Sunday, December 2, 2012

Creature Feature: Chitons.

Some people really like the idea of techno-organic lifeforms. I don't just mean cyborgs - I mean, theoretically, lifeforms that are mechanical, but reproduce like normal organisms. How this would work, I have very little idea. On one level, however, nature has already beaten them to the punch:

Chitons (Polyplacophores) are a large group of molluscs that, once again, I feel guilty lumping into one entry. I am quite certain that they are all individually fascinating. Chitons are all marine and can be found in virtually any ocean, eating algae off of rocks with a sort of toothy tongue called a radula. The lined chiton (Tonicella lineata) above actually looks pretty trippy. Mollusc-lovers, please don't kill me.

Chitons are a lot like pillbugs. They roll up in defense and can ever roll away from predators. The 8-piece shell is still flexible enough to let the squishy creature beneath it climb up rocks and the like. When a chiton dies, its shells can be washed up on the shore; these are sometimes called "butterfly shells," but they look too edgy to be butterflies. 

This does not look real. Source.

Chiton shells contain a lot of the mineral aragonite. For those of you who know absolutely nothing about organic chemistry, aragonite is not a common organic compound. It's made of calcium, carbon, and oxygen, which are all pretty common, but it is a rock.

Although a lot of mollusc shells are blessed with aragonite in their structures, chitons are the only molluscs that use it like a suit of armor, curling up into calcerous balls while still being allowed to move freely when not under threat. That makes this mollusc the closest thing to a real-life golem on the planet. Sure, it's not quite a robot, but look at it. It's a footfall away from being the next Hex Bug. Get one on your Christmas list today!


That's not all. Chitons have done something that no other mollusc has ever done with their aragonite: evolved eyes in their shells. The aragonite in chiton shells forms simple lenses that can see light and dark above the armored little slug (again: please don't kill me, mollusc-lovers). THey can, amazingly enough, see equally well above or below water. The most ancient chitons do not have these eyes; if the fossil record is correct, this makes these pseudo-eyes the most recently-evolved eyes in existence. They're almost inorganic eyes.  Tell that to your eye doctor next time you need new glasses!

Although not quite cybernetic, it would be extremely easy to create a mechanical chiton with "eyes" in its metallic shell. Hell add something in there to strengthen the calcium; then we would have a real armored mollusc. The only issue would be making sure the fleshy part could reproduce. Just another thing for science to work on.

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