Confirms a suspicion I've harbored for some time. "Folk" taxonomies,
regardless of culture, have utility in terms of cultural bias, but are not
necessarily The Word. Does this mean that "science" is one thing,
"academic" another?
WT
www.chicagotribune.com/news/local/chi-birds-web-jun27,0,3626366.story
chicagotribune.com
Field Museum's genetic study rewrites family tree on birds
By Jeremy Manier and Tim De Chant
Chicago Tribune reporters
11:09 PM CDT, June 26, 2008
When a falcon swoops from the sky to seize its fleeing prey, no one would
mistake the sleek predator for a gaudy parrot.
Yet the secret kinship of falcons and parrots is one of many surprises in a
landmark genetic study of 169 bird species being published by Field Museum
researchers.
The lovely birds we see each day may never look quite the same again.
One likely consequence of the study in Friday's edition of the journal
Science is a re-ordering of the field guides that many of America's 80
million bird-watchers use. Most bird guides are based on scientific
classifications, which experts said the new work could change in numerous
ways.
"This is the most important single paper to date on the higher-level
relationships of birds," said Joel Cracraft, curator of birds at the
American Museum of Natural History in New York, who was not part of the
study.
Birds are all around us, having evolved into a dazzling variety of forms in
every part of the world, but the chore of mapping their family tree has long
stumped scientists. Many previous studies relied on painstaking comparisons
of outward characteristics and behaviors.
Genetic comparisons can tell a deeper story, so the Field Museum launched a
five-year effort with seven other institutions to do an unprecedented
genetic analysis using powerful computers. They discovered many cases in
which seemingly similar birds were merely distant relatives, or birds long
assumed to be unrelated were closely linked.
Grebes, a type of diving bird, are not related to loons, as ornithologists
had long believed. Surprisingly, grebes appear closely related to flamingos.
The analysis also showed falcons are more closely related to parrots than to
other hunters such as hawks and eagles. If true, the finding would mean that
falcons do not even belong in the scientific order originally named for
them.
"It's kind of crazy to us too," said Shannon Hackett, a lead author of the
study and associate curator of birds at the Field Museum. "People have been
studying birds a long time, but now we're in a time when we should question
everything, because for the first time we have the tools to answer these
questions."
The bird project was part of a larger, federally funded effort called
Assembling the Tree of Life, which aims to trace the evolutionary origins of
all living things, from marine bacteria to domesticated corn and Australian
snakes.
Using birds to study evolution is nothing new-the diversity of Galapagos
finches helped fuel Charles Darwin's theory of evolution. But many details
of avian evolution remained a mystery, in part because the animals' light,
hollow bones left few fossils.
Genetic studies can reconstruct evolutionary links by comparing small
changes that have accumulated within the genes of different species. But
studying birds that way posed a challenge because the major bird groups
emerged in quick succession more than 65 million years ago, making all of
their genetic changes harder to decipher.
The new report analyzed more than 30,000 pieces of 19 bird genes, yielding a
family tree of unprecedented detail, said Scott Edwards, a bird specialist
and professor of evolutionary biology at Harvard University.
"The great thing about this molecular data is that you can compare species
that don't share any obvious traits," said Edwards, who was not one of the
study authors.
The new lineage helps showcase how evolution works, experts said. Although
falcons do not appear closely related to hawks, each species developed
similarly shaped beaks and talons to hunt prey-an evolutionary process that
biologists call convergence.
Working the new results into the guidebooks that birders use could take
years, but many experts said some change is likely. Such books normally take
their cue from the American Ornithologists' Union, which releases an updated
checklist of bird species each year.
Carla Cicero, curator of birds at the University of California-Berkeley's
museum of ornithology and a member of the committee that decides on changes
to the checklist, said the committee typically waits for many teams to
duplicate new findings before changing its bird classifications.
Still, "there are going to be a lot of changes, I can tell you that," Cicero
said.
For Hackett, who led the group along with Field Museum researcher Sushma
Reddy and University of Florida zoologist Rebecca Kimball, the genetic study
is the fulfillment of daydreams she had as a child while leafing through
picture books of birds.
"For me this is the grown-up, scientific equivalent of looking through those
picture books and speculating why those birds looked the way they did,"
Hackett said.
Although conclusions like the falcon-parrot link may rattle some bird
specialists, Joel Greenberg, an expert bird-watcher and editor of an
anthology of Chicago nature writing, said such surprises can deepen the
delight of studying birds.
"This may be one more of God's little jokes," Greenberg said.
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