naturewn.com

Trending Topics stress men women female brain

Scientists explore causes of biodiversity in perching birds

Apr 08, 2019 09:19 AM EDT
Close
Cape Sugarbird (IMAGE)
Cape Sugarbird (Promerops afer) perched atop a Protea (also known as a sugarbush) along the coast of the Western Cape, South Africa. Both the sugarbird clade and Protea, their preferred source of nectar, are endemic to southern Africa.


(Photo : Daniel Field.)
Green-headed Tanager (IMAGE)
Green-headed Tanager (Tangara seledon) in Itatiaia National Park, Brazil. Tanagers comprise the most diverse extant avian family, with numerous species, including T. seledon, endemic to the Atlantic Rainforest of South America.


(Photo : Daniel Field.)
Tui (IMAGE)
A Tui (Prosthemadera novaeseelandiae) on Tiritiri Matangi Island, New Zealand. These spectacular members of the honeyeater clade are a conspicuous presence on this conservation island that has been ridden of introduced mammalian predators.


(Photo : Daniel Field)

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."

Another large portion of the study looks at the origin of perching birds, including a finding that perching birds originated on the Australian landmass around 47 million years ago.

"However, not just one single event in earth's history explains how they became so diverse and widespread," said Elizabeth Derryberry, UT assistant professor of ecology and evolutionary biology. "Instead, diversification and dispersal of this group has been affected by a number of different climatological and geological events, such as glaciation, global temperature changes and colonization of new continents."

According to Harvey, the next step is to fill in the missing gaps in passerine evolution not fully explained by Earth's history.

"We found that changes in geology and climate cannot explain everything," he said. "Future research needs to focus on explaining those aspects of bird evolution that are not determined by the Earth's geological and climatic history, but instead by the evolution of new characteristics in the birds themselves. For example, did the evolution of the ability to complete long-distance migrations in some perching birds help them get to new areas, or lead to the evolution of new species?"

Derryberry believes the research serves as a template for future exploration.

"The study provides a framework for how to conduct these types of analyses on large radiations and should provide a path forward for this type of research on all birds," she said.

© 2018 NatureWorldNews.com All rights reserved. Do not reproduce without permission.

Join the Conversation

arrow
Email Newsletter
About Us Contact Us Privacy Policy Terms&Conditions
Real Time Analytics