Biogeography. Группа авторовЧитать онлайн книгу.
e. High Asia
Sclater mentions the relationships of natural areas, a concept that was to appear over a century later (see Hennig 1950, 1966; Brundin 1966), but was never explored further in his 1858 essay. Sclater’s regions were adopted by Wallace (1876), who shared similar sentiments regarding arbitrary lines:
The divisions in use till quite recently were of two kinds; either those ready made by geographers, more especially the quarters or continents of the globe; or those determined by climate and marked out by certain parallels of latitude of by isothermal lines. Either of these methods was better than none at all; [but] it will be evident, that such divisions must have often been very unnatural, and have disguised many of the most important and interesting phenomena which a study of the distribution of animals presents to us … The merit of initiating a more natural system, that of determining zoological regions, not by any arbitrary or a priori consideration but by studying the actual ranges of the more important groups of animals, is due to Mr. Sclater (Wallace 1876, vol. 1, pp. 52–53).
Wallace’s revision of Sclater’s regions is perhaps the most significant of all the geographical classification of the 19th century as it unified zoogeography under a single classification. Even though there were certain disagreements over terminology (see Ebach 2015), the areas have withstood the test of time, with the same divisions appearing in the 21st century studies (e.g. Holt et al. 2013; Morrone 2015). Regardless of its popularity today, the Sclater–Wallacean areas and the whole notion of topographical zoogeography were challenged as “essentially static” and “wrong”. “Instead of thinking of fixed regions, it is necessary to think of fluid faunas” (Mayr 1946, p. 5). For the newly developing field of population genetics and the Modern Synthesis, “zoogeography has had a similar fate very much like taxonomy. It was flourishing during the descriptive period of biological sciences. Its prestige, however, declined rapidly” (Mayr 1944, p. 1). Taxonomy apparently had run its course. Long live populations!
1.3. Ecology versus taxonomy: populations not species
The “two courses” of plant classification did not sit well with early ecologists. Linnaean taxonomy and species were considered to be arbitrary and artificial, while vegetations and plant forms were considered to be natural. Ecologists Eugenius Warming, Andreas Schimper, Frederic Clements and Henry Chandler Cowles were incredibly wary of taxonomic description, something Clements (1905, p. 11) decried as “vague descriptive articles” (Hagen 1986). Cowles warned:
Taxonomy must be scientific. It must require for its devotees a training as rigid as that required by professional workers in morphology, physiology or ecology. Species-making by taxonomic tyros must be abandoned … These things will not, be endured much longer; a little more and the sinning taxonomists will be cast out into the outer darkness where there shall be wailing and gnashing of teeth (Cowles 1908, pp. 270–271).
Were ecologists truly enraged with taxonomy, or were they after recognition for their newly developing field? Hagen (1986) proposed that early ecologists such as Clements were attempting to legitimize their discipline by distancing it from amateur botany “and to place it on a credible scientific basis” (Hagen 1986, p. 200). One way to draw attention to this is by defining their “new discipline in opposition to what they believed was a moribund, nineteenth-century, natural-history tradition” (Hagen 1986, p. 213). The move towards communities of plant forms, rather than species, was not unique to early 20th century ecologists. Neither was the notion that descriptive taxonomy and zoogeography were static and moribund. Species are essentially hypothetical, in the sense that a set of diagnostic characteristics are given a name and assigned to various types. Organisms that show these diagnostic characteristics are then assigned that name. Plant or life forms, however, were based on the traits of a community or a population. Moreover, populations were observable, that is, quantifiable, rather than abstract in the way species are defined.