A Critique of the Theory of Evolution

by Thomas Hunt Morgan

TABLE OF CONTENTS

CHAPTER I
A REVALUATION OF THE EVIDENCE ONWHICH THE THEORY OF EVOLUTIONWAS BASED
			PAGE
Preface			[v]
1.	Three Kinds of Evolution		[1]-[7]
2.	The Evidence for Organic Evolution		[7]-[27]
	a.	The Evidence from Comparative Anatomy	[7]-[14]
	b.	The Evidence from Embryology	[14]-[23]
	c.	The Evidence from Paleontology	[24]-[27]
3.	The Four Great Historical Speculations		[27]-[39]
	a.	The Environment	[27]-[31]
		Geoffroy St. Hilaire
	b.	Use and Disuse	[31]-[34]
		From Lamarck to Weismann
	c.	The Unfolding Principle	[34]-[36]
		Nägeli and Bateson
	d.	Natural Selection	[36]-[39]
		Darwin
CHAPTER II
THE BEARING OF MENDEL'S DISCOVERY ONTHE ORIGIN OF HEREDITY CHARACTERS
1.	Mendel's First Discovery—Segregation		[41]-[52]
2.	Mendel's Second Discovery—Independent Assortment		[52]-[59]
3.	The Characters of Wild Animals and PlantsFollow the Same Laws of Inheritance as dothe Characters of Domesticated Animals andPlants		[59]-[84]
	a.	Sexual Dimorphism	[61]-[64]
		Eosin eye color of Drosophila	[61]-[62]
		Color of the Clover Butterfly, Colias philodice	[62]-[63]
		Color of Papilio turnus	[63]
		Color pattern of Papilio polytes	[63]-[64]
	b.	Duplication of parts	[65]-[66]
		Thorax of Drosophila	[65]
		Legs of Drosophila	[65]-[66]
	c.	Loss of characters	[66]-[68]
		"Eyeless" of Drosophila	[66]-[67]
		Vestigial wings of Drosophila	[67]
		Bar eye of Drosophila	[67]-[68]
	d.	Small changes of characters	[68]-[70]
		"Speck"	[68]
		Bristles of "club"	[70]
	e.	Manifold effects of same factor	[71]
	f.	Constant but trivial effects may be theproduct of factors having other vitalaspects	[73]
	g.	Sex-linked inheritance	[75]-[80]
		in Drosophila ampelophila	[75]-[76]
		in the wild species D. repleta	[76]
		in man	[77]
		in domesticated Fowls	[77]-[78]
		in the wild moth, Abraxas	[78]-[80]
	h.	Multiple allelomorphs	[81]-[84]
		in the wild Grouse Locust	[81]-[83]
		in domesticated mice and rabbits	[83]
		in Drosophila ampelophila	[84]
4.	Mutation and Evolution		[84]-[88]
CHAPTER III
THE FACTORIAL THEORY OF HEREDITYAND THE COMPOSITION OF THEGERM PLASM
1.	The Cellular Basis of Organic Evolution and Heredity		[89]-[98]
2.	The Mechanism of Mendelian Heredity Discovered in the Behavior of the Chromosomes		[98]-[102]
3.	The Four Great Linkage Groups of Drosophila Ampelophila		[103]-[118]
	a.	Group I.	[104]-[109]
	b.	Group II.	[109]-[112]
	c.	Group III.	[112]-[115]
	d.	Group IV.	[115]-[118]
4.	Localization of Factors in the Chromosomes		[118]-[142]
	a.	The Evidence from Sex Linked Inheritance	[118]-[137]
	b.	The Evidence from Interference	[137]-[138]
	c.	The Evidence from Non-Disjunction	[139]-[142]
5.	How Many Genetic Factors are there in the Germ-plasm of a Single Individual?		[142]-[143]
6.	Conclusions		[144]
CHAPTER IV
SELECTION AND EVOLUTION
1.	The Theory of Natural Selection		[145]-[161]
2.	How has Selection in Domesticated Animals and Plants brought about its Results?		[161]-[165]
3.	Are Factors Changed through Selection?		[165]-[187]
4.	How does Natural Selection Influence the course of Evolution?		[187]-[193]
5.	Conclusions		[193]-[194]
Index			[195]-[197]

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CHAPTER I

A REVALUATION OF THE EVIDENCE ON WHICH THE THEORY OF EVOLUTION WAS BASED

We use the word evolution in many ways—to include many different kinds of changes. There is hardly any other scientific term that is used so carelessly—to imply so much, to mean so little.

Three Kinds of Evolution

We speak of the evolution of the stars, of the evolution of the horse, of the evolution of the steam engine, as though they were all part of the same process. What have they in common? Only this, that each concerns itself with the history of something. When the astronomer thinks of the evolution of the earth, the moon, the sun and the stars, he has a picture of diffuse matter that has slowly condensed. With condensation came heat; with heat, action and