In:
Canadian Journal of Zoology, Canadian Science Publishing, Vol. 63, No. 10 ( 1985-10-01), p. 2233-2239
Abstract:
This study examines the origin and consequences of the disregard of evolutionary biologists towards the historical constraints emerging from phylogenetic studies. An attempt is made to establish the theoretical basis that would allow the integration of these constraints in studies related to the understanding of evolutionary processes responsible for the origin of traits. First, the historical context is defined following the concepts of cladistic methodology. Then the empirical limits intrinsic to the structure of the theory of natural selection are outlined. Extrapolations of this evolutionary process at a historical level are not justifiable because of the impossibility of empirical verification. As a prerequisite for the study of species, it becomes essential to distinguish the autapomorphies (evolutionary novelties) from the plesiomorphies (primitive characters). Only the autapomorphies are potentially open to studies concerned with the ultimate causes related to their origin, since it is possible to gather the relevant data. On the other hand, since the selective pressures now affecting the plesiomorphies are not necessarily the same as those responsible for their origin, and since it is impossible to recreate the historical context in which they have originated, it is preferable that evolutionary biologists refrain from elaborating scenarios pertaining to the origin of those traits. A parallel is made between these two types of features and previous concepts of adaptation and exaptation. An example related to the origin of the "reversed" size dimorphism of the Falconiformes is used to illustrate these theoretical concepts.
Type of Medium:
Online Resource
ISSN:
0008-4301
,
1480-3283
Language:
English
Publisher:
Canadian Science Publishing
Publication Date:
1985
detail.hit.zdb_id:
1490831-1
SSG:
12
