Date: April 5, 2019
Source: University of Tennessee at Knoxville
New
research by a global team of scientists has resulted in significant strides in
ornithological classification and identified possible causes of diversity among
modern bird species.
The
study, coauthored by researchers at the University of Tennessee, Knoxville and
published in Proceedings of the National Academy of Sciences, focuses on
perching birds, or passerines. Comprised of over 6,000 species, this group --
which constitutes over half of all known bird species -- includes familiar
birds such as robins, jays, bluebirds, finches, and sparrows.
Scientists
analyzed genetic samples and fossils of all major groups within the passerine
family to better understand the way these species are related. The large data
set allowed for much more accurate inferences into the development of perching
birds.
The
result is the most accurate and comprehensive "tree of life" of
passerine species to date.
The
report also includes an analysis of the impact some events in Earth's history
could have had on passerines' biodiversity.
"Our
main discovery is that the evolution of perching birds around the world was
determined in part by connections between continents over the Earth's history,
as well as changes in global climate," said Michael Harvey, a postdoctoral
fellow with UT's Department of Ecology and Evolutionary Biology. "We
found, for example, evidence that glaciations during the Oligocene Epoch
(between 24 and 33 million years ago) wiped out a lot of perching birds, but
that the warming period immediately after prompted the evolution of many of the
groups of perching birds alive today."
