THE GROWTH FORM OF POPULATIONS 



307 



Laboratory Populations 



Five examples of the logistic growth 

 curves of laboratory populations, chosen 

 from Pearl (1930), for Drosophila melano- 

 gaster; from Carlson (1913) and Pearl 



(1930), for yeast; from Cause (1934) for 

 Paramecium caudatum; from Cause (1931), 

 for Tribolium confusum; and from Terao 

 and Tanaka (1928), for the water flea, 

 Moina macrocopa Strauss; are reproduced 

 as Figures 94, and 97, 98, 99, and 100. 



250 



ASYMPTOTE = 212.0 



1 I I L 



2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 



AGE IN DAYS 



Fig. 97. The logistic growth of a laboratory population of Drosophila melanogaster. (From 



Pearl.) 



< 

 UJ 



> 



750 



600 - 



450 - 



300 - 



o 



< 150 - 



20 



10 12 



HOURS 



Fig. 98. The logistic growth of a laboratory population of yeast cells. ( From Pearl. ) 



