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OriginOfSpecies - 475 Rows
Column Type #Values Column Stats
id int(11) 475 Column Stats
subject varchar(80) 14 Column Stats
title varchar(250) 139 Column Stats
ordinal int(11) 30 Column Stats
description text 474 Column Stats

475 rows, page 27 of 119 (4/p)
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Export to Excel select * from OriginOfSpecies order by ordinal desc limit 104, 4 (Page 27: Row)
subject
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05 - Laws of Variation 05-02 - Use and Disuse of Parts, combined with Natural Selection, Organs of Flight and Vision 60 It is well known that several animals, belonging to the most different classes, which inhabit the caves of Carniola and of Kentucky, are blind. in some of the crabs the foot-stalk for the eye remains, though the eye is gone;- the stand for the telescope is there, though the telescope with its glasses has been lost.

cave
cave

Kentucky
Kentucky

crab
crab

telescope
telescope

glasses
glasses


As it is difficult to imagine that eyes, though useless, could be in any way injurious to animals living in darkness, their loss may be attributed to disuse. In one of the blind animals, namely, the cave-rat (Noetoma), two of which were captured by Professor Silliman at above half a mile distance from the mouth of the cave, and therefore not in the profoundest depths, the eyes were lustrous and of large size; and these animals, as I am informed by Professor Silliman, after having been exposed for about a month to a graduated light, acquired a dim perception of objects.
06 - Difficutiles in Theory 06-04 - Transitions in Habits of Life 60 Seeing that a few members of such water-breathing classes as the Crustacea and Mollusca are adapted to live on the land; and seeing that we have flying birds and mammals, flying insects of the most diversified types, and formerly had flying reptiles, it is conceivable that flying-fish, which now glide far through the air, slightly rising and turning by the aid of their fluttering fins, might have been modified into perfectly winged animals.

crab
crab

mollusca
mollusca

pterosaurs
pterosaurs

Flying Fish
Flying Fish


If this had been effected, who would have ever imagined that in an early transitional state they had been the inhabitants of the open ocean, and had used their incipient organs of flight exclusively, as far as we know, to escape being devoured by other fish?
06 - Difficutiles in Theory 06-08 - Means of Transition 60 There is another possible mode of transition, namely, through the acceleration or retardation of the period of reproduction.

This has lately been insisted on by Prof. Cope and others in the United States.

United States
United States


It is now known that some animals are capable of reproduction at a very early age, before they have acquired their perfect characters; and if this power became thoroughly well developed in a species, it seems probable that the adult stage of development would sooner or later be lost; and in this case, especially if the larva differed much from the mature form, the character of the species would be greatly changed and degraded.

Again, not a few animals, after arriving at maturity, go on changing in character during nearly their whole lives.

With mammals, for instance, the form of the skull is often much altered with age, of which Dr. Murie has given some striking instances with seals; every one knows how the horns of stags become more and more branched, and the plumes of some birds become more finely developed, as they grow older. Prof. Cope states that the teeth of certain lizards change much in shape with advancing years; with crustaceans not only many trivial, but some important parts assume a new character, as recorded by Fritz Muller, after maturity. In all such cases,- and many could be given,- if the age for reproduction were retarded, the character of the species, at least in its adult state, would be modified; nor is it improbable that the previous and earlier stages of development would in some cases be hurried through and finally lost.
seal
seal

stag
stag

bird
bird

lizard
lizard

crustacean
crustacean


Whether species have often or ever been modified through this comparatively sudden mode of transition, I can form no opinion; but if this has occurred, it is probable that the differences between the young and the mature, and between the mature and the old, were primordially acquired by graduated steps.
06 - Difficutiles in Theory 06-11 - Organs of Small Importance 60 We are profoundly ignorant of the cause of each slight variation or individual difference; and we are immediately made conscious of this by reflecting on the differences between the breeds of our domesticated animals in different countries,- more especially in the less civilised countries where there has been but little methodical selection.

Animals kept by savages in different countries often have to struggle for their own subsistence, and are exposed to a certain extent to natural selection, and individuals with slightly different constitutions would succeed best under different climates.

With cattle susceptibility to the attacks of flies is correlated with colour, as is the liability to be poisoned by certain plants; so that even colour would be thus subjected to the action of natural selection.
cattle
cattle

fly
fly



Some observers are convinced that a damp climate affects the growth of the hair, and that with the hair the horns are correlated.

Mountain breeds always differ from lowland breeds; and a mountainous country would probably affect the hind limbs from exercising them more, and possibly even the form of the pelvis; and then by the law of homologous variation, the front limbs and the head would probably be affected.

The shape, also, of the pelvis might affect by pressure the shape of certain parts of the young in the womb.

The laborious breathing necessary in high regions tends, as we have good reason to believe, to increase the size of the chest; and again correlation would come into play.

The effects of lessened exercise together with abundant food on the whole organisation is probably still more important; and this, as H. von Nathusius has lately shown in his excellent treatise, is apparently one chief cause of the great modification which the breeds of swine have undergone.
pig
pig


But we are far too ignorant to speculate on the relative importance of the several known and unknown causes of variation; and I have made these remarks only to show that, if we are unable to account for the characteristic differences of our several domestic breeds, which nevertheless are generally admitted to have arisen through ordinary generation from one or a few parent-stocks, we ought not to lay too much stress on our ignorance of the precise cause of the
slight analogous differences between true species.