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| (photo: Eric Lewallen) |
In a new study that would have made Rudyard Kipling proud, a UTSC
graduate student has provided the most definitive answer yet to the
curious question, “How did flying fish get their
wings?”
Eric Lewallen, a PhD student in professor Nathan Lovejoy’s
ecology and evolutionary biology lab at UTSC, is the lead author on
the first molecular study of genetic relatedness among species of
flying fish. Appearing in the Biological Journal of the Linnean
Society, Lewallen’s paper confirms what scientists have
long hypothesized—that the wide variety of “flying”
strategies found in fish around the world are all the result of a
single evolutionary chain of events.
“Our results show that flying fish are monophyletic, which means
they all share a common ancestor,” says Lewallen. “This
suggests that true gliding behavior in fish evolved just once, and all
the modifications we see today can be traced back to that one
event.”
There are approximately 50 species of flying fish to be found in the
tropical and subtropical regions of the Pacific, Atlantic and Indian
oceans. Their “wings” are really just enlarged fins,
accompanied by specialized muscles, which together allow them to burst
out of the water and glide above the ocean surface for short periods
of time.
Some species have two pectoral wings, while others have two pectoral
and two pelvic wings. The two-winged species can exit the water
quickly and usually glide in a straight line. Four-winged species can
glide for hundreds of metres at a time and can even manouevre in
mid-air to change direction.
Scientists believe fish evolved various gliding abilities in order to
evade specific predators such as tunas, dolphins and seabirds.
Over the last few years, Lewallen has had his fair share of adventures
while collecting his fish specimens. Due to the high cost of
conducting research on the high seas, he has often worked aboard boats
operated by the National Oceanic and Atmospheric Administration (NOAA)
in return for the opportunity to collect specimens. By day, he would
work as an independent marine mammal observer for NOAA studies. By
night, he would catch his flying fishes using spotlights and
dipnets.
“The shocking part,” says Lewallen, “is that flying
fishes are so abundant—they’re found in every major
tropical ocean—yet many basic questions regarding their ecology
and evolution remain unanswered.” Lewallen’s paper, which
will serve as the first chapter of his PhD dissertation at UTSC,
provides an exciting foundation for future studies involving open
ocean organisms.
“There are many complex questions I would like to address
regarding these creatures and their habitats,” he says.
“But we’ve got to lay some of the groundwork
first.”
As the International Year of Biodiversity winds down, Lewallen’s
work is a great example of UTSC’s commitment to fundamental
research that is informed by a truly global perspective. It
also provides further evidence of UTSC’s emerging
leadership in the field of conservation biology. Professor Lovejoy
adds, “The great success of Eric’s study is that it
highlights UTSC’s growing strength in field biology, graduate
research and internationally collaborative science.”
To view a slideshow on Lewallen’s work courtesy of BBC Earth News, click here.