Ring species

During our September meeting while discussing evolution, Ryan brought up a great example that I was not familiar with. It is an evolutionary concept called "Ring Species", it is a great example of evolution in action. As an animal population spreads, the neighboring populations can continue to interbreed with one another. So, in this example there are 7 subspecies of the  Ensatina salamander. Subspecies 1 can interbreed with subspecies 2, and 2 with 1 or 3, and so on. However, subspecies 1 and 7 which live side by side can not interbreed with one another. As they descended down each side of the valley, they evolved with subtle differences and by the time the salamanders met at the bottom of the valley, while looking very much like the same animal, they are essentially 2 different species.      

Now of course this did not just happen overnight and would have taken many years and generations for this to have taken place. What makes this so interesting is that you can see the transition species along the way, of course all of the species have continued to adapt. Being able to track the animal as it moved and adapted to it's environment, while still being able to see the original species, make it a great tool to show evolution in action. There are other ring species as well, but the Ensatina salamander is one of the better known examples. For further information, I would recommend  checking out this link and look at the work Tom Devitt is doing, it also contains a more in-depth explanation and some experiments he has done with the salamanders. http://evolution.berkeley.edu/evolibrary/article/0_0_0/devitt_01