October 24, 2005
This is just cool!
by Jeff Langstraat
I've always had an interest in the creation/evolution wars. They've been heating up again, what with Kitzmiller v. Dover Area School District being argued in court the past few weeks. While I started reading sites like PZ Meyer's Pharyngula (I also like this because it's from Minnesota), Ed Brayton's Dispatches from the Culture Wars and the group blog The Panda's Thumb for news about the ID movement and Right-Wing attacks on biology (and to get news about Kitzmiller; the ACLU of Pennsylvania has set up an indispensable blog with resources on the trial), I've also found myself reading about things that make me say, "That's really cool!" I've been learning stuff, and it's fun. A post today by PZ Meyers gave me that "Cool!" feeling. It's about the evolution of insect wings from gills:
The question is how insect wings evolved. Wings are a classic issue in evolution, because they aren't going to function for flight at all until they've achieved a certain minimal size—half a wing isn't any good at all for getting an animal in the air, so any explanation for their selective evolution has to incorporate alternative functions: as stabilizers for cursorial animals, for instance, or traps for catching small prey on the run.In insects, we have an interesting origin explanation for wings: they're modified gills. It makes sense. For gills, you want to have an increased surface area for gas exchange, and you want them exposed to the external environment. Most animals evolved sophisticated gills with convoluted surfaces and tucked them away in a protective chamber, with a mechanism to pump water over them, but others took a simpler path. Mayflies, for instance, have flat vanes on each segment in the larval stage as respiratory surfaces—they even look like wings. Arthropods evolved a recipe for flat, cuticular structures to serve as gills, and perhaps one explanation for the evolution of wings is that they simply re-evoked that recipe as adults, used it for gliding, and then expanded and elaborated on the formula incrementally to generate flapping, powered flight.
Just go read the whole post. It's quite fascinating for people like me who have some background in the "hard" sciences but now work in the social sciences, including doing some of that nasty PoMo Social Studies of Science stuff (we can talk about that another time). I just like things like this that teach me something I didn't know before. (No, I didn't take biology in college, but I had more than my share of chemistry and physics.)
Posted by in Culture War, Ephemera, Science, Sidelinks
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