Carl Zimmer writes: It’s hard to see what’s so special about a scallop. It looks a lot like a clam, mussel or any other bivalve. Inside its hinged shell lurks a musclebound creature that’s best enjoyed seared in butter.
But there’s something more to this ubiquitous entree: the scallop sees its world with hundreds of eyes. Arrayed across the opening of its shell, the eyes glitter like an underwater necklace. Each sits at the tip of its own tentacle and can be extended beyond the rim of the shell.
While some invertebrate eyes can sense only light and dark, scientists have long suspected that scallops can make out images, perhaps even recognizing predators quickly enough to jet away to safety. But scallop eyes — each about the size of a poppy seed — are so tiny and delicate that scientists have struggled to understand how they work.
Now, a team of Israeli researchers has gotten a look at the hidden sophistication of the scallop eye, thanks to powerful new microscopes. On Thursday, they reported in the journal Science that each eye contains a miniature mirror made up of millions of square tiles. The mirror reflects incoming light onto two retinas, each of which can detect different parts of the scallop’s surroundings.
Our own eye has been likened to a camera: it uses a lens to focus light on the retina. The new research suggests that scallop eyes are more akin to another kind of technology: a reflector telescope of the sort first invented by Newton. Today, astronomers build gigantic reflector telescopes to look in deep space, and they also build their mirrors out of tiles.
“For me, Newton and Darwin come together in these eyes,” said Gáspár Jékely, a neuroscientist at the University of Exeter who was not involved in the new study. [Continue reading…]