THE SCOPE AM) IMFOHT OF GENECOLOGY 17^i 



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true interpretation oi tlu' facts. I'or liirlhcr information as to tlu- 

 workinf^ j)rin(ii)les I may perhaps he |)erniitte(l to refer to my prcx ions 

 Avork on this topie. 



The grouping in nature of individuals into ecospecies and ecotypes, 

 representing various eomhinations of Mendelian factors, and the causes 

 controlling this grouping, might thus he said to he the main ohjecls 

 of genecology. That the genecological units do not necessarily — and 

 prohahly quite often do not — coincide with the units of the systeniatists 

 is clear. The divergences are due to a large extent to different concep- 

 tions of the species. The point of view of the genecologist — that the 

 species represent an intercrossing community, the memhers of whicli 

 have secondarily hecome clustered in groups (viz. ecotypes) on account 

 of the differentiating effect of environmental factors upon the geno- 

 typically heterogeneous population — is very different from the 

 systematist's view of the species. From the point of view of traditional 

 systeniatism a species is composed of a forma genuine, and deviations 

 are subordinated under this type as varieties and forms of less syste- 

 matic» value. Apart from the untenability of this view, the supposed 

 type may include a number of ecotypes, and several varieties may 

 conversely be found as normal constituents forming parts in one and 

 the same ecotype, as has been shown in my previous work. There is 

 another point of divergence in the unit conception of genecology and 

 systeniatism, viz. the tendency of the latter to s[)lit the species into 

 smaller ones, thus creating a swarm of units which all rank as 'Spe- 

 cies». From a genecological point of view this is to mistake the bricks 

 of a building for the building itself. Only as long as these small 

 »species» (elementary species,, microspecies, vicarial species, etc.) re- 

 present ecotypes — a point which has to be investigated in each par- 

 ticular case — ■ and only as long as they are presented as constituent 

 parts of the community of individuals which we have called an eco- 

 species, do they tell us anything of the morphology of that community 

 from a genecological point of view. 



It is also evident that purely genetical units do not cover the 

 genecological. It is, however, interesting to see how the genotype-con- 

 ception is reflected in the species-concepts recently propounded by some 

 geneticists (Lotsy, 1916 and 1922: Hagedoorn, 1921). The genetical 

 analyses of Linnean species brought the proof of the constancy of the 

 genotype, which then became the real unit in genetics, while the 

 Linnean species, being an aggregate of individuals with different geno- 

 typical construction, is still held to be a purely conventional concep- 



