Scientists have created an evolutionary maps for all the world’s nearly 10,000 bird species. The ‘tree of life’ is published in the current issue of the journal Nature.
The international team researchers used DNA-sequencing data — when available — to show the evolutionary relationships between living bird species. It also shows bird speciation rates across time and geographies.
“We have built the first ever family tree showing the evolutionary relationship among the species of birds. We used fossils and genetic data to estimate the ages of all the different branches of the bird tree so that we could assess how diversity has accumulated through time,” said co-author Gavin Thomas of the University of Sheffield in a statement. “Our work is indebted to researchers from museums and universities who have collected astounding amounts of genetic data from birds around the world.”
However while the effort is impressive, some biologists are cautious about the map given that there is no genetic data for many species, according to a report published in Nature News.
“This is a conceptually brilliant attempt to link space with time while crafting a complete phylogeny,” Trevor Price, an evolutionary biologist at the University of Chicago in Illinois, told Nature News. “But there are almost certainly introduced artefacts by lacking one-third of the sequences used to create it.”
Nonetheless the authors say their work is an important contribution to understanding the evolutionary history of birds. For example, they note a surprising finding that the diversification rate does not vary with latitude. Instead it varies by longitude, with a faster rate in the Western Hemisphere compared to the Eastern Hemisphere.
The authors say the study could help prioritize conservation efforts.
“We can identify where species at greatest risk of extinction are on the tree and ask how much distinct evolutionary history they represent,” said Thomas. “Some species have many close relatives and represent a small amount of distinct evolutionary history whereas others have few close relatives and their loss would represent the disappearance of vast amounts of evolutionary history that could never be recovered.”
CITATION: Jetz, W., Thomas, G. H., Joy, J. B., Hartmann, K., & Mooers, A. O. Nature. http://doi:10.1038/nature11631 (2012)