REPRODUCTION AND SEX 



455 



Reproductive and Other Functions. — It is often and rightly 

 said that most of the activities of organisms centre round the con- 

 trasted functions of nutrition and reproduction. The activities of the 

 green leaf stand in marked contrast to those of the flower. The 

 zoophyte colony is nutritive and vegetative, the swimming-bells or 

 medusoids that they bud off are reproductive and energetic. The 

 larval Mayfly may have a nutritive sub-aquatic life of two or three 

 years, and a reproductive aerial life of two or three evenings. In 

 the year's life of migratory birds the courting, mating, nesting, and 

 brooding period is sharply punctuated off from the resting and 

 recuperating period spent in the winter-quarters. Life is often a 

 see-saw between Nutrition and Reproduction, using both terms 

 widely. 



Yet it is evident that nutrition and reproduction are not neces- 



FlG. 58. 



Budding in Stalked Infusorian (Ephelota). After Butschli and Saville Kent. 



A, the intact animal on its stalk (ST), with a nucleus (N) in each bud. 



B, a diagram showing the branching of the original nucleus to form the 

 nuclei of the several buds. 



sarily to be regarded as two sharply circumscribed functions, for they 

 each imply the direction of numerous activities towards two par- 

 ticular ends: {a) the preservation of the individual, and (b) the 

 continuance of the race. Thus in studying higher animals it is 

 impossible to consider either reproduction or nutrition apart from 

 the functions of moving and feeling, or apart from the circulation 

 and the hormones. There may be an abstracting fallacy in too 

 sharply punctuating off the reproductive function, which means 

 much more than the activity of the reproductive organs or gonads. 

 Many other functions may be ancillary to reproduction, which, 

 moreover, in the higher reaches of life, has its psychological as well 

 as its physiological aspect. The point is that reproduction and 

 nutrition in their more complicated expressions must be regarded as 

 co-ordinations of several functions towards a particular end or 

 satisfaction. The quest for food and the search for mates may be 

 orchestrations of many functions. 



