mobile - desktop
3 months for $50.00
News & Events:
Posted by Kenny Wray on December 11, 2002 at 17:39:23:
In Reply to: Assumptions, definitions and generalizations posted by emoneill on December 09, 2002 at 20:16:06:
"I recognize that geographic variation exists, but the subspecies concept is outdated and rather difficult to defend."
***This is hard to defend if you follow the evolutionary species concept, but not everyone does. There are still many subspecies being described of all forms of life. Many people do not agree entirely with the evolutionary species concept and accept it for what it is, just another species concept with its benefits and drawbacks. As Troy said in a post above, there is a certain degree of over use of subspecies out there (often because a grad student working on a Masters is in a rush to put their name on something), but there are also many valid geographic variants that are distinctive but exchange gene flow across their boundaries with other geographic variants (i.e. subspecies).
:You are saying in (a) that they are distinct but in (b) that they are not. You obviously mean distinct in two different ways in these, can you explain?
***Yes. Yellow Rat Snakes differ in their color, pattern, and habitat preference (to name a few things). They can be differentiated from other races of obsoleta based on these characters (i.e. they are a distinct geographic variant or race = subspecies). On the other hand, if one follows the Atlantic Coastal Plain northward where the land begins to increase in elevation, one finds a small area in which the Black Ratsnake of the uplands meets the lowland Yellow Ratsnake and interbreeding between the two geographic variants takes place. Because these two populations exchange gene flow across a broad area, they are not on separate evolutionary trajectories (distinct trajectories). Another example: ~3000 years ago before modern man traveled far and wide, I think you'd agree that a fair-skinned, blue-eyed, blond-haired, Norwegian was obviously distinct from a dark-skinned, dark-haired, dark-eyed, equatorial African. But with gene flow occuring, these two races are on the same evolutionary trajectory and not two distinct species.
:I am part of that generation and I do make a considerable effort to understand the methods I use as well as is possible as do many people I know. So your generalization "an entire generation" is simply not true.
***Yes, you are correct. This is a generalization that I did not intend to make. However, I did mean to refer to the majority of systematists/taxonomists coming up through the ranks today. I am glad you dedicate a large amount of effort into understanding the methods you employ, but I think you are the exception, rather than the rule. Just attending meetings and questioning grad students on their methods and conclusions, I have seen alot of young biologists who had no clue what they were doing, but rather were regurging what their major professor told them. In asking them about other researcher's works and theory papers, they often do not have a clue (and I am not the most well-versed person on the subject myself). Its not hard to see the different cliques around the country and how they are producing clones, rather than free-thinkers. I am just calling it as I see it.
:Your complaint is legitimate though, where it applies. It is relatively easy to analyze data these days with unversal mtDNA primers and programs like PAUP, anyone can do it. But I am not saying this is the case with Burbrink's work.
***It is easy to obtain data with these tools, not analyze it, and therein lies the problem. My thoughts on his research is that his conclusions are not all well supported and his lack of knowledge on the natural history of the animal is glaring.
:Another thing to take into account is that many people on this forum don't know the first thing about molecular data, species concepts, or philosophy of science. These are all important to the issue at hand.
***I agree with you that some are definitely more versed than others. But, to imply that some do not know the first thing, is to imply that they don't know anything, and on this, I disagree. I would find it hard for them to contribute to any discussion if they were clueless in these areas. Unless, you are being facetious and are refering to me (you'd probably be right! LOL).