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Old Friday 4th September 2009, 11:20   #17
Rasmus Boegh
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Originally Posted by admmoon View Post
I must disagree. One of the problems with literature out there is there are too many people who do not use the correct definitions and that leads to confusion. The scientific and medical fields do have a standard set of definitions for a reason. When laymen begin to throw words around in the improper context, generating erroneous definitions, it leads to a large amount of confusion.
From above it appears you're suggesting that scientists working with birds (probably the single field in biology with most scientists, at least when disregarding human biology) are laymen? Check the previous ornithological references and please do explain why these should be regarded as layman, but your references (at present, actually based entirely on an entry by a semi-anonymous blogger just labelled "Dr. Walden") dealing with other fields are not? I have never, and will never, claim to know what is the correct use in e.g. herpetopathology (which appears to be the primary focal point of the previously mentioned blog), but likewise find it puzzling why people that clearly have little, if any, involvement in ornithology try to explain what is the correct definition in... ornithology! I can see the blogger now warns about the Cornell Lab of Ornithology under the headline "Be Careful of Hobbyist and Birding Book Terms". Evidently, he is not familiar with the Cornell Lab of Ornithology. Until the blogger provides a reference that supports his opinion on the use of these terms in ornithology, it remains just that; an opinion by a single person with little or no actual involvement in ornithology.

Originally Posted by admmoon View Post
Secondly, if you have not been keeping up with phylogenetics Aves is not considered a class anymore but is placed under Reptilia under Archosauria. Therefore the herpetologic definitions have been applied. In fact they have been more or less accepted by paleontology for years and the rest of the biological sciences are just now catching up.
I *never* said anything about the phylogeny of Aves (which I deal with on an every day basis) in this thread, and why you suddenly bring this up is somewhat puzzling. But regardless - the above is only partially correct. From a purely phylogenetic point of view, you are entirely right when saying that Aves is potentially problematic - certainly, but this isn't news and has been known for decades. But, even when strictly limiting it to phylogenetics, there are several solutions to this, and only one of them involves removing Aves as a class. Others involve splitting up other groups. Regardless, strictly speaking this isn't necessary to keep Aves. Today all animals are classified using the Linnaean System (which certainly has its flaws), and no-where did Linnaeus (or, more recently, ICZN) require for taxa to be monophyletic. The Linnean System does not necessarily equal cladistics. This is true both at higher and lower levels - even species (see e.g. Funk & Omland, 2003: Annual Review of Ecology, Evolution, and Systematics 34). Furthermore, if used as described in the above quote, it can actually be argued that Aves is a senior synonym of Reptilia (it was coined ~10 years before), and in any case what generally has been placed under Archosauria are birds, crocodiles, dinosaus, and alike. Not Reptilia in its entirety (contra above quote - unless what actually was meant was, in logical order [highest to lowest], Reptilia, Archosauria, Aves), which would result in further phylogenetic problems unless defining the combined clade as broadly as Sauropsida. Anyhow, if you search through recent literature, you will notice that few authorities working with extant birds treat Aves as anything but a class, even if people working with reptiles and especially paleontology generally dislike this.

As a final comment from me on this matter, I can only recommend you read the previously mentioned article (Davis, 2007 - see comment #14). In addition to a number of recommendation for accurately describing plumage abnormalities in ornithology, it also provides a brief history of the often confusing and conflicting use of these terms. Here it is worth mentioning that the use of the terms "albinism" and "leucism" for describing abnormalities in birds actually predates knowledge of most of the processes described in the previously mentioned blog. So, while the blog may well be correct in the use of these terms in herpetopathology, it matches neither the original nor the current use in ornithology.

Last edited by Rasmus Boegh : Friday 4th September 2009 at 17:41.
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