The Descent of Man and Selection in Relation to Sex HTML version

On The Affinities And Genealogy Of Man
Position of man in the animal series--The natural system genealogical-- Adaptive
characters of slight value--Various small points of resemblance between man and the
Quadrumana--Rank of man in the natural system-- Birthplace and antiquity of man--
Absence of fossil connecting links--Lower stages in the genealogy of man, as inferred,
firstly from his affinities and secondly from his structure--Early androgynous condition
of the Vertebrata--Conclusion.
Even if it be granted that the difference between man and his nearest allies is as great in
corporeal structure as some naturalists maintain, and although we must grant that the
difference between them is immense in mental power, yet the facts given in the earlier
chapters appear to declare, in the plainest manner, that man is descended from some
lower form, notwithstanding that connecting-links have not hitherto been discovered.
Man is liable to numerous, slight, and diversified variations, which are induced by the
same general causes, are governed and transmitted in accordance with the same general
laws, as in the lower animals. Man has multiplied so rapidly, that he has necessarily been
exposed to struggle for existence, and consequently to natural selection. He has given rise
to many races, some of which differ so much from each other, that they have often been
ranked by naturalists as distinct species. His body is constructed on the same homological
plan as that of other mammals. He passes through the same phases of embryological
development. He retains many rudimentary and useless structures, which no doubt were
once serviceable. Characters occasionally make their re-appearance in him, which we
have reason to believe were possessed by his early progenitors. If the origin of man had
been wholly different from that of all other animals, these various appearances would be
mere empty deceptions; but such an admission is incredible. These appearances, on the
other hand, are intelligible, at least to a large extent, if man is the co-descendant with
other mammals of some unknown and lower form.
Some naturalists, from being deeply impressed with the mental and spiritual powers of
man, have divided the whole organic world into three kingdoms, the Human, the Animal,
and the Vegetable, thus giving to man a separate kingdom. (1. Isidore Geoffroy St.-
Hilaire gives a detailed account of the position assigned to man by various naturalists in
their classifications: 'Hist. Nat. Gen.' tom. ii. 1859, pp. 170-189.) Spiritual powers cannot
be compared or classed by the naturalist: but he may endeavour to shew, as I have done,
that the mental faculties of man and the lower animals do not differ in kind, although
immensely in degree. A difference in degree, however great, does not justify us in
placing man in a distinct kingdom, as will perhaps be best illustrated by comparing the
mental powers of two insects, namely, a coccus or scale-insect and an ant, which
undoubtedly belong to the same class. The difference is here greater than, though of a
somewhat different kind from, that between man and the highest mammal. The female
coccus, whilst young, attaches itself by its proboscis to a plant; sucks the sap, but never
moves again; is fertilised and lays eggs; and this is its whole history. On the other hand,
to describe the habits and mental powers of worker-ants, would require, as Pierre Huber
has shewn, a large volume; I may, however, briefly specify a few points. Ants certainly
communicate information to each other, and several unite for the same work, or for
games of play. They recognise their fellow-ants after months of absence, and feel
sympathy for each other. They build great edifices, keep them clean, close the doors in