[Tweeters] Convergent Evolution

Barry Ulman ubarry at qwest.net
Fri Oct 21 11:45:23 PDT 2011

With global warming, we might end up with rail-size fleas! Yikes!

Barry Ulman
Bellingham, WA.

On Oct 20, 2011, at 10:51 PM, jeff gibson wrote:

> For some reason I've been thinking of Rails lately. The other night I woke up from a dream, or vision of some sort, wherein I was gliding above a marsh and, looking down, saw a Rail slipping through the mass of cattails like a flea on a big green-haired dog. In a case of convergent evolution spanning several phyla, Rails (some anyway) are shaped remarkably like fleas - sort of tubby and pot-bellied viewed from the side, yet very narrow viewed from above - for similar reasons: to easily move through the dense vertical habitats of greenery or fur they live in. I always thought that was kind of cool. 'Form follows function' - that sort of thing.


> Luckily this convergence has happened in our currently coolish climate and didn't get too carried away. Can you imagine fleas as large as a rail? Jumping on you from a hundred yards away, and draining all your body fluids out in a minute? After all, in times of warmer climate and more oxygen, or whatever, dragonflies developed wingspans of 30 inches or so. So I think we can all be glad to live in the times we do. Giant fleas could ruin a perfectly good marshland birding experience.


> Like a flea jumping ship off some cat or dog onto a human arm with not enough hair-cover, I always thought rails look a bit out of place when too far out of the weeds. Or like a Bittern I saw a few years back near Spencer Island - in full erect camo-mode but about 10 feet away from the nearest cattails. "Move over a bit, everybody can see you!" I wanted to say.


> Of course there are many other examples of convergent evolution in nature - Auks and Penguins for example. But after thinking about all of this stuff after my dream I kept coming back to one evolutionary question that I've always wondered about: what's that thing with Hutton's Vireos and Ruby-crowned Kinglets all about? Had to sleep on that one.


> Jeff Gibson

> Dreaming in

> Everett Wa

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