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Origin and Causes of the Sterility of first Crosses and of Hybrids.
At one time it appeared to me probable, as it has to others, that the sterility of first crosses ...
Laws governing the Sterility of first Crosses and of Hybrids.
We will now consider a little more in detail the laws governing the sterility of first crosses an...
Distinction between the Sterility of First Crosses and of Hybrids
The view commonly entertained by naturalists is that species, when intercrossed, have been specia...
Summary.
I have endeavoured in this chapter briefly to show that the mental qualities of our domestic anim...
Objections to the Theory of Natural Selection as applied to Instincts: Neuter and Sterile Insects.
It has been objected to the foregoing view of the origin of instincts that "the variations of str...
Special Instincts.
We shall, perhaps, best understand how instincts in a state of nature have become modified by sel...
Inherited Changes of Habit or Instinct in Domesticated Animals.
The possibility, or even probability, of inherited variations of instinct in a state of nature wi...
Instincts Comparable with Habits, but Different in Their Origin
Many instincts are so wonderful that their development will probably appear to the reader a diffi...
Miscellaneous Objections to the Theory of Natural Selection
I will devote this chapter to the consideration of various miscellaneous objections which have be...
Summary: The Law of Unity of Type and of the Conditions of Existence embraced by the Theory of Natural Selection.
We have in this chapter discussed some of the difficulties and objections which may be urged agai...
Utilitarian Doctrine, how far true: Beauty, how acquired.
The foregoing remarks lead me to say a few words on the protest lately made by some naturalists a...
Organs of little apparent Importance, as affected by Natural Selection.
As natural selection acts by life and death,— by the survival of the fittest, and by the destruct...
Special difficulties of the theory of natural selection.
Although we must be extremely cautious in concluding that any organ could not have been produced ...
Modes of transition.
If it could be demonstrated that any complex organ existed, which could not possibly have been fo...
Organs of extreme Perfection and Complication.
To suppose that the eye with all its inimitable contrivances for adjusting the focus to different...
On the Origin and Transition of Organic Beings with peculiar Habits and Structure.
It has been asked by the opponents of such views as I hold, how, for instance, could a land carni...
On the absence or rarity of transitional varieties.
As natural selection acts solely by the preservation of profitable modifications, each new form w...
Difficulties of the Theory of Descent with Modification
Long before the reader has arrived at this part of my work, a crowd of difficulties will have occ...
Summary.
Our ignorance of the laws of variation is profound. Not in one case out of a hundred can we prete...
Specific characters more variable than generic characters.
The principle discussed under the last heading may be applied to our present subject. It is notor...