152 SUMMARY AND CONCLUSION. 
though there can be no doubt that it is sometimes operative. Social 
organization is often affected by the conditions in the environment; 
but though the environment remains unchanged, vast changes in 
social organization may take place. For example, while remaining in 
the same region, and without special change in the environment, a 
tribe of men may pass from the hunter stage of life, through some- 
thing of pastoral life, into agricultural and diversified industrial life. 
This has probably been the experience of the Chinese race. 
(6) That endonomic selection, resting on the power of different 
individuals of the same species to deal with the same environment in 
different ways, is a fruitful cause of divergent evolution in isolated 
sections of the same species. This diversity of power is sometimes 
due to diversity of aptitudes, producing what I call aptitudinal selec- 
tion; and sometimes to diversity of training and of habitudes, pro- 
ducing what I call habitudinal selection; and at still other times to 
different methods of using the same aptitudes and habitudes, for 
which a suitable name has not yet been suggested. 
(7) That organic (or coincident) selection is of great importance in 
securing a new adjustment when the organism is suddenly exposed to 
an environment very different from that to which it was previously 
adjusted. 
(8) That the indiscriminate isolation of a small fragment of a species 
leads directly to the modification of type in the descendants of the 
isolated fragment, for the character of a single individual (or even 
the average character of several individuals) seldom if ever represents 
the average character of the original stock in every respect. 
(9) That indiscriminate isolation of a large section of aspecies 
interrupts the unifying influences of tradition and of heredity between 
separated branches of the original stock ; and, even though the environ- 
ment surrounding each branch is the same, the traditional method of 
dealing with the environment may in one or in both branches become 
modified, and the separate branches be thus subjected to divergent 
forms of endonomic selection. 
(10) That the indiscriminate elimination of all but a small fragment 
of an intergenerating group may be an important factor in introducing 
transformation, for one or two individuals may not be able to transmit 
all the traditions of the original group, or to reproduce in the innate 
characters of their offspring the unchanged average character of the 
original stock. 
(11) That advancing powers of accommodation, codperating with 
higher degrees of altruistic social organization, are in an ever-increasing 
measure setting aside both environal and dominational selection, and 
so lowering the racial standards of civilized man. 
