252 READINGS IN EVOLUTION, GENETICS, AND EUGENICS 
15. There is a growing skepticism on the part of biologists as to 
the extreme fierceness of the struggle for existence and of the conse- 
quent rigor of selection. It may be answered that no very obvious 
fierceness is implied in the theory. So long as overproduction and a 
shortage of space and food exists the struggle for existence is inevitable. 
16. Special objections are offered to the subsidiary theory of 
sexual selection. It is said that the type of sexual selection involving 
active rivalry and battling for mates needs no special theory, inasmuch 
as this is a mere phase of the struggle for the maintenance of the full 
life, including the chance to leave offspring. It is against the other 
side of sexual selection, which involves passivity on the part of the 
male and active choice on the part of the female of the more beautiful 
or otherwise attractive male, that objection is raised. It is claimed 
that such choice implies too high aesthetic powers in animals of 
relatively poor vision and mentality. Experiments have been per- 
formed with moths, in which the male and female coloration is 
strikingly different, in order to determine whether females actually 
do exercise any choice of mates that is based on considerations of 
appearance. The result proved conclusively that color patterns have 
no value in mating, but that the female is passive and mates with the 
first male to present himself, while the male finds the female through 
his exquisitely effective sense of smell. 
We know now, however, that secondary sexual characters are 
intimately bound up in a physiological way with the functioning of 
the sex glands and are therefore doubtless to be interpreted as mere 
non-adaptive correlative variations that need no special evolutionary 
explanation. 
DEFENSE OF DARWINISM 
In presenting these sixteen objections, we have in most cases 
indicated the lines upon which the objections have been met, if they 
have been met. Not all of these objections are considered serious at 
the present time, for some are based upon lack of a full knowledge of 
what Darwin actually wrote; others are largely academic in character 
and fail to stand up under actual test; still others have been more or 
less adequately met by subsidiary or supporting theories which have 
been advanced by various neo-Darwinians. 
Most of the special objections raised in this chapter have received 
the attention of various able Darwinians, and the student of evolution 
would doubtless be interested in the expert and fair-minded defense 
