146 VICTOR E. -Ill 1.1 (>R1>. 



the soil or pond bottom in much tin- same way as the pimieer 

 plants of the present climate would affect them. The difference- 

 resulting from the change of (limale are ihen, those of detail 

 rather than of principle. 



4. The Relation of Ecological Succession to .S'/'rr/V.v of /-'/v//. 

 If fish were found fossil in tin- bottom of Pond 14, in the order 

 which we have indicated, one might conclude at once that it 

 constituted a proof of ecological su< > ssion. This seems to have 

 been the general impression of zoologists who have heard tin- 

 presentation of these data. The que-tion has been asked, "Do 

 you find fossil in 14 all the fish which you mention as occurring in 

 succession there?' My answer to the effect that no such fact 

 has been discovered seems to have been regarded as constituting 

 a refutation of the entire statement of ecological succession. 



If fish were found fo-sil in the order described above, and the 

 species and order of species, the same as now found in the hori- 

 zontal series of ponds, we would have some important data bear- 

 ing on succession, migration, and other matters of interest to be 

 discussed presently, but this would yield no crucial ci-idence for 

 or against ecological succession. Ecological suciv-^ion is based 

 upon physiology, habits, behavior, mode of life, and the like, 

 which I have proposed to call mores (opposed to the term form). 

 Unless the mores of the morphological species found fossil were 

 the same as the mores of the same morphological species at 

 present, they would have no weight in the matter, and it would 

 be impossible to ascertain mores from fossils if Mich fossils were 

 found. 



If the same one or more species were found fossil in each and 

 all of the vertical stages of a pond like i_|, the evidence would not 

 refute the proposition of ecological succession because the physio- 

 logical char.ie'er- of the individual- of a gi\en species living in 

 the early stages could have been very different from tho-e of 

 individuals living in later Stages, without the differences beir.L' 

 shown in the preservable skeletal strueture. Furthermore the 

 modi liability of animal behavior seems well established. The 

 same species of plant may remain in a number of dill-Tent pond 

 stages. Such plants .-how -uiiable functional responses mani- 

 fested by different gn>\\ th-lOrm- in different stages. 



