GROWTH IN TIME OF THE TOTAL ORGANISM 



217 



TABLE 12 



CELL SIZE AND TEMPERATURE IN PROTOZOA 



After R. Hertwig from Bertalanffy, 1951a 



Tempera til I 



Dileptiis anser, Actinosphaeriurn, 



length width in mm diameter of a cyst in mm 



0.510 

 0.384 



0.1 12 

 0.096 



0.090 

 0.065 



geography and ecology showing that growth rate increases and final size decreases with 

 increasing temperature (Fig. 22). This was found, for instance, in the mussel, Alya arenaria 

 (Newcombe, 1936). Broch (1933) found in hydroids that individuals of the same species 

 grow larger in colder than in warmer regions; corresponding to the considerations given 

 above, although without quantitative analysis, he concluded that body size is determined 

 by a steady state between anabolic and catabolic processes which are both, though to a 

 different extent, dependent on temperature. Exceptions from the rules mentioned are 

 apparently due to the fact that physiological processes follow an optimum curve rather 

 than Van 't Hoff 's rule. The mechanism described will therefore be modified by optimum 

 conditions characteristic of the species concerned. This is the case, for example, in marine 

 snails : Increased size in cold waters was found in 64 percent of the species investigated, 

 while larger varieties in warm oceans were found in the rest, i.e. species with a high 

 temperature optimum (Chen-Ya-Shih, 1937). 



75 



550 



25 





10 



20 



30 



40 

 Time in years 



50 



Fig. 22. Effect of temperature on growth in plaice {Pleuromctes platessa). Heincke's data. 

 a from the Southern North Sea (summer temperature 15-16°); b from the Barents Sea 

 (summer teinperature 0-4^). At higher temperature growth is faster and final size smaller. 



After Bertalanffy, 1951a. 



TABLE 13 



BODY WEIGHT AND TEMPERATURE IN Plduaria maciilata 



After Abeloos from Bertalanffy, 1951a 



Temperature 



r 



12'' 



18= 



Final weight in mg 



53 

 35 



25 



Literature p. z^j 



