New bird family tree reveals some odd ducks
By Julie SteenhuysenThu Jun 26, 6:54 PM ET
The largest study ever of bird genetics has uncovered some surprising facts about the avian evolutionary tree, U.S. researchers said on Thursday, including many that are bound to ruffle some feathers.
Falcons, for example, are not closely related to hawks and eagles, despite many similarities, while colorful hummingbirds, which flit around in the day, evolved from a drab-looking nocturnal bird called a nightjar. And parrots and songbirds are closer cousins than once thought. The findings challenge many assumptions about bird family relationships and suggest many biology textbooks and bird-watchers' field guides may need to be changed.
"One of the lessons we've learned is appearances seem to be very deceiving," said Sushma Reddy of Chicago's Field Museum of Natural History, whose study appears in the journal Science. "Things that are quite different-looking sometimes end up being related," she said.
For the study, Reddy and colleagues studied the genetic sequences of 169 bird species in an effort to sort out family relationships in the bird family tree. Scientists believe birds, which first appeared roughly 150 million years ago, evolved from small feathered carnivorous dinosaurs.
"Modern birds as we know them evolved really rapidly, probably within a few million years, into all of the forms we see. That happened 65 to 100 million years ago," Reddy said in a telephone interview. Reddy said these quick changes have made bird evolution hard to pin down, and several smaller prior studies have led to conflicting results. "We didn't have a good sense of how any of these major bird groups were related to each other," said Reddy, who worked with researchers at several other labs. "We've tried to represent all of the major groups of birds and all of the major lineages," Reddy said.
Their findings suggest birds can be grouped broadly into land birds, like the sparrow; water birds, like the penguin; and shore birds, like the seagull. But there are many paradoxes within these groupings. For example, water-loving flamingos and some other aquatic birds did not evolve from water birds. Instead, they adapted to life on water.And some flightless birds are grouped with birds that fly.
Reddy acknowledges the results are likely to stir debate in many circles, but she said she is confident in the findings. "I think a good study brings up as many questions as it answers," she said.
[Adapted from: http://news.yahoo.com/s/nm/20080626/sc_nm/birds_evolution_dc_1&printer=1;_ylt=Artq_SH434f8LPm5rdR3fAIiANEA