The foundations of The origin of species : a sketch written in 1842 / edited by Francis Darwin.
- Charles Darwin
- Date:
- 1909
Licence: Public Domain Mark
Credit: The foundations of The origin of species : a sketch written in 1842 / edited by Francis Darwin. Source: Wellcome Collection.
66/94 page 34
![ated points, even the trivial ones, which on any other (theory ?) can be viewed as so many ultimate facts, all follow (in) a simple manner on the theory of the occurrence of species by (illegible) and being adapted by selection to (illegible), conjoined with their power of dispersal, and the steady geographico- geological changes which are now in progress and which undoubtedly have taken place. Ought to state the opinion of the immutability of species and the creation by so many separate acts of will of the Creator1. 1 (From the back of ms.) Effect of climate on stationary island and on continent, but continent once island. Moreover repeated oscillations fresh diffusion when non-united, then isolation, when rising again immigra¬ tion prevented, new habitats formed, new species, when united free immi¬ gration, hence uniform characters. Hence more forms (on ?) the island. Mountain summits. Why not true species. First let us recall in Part I, conditions of variation : change of conditions during several generations, and if frequently altered so much better [perhaps excess of food]. Secondly, continued selection [while in wild state]. Thirdly, isolation in all or nearly all,—as well to recall advantages of. [In continent, if we look to terrestrial animal, long continued change might go on, which would only cause change in numerical number (? proportions): if continued long enough might ultimately affect all, though to most continents (there is) chance of immigration. Some few of whole body of species must be long affected and entire selection working same way. But here isolation absent, without barrier, cut off such (illegible). We can see advantage of isolation. But let us take case of island thrown up by volcanic agency at some distances, here we should have occasional visitants, only in few numbers and exposed to new conditions and (illegible) more important,—a quite new grouping of organic beings, which would open out new sources of subsistence, or (would) control (?) old ones. The number would be few, can old have the very best opportunity. (The con¬ quest of the indigenes by introduced organisms shows that the indigenes were not perfectly adapted, see Origin, Ed. i. p. 390.) Moreover as the island continued changing,—continued slow changes, river, marshes, lakes, mountains &c. &c., new races as successively formed and a fresh occasional visitant. If island formed continent, some species would emerge and immigrate. Everyone admits continents. We can see why Galapagos and C. Verde differ (see Origin, Ed. i. p. 398)], depressed and raised. We can see from this repeated action and the time required for a continent, why many more forms than in New Zealand (see Origin, Ed. i. p. 389 for a comparison be¬ tween New Zealand and the Cape) no mammals or other classes (see however, Origin, Ed. i. p. 393 for the case of the frog). We can at once see how it comes when there has been an old channel of migration,—Cordilleras; we can see why Indian Asiatic Flora,—[why species] having a wide range gives better chance of some arriving at new points and being selected, and adapted to new ends. I need hardly remark no necessity for change.](https://iiif.wellcomecollection.org/image/b31351761_0068.jp2/full/800%2C/0/default.jpg)
