Friday, August 19, 2005

Ok, so there is one more thing about which I want to blog. Hubbell's neutral model. It's interesting to see how it has become a lightning rod. My reaction to it was "cool". It seems like most other people reacted with "how can I disprove this?" Maybe that is my limitation as a scientist - maybe I am too willing to accept new ideas, instead of putting them through the ringer like I am supposed to...

Sure, the neutral theory bothered me. What do you mean, tropical trees are competitively neutral? Of course they aren't - any idiot can see that. But you need to look at the analogy with neutral models in genetics. Of course genes are not neutral - the point is that selection theory cannot explain a lot a what goes on in genetics. Rather than trying to explain everything through selection and adaptation, you need to partition variation into selective and neutral variation. Not only does it make it easier to tease apart the variation that matters, it also allows you do trace ancestry and relatedness, and come up with both tools to identify individuals and tools to trace the relatedness between plant Divisions. The idea that niche differentiation can explain the existence of thousands of tropical trees is pretty far-fetched. Even as simple things as light gradients in gaps are pretty hard to demonstrate. It isn't that trees are competitively neutral, it's that neutral models can explain a lot of the variation that exists. So let's refine our understanding of neutral vs. competitive forces, and make use of this information. Or not, if that's what you prefer.

No comments: