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A Phylogenomic Tree of Passerine Birds

Passerine birds are birds in the order Passeriformes. The order’s name means roughly “with the form of a sparrow,” passer being the Latin word for that bird. The order includes not only sparrows, but a huge variety of species from tiny kinglets to massive ravens, from the plainest flycatchers to the most ornate birds of paradise. One of the facts about passerines that has intrigued scientists for decades is that this one order (of only about 30 recognized orders of birds) comprises more than 60% of bird species. Under the assumption that orders were roughly equivalent in age, this was considered one of the most striking examples of uneven diversity among bird groups. It turns out that this unevenness among groups, though unexpected in some simple models of diversification (the building up of species numbers and morphological variation), is ubiquitous in living organisms, and has profound implications for understanding the broad-scale patterns of evolution that we call macroevolution. For example, one species of shrub in New Caledonia (Amborella trichopoda) is the sister to all other flowering plants (~400,000 species), despite these two lineages being of equal age! Either something has kept Amborella from evolving into new species, or something has […]

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