Penguins lose their ability to fly millions of years ago , and now a new study explains why - the birds become lean and mean machine diving , flying trade for these skills .
(see also: pakan burung)
The study, published in the latest Proceedings of the National Academy of Sciences , showed that good fins can not fly very well .
" After the surrender penguins to fly , change the wing structure and overall body size and shape may be followed quickly because flying is no longer a constraint on the shape of her body , " said co - author Robert Ricklefs Discovery News .
" Note that the penguins are much more at risk of predation in the water than they are on land , and so there has been strong selection to make them swim and dive as efficiently as possible , " added Ricklefs , who is a professor of biology at the University of Missouri at St. Louis .
bird Penguin
Ricklefs , writer Kyle Elliott and their team initially wondered why birds black and white everywhere lose their ability to fly millions of years ago , considering how beneficial can fly . Emperor penguin painstakingly walked more than 32 miles between rookeries and sea . The journey takes them a few days , which can be reduced to just a few hours if they could fly . Then why do they not ?
To solve this mystery , the researchers focused on a bird - especially Murren - were both flying and diving . The scientists include 41 wild birds were captured with equipment to measure energy expenditure of birds . Thus , the researchers came up with a new world record . Murres and pelagic cormorants appeared to have the highest spending ever recorded for each animal fly .
While murres can fly and dive , it seems there is a limit where one activity after another in evolution . If the bird needs to fly , he would lose about diving and swimming ability . Conversely , if the bird is very dependent on the swimming and diving to hunt and survive , it will tend to lose their flight skills . In the case of penguins , skills completely disappeared , with wings developed into flippers types of marine mammals .
" The ancestors of penguins flying was probably not much different in appearance than the common murres and their relatives , and possibly much behave the same way , " said Ricklefs .
The findings may help explain how other birds lose their ability to fly . There Kormoran flew in the Galapagos Islands , and the southern ocean steamer ducks also flew .
Flightlessness different reasons for ostrich and emu , which does not dive . Large birds , not traded cost for running ability . The possibility that the ancestors of ostriches and emus do not have to migrate . They may live in the southern continent with relatively few predators . Run with their legs strong enough , than have to rely on aircraft to take them and go .
Tony Diamond of the University of New Brunswick , James Lovvorn at Southern Illinois University , and Daniel Roby from the Department of Fisheries and Wildlife all told Discovery News that they agree with the conclusions of the new study .
Diamond said that the study " refers to the unique diversity of mobility - mode in birds - walking, running , swimming , flying - . To clarify and explain the otherwise puzzling patterns of evolution "
(see also: pakan burung cendet)
Rory Wilson of Swansea University , had a more measured response , say the authors of the study " may be true , but the result would be more assured if they are compared with the duck diving auks . " He explained that some birds have very different types of hair loss that can affect heat . Heat loss , in turn , can affect energy when flying and diving birds .
source:http://www.satwa.net/
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