Origin of Species Variorum

Comparison with 1861

importance to characters which are really of very little importance, and which have originated from quite secondary causes, independently of natural selection. We should remember that climate, food, &c., probably have some little direct influence on the organisation; that characters reappear from the law of reversion; that correlation of growth will have had a most important influence in modifying various structures; and finally, that sexual selection will often have largely modified the external characters of animals having a will, to give one male an advantage in fighting with another or in charming the females. Moreover when a modification of structure has primarily arisen from the above or other unknown causes, it may at first have been of no advantage to the species, but may subsequently have been taken advantage of by the descendants of the species under new conditions of life and with newly acquired habits.

To give a few instances to illustrate these latter remarks. If green woodpeckers alone had existed, and we did not know that there were many black and pied kinds, I dare say that we should have thought that the green colour was a beautiful adaptation to hide this tree-frequenting bird from its enemies; and consequently that it was a character of importance and might have been acquired through natural selection; as it is, we cannot doubt that the colour is due to some quite distinct cause, probably to sexual selection. A trailing bamboo in the Malay Archipelego climbs the loftiest trees by the aid of exquisitely constructed hooks clustered around the ends of the branches, and this contrivance, no doubt, is of the highest service to the plant; but as we see nearly similar hooks on many trees which are not climbers, the hooks on the bamboo may have arisen from unknown laws of growth, and have been subsequently taken advantage of by the plant undergoing further modification

importance to characters which have originated from quite secondary causes, independently of natural selection. We should remember that climate, food, &c., probably have had some, perhaps a considerable, direct influence on the organisation; that characters reappear from the law of reversion; that correlation is an important element of change; and finally, that sexual selection has often largely modified the external characters of the higher animals, so as to give one male an advantage in fighting with other males, or in charming the female; and characters gained through sexual selection may be transmitted to both sexes. Moreover a modification, caused in any of the above specified ways, may at first have been of no direct advantage to a species, but may subsequently have been taken advantage of by its descendants under new conditions of life and .. newly acquired habits. ↑

If, for instance, green woodpeckers alone had existed, and we did not know that there were many black and pied kinds, I dare say that we should have thought that the green colour was a beautiful adaptation to hide this tree-frequenting bird from its enemies; and consequently that it was a character of importance and had been acquired through natural selection; as it is, ... the colour is probably in chief part due to sexual selection. A trailing palm in the Malay Archipelago climbs the loftiest trees by the aid of exquisitely constructed hooks clustered around the ends of the branches, and this contrivance, no doubt, is of the highest service to the plant; but as we see nearly similar hooks on many trees which are not climbers, and which there is reason to believe from the distribution of the thorn-bearing species in Africa and South America, serves as a defence against browsing quad- rupeds, so the hooks on the palm may first have been developed for this object, and subsequently been taken advantage of by the plant as it underwent further modification