p vi
The natural selection of those individuals most fitted to their environment is a truism, especially when expressed in its inverted form as 'the survival of the fittest', a phrase first used by Herbert Spencer. As early as 1831, the importance of natural selection had been pointed out by Patrick Matthew [...]
[...] it is quite immaterial whether or not Professor Owen preceded me, for both of us, as shown in this historical sketch, were long ago preceded by Dr. Wells and Mr. Matthews.
[...] no observer can determine for another, even if he can do it for himself, which of these Phytophagic forms ought to be called species and which varieties. Mr. Walsh ranks the forms which it may be supposed would freely intercross, as varieties; and those which appear to have lost this power, as species.
I mean by Nature, only the aggregate action and product of many natural laws, and by laws the sequence of events as ascertained by us.
In some cases, as we shall hereafter see, lowly organized forms appear to have been preserved to the present day, from inhabiting confined or peculiar stations, where they have been subjected to less severe competition, and where their scanty numbers have retarded the chance of favourable variations arising.
All physiologists admit that the swimbladder is homologous, or "ideally similar" in position and structure with the lungs of the higher vertebrate animals: hence there is no reason to doubt that the swimbladder has actually been converted into lungs, or an organ used exclusively for respiration.pp 171-172
We can thus [...] understand the strange fact that every particle of food which we swallow has to pass over the orifice of the trachea, with some risk of falling into the lungs, notwithstanding the beautiful contrivance by which the glottis is closed.
Hence in the several fishes furnished with electric organs, these cannot be seen as homologous, but only as analogous in function.
I am surprised that no one has hitherto advanced this demonstrative case of neuter insects against the well-known doctrine of inherited habits, as advanced by Lamarck.
From the most remote periods in the history of the world organic beings have been found to resemble each other in descending degrees, so that they can be classed in groups under groups. This classification is not arbitrary like the grouping of stars in constellations.p 396
Expressions such as that famous one by Linn�us, which we often meet with in a more or less concealed form, namely, that the characters do not make the genus, but that the genus gives the characters seems to imply that some deeper bond is included in our classifications than mere resemblance. I believe that this is the case, and that community of descent—the one known cause of close similarity in organic beings—is the bond [...]
[...] in some districts of South America, where, for instance, an Ithomia abounds in gaudy swarms, another butterfly, namely a Leptalis, is often found mingled in the same flock; and the latter so closely resembles the Ithomia in every shade and stripe of colour and even in the shape of its wings, that Mr. Bates, with his eyes sharpened by collecting during eleven years, was, though always on his guard, continually deceived.
[...] the fact is striking that the discovery of Australia has not added an insect belonging to a new class; and that in the vegetable kingdom [...], it has added only two or three families of small sizes.
Flowers and fruit have been rendered conspicuous by brilliant colours in contrast with the green foliage, in order that the flowers may be easily seen, visited, and fertilised by insects, and the seeds disseminated by birds. How it comes that certains colours, sounds, and forms should give pleasure to man and the lower animals,—that is, how the sense of beauty in its simplest form was first acquired,—we do not know any more than how certain odours and flavours were first rendered agreeable.p 455
Who can explain what is the essence of the attraction of gravity? No one now objects to following out the results consequent on this unknown element of attraction; notwithstanding that Leibniz formerly accused Newton of introducing "occult qualities and miracles into philosophy".p 460
[...] we shall at least be freed from the vain search for the undiscovered and undiscoverable essence of the term species.