Comments on: The lumping of the gulls http://www.nemesisbird.com/2007/02/the-lumping-of-the-gulls/ birding and ornithology in Pennsylvania and beyond Tue, 07 Feb 2012 16:00:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: djr http://www.nemesisbird.com/2007/02/the-lumping-of-the-gulls/#comment-11 djr Wed, 21 Feb 2007 03:37:00 +0000 http://drewweber.wordpress.com/2007/02/19/the-lumping-of-the-gulls/#comment-11 Certainly, there are "species" that exhibit tremendous differences in physical appearance. The <a HREF="http://images.google.com/images?q=%22turdus%20poliocephalus%22&ie=UTF-8&oe=UTF-8&rls=org.mozilla:en-US:official&client=firefox-a&sa=N&tab=wi" REL="nofollow">Island Thrush</a> comes to mind. External appearance alone is not a reliable indication of how birds (or other living things) are connected to each other.<br/><br/>But as I stated in my own <a HREF="http://djringer.com/birding/2007/02/19/1000-new-bird-species/" REL="nofollow">post on this topic</a>, I am not comfortable defining species based on a percentage range. I prefer a more holistic approach, but such an approach is messy, confusing, and necessarily self-contradictory.<br/><br/>Will genetic data eventually be recognized as sort of a trump card, overruling other kinds information? Well, "species" is a rather arbitrary concept after all, and if we wanted to, we could change the definition of species to mean "populations that show greater than a 2 percent difference in their DNA barcodes."<br/><br/>But I for one wouldn't like it. Certainly, there are “species” that exhibit tremendous differences in physical appearance. The Island Thrush comes to mind. External appearance alone is not a reliable indication of how birds (or other living things) are connected to each other.

But as I stated in my own post on this topic, I am not comfortable defining species based on a percentage range. I prefer a more holistic approach, but such an approach is messy, confusing, and necessarily self-contradictory.

Will genetic data eventually be recognized as sort of a trump card, overruling other kinds information? Well, “species” is a rather arbitrary concept after all, and if we wanted to, we could change the definition of species to mean “populations that show greater than a 2 percent difference in their DNA barcodes.”

But I for one wouldn’t like it.

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