8o 



ZOOLOGY 



Diversity 

 resulting 

 from conju- 

 gation 



but a little study of the more primitive organisms con- 

 vinces us that this is not the case. That it does so in 

 the higher animals must be only because there are cer- 

 tain advantages, for such animals, in this mode of re- 

 production. Our second thought may well be that it 

 is not primarily a matter of reproduction at all but of 

 diversity of vital functions. The male and female have 

 different duties, and between them, like Jack Spratt and 

 his wife in the nursery rhyme, they cover the field of 

 opportunity. We observe that among the social insects 

 such as the ants, there appear to be three sexes : males, 

 females, and workers. The workers are not really 

 another sex ; they are sterile females, lacking sex, but 

 they represent a further diversity of function. There 

 is no doubt, of course, that diversities in the abilities 

 and behavior of the sexes are useful in many cases. Out 

 of the fact of sex has grown a multitude of consequences, 

 which in man especially are of the greatest significance. 

 Yet it is impossible to explain the origin and rise of sex 

 on the basis of results which were millions of years 

 ahead. Of what value is sex in its simplest form, when 

 it is narrowed down to the primary function of produc- 

 ing germ cells which are capable of uniting to form a 

 new individual ? 



4. Professor H. S. Jennings found that even in such 

 non-sexual animals as the Paramecium, conjugation 

 increased variability. This is easily understood if we 

 suppose that the germinal constitution of different in- 

 dividuals is not exactly alike. If one is ABC, the other 

 abc, then after conjugation we may get Abe, or aBC, or 

 abC, etc. Granting that increased variability is bene- 

 ficial, in so far as it produces new combinations which 

 may prosper under particular conditions, we can see 

 how conjugation was justified. Its function, from the 



