WAS
IT DESIGNED?
THE reef-dwelling brittle
star has an amazing form of armor on its upper surface. This part of its
skeleton is studded with microscopic lenses that turn the animal’s armor into a
compound eye.
Crystalline bumps on the skeleton serve as
high-quality microlenses
Consider: When
scientists examined the skeletal plates of the brittle star, they saw “an
unusual pattern of densely packed, crystal-clear bumps, each thinner than a
human hair,” says the magazine Natural History. These crystalline bumps,
made of calcium carbonate (calcite), proved to be high-quality microlenses that
focus light onto what seem to be photosensitive nerves just below the plates.
Moreover, the lenses have the exact shape needed to produce the desired image.
According to chemist
Joanna Aizenberg, the brittle star’s dual-purpose shell “demonstrates an
important principle: in biology, materials are often optimized for multiple
functions.”
Taking a lesson from the
biology of the brittle star, researchers have devised a simple, low-cost method
of producing arrays of microlenses made of calcium carbonate. The many
applications of these arrays include telecommunications, where they are used to
conduct light signals through optical fibers.
What do you think? Did
the “seeing” skeleton of the brittle star come about by evolution? Or was it
designed?
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