NaturalSelection36Times

TableOfContents

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Theory 1
''Here is the first instance Darwin used the term Theory of natural selection, yet he never actually gave any theory! He just kept on talking about the "theory" which is like somebody talking about how we will have lunch but never actually gets to the actual act of eating.''

I also gave some extracts from a correspondence between Professor Owen and the editor of the "London Review", from which it appeared manifest to the editor as well as to myself, that Professor Owen claimed to have promulgated the theory of natural selection before I had done so; and I expressed my surprise and satisfaction at this announcement;

Theory 2
Where can we get hold of this ?

The third volume of the "Journal of the Linnean Society" contains papers, read July 1, 1858, by Mr. Wallace and myself, in which, as stated in the introductory remarks to this volume, the theory of Natural Selection is promulgated by Mr. Wallace with admirable force and clearness.

Theory 3
SPECIAL DIFFICULTIES OF THE THEORY OF NATURAL SELECTION. Although we must be extremely cautious in concluding that any organ could not have been produced by successive, small, transitional gradations, yet undoubtedly serious cases of difficulty occur.

The electric organs of fishes offer another case of special difficulty; for it is impossible to conceive by what steps these wondrous organs have been produced.

Beyond this we cannot at present go in the way of explanation; but as we know so little about the uses of these organs, and as we know nothing about the habits and structure of the progenitors of the existing electric fishes, it would be extremely bold to maintain that no serviceable transitions are possible by which these organs might have been gradually developed.

What does the process of natural selection implie
very process of natural selection implies the continual supplanting and extinction of preceding and intermediate gradations

TAUTOLOGY ALERT
When two varieties are formed in two districts of a continuous area, an intermediate variety will often be formed, fitted for an intermediate zone; but from reasons assigned, the intermediate variety will usually exist in lesser numbers than the two forms which it connects; consequently the two latter, during the course of further modification, from existing in greater numbers, will have a great advantage over the less numerous intermediate variety, and will thus generally succeed in supplanting and exterminating it

Theory 4
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 against the theory. Many of them are serious; but I think that in the discussion light has been thrown on several facts, which on the belief of independent acts of creation are utterly obscure. We have seen that species at any one period are not indefinitely variable, and are not linked together by a multitude of intermediate gradations, partly because the process of natural selection is always very slow, and at any one time acts only on a few forms; and partly because the very process of natural selection implies the continual supplanting and extinction of preceding and intermediate gradations. Closely allied species, now living on a continuous area, must often have been formed when the area was not continuous, and when the conditions of life did not insensibly graduate away from one part to another. When two varieties are formed in two districts of a continuous area, an intermediate variety will often be formed, fitted for an intermediate zone; but from reasons assigned, the intermediate variety will usually exist in lesser numbers than the two forms which it connects; consequently the two latter, during the course of further modification, from existing in greater numbers, will have a great advantage over the less numerous intermediate variety, and will thus generally succeed in supplanting and exterminating it.

We have seen in this chapter how cautious we should be in concluding that the most different habits of life could not graduate into each other; that a bat, for instance, could not have been formed by natural selection from an animal which at first only glided through the air.

Hence we can understand, bearing in mind that each organic being is trying to live wherever it can live, how it has arisen that there are upland geese with webbed feet, ground woodpeckers, diving thrushes, and petrels with the habits of auks.

''"..trying to live wherever it can live ..." is a tautology.''

'''Although the belief that an organ so perfect as the eye could have been formed by natural selection, is enough to stagger any one; yet in the case of any organ, if we know of a long series of gradations in complexity, each good for its possessor, then under changing conditions of life, there is no logical impossibility in the acquirement of any conceivable degree of perfection through natural selection.'''

For instance, a swim-bladder has apparently been converted into an air-breathing lung. The same organ having performed simultaneously very different functions, and then having been in part or in whole specialised for one function; and two distinct organs having performed at the same time the same function, the one having been perfected whilst aided by the other, must often have largely facilitated transitions.

Theory 5
On the theory of natural selection we can clearly understand the full meaning of that old canon in natural history, "Natura non facit saltum." This canon, if we look to the present inhabitants alone of the world, is not strictly correct; but if we include all those of past times, whether known or unknown, it must on this theory be strictly true.

It is generally acknowledged that all organic beings have been formed on two great laws--Unity of Type, and the Conditions of Existence. By unity of type is meant that fundamental agreement in structure which we see in organic beings of the same class, and which is quite independent of their habits of life. On my theory, unity of type is explained by unity of descent. The expression of conditions of existence, so often insisted on by the illustrious Cuvier, is fully embraced by the principle of natural selection. For natural selection acts by either now adapting the varying parts of each being to its organic and inorganic conditions of life; or by having adapted them during past periods of time: the adaptations being aided in many cases by the increased use or disuse of parts, being affected by the direct action of external conditions of life, and subjected in all cases to the several laws of growth and variation. Hence, in fact, the '''law of the Conditions of Existence''' is the higher law; as it includes, through the inheritance of former variations and adaptations, that of Unity of Type.

