An extensive study of bird genetics has revealed so many surprises about avian evolution that researchers say textbooks and field guides will have to be rewritten. After comparing the genetic codes of 169 species researchers realized that many assumptions about bird evolution are wrong; for example, they found that falcons are not closely related to hawks and eagles, and that flamingos didn’t evolve from other waterbirds.
“With this study, we learned two major things,” said Sushma Reddy, lead author and a fellow at The Field Museum in Chicago, Illinois. “First, appearances can be deceiving. Birds that look or act similar are not necessarily related. Second, much of bird classification and conventional wisdom on the evolutionary relationships of birds is wrong” [AFP].
Scientists believe birds, which first appeared roughly 150 million years ago, evolved from small feathered carnivorous dinosaurs. “Modern birds as we know them evolved really rapidly, probably within a few million years, into all of the forms we see. That happened 65 to 100 million years ago,” Reddy said in a telephone interview. Reddy said these quick changes have made bird evolution hard to pin down [Reuters].
The study, which appears in the journal Science [subscription required], divides birds into three major groups: land birds, like the sparrow; water birds, like the diving penguin; and shore birds, like the seagull. But in a surprising result, the genetic analysis revealed that shorebirds evolved later, which refutes the widely held view that shorebirds gave rise to all modern birds [Telegraph]. The study also suggests that distinctive lifestyles, like hunting from the air in the case of falcons and eagles, evolved several times during avian history. In another example, researchers say that flamingos didn’t evolve from other wading birds, but instead from a land-based bird that adapted to coastal living.
The bird project was part of a larger, federally funded effort called Assembling the Tree of Life, which aims to trace the evolutionary origins of all living things, from marine bacteria to domesticated corn and Australian snakes [Chicago Tribune].
Image: flickr/mape_s
July 1st, 2008 at 6:49 pm
The June 2008 bird genetics study of Chicago’s Field Museum of Natural History (the Early Bird Assembling the Tree-of-Life Research Project) completely re-writes the avian evolutionary tree, and is stunning in its impact. The genetics study shows that, though they look alike, for example, falcons with their acute ultraviolet vision are not closely related to other birds of prey, hawks or eagles. Several birds that look very different, including woodpeckers, hawks, owls and hornbills, are all closely related to perching birds. Flamingos, tropicbirds and grebes, all of which are closely related, did not evolve from water birds. Contrary to conventional wisdom, daytime hummingbirds evolved from drab nocturnal nightjars. Tropicbirds (white, swift-flying ocean birds) are not closely related to pelicans or other waterbirds. But perching birds, on the one hand, and parrots and falcons on the other, which do not look all that much alike, in fact descend from a recent common ancestor. Shorebirds are not a basal evolutionary group, which refutes the established view that all modern birds evolved from shorebirds. It is an understatement that appearances are deceiving. Birds that look or act similar are not necessarily related. Modern birds evolved relatively rapidly within a few million years during an explosive radiation, sometime between 65 million and 100 million years ago. The same is true of flower evolution. One day there are no flowers in the fossil record, and the next ‘day’ there are flowers, as Charles Darwin observed. Likewise, flowers that look alike are frequently not closely related. So how does this genome-scale phylogenetic evidence on avian evolution possibly jive with Darwinian gradualism, incremental changes over millions of years? It does not and cannot. Something else is going on to explain this planet’s remarkable biodiversity. The best hope to answer these questions is more and better science, not reliance on rote 19th century conjecture. Whatever the causative mechanism for bird or other biological evolution, avian evolution is not the result of ‘natural selection.’
July 31st, 2008 at 11:19 am
John Umana’s comment (July 1st, 2008 at 6:49 pm) was very informative and interesting to this life-long birdwatcher and avid user of the best of current field guides to birds. I thank him for his information. This is to comment on Umana’s question: “So how does this genome-scale phylogenetic evidence on avian evolution possibly jive with Darwinian gradualism, incremental changes over millions of years?” I would like to suggest, if I may, that he become more familiar with the definition of the term, “jive,” for I think he must have been aiming instead for the connotation of the term, “jibe.”
The term, “jive,” is synonymous with such terms “as to tease or mock good-humoredly: banter, chaff, joke, josh. Informal kid, rib, ride. Slang rag, razz.” (Roget’s II: Thesaurus)
In contrast, the term “gibe,” is synonymous with such terms as “to be compatible or in correspondence: accord, agree, check, chime, comport with, conform, consist, correspond, fit, harmonize, match, square, tally.” (Roget’s II: Thesaurus)
December 28th, 2008 at 8:47 pm
Dear Mr. Wetzel, Please note the erratum: line 18, change jive to jibe.
Happy New Year to all
Regards,
John Umana
August 6th, 2009 at 7:30 pm
cool read