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OriginOfSpecies - 475 Rows
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subject varchar(80) 14 Column Stats
title varchar(250) 139 Column Stats
ordinal int(11) 30 Column Stats
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05 - Laws of Variation 05-12 - Reversion to Long Lost Characters 90 What now are we to say to these several facts?

We see several distinct species of the horse-genus becoming, by simple variation, striped on the legs like a zebra, or striped on the shoulders like an ass. In the horse we see this tendency strong whenever a dun tint appears- a tint which approaches to that of the general colouring of the other species of the genus.

horse
horse

ass
ass

Dun Horse
Dun Horse


The appearance of the stripes is not accompanied by any change of form or by any other new character.

We see this tendency to become striped most strongly displayed in hybrids from between several of the most distinct species.

Now observe the case of the several breeds of pigeons: they are descended from a pigeon (including two or three sub-species or geographical races) of bluish colour, with certain bars and other marks; and when any breed assumes by simple variation a bluish tint, these bars and other marks invariably reappear; but without any other change of form or character.

pigeon
pigeon


When the oldest and truest breeds of various colours are crossed, we see a strong tendency for the blue tint and bars and marks to reappear in the mongrels.

I have stated that the most probable hypothesis to account for the reappearance of very ancient characters, is- that there is a tendency in the young of each successive generation to produce the long-lost character, and that this tendency, from unknown causes, sometimes prevails.

And we have just seen that in several species of the horse-genus the stripes are either plainer or appear more commonly in the young than in the old.

Call the breeds of pigeons, some of which have bred true for centuries, species; and how exactly parallel is the case with that of the species of the horse-genus!

horse
horse

pigeon
pigeon


For myself, I venture confidently to look back thousands on thousands of generations, and I see an animal striped like a zebra, but perhaps otherwise very differently constructed, the common parent of our domestic horse (whether or not it be descended from one or more wild stocks), of the ass, the hemionus, quagga, and zebra.

horse
horse

ass
ass

hemionus
hemionus

quagga
quagga

zebra
zebra
06 - Difficutiles in Theory 06-12 - Organs not in all Cases Absolutely Perfect 90 How the sense of beauty in its simplest form- that is, the reception of a peculiar kind of pleasure from certain colours, forms, and sounds- was first developed in the mind of man and of the lower animals, is a very obscure subject.

The same sort of difficulty is presented, if we enquire how it is that certain flavours and odours give pleasure, and others displeasure.

Habit in all these cases appears to have come to a certain extent into play; but there must be some fundamental cause in the constitution of the nervous system in each species.
06 - Difficutiles in Theory 06-03 - Absence or Rarity of Transitional Varieties 90 Thirdly, when two or more varieties have been formed in different portions of a strictly continuous area, intermediate varieties will, it is probable, at first have been formed in the intermediate zones, but they will generally have had a short duration.

For these intermediate varieties will, from reasons already assigned (namely from what we know of the actual distribution of closely allied or representative species, and likewise of acknowledged varieties), exist in the intermediate zones in lesser numbers than the varieties which they tend to connect.

From this cause alone the intermediate varieties will be liable to accidental extermination; and during the process of further modification through natural selection, they will almost certainly be beaten and supplanted by the forms which they connect; for these from existing in greater numbers will, in the aggregate, present more varieties, and thus be further improved through natural selection and gain further advantages.
01 - Variations Under Domestication 01-08 - Breeds of the Domestic Pigeons, their Differences and Origin 90 I have discussed the probable origin of domestic pigeons at some, yet quite insufficient, length; because when I first kept pigeons and watched the several kinds, well knowing how truly they breed, I felt fully as much difficulty in believing that since they had been domesticated they had all proceeded from a common parent, as any naturalist could in coming to a similar conclusion in regard to the many species of finches, or other groups of birds, in nature. One circumstance has struck me much; namely, that nearly all the breeders of the various domestic animals and the cultivators of plants, with whom I have conversed, or whose treatises I have read, are firmly convinced that the several breeds to which each has attended, are descended from so many aboriginally distinct
species.

Ask, as I have asked, a celebrated raiser of Hereford cattle, whether his cattle might not have descended from long-horns, or both from a common parent-stock, and he will laugh you to scorn. I have never met a pigeon, or poultry, or duck, or rabbit fancier, who was not fully convinced that each main breed was descended from a distinct species.

Hereford Cow
Hereford Cow

Long Horn Cow
Long Horn Cow


Van Mons, in his treatise on pears and apples, shows how utterly he disbelieves that the several sorts, for instance a Ribston-pippin or Codlin-apple, could ever have proceeded from the seeds of the same tree.

Pear
Pear

apple
apple


Innumerable other examples could be given.

The explanation, I think, is simple: from long-continued study they are strongly impressed with the differences between the several races; and though they well know that each race varies slightly, for they win their prizes by selecting such slight differences, yet they ignore all general arguments, and refuse to sum up in their minds slight differences accumulated during many successive generations.

May not those naturalists who, knowing far less of the laws of inheritance than does the breeder, and knowing no more than he does of the intermediate links in the long lines of descent, yet admit that many of our domestic races are descended from the same parents- may they not learn a lesson of caution, when they deride the idea of species in a state of nature being lineal descendants of other species?