558 



THE COMMUNITY 



Table 50. Comparison of the Mammalian Faunas of a Temperate Deciduous Forest and a 



Tropical Rain Forest Region, with Respect to the Period of Activity for Species 



and Subspecies (Modified from O. Park, 1940) 



has been made, and in such a discussion 

 as the present one, where the community 

 is being examined for periodism, an exten- 

 sive analysis of the experimental findings on 

 species is not feasible.* 



From the viewpoint of the whole com- 

 munity, such activities have been classified 

 as follows (O. Park, 1937, 1941): 



I. Periodic Activity: An activity pat- 

 tern in which the fundamental char- 

 acteristics for a species population 

 recur through successive diel periods 



1. Exogenous Type: Periodic activ- 

 ity in which the pattern is directly 

 induced and controlled by the 

 periodic environmental influences 



2. Endogenous Type: Periodic activ- 

 ity in which the pattern is resi- 

 dent in the organism 



• This experimental field has been sum- 

 marized (O. Park, 1940), and further informa- 

 tion will be found in: Harden (1942), Brown 

 and Webb, (1948), Calhoun (1944, 1945), 

 Fulton (1941), Orison (1944), Gunn (1940), 

 Gunn and Pielou (1940), Higginbotham (1939, 

 1947), Hutchison (1947), Kalmus (1940), 

 Lewis and Bletchly (1943), Mellanby (1940), 

 O. Park, (1941, 1941a), O. Park and Noskin 

 (1947), O. Park, Roberts, and Harris (1941), 

 Pielou and Gunn (1940), Smith and Cole 

 (1941), Waloff (1941), and Warden, Jenkins, 

 and Warner (1940). 



a. Habitual activity: Endogenous 

 activity that is the result of 

 induction or previous experi- 

 ences of the individual, and, 

 hence, indirectly induced by 

 the environment 



b. Inherent Activity: Endogenous 

 activity that is a part of the 

 species heredity 



3. Composite Type: Periodic activity 

 in which the pattern is in part 

 exogenous, and in part endo- 

 genous 

 II. Aperiodic (Arrhythmic) Activity: Ac- 

 tivity of a species population, the in- 

 dividuals of which do not exhibit the 

 same average pattern with respect to 

 the diel time sequence, but in which 

 the individuals exhibit a varying 

 activity and inactivity through suc- 

 cessive diel periods. 



It seems certain that (1) the periodic 

 activity pattern of a species population is 

 both complex and specific with respect to 

 normal diel rhythm; (2) that the activity 

 pattern is usually, if not always, modifiable 

 by the environment; (3) that many forms 

 of periodic activity are involved, such as 

 alternation of overt active and inactive 

 periods, rhythms in pupation and in biolu- 

 minosity; (4) that the great majority of 

 species have composite patterns; (5) that 



