientific thought regarding species modification prior to the publication of this work.
Introduction: Outlines the author's observations made during the voyage of H.M.S. Beagle and the foundational concepts of the theory of natural selection.
Chapter 1 - Variation Under Domestication: Explores how human-directed selection and environmental changes contribute to the hereditary modification of plants and animals.
Chapter 2 - Variation Under Nature: Discusses individual differences and the difficulty of distinguishing between varieties and species in the wild.
Chapter 3 - Struggle For Existence: Examines the necessity of competition among organisms due to the geometrical ratio of their population increase.
Chapter 4 - Natural Selection: Explains the mechanism of survival of the fittest and how it leads to the divergence of character among species.
Chapter 5 - Laws Of Variation: Delves into the complex factors, such as use and disuse, correlated variation, and inheritance, that influence organic change.
Chapter 6 - Difficulties Of The Theory: Addresses significant objections to the theory, including the rarity of transitional forms and the complexity of perfect organs.
Chapter 7 - Miscellaneous Objections To The Theory Of Natural Selection: Continues to address specific criticisms regarding the plausibility of abrupt versus gradual evolution.
Chapter 8 - Instinct: Argues that complex behaviors and instincts are inherited and subject to refinement through natural selection.
Chapter 9 - Hybridism: Analyzes the sterility of hybrids and its implications for the distinction between species and varieties.
Chapter 10 - On The Imperfection Of The Geological Record: Argues that the absence of intermediate fossil links is a result of the extreme incompleteness of the geological record.
Chapter 11 - On The Geological Succession Of Organic Beings: Shows that the pattern of extinct and living forms in geological time aligns with the theory of descent with modification.
Chapter 12 - Geographical Distribution: Explains how physical and biological barriers influence the migration and distribution of species across the globe.
Chapter 13 - Geographical Distribution--Continued: Focuses on the unique biological characteristics of islands and the dispersal of fresh-water species.
Chapter 14 - Mutual Affinities Of Organic Beings: Morphology -- Embryology -- Rudimentary Organs: Demonstrates that classification, morphology, and embryology all point toward a common genealogical origin.
Chapter 15 - Recapitulation And Conclusion: Provides a final synthesis of the evidence and reaffirms the validity of the theory of evolution by natural selection.
Keywords
Natural Selection, Evolution, Variation, Species, Heredity, Struggle for Existence, Adaptation, Fossil Record, Morphology, Embryology, Geographical Distribution, Hybridism, Instinct, Modification, Common Descent
Frequently Asked Questions
What is the core argument of this work?
The work argues that species are not immutable but have evolved over time from common ancestors through the process of natural selection, driven by the struggle for existence and the inheritance of beneficial variations.
What are the central thematic fields?
The core themes include population dynamics, genetics (referred to as hereditary principles), geological evidence of life, and the study of behavioral adaptation and biological classification.
What is the primary scientific method used?
The author employs observational, comparative, and synthesis methods, combining vast amounts of empirical data from natural history, paleontology, and breeding practices to support the theoretical framework.
What is the "struggle for existence"?
It is the competition among individuals within and between species for resources and reproductive success, which dictates which variations are preserved by natural selection.
How are rudimentary organs explained?
Rudimentary organs are viewed as remnants of structures that were fully developed in ancestral forms, preserved by inheritance but rendered vestigial due to their loss of function over time.
What defines the "Natural System" in classification?
The Natural System is proposed to be a genealogical classification, where organisms are grouped according to their degree of descent from common progenitors.
Why are transitional forms rare in the fossil record?
The author argues that this is due to the extreme imperfection of the geological record and the specific conditions required for the preservation of fossils, rather than an absence of transitional links.
How does natural selection affect instincts?
Instincts, like physical structures, are subject to modification; beneficial instinctive behaviors are accumulated through natural selection over many generations, just as physical traits are.
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- Charles Darwin (Autor), 2008, The Origin of Species by Means of Natural Selection, Múnich, GRIN Verlag, https://www.grin.com/document/119752