Theory 6
MISCELLANEOUS OBJECTIONS TO THE THEORY OF NATURAL SELECTION.

* Longevity * -- Modifications not necessarily simultaneous * -- Modifications apparently of no direct service * -- Progressive development * -- Characters of small functional importance, the most constant * -- Supposed incompetence of natural selection to account for the incipient stages of useful structures * -- Causes which interfere with the acquisition through natural selection of useful structures * -- Gradations of structure with changed functions * -- Widely different organs in members of the same class, developed from one and the same source * -- Reasons for disbelieving in great and abrupt modifications.

Theory 7
A distinguished zoologist, Mr. St. George Mivart, has recently collected all the objections which have ever been advanced by myself and others against the theory of natural selection, as propounded by Mr. Wallace and myself, and has illustrated them with admirable art and force.

Theory 8
For if each part is liable to individual variations at all ages, and the variations tend to be inherited at a corresponding or earlier age--propositions which cannot be disputed--then the instincts and structure of the young could be slowly modified as surely as those of the adult; and both cases must stand or fall together with the whole theory of natural selection.

rephrase:
Each part is liable to variations this truism and propositions cannot be disputed--then the instincts and structure of the young could be slowly modified as surely as those of the adult; and both cases must stand or fall together with the whole theory of natural selection.

rephrase:
Parts of an animal are liable to variations, this truism means that the structure of the young could be slowly modified as surely as those of the adult; and both cases must stand or fall together with the whole theory of natural selection.

rephrase:
Parts of an animal are liable to variations, this truism means that the structures are modified  and this  must stand or fall together with the whole theory of natural selection.

rephrase:
Animal undergo variations, this truism means that the  theory of natural selection is either correct or incorrect.

Theory 9
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 structure and of instinct must have been simultaneous and accurately adjusted to each other, as a modification in the one without an immediate corresponding change in the other would have been fatal."

The force of this objection rests entirely on the assumption that the changes in the instincts and structure are abrupt. To take as an illustration the case of the larger titmouse, (Parus major) alluded to in a previous chapter; this bird often holds the seeds of the yew between its feet on a branch, and hammers with its beak till it gets at the kernel.

Now what special difficulty would there be in natural selection preserving all the slight individual variations in the shape of the beak, which were better and better adapted to break open the seeds, until a beak was formed, as well constructed for this purpose as that of the nuthatch, at the same time that habit, or compulsion, or spontaneous variations of taste, led the bird to become more and more of a seed-eater? In this case the beak is supposed to be slowly modified by natural selection, subsequently to, but in accordance with, slowly changing habits or taste; but let the feet of the titmouse vary and grow larger from correlation with the beak, or from any other unknown cause, and it is not improbable that such larger feet would lead the bird to climb more and more until it acquired the remarkable climbing instinct and power of the nuthatch.

rephrase
OBJECTIONS TO THE THEORY OF NATURAL SELECTION AS APPLIED TO INSTINCTS: NEUTER AND STERILE INSECTS.

It has been objected that the origin of instincts that "the variations of structure and of instinct must have been simultaneous and accurately adjusted to each other, as a modification in the one without an immediate corresponding change in the other would have been fatal."

The assumption is that the changes in the instincts and structure are abrupt. To take as an illustration the case of the larger titmouse, (Parus major) alluded to in a previous chapter; this bird often holds the seeds of the yew between its feet on a branch, and hammers with its beak till it gets at the kernel.

'''There would no difficulty in NS preserving the variations in the shape of the beak, which were better adapted to break open the seeds, until a beak was formed that led the bird to become more and more of a seed-eater? '''

The beak is slowly modified by natural selection in accordance with changing habits. If the feet of the titmouse grows larger it will lead to the bird acquiring greater climbing power. As much power as the nuthatch.

rephrase1
It has been objected that the origin of instincts that "the variations of structure and of instinct must have been simultaneous and accurately adjusted to each other, as a modification in the one without an immediate corresponding change in the other would have been fatal."

The larger titmouse, (Parus major) holds the seeds of the yew between its feet on a branch, and hammers with its beak till it gets at the kernel.

'''NS preserves the variations in the shape of the beak, which were better adapted to break open the seeds, until a beak was formed that led the bird to become more and more of a seed-eater. The beak is slowly modified by natural selection'''

. If the feet of the titmouse grows larger it will lead to the bird acquiring greater climbing power. As much power as the nuthatch.

rephrase2
The larger titmouse, (Parus major) holds the seeds of the yew between its feet on a branch, and hammers with its beak till it gets at the kernel.

