32 FOOT-NOTES TO EVOLUTION. 
ones. The evolution of the earth and its life has rarely 
been subject to great leaps and catastrophes. Yet 
epoch-making events have taken place 
Epoch making on the earth. Such changes in life, as 
a the acquisition of lungs, of wings, of 
speech, are marked by the increased rapidity of the pro- 
cesses of evolution. 
Professor Bergen says: “ Until an evolutionary rise 
of species had been assigned as an explanation of the 
succession of higher and higher animals and plants 
throughout the geological ages, what adequate reason 
for this progress of life could be given? Strike out 
from our present conception of the organic world, class 
after class, all notion of actual relationship by descent, 
and what have we left but a mighty host of extinct 
creatures whose rise, progress, and disappearance are 
far more unaccountable than that of the genii in the 
Arabian Nights?” 
But not all change has been progress. The idéa of 
some of the earlier evolutionists that the advance of 
life has been the simple result of an in- 
nate “uniform tendency toward pro- 
gression” can not be maintained. For 
progress, while general, is by no means uniform or uni- 
versal, Progress ceases when its direct cause ceases. 
In every group there are some members characterized 
by degeneration and loss of specialization. This is in- 
volved in the theory of “natural selection.” If prog- 
ress comes through competition, lack of competition 
would imply retrogression. When animals or plants are 
withdrawn from the stress of life to some protected con- 
dition, the character of the type is lowered. ‘There is 
less need for specialization when the range of wants is 
narrowed. Hence it is that all parasitic animals or 
plants—lice, leeches, dodders, mistletoe, Indian pipe—are 
Change not 
progress. 
