Looking to the first dawn of life, when all organic beings, as we may
believe, presented the simplest structure, how, it has been asked, could
the first step in the advancement or differentiation of parts have arisen?
Mr. Herbert Spencer would probably answer that, as soon as simple
unicellular organisms came by growth or division to be compounded of
several cells, or became attached to any supporting surface, his law "that
homologous units of any order become differentiated in proportion as their
relations to incident forces become different" would come into action. But
as we have no facts to guide us, speculation on the subject is almost
useless. It is, however, an error to suppose that there would be no
struggle for existence, and, consequently, no natural selection, until many
forms had been produced: variations in a single species inhabiting an
isolated station might be beneficial, and thus the whole mass of
individuals might be modified, or two distinct forms might arise. But, as
I remarked towards the close of the introduction, no one ought to feel
surprise at much remaining as yet unexplained on the origin of species, if
we make due allowance for our profound ignorance on the mutual relations of
the inhabitants of the world at the present time, and still more so during
past ages.
CONVERGENCE OF CHARACTER.
Mr. H.C. Watson thinks that I have overrated the importance of divergence
of character (in which, however, he apparently believes), and that
convergence, as it may be called, has likewise played a part.
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