New species emerge just as often as they die out.Byline: ANI Washington, August 1 (ANI): A new study by paleontologists has statistically proven that new species emerge just as often as they die out, with most evolution occurring in small bursts. The study, by Luke Harmon, professor of biological sciences at the University of Idaho The university was formed by the territorial legislature of Idaho on January 30, 1889, and opened its doors on October 3, 1892 with an initial class of 40 students. The first graduating class in 1896 contained two men and two women. , who worked with a research team led by Michael Alfaro, UCLA UCLA University of California at Los Angeles UCLA University Center for Learning Assistance (Illinois State University) UCLA University of Carrollton, TX and Lower Addison, TX (University of California, Los Angeles UCLA comprises the College of Letters and Science (the primary undergraduate college), seven professional schools, and five professional Health Science schools. Since 2001, UCLA has enrolled over 33,000 total students, and that number is steadily rising. ) assistant professor of ecology and evolution biology, analyzed the evolution of the 60,000 species of jawed jawed adj. Having a jaw or jaws, especially of a specified kind. Often used in combination: slack-jawed; the jawed fishes. Adj. 1. vertebrates using genetic data. "We wanted to see how much information we could get about speciation speciation Formation of new and distinct species, whereby a single evolutionary line splits into two or more genetically independent ones. One of the fundamental processes of evolution, speciation may occur in many ways. and extinction when we don't have much direct information from the fossil record," said Harmon, who led the effort to analyze the data. The researchers scoured records for genetic data on all of the species of jawed vertebrates, which includes everything from sharks to birds. They used that data to create an evolutionary tree that maps which species are closely related and when they diverged from a common ancestor. Once that was accomplished, a computer program determined how close different models of speciation and extinction fit the facts. The research team found that the best-fit system features an extinction rate nearly identical to the rate of new species being formed. The group also found that the data support distinct rates of speciation and extinction among major groups of animals during different periods of time. "Neoaves - most modern birds Modern birds (subclass Neornithes) are the members of class Aves that have survived into recent times and have coexisted with humans. Modern birds are characterised primarily by their toothless beaks, as most prehistoric bird groups possessed teeth. - and percomorphs - fish related to perch - are very diverse given their age," said Harmon. "In fact, if you add up the numbers of these and other unusually diverse groups then you find that most of the jawed vertebrate species on Earth are the result of explosive, young radiations," he added. On the other end of the scale, the study identified several "living fossils" that have been around for hundreds of millions of years, but have very few species. One example is the Tuatara tuatara (t  'ətär`ə) or tuatera (–tā`rə), lizardlike reptile, Sphenodon punctatus, , a 200 million-year-old order containing
only two species that today are found only on remote islands in New
Zealand New Zealand (zē`lənd), island country (2005 est. pop. 4,035,000), 104,454 sq mi (270,534 sq km), in the S Pacific Ocean, over 1,000 mi (1,600 km) SE of Australia. The capital is Wellington; the largest city and leading port is Auckland. .
Though they resemble lizards, they are actually very distantly related to all living species of lizards and snakes. Another oddity is the crocodilian family, which consists of crocodiles and alligators. "Crocodiles have been around for over 200 million years, but there are only 23 species of them now. Given their age, there should be more," said Harmon. "This implies that, just like there are processes that can elevate the rates of speciation and extinction, there must be some kind of process that can depress them as well," he added. (ANI) Copyright 2009 Asian News International The Asian News International (ANI) agency provides multimedia news to China and 50 bureaus in India. It covers virtually all of South Asia since its foundation and presently claims, on its official website, to be the leading South Asia-wide news agency. (ANI) - All Rights Reserved. Provided by Syndigate.info an Albawaba.com company |
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