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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 7 of 119 (4/p)
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Export to Excel select * from OriginOfSpecies order by ordinal desc limit 24, 4 (Page 7: Row)
subject
title
ordinal Desending Order (top row is last)
description
04 - Natural Selection 04-12 - On the Degree to which Organisation tends to advance 110 It is, however, an error to suppose that there would be no struggle for existence, and, consequently, no natural selection, until many forms had been produced: variations in a single species inhabiting an isolated station might be beneficial, and thus the whole mass of individuals might be modified, or two distinct forms might arise.

But, as I remarked towards the close of the Introduction, no one ought to feel surprise at much remaining as yet unexplained on the origin of species, if we make due allowance for our profound ignorance on the mutual relations of the inhabitants of the world at the present time, and still more so during past ages.
06 - Difficutiles in Theory 06-12 - Organs not in all Cases Absolutely Perfect 110 It is a much more probable view that the rattlesnake uses its rattle, the cobra expands its frill, and the puff-adder swells whilst hissing so loudly and harshly, in order to alarm the many birds and beasts which are known to attack even the most venomous species.

rattlesnake
rattlesnake

adder
adder


Snakes act on the same principle which makes the hen ruffle her feathers and expand her wings when a dog approaches her chickens; but I have not space here to enlarge on the many ways by which animals endeavour to frighten away their enemies.
chicken
chicken

dog
dog


Natural selection will never produce in a being any structure more injurious than beneficial to that being, for natural selection acts solely by and for the good of each.

No organ will be formed, as Paley has remarked, for the purpose of causing pain or for doing an injury to its possessor.

If a fair balance be struck between the good and evil caused by each part, each will be found on the whole advantageous.

After the lapse of time, under changing conditions of life, if any part comes to be injurious, it will be modified; or if it be not so, the being Will become extinct as myriads have become extinct.
04 - Natural Selection 04-11 - Divergence of Character 110 Full Size
The intervals between the horizontal lines in the diagram, may represent each a thousand or more generations.

After a thousand generations, species (A) is supposed to have produced two fairly well-marked varieties, namely a1 and m1.

These two varieties will generally still be exposed to the same conditions which made their parents variable, and the tendency to variability is in itself hereditary; consequently they will likewise tend to vary, and commonly in nearly the same manner as did their parents.

Moreover, these two varieties, being only slightly modified forms, will tend to inherit those advantages which made their parent (A) more numerous than most of the other inhabitants of the same country; they will also partake of those more general advantages which made the genus to which the parent-species belonged, a large genus in its own country.

And all these circumstances are favourable to the production of new varieties.
14 - Recapitulation and Conclusion 14-03 - Causes of the general belief in the immutability of species 110 Disuse, aided sometimes by natural selection, will often tend to reduce an organ, when it has become useless by changed habits or under changed conditions of life; and we can clearly understand on this view the meaning of rudimentary organs.

But disuse and selection will generally act on each creature, when it has come to maturity and has to play its full part in the struggle for existence, and will thus have little power of acting on an organ during early life; hence the organ will not be much reduced or rendered rudimentary at this early age.

The calf, for instance, has inherited teeth, which never cut through the gums of the upper jaw, from an early progenitor having well-developed teeth; and we may believe, that the teeth in the mature animal were reduced, during successive generations, by disuse or by the tongue and palate having been fitted by natural selection to browse without their aid; whereas in the calf, the teeth have been left untouched by selection or disuse, and on the principle of inheritance at corresponding ages have been inherited from a remote period to the present day.

On the view of each organic being and each separate organ having been specially created, how utterly inexplicable it is that parts, like the teeth in the embryonic calf or like the shrivelled wings under the soldered wing-covers of some beetles, should thus so frequently bear the plain stamp of inutility! Nature may be said to have taken pains to reveal, by rudimentary organs and by homologous structures, her scheme of modification, which it seems that we wilfully will not understand.

beetle
beetle