what evolution means in the first of these senses.

The Darwinian Theory of Descent.--Darwin's theory of descent is the
doctrine that all forms of life now existing or that have existed upon
the earth have sprung from a few simple primitive types. According to
this theory all forms of animals and plants have sprung from a few
primitive stocks, though not necessarily one, because even in the
beginning there may have existed a distinction at least between the
plant and the animal types. So far as the animal world is concerned,
then, this theory amounts to the assertion of the kinship of all life.
From one or more simple primitive unicellular forms have arisen the
great multitude of multicellular forms that now exist. Popularly,
Darwin's theory is supposed to be that man sprang from the apes, but
this, strictly speaking, is a misconception. Darwin's theory
necessitates the belief, not that man sprang from any existing species
of ape, but rather that the apes and man have sprung from some common
stock. It is equally true, however, that man and many other of the lower
animals, according to this theory, have come from a common stock. As was
said above, the theory is not a theory of the descent of man from any
particular animal type, but rather the theory of the kinship, the
genetic relationship, of all animal species.

It is evident that if we assume Darwin's theory of descent in sociology
we must look for the beginnings of many peculiarly human things in the
animal world below man. Human institutions, according to this theory,
could not be supposed to have an independent origin, or human society in
any of its forms to be a fact by itself, but rather all human things are
connected with the whole world of animal life below man. Thus if we are,
according to this theory, to look for the origin of the family, we
should have to turn first of all to the habits of animals nearest man.