| → the alimentary canal respires, digests, and excretes 1859 1860 1861 1866 1869 |
| OMIT 1872 |
|
| → Cobites. 1859 1860 1861 1866 1869 |
| Cobites the alimentary canal respires, digests, and excretes. 1872 |
|
| → the whole or part of an 1866 1869 1872 |
| a part or 1859 1860 1861 |
|
| → OMIT 1869 1872 |
| wholly change its nature 1859 1860 1861 |
| greatly change its nature 1866 |
|
| → steps greatly change its nature. 1869 1872 |
| steps. 1859 1860 1861 1866 |
|
| ↑ 1 blocks not present in 1859 1860 1866 1869 1872; present in 1861 |
| Certain plants, as some Leguminosæ, Violaceæ, &c., bear two kinds of flowers; one having the normal structure of the order, the other kind being degraded, though sometimes more fertile than the perfect kind: if the plant ceased to bear its perfect flowers, and this did occur during several years with an imported specimen of Aspicarpa in France, a great and sudden transition would apparently be effected in the nature of the plant.
|
|
| → in some cases 1869 |
| OMIT 1872 |
|
| Modes
of
|
| If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case. No doubt many organs exist of which we do not know the transitional grades, more especially if we look to much-isolated species, round which, according to
theory, there has been much extinction. Or again, if we
an organ common to all the members of a
class, for in this latter case the organ must have been
formed at
remote period, since which all the many members of the class have been developed; and in order to discover the early transitional grades through which the organ has passed, we should have to look to very ancient ancestral forms, long since become extinct. |
|
| We should be extremely cautious in concluding that an organ could not have been formed by transitional gradations of some kind. Numerous cases could be given amongst the lower animals of the same organ performing at the same time wholly distinct functions; thus
→the alimentary canal respires, digests, and excretes
in the larva of the dragon-fly and in the fish
→Cobites. In the Hydra, the animal may be turned inside out, and the exterior surface will then digest and the stomach respire. In such cases natural selection might
specialise, if any advantage were thus gained,
→the whole or part of an
organ, which had
two functions, for one function alone, and thus
→OMIT
by insensible
→steps greatly change its nature.
↑ Many plants are known which regularly produce at the same time differently constructed flowers; and if such plants were to produce one kind alone, a great change would
→in some cases
|
