Posted by:
FR
at Mon Sep 19 23:33:05 2005 [ Email Message ] [ Show All Posts by FR ]
Please understand, I am not arguing anything. I have my beliefs and you can have yours. We are here to think, and ponder these snakes.
First, I disagree on continous gene flow. If that were so, there would not be locality types, But hey, there are locality types. You mention corn snakes, they are a great example on this. Every county has its own morph of corn snake. While they are all corn snakes, they all have unique local qualities. Just look at them. If they outbred, this would not be so prevalent. This occurs with kingsnakes as well as many many kinds of snakes.
Let me ask, do you fellas just step out your door and collect, or just stop the car and collect? No sir, you go to a particular place, Why??????? why there and not anywhere? Does every acre of south texas have getulus????? I don't think so.
I think the problem is understanding range maps, in the old days, they used site maps, that is, there was a dot for an individual snake. These dots were not space evenly over the range, but in clumps. Then someone decided to draw a line around the outside dots, and call that their range. But that is false, the dots are the range and not the areas inbetween. Now what that really says is, is their perferred habitat continious, again that answer is no, their perferred habitat is fragmented. Now because its fragmented, geneflow is also fragmented.
I would bring up behavior, but that would do no good here. But I will say, behaviorally snakes are territorial and inbreed by nature. One would have to ask why a snake combats some males and not others. In all the groups I have studied, there are many males and they never combat. Yet on a very rare occasion, you see two males combating and on even rarer occasions, you can find females combating. They combat, individuals that are not of their group. Even if this is absolutely correct, it still does not prevent occassional outbreedings or even mass outbreedings for particular events. Take the gulf coast, if the colonies of reptiles were all clean cut and set, after the flood, it certainly changes the whole dynamic. This is most likely how outbreeding(geneflow) occurs.
Snake populations are never static, they are either expanding or contracting. In a very wide view, this happens over tens of thousands of years as well on a year by year basis.
When a reptile is rapidly expanding its range, there is rapid geneflow, when they are contracting their range, there is no gene flow. This develops locality types.
Now with time, and another expansion, they out breed again, then are isolated for thousands of years. This is a better picture of how it works. They do not have continious anything. Its all a matter of history.
What I find odd is, why people think its one or the other, and not all of the above and more. Mostly whats misunderstood is time. Man has been on earth for less time then it takes a snake species to migrate. Again, just something to think about. FR
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