Sunday, 6 July 2008
New Bird Study: The Tree of Life Has to be Rewritten
Who is my new relative?
The Tree of Life is a concept Charles Darwin used in his On The Origin of Species (1859) to explain the relationships of all forms of life. Since then, the concept has evolved considerably but has not been discarded. Even a recent study of birds is known as the Early Bird Assembling the Tree-of-Life Research Project.
The five-year bird genome project, conducted by the Field Museum, has extracted DNA samples from all major groups of birds still living today. The study was published in Science on June 27, 2008, with a layman’s version in ScienceDaily.
The results of the study were astounding. According to ScienceDaily, “the scientific names of dozens of birds will have to be changed, and biology textbooks and birdwatchers' field guides will have to be revised.” Contrary to what was supposed, falcons, for instance, are not closely related to hawks or eagles. Sushma Reddy, a postdoctoral fellow at the Field Museum and one of the three lead authors of the study, said, “appearances can be deceiving. Birds that look or act similar are not necessarily related. .. much of bird classification and conventional wisdom on the evolutionary relationships of birds is wrong.”
The Darwinian tree of life was to a large extent based on the premise that species that look alike have to be closely related. Some previous observations have already questioned this view, since as Carl Wieland for instance has pointed out, the now extinct Tasmanian wolf (Thylacinus cynocephalus) was a marsupial but looked like the wolf that is a placential and The Flying Phalanger (Petaurus) living in Australia and New Guinea is a marsupial that looks like the flying squirrel. The Darwinian explanation for this phenomenon is convergent evolution, that is, different species are thought to have evolved the same traits independently. However, this does not seem to be based on facts but the obvious purpose of this view is to preserve the theory of evolution from extinction.
The new avian study suggests that when it comes to birds, the tree of life is on the verge of extinction. It has to be dramatically re-drawn just to keep it alive.
Recently, birds have often been in the news, and old evolutionary views have been discarded.
Huge Genome-scale Phylogenetic Study Of Birds Rewrites Evolutionary Tree-of-life. ScienceDaily 27 June 2008 http://www.sciencedaily.com/releases/2008/06/080626141117.htm
Wieland, Carl. 2004. Dynamic Life: Changes in Living Things. (DVD). Answers in Genesis.