When the sexes differ in beauty, in the power of singing, or in producing what I have called instrumental music, it is almost invariably the male which excels the female.

It is a truly wonderful fact - the wonder of which we are apt to overlook from familiarity - that all animals and all plants throughout all time and space should be related to each other in group subordinate to group.

We cannot fathom the marvelous complexity of an organic being; but on the hypothesis here advanced this complexity is much increased. Each living creature must be looked at as a microcosm--a little universe, formed of a host of self-propagating organisms, inconceivably minute and as numerous as the stars in heaven.

we are always slow in admitting any great change of which we do not see the intermediate steps

When the views entertained in this volume on the origin of species, or when analogous views are generally admitted, we can dimly forsee that there will be a considerable revolution in natural history.

I find in the domestic duck that the bones of the wing weigh less and the bones of the leg more, in proportion to the whole skeleton, than do the same bones in the wild duck; and this change may be safely attributed to the domestic duck flying much less, and walking more, than its wild parents.

I conclude that the musical notes and rhythms were first acquired by the male or female progenitors of mankind for the sake of charming the opposite sex.