Eight feet under
Someone wearing a burqa is totally covered from head to foot, aren't they? Makes you wonder what would have happened if it'd been the ancient Greeks who'd invented it. They were logical guys so they'd probably have and called a head-foot. Well, Greek being Greek, that means they'd have said `cephalo' (Greek for `head') `pod' (Greek for `foot'). Which would have given them cephalopod. Which is an octopus. So that wouldn't have worked. But now that we're on the subject of octopuses, let's talk about them a bit. (How's that for an oblique lead-in?)
A few weeks back Nicky spent some quality time with a friendly octopus seemingly named Gus (and who's been known to show up at squidrowcomics from time to time as well). In the strip we saw Gus doing some pretty intelligent stuff. But that's just a comic, right? They're just primitive little beasties, no?
Well … no. They're actually pretty darn amazing. First off, the reason they got tagged with the name cephalopod is because that's pretty much what they are – a large head with legs attached. Seems like a standard recipe for a horror film but on them it looks good.
There are too many cool things about these guys so today we'll only touch on a couple. The first, and the one that's always struck me as particularly jaw-dropping, is that they have eyes that are very, very similar to ours (and to most of our fellow land-dwellers). They've got two of them and each has a retina (to sense the light), a lens (to focus the light), and iris (to stop down the eye if there's too much light) and a cornea (which covers the front of the eye). Wow. That's pretty much the same machinery. And to top it off, the inside is filled with liquid, just as ours are.
But did they evolve in the same way as ours? Nope. If you examine how octopuses develop (pre-birth) you'll see their eyes forming from the skin. Our eyes, on the other hand, form as extensions of the brain. That's pretty darn different. And the mechanics of how they operate is quite different as well. You probably know that what we do to focus is use little muscles in our eyes to actually distort the lens. A squashed fat lens will focus light differently than a non-squashed one. The octopus eye, on the other hand (or foot), operates pretty much like a camera lens. The camera lens contains a rigid piece of glass (very non-squashable) and to alter the focus this lens is moved closer or further away from the film/sensor. The octopus does the same. His or her little bitty eye muscles work to move the lens further out or closer in.
Okay, enough talking. It's time for some action. There's a video that's been making the rounds lately and if you haven't seen it, you should (and can now). Back on the 13th I was talking about how different sorts of animals have shown the ability to use tools. Well, there's a new one to add to the list – the octopus. Just check out this video clip and you'll see why.
- And that's today's word from the bird