'''NS preserves the variations in the shape of the beak, which were better adapted to break open the seeds, until a beak was formed that led the bird to become more and more of a seed-eater. The beak is slowly modified by natural selection'''

'''Of the multiple possible variations in the shape of the original primitive beak those that were better adapted to break open the seeds led to the formation of a seed eating adapted  beak. This process is natural selection''' If the feet of the titmouse grows larger it will lead to the bird acquiring greater climbing power. As much power as the nuthatch and this is also natural selection.

rephrase3
'''Of the multiple possible variations in the shape of the original primitive beak those titmice that were better adapted to break open the seeds survived and their offspring inherited the seed eating adapted  beak. This process is natural selection'''

If the feet of the titmouse grows larger it will lead to the bird acquiring greater climbing power. As much power as the nuthatch and this is also natural selection.

rephrase4
Originally there wasn't a titmouse but a creature with a beak, of the variations in the shape of the original beak those creatures that were better adapted to break open the seeds survived and their offspring inherited the seed eating adapted beak eventually transforming into a titmouse. This process is natural selection''' If the feet of the titmouse grows larger it will lead to the bird acquiring greater climbing power and this is natural selection.

rephrase5
Originally there wasn't a titmouse but some creature(X) with a beak, of the variations in the shape of the original beak those creatures that were better adapted to break open the seeds survived and their offspring eventually transforming into a titmouse. This process is natural selection. And before this (X) there was a lesser creature until we find the first living cell. Before this cell was a molten earth that cooled down as per AnaxiMander. The cooled earth formed rocks and from this rock the first living cell arose - the mechanism by which this happened is natural selection.

If the feet of the titmouse grows larger it will lead to the bird acquiring greater climbing power and this is natural selection.

Theory 10
No doubt many instincts of very difficult explanation could be opposed to the theory of natural selection--cases, in which we cannot see how an instinct could have originated; cases, in which no intermediate gradations are known to exist; cases of instincts of such trifling importance, that they could hardly have been acted on by natural selection; cases of instincts almost identically the same in animals so remote in the scale of nature that we cannot account for their similarity by inheritance from a common progenitor, and consequently must believe that they were independently acquired through natural selection.

rephrase
instincts of very difficult explanation could be opposed to the theory of natural selection--cases, in which we cannot see how an instinct could have originated; cases, in which no intermediate gradations are known to exist; cases of instincts of such trifling importance, that they could hardly have been acted on by natural selection; cases of instincts almost identically the same in animals so remote in the scale of nature that we cannot account for their similarity by inheritance from a common progenitor, and consequently must believe that they were independently acquired through natural selection.

Theory 11
But with the working ant we have an insect differing greatly from its parents, yet absolutely sterile; so that it could never have transmitted successively acquired modifications of structure or instinct to its progeny. It may well be asked how it is possible to reconcile this case with the theory of natural selection?

First, let it be remembered that we have innumerable instances, both in our domestic productions and in those in a state of nature, of all sorts of differences of inherited structure which are correlated with certain ages and with either sex. We have differences correlated not only with one sex, but with that short period when the reproductive system is active, as in the nuptial plumage of many birds, and in the hooked jaws of the male salmon. We have even slight differences in the horns of different breeds of cattle in relation to an artificially imperfect state of the male sex; for oxen of certain breeds have longer horns than the oxen of other breeds, relatively to the length of the horns in both the bulls and cows of these same breeds. Hence, I can see no great difficulty in any character becoming correlated with the sterile condition of certain members of insect communities; the difficulty lies in understanding how such correlated modifications of structure could have been slowly accumulated by natural selection.

rephrase1:
But with the working ant we have an insect differing greatly from its parents, yet sterile. It may well be asked how it is possible to reconcile this case with the theory of natural selection? We have differences in the horns of different breeds of cattle. Hence, I can see no great difficulty in any character becoming correlated with the sterile condition of certain members of insect communities; the difficulty lies in understanding how such correlated modifications of structure could have been slowly accumulated by natural selection.

rephrase2:
The working ant differs from its parent, yet sterile. It may well be asked how it is possible to reconcile this case with the theory of natural selection? We have differences in the horns of different breeds of cattle. I can see no difficulty in a character becoming correlated with the sterile condition of certain members of insect communities; the difficulty lies in understanding how such correlated modifications of structure could have been slowly accumulated by natural selection.

rephrase3:
Unfalsifiable:  The working ant differs from its parent, yet sterile. It may well be asked how it is possible to reconcile this case with the theory of natural selection? The horns of different breeds of cattle differ. Because of this truism I can see no difficulty in a character  becoming correlated with the sterile condition of certain members of insect communities; the difficulty lies in understanding how such correlated modifications of structure could have been slowly accumulated by natural selection.

Darwin isnt' looking for ways to disprove his theory but how he can bend his observations to fit with it.

Theory 12
On the other hand, the fact that instincts are not always absolutely perfect and are liable to mistakes; that no instinct can be shown to have been produced for the good of other animals, though animals take advantage of the instincts of others; that the canon in natural history, of "Natura non facit saltum," is applicable to instincts as well as to corporeal structure, and is plainly explicable on the foregoing views, but is otherwise inexplicable--all tend to corroborate the theory of natural selection.

rephrase
Instincts are liable to mistakes; that no instinct can be shown to have been produced for the good of other animals, though animals take advantage of the instincts of others; --all tend to corroborate the theory of natural selection.