Good piece here at Birder's World blog on (long overdue) re-evaluation of bird classification based upon
(The post is actually referencing an article about to appear in the journal Science, the focus of which may be more on genera and above than species, but similar earlier work had already suggested much possible "lumping" and "splitting" of species.) [ Addendum: the article is getting a lot of play across the 'net'; another good overview from "Grrlscientist" here.]
The DNA evidence itself will likely be debatable over time, but at least is headed in the right direction, even if not as definitive as some think. A lot more work in the area is needed and will be stimulated --- our understanding of DNA changes and their relationship to evolution still being quite primitive.
(BTW, just 'nuther new bird species discovered in China here.)
DNA evidence for the Ivory-bill would also not be conclusive of its current existence (unless it came in direct conjunction with a specific sighting); sightings and photography remain key.
Am beginning to think that normal physical approaches to this bird may be doomed to fail, and that what is needed are stationary (not-easily-bored) searchers, posted at key positions, scanning the forest distances, 100+ yds. away, for the species with binoculars and birdscopes (for hours on end), and ready to digiscope a shot when needed (forget close views and hand-held video) --- some of this has been done. Still chagrined that there have not already been more long-distance sightings publicly reported by now. A lengthy close view may only follow finding a nesthole; easier wished than done.
In the end, maybe it's all just math anyway; the entire universe(s) that is.
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3 comments:
Some clarifications here:
The study is NOT about mitochondrial DNA, and as such it has little direct relationship to the highly publicized "DNA bar coding" study published last year (or the Tanager reorganization mentioned in the intro of the bird world article). This new study used nuclear DNA -- the stuff of chromosomes that makes up the vast majority of the genome and is inherited from both parents, with sexual recombination and all that good stuff. It is concerned with higher levels of taxonomy above genus and species: families, orders, and the great divisions that reflect profound divides in the earliest stages of avian evolution. These results aren't just going to tweak life lists up or down by a few tickies. They are proposing to fundamentally restructure the basic architecture of our understanding of avian relationships and evolution. And as a byproduct of this, you can of course expect the AOU checklist order to be COMPLETELY rearranged -- AGAIN. Maybe they'll fix their hyphenation this time?
thanks for clarification Bill; I noticed after reading the 'grrrlscientist' account it was all nuclear DNA, which made more sense (corrected above).
You know it's all just a plot from book publishers to get us all to buy new field guides next year, right? ;-)
Among the problems that may never be resolved by DNA: just how many (nuclear) genes does reproductive isolation require? Can a single gene lead to reproductive isolation? I think the answer is yes. Can the new technology detect this without concomitant behavioral and/or ecological study? I don't think so.
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