Nearly every group of animals in which it is found
belongs, to put it moderately, to the last tenth of the story of
life, and in some of the chief instances the animals have only
gradually developed social life.* The first nine-tenths of the
chronicle of evolution contain no indication of social life,
except--curiously enough--in such groups as the Sponges, Corals,
and Bryozoa, which are amongst the least progressive in nature.
We have seen plainly that during the overwhelmingly greater part
of the story of life the predominant agencies of evolution were
struggle against adverse conditions and devouring carnivores; and
we shall find them the predominant agencies throughout the
Tertiary Era.
* Thus the social nature of man is sometimes quoted as one of the
chief causes of his development. It is true that it has much to
do with his later development, but we shall see that the
statement that man was from the start a social being is not at
all warranted by the facts. On the other hand, it may be pointed
out that the ants and termites had appeared in the Mesozoic. We
shall see some evidence that the remarkable division of labour
which now characterises their life did not begin until a much
later period, so that we have no evidence of social life in the
early stages.
Pages:
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341