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Sunday, April 20, 2014

Bonus Letter: T is for Tiktaalik Roseae

T is for Tiktaalik Roseae.

According to the time-honored rules of the A-to-Z Blogging Challenge, I'm permitted Sundays off, so the number of days in April and number of letters in the alphabet will come out even.  I'm using Sundays, however, to catch up on animals that "slipped through the cracks," as it were.

The Tiktaalik, or lobe-finned fish, may be the evolutionary link between fish and amphibians: ancestor, therefore, of all us land-dwelling chordates.  The front fins of the Tiktaalik were not your ordinary fins; they were designed to bear weight.  Moreover, they have wrist bones, and even structures resembling fingers.  Little holes behind the eyes suggest it had lungs as well as gills.

This, ladies and gentlemen, is the living incarnation of the "Darwin Fish," pictured on chromium bumper-stickers throughout the land.

Why it evolved the way it did, why anything evolved the way it did, was necessity.  In its specific environment, this remote ancestor of ours simply had to venture onto land or die.  We didn't leave the sea willingly; we were chased.

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