M Database Inspector
Not logged in. Login

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 4 of 119 (4/p)
1 2 3 4 5 6 7 8 9 10 20 30 40 50 60 100 119

Export to Excel select * from OriginOfSpecies order by subject, title, ordinal limit 12, 4 (Page 4: Row)
subject
title
ordinal
description
01 - Variations Under Domestication 01-04 - Inheritance 40 Having alluded to the subject of reversion, I may here refer to a statement often made by naturalists- namely, that our domestic varieties, when run wild, gradually but invariably revert in character to their aboriginal stocks.

Hence it has been argued that no deductions can be drawn from domestic races to species in a state of nature.

I have in vain endeavoured to discover on what decisive facts the above statement has so often and so boldly been made.

There would be great difficulty in proving its truth: we may safely conclude that very many of the most strongly marked domestic varieties could not possibly live in a wild state.

In many cases, we do not know what the aboriginal stock was, and so could not tell whether or not nearly perfect reversion had ensued. It would be necessary, in order to prevent the effects of intercrossing, that only a single variety should have been turned loose in its new home.

Nevertheless, as our varieties certainly do occasionally revert in some of their characters to ancestral forms, it seems to me not improbable that if we could succeed in naturalising, or were to cultivate, during many generations, the several races, for instance, of the cabbage, in very poor soil (in which case, however, some effect would have to be attributed to the definite action of the poor soil), that they would, to a large extent, or even wholly,
revert to the wild aboriginal stock.

cabbage
cabbage
.

Whether or not the experiment would succeed, is not of great importance for our line of argument; for by the experiment itself the conditions of life are changed.

Heisenberg
Heisenberg
.

If it could be shown that our domestic varieties manifested a strong tendency to reversion,- that is, to lose their acquired characters, whilst kept under the same conditions, and whilst kept in a considerable body, so that free intercrossing might check, by blending together, any slight deviations in their structure, in such case, I grant that we could deduce nothing from domestic varieties
in regard to species. But there is not a shadow of evidence in favour of this view: to assert that we could not breed our cart- and race-horses, long and short-horned cattle, and poultry of various breeds, and esculent vegetables, for an unlimited number of generations, would be opposed to all experience.
Full Size
horses
horses

cow
cow

fowl
fowl
01 - Variations Under Domestication 01-05 -Character of Domestic Varieties 10 When we look to the hereditary varieties or races of our domestic animals and plants, and compare them with closely allied species, we generally perceive in each domestic race, as already remarked, less uniformity of character than in true species.
Full Size Full Size

Domestic races often have a somewhat monstrous character; by which I mean, that, although differing from each other, and from other species of the same genus, in several trifling respects, they often differ in an extreme degree in some one part, both when compared one with another, and more especially when compared with the species under nature to which they are nearest allied. With these exceptions (and with that of the perfect fertility of varieties when crossed,- a subject hereafter to be discussed), domestic races of the same species differ from each other in the same manner as do the closely-allied species of the same genus in a state of nature, but the differences in most cases are less in degree.

This must be admitted as true, for the domestic races of many animals and plants have been ranked by some competent judges as the descendants of aboriginally distinct species, and by other competent judges as mere varieties.
01 - Variations Under Domestication 01-05 -Character of Domestic Varieties 20 If any well marked distinction existed between a domestic race and a species, this source of doubt would not so perpetually recur.

It has often been stated that domestic races do not differ from each other in character of generic value.

It can be shown that this statement is not correct; but naturalists differ much in determining what characters are of generic value; all such valuations being at present empirical.

When it is explained how genera originate under nature, it will be seen that we have no right to expect often to find generic amount of difference in our domesticated races.
01 - Variations Under Domestication 01-06 - Difficulty of distinguishing between Varieties and Species 10 In attempting to estimate the amount of structural differencebetween allied domestic races, we are soon involved in doubt, from not knowing whether they are descended from one or several parent species.

This point, if it could be cleared up, would be interesting; if, for instance, it could be shown that the greyhound, bloodhound, terrier, spaniel, and bull-dog, which we all know propagate their kind truly, were the offspring of any single species, then such facts would have great weight in making us doubt about the immutability of the many closely allied natural species-

greyhound
greyhound

bloodhound
bloodhound

terrier
terrier

spaniel
spaniel

bulldog
bulldog


for instance, of the many foxes- inhabiting different quarters of the world. I do not believe, as we shall presently see, that the whole amount of difference between the several breeds of the dog has been produced under domestication;

fox
fox


I believe that a small part of the difference is due to their being descended from distinct species.

In the case of strongly marked races of some other domesticated species, there is presumptive or even strong evidence, that all are descended from a single wild stock.