Thursday, 18 February 2016

Superb Design in Beautiful Sea Butterfly that Flies Under Water

Limacina helicina. Image courtesy of Russ Hopcroft, University of Alaska, Fairbanks. NOAA, Public domain.

Joel Kontinen

It’s a snail and it lives in the ocean. It is so beautiful it is called a sea butterfly.

And it can fly – by flapping its wings – or appendages that look like wings – under the water.

The tiny snail Limacina helicina only lives in the Arctic and Antarctic waters. As it has a heavy shell, it would sink to the bottom if it didn’t fly.

Recently, David Murphy at John Hopkins University in Baltimore and colleagues examined how the sea snails fly. They published their findings in the Journal of Experimental Biology.

Reporting on the discovery, New Scientist included some evolutionary spin and the standard millions of years dogma:

Even though gastropods and insects diverged from a common ancestor 550 million years ago, sea snails use the same clap-and-fling mechanism flies use, which involves bringing their wings together then quickly pushing them apart.”

If a similar trait appears in two widely distinct animals, the usual Darwinian explanation is convergent evolution, which amounts to hand waving. Or we might see it is Darwinspeak for no comprendo. In any case, it does not really explain anything.

New Scientist also includes a biomimicry connection:

Brad Gemmell at the University of South Florida, who studies the swimming techniques of marine animals, thinks that the unique propulsive mechanism could be incorporated into new designs of micro flying vehicles.

Unfortunately, he can’t resist putting a bit of Darwinian spin on what appears to be an obvious example of excellent design:

Animals have had millions of years of selective pressure helping to test and design the best strategies and how to move through a fluid using comparatively little energy.”

Evolutionary design is an oxymoron, as the Darwinian watchmaker is supposed to be blind.

It would be more logical and more honest to admit that the beautiful little snail has always known how to move efficiently in water.


Ceurstemont, Sandrine. 2016. Sea butterflies fly underwater just like insects do in the air. New Scientist (17 February).