| After my return to England it appeared
to me that by following the example of Lyell in Geology, and by collecting all facts which
bore in any way on the variation of animals and plants under domestication and nature,
some light might perhaps be thrown on the whole subject.... I worked on true Baconian
principles, and without any theory collected facts on a wholesale scale, more especially
with respect to domesticated productions, by printed enquiries, by conversation with
skilful breeders and gardeners, and by extensive reading.... I soon perceived that
selection was the keystone of man's success in making useful races of animals and plants.
But how selection could be applied to organisms living in a state of nature remained for
some time a mystery to me.
In October 1838, that is fifteen months after I had begun my systematic
enquiry, I happened to read for amusement Malthus on Population, and being well
prepared to appreciate the struggle for existence which everywhere goes on from
long-continued observation of the habits of animals and plants, it at once struck me that
under these circumstances favourable variations would tend to be preserved, and
unfavourable ones to be destroyed. The result of this would be the formation of a new
species. Here, then, I had at last got a theory by which to work....
But at that time I overlooked one problem of great importance and it is
astonishing to me...how I could have overlooked it and its solution. This problem is the
tendency in organic beings descended from the same stock to diverge in character as they
become modified. That they have diverged greatly is obvious from the manner in which
species of all kinds can be classed under genera, genera under families...and so forth;
and I can remember the very spot in the road, whilst in my carriage, when to my joy the
solution occurred to me.... The solution, as I believe, is that the modified offspring of
all dominant and increasing forms tend to become adapted to many and highly diversified
places in the economy of nature. |
