CHAPTER VIII 

 ASEXUAL GENESIS AND OVULATION 



HAVING shown why the principle is a law governing the 

 union of sperm cell and ovum, it will now be desirable 

 to examine the relation between sexual and asexual 

 reproduction. The reasons why the principle does not 

 apply to the latter are, briefly, that the two forms of 

 reproduction are suitable for very different conditions 

 of life, and react in diametrically opposite manner to the 

 same conditions. We have seen that it is a necessary 

 condition of the successful maintenance of any species 

 that its reproductive capacity should bear an inverse 

 ratio to its survival-capacity under the environment in 

 which it lives. That is to say, the birthrate must be 

 sufficient to compensate for the deathrate. Now, asexual 

 reproduction accomplishes this efficiently enough, but by 

 a different method to the sexual form of genesis. It is 

 a method suitable for those forms of life which enjoy 

 periods highly favourable alternating with extremely un- 

 favourable periods. 



The peculiar functions of these lower forms of life in 

 the evolutionary scheme are best secured by the power 

 to multiply with extraordinary rapidity when circum- 

 stances are favourable and opportunity offers, as during 

 unfavourable periods they are either swept out of existence 

 altogether or reproduction is entirely stopped, as, for 

 instance, with plants and insects in winter. Those species 

 which generally reproduce by the asexual method are 



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