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DAVID MINDELL: We're doing three things basically. The
first was to look at relationships amongst all the
extant birds, all of today's birds, we wanted to figure out
how they're related to each other. What's the genealogy for
these groups of birds. Secondly, we wanted to determine something
about how old they were, determine their ages. And the
third part of the study, we wanted to find out if whole
genomes, genome scale data sets would really provide sort of a
magic bullet that people have hoped it would in determining
the relationships. So those are three broad aspects of the
study. Our most novel finding was that within this group that
I talk about, is neoaves, including the vast majority of
today's birds, we found a basic division between two groups,
which we've had to name and we've called them Columbea and
Passerea. And the Columbea includes all the pigeons and
doves as well as sandgrouse and mesites and grebes and
flamingos. And the other group, Passerea, includes everything
else. The earliest diversification within birds
happened over 90 million years ago, so it's a very ancient
group. The earliest split within neoaves is more on the order of
between 72 and 66 million years ago so that's right at the end
of the cretaceous. And that diversification is really
younger than people had thought prior to this analysis of a very
large data set. So we've kind of moved the ages up closer in time
to the present. Our efforts to get whole genomes for 48 new
species of birds really has paid off because it has allowed us to
resolve some of these relationships within this
diverse group that I mentioned called neoaves. And we've found
that as we've added more data to our datasets, we got
increasingly clearer picture and better statistical support for
the nodes. And so what we found too that's interesting and that
supports some earlier work, is that falcons in fact are
relatively closely related to songbirds. The only bird that's
inside that relationship is the parrots so you've got all the
songbirds being most closely related to the parrots, and then
most closely related to that group are the falcons. One of
the other findings is that actually raptors are not a
single group that arose once but a group that has two independent
origins and in fact the falcons are very much different from the
hawks and eagles. They are not each other's closest relatives.
So that's a independent origins for the raptorial lifestyle so
it was a very relatively deep split that separated those two
groups. As people are looking outside and seeing birds in
their backyard and doing Christmas bird counts, it's
worth noting the extent to which human behavior now has an
influence on avian populations and that maintaining this
diversity of unique lifestyles that we see is increasingly
dependent on human beings and their abilities to do, to
practice wise stewardship of natural habitats. So we have
sort of received these different forms of birds over evolutionary
time periods into the present and what their future might be
in a way is dependent upon our own wise stewardship
of the environments.
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