But all adaptations can be referred to selection; the only point that remains doubtful is whether they all must be referred to it.
However that may be, whether the Lamarckian principle is a factor that has coöperated with selection in evolution, or whether it is altogether fallacious, the fact remains, that selection is the cause of a great part of the phyletic evolution of organisms on our earth. Those who agree with me in rejecting the Lamarckian principle will regard selection as the only guiding factor in evolution, which creates what is new out of the transmissible variations, by ordering and arranging these, selecting them in relation to their number and size, as the architect does his building-stones so that a particular style must result.[55] But the building-stones themselves, the variations, have their basis in the influences which cause variation in those vital units which are handed on from one generation to another, whether, taken together they form the whole organism, as in Bacteria and other low forms of life, or only a germ-substance, as in unicellular and multicellular organisms.
FOOTNOTES:
[33] Vorträge über Descendenztheorie, Jena, 1904, ii. 269. Eng. Transl. London, 1904, ii. p. 317.
[34] See Poulton, Essays on Evolution, Oxford, 1908. pp. xix-xxii.
[35] Origin of Species (6th edit), pp. 176 et seq.
[36] Chun, Reise der Valdivia, Leipzig, 1904.
[37] Plate, Selektionsprinzip u. Probleme der Artbildung (3rd edit.), Leipzig, 1908.
[38] Studien zur Descendenz-Theorie ii., "Die Enstehung der Zeichnung bei den Schmetterlings-raupen," Leipzig, 1876.
[39] Origin of Species (6th edit.), p. 232.