DNA Analysis Rewrites the Family Trees of Birds
“NEW YORK-Scientists have produced a
new family tree for nearly all species of birds alive today, drawing on a
massive DNA analysis to gain insights into evolutionary history.
The tree was built by comparing the
complete DNA codes, or genomes, of 48 species…
Early Split
Very early in the lineages leading
to about 95% of today’s birds, the researchers propose that a split happened
some 68 million to 69 million years ago. One branch leads to doves, flamingos,
& a few other species, while the other branch leads to basically everything
else. That implies, for example, that flamingos are more closely related to
pigeons than they are to pelicans or other water birds.
A second split followed soon after,
so that the resulting 4 lineages faced & survived the brutal extinction
some 66 million years ago that’s most famous for wiping out the dinosaurs, said
Erich Jarvis of Duke University & the Howard Hughes Medical Institute, a
lead author of the work.
Learning to Sing (or Speak)
When a songbird sings, or a parrot
says, “Polly wants a cracker,’…it’s the result of learning by imitation. The
study found that birds with this ‘vocal learning’ ability share some similarities
with humans in the activity of certain genes in the brain…
Ancestral Predator
A large group of land birds may have
all descended from an ancient hunter at the top of the food chain…The group
includes not only falcons & eagles, but also parrots, woodpeckers, &
songbirds. The hawk-like curved bill of the parrot may be a lingering signature
of predatory origins…
Lost Teeth
Although birds are descended from
dinosaurs, they have no teeth. Most previous studies have suggested the common
ancestor of modern birds lacked teeth, but other work disagreed. The new
findings add support to the idea of a toothless common ancestor, because all
birds sampled share some mutations that turn off 5 genes for building teeth.”
Malcolm
Ritter
ASSOCIATED
PRESS
Montreal Gazette
Dec.
12/2014
Cute Critter Pic
No comments:
Post a Comment