The most complete bird family tree is now available, according to research published in the journal Nature on October 7.
The study was conducted by experts from Florida State University, Cornell University, Yale University and North Carolina Museum of Natural Sciences. The focus of the analysis consisted in modern birds from the Neoaves group, which contain around 90% of current avian species with the exception of Paleognathae (kiwis, ostriches, emus etc.) and Galloanserae (ducks, chickens, turkeys, geese etc.)
Researchers have managed to aggregate genome data pertaining to 198 living avian species, in order to establish the network of relationships between them.
It was proven that birds nowadays have evolved from 3 dinosaur lineages which survived the mass extinction that occurred approximately 66 million years ago. As Yale paleontologist Daniel Field explained, the most recent common precursor of modern-day avian creatures roamed the Earth around 75 million years ago, and it was most likely a small, feathered velociraptor.
Furthermore, experts discovered that Neoaves are divided into 5 separate subgroups. One of them is represented by water birds, which include wading, diving and shorebirds, with the exception of ducks. In fact most of the species in this group are closely related, which contradicts the previously held theory that their evolutionary history involved several lineages.
“It means that all of these aquatic birds may have evolved from a single common ancestor, as opposed to evolving an aquatic ecology multiple times independently”, explained Jacob Berv, PhD student at the Cornell Laboratory of Ornithology, Ithaca.
The analysis also provided new insight into the evolution of hummingbirds. These New World tiny birds are normally diurnal and depend greatly on their visual acuity, but they have evolved from nocturnal ancestors. This has led to speculations regarding how the birds managed to maintain color vision for over 10 million years, despite being active just during the night.
In addition, researchers confirmed that the majority of land birds are descended from a common ancestor which displayed a predatory nature. Therefore, even delicate-looking birds like cardinals, chickadees or woodpeckers actually derive from a “vicious, hawk-like meat-eater”, according to Richard Prum, Yale University ornithologist.
Further work will be conducted by researchers in the next 5 to 10 years, to submit a final version of this family tree. For now however, these recent findings help answer many of the evolutionary questions that the history of avian creatures has posed throughout the centuries.
Currently, there are approximately 10,000 bird species in the world, and their diversity in shape, size and coloring is overwhelming. As more data is gathered, ornithologists will gain further understanding of how this medley came to be. Moreover, this will also aid scientists in explaining the mechanisms that guide bird behavior and processes nowadays.
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