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The non evolution of flying birds

 
 
cicerone imposter
 
  1  
Reply Sat 6 Sep, 2008 01:04 pm
@gungasnake,
gunga, Here's something much more recent than your article from the Field Museum:

www.chicagotribune.com/news/local/chi-birds-frijun27,0,5786768.story
chicagotribune.com
Field Museum's genetic study rewrites family tree on birds

By Jeremy Manier and Tim De Chant

Chicago Tribune reporters

June 27, 2008

When a falcon swoops from the sky to seize its fleeing prey, no one would mistake the sleek predator for a gaudy parrot.

Yet the secret kinship of falcons and parrots is one of many surprises in a landmark genetic study of 169 bird species being published by Field Museum researchers.

The lovely birds we see each day may never look quite the same again.

One likely consequence of the study in Friday's edition of the journal Science is a re-ordering of the field guides that many of America's 80 million bird-watchers use. Most bird guides are based on scientific classifications, which experts said the new work could change in numerous ways.

"This is the most important single paper to date on the higher-level relationships of birds," said Joel Cracraft, curator of birds at the American Museum of Natural History in New York, who was not part of the study.

Birds are all around us, having evolved into a dazzling variety of forms in every part of the world, but the chore of mapping their family tree has long stumped scientists. Many previous studies relied on painstaking comparisons of outward characteristics and behaviors.

Genetic comparisons can tell a deeper story, so the Field Museum launched a five-year effort with seven other institutions to do an unprecedented genetic analysis using powerful computers. They discovered many cases in which seemingly similar birds were merely distant relatives, or birds long assumed to be unrelated were closely linked.

Grebes, a type of diving bird, are not related to loons, as ornithologists had long believed. Surprisingly, grebes appear closely related to flamingos.

The analysis also showed falcons are more closely related to parrots than to other hunters such as hawks and eagles. If true, the finding would mean that falcons do not even belong in the scientific order originally named for them.

"It's kind of crazy to us too," said Shannon Hackett, a lead author of the study and associate curator of birds at the Field Museum. "People have been studying birds a long time, but now we're in a time when we should question everything, because for the first time we have the tools to answer these questions."

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.

Using birds to study evolution is nothing new"the diversity of Galapagos finches helped fuel Charles Darwin's theory of evolution. But many details of avian evolution remained a mystery, in part because the animals' light, hollow bones left few fossils.

Genetic studies can reconstruct evolutionary links by comparing small changes that have accumulated within the genes of different species. But studying birds that way posed a challenge because the major bird groups emerged in quick succession more than 65 million years ago, making all of their genetic changes harder to decipher.

The new report analyzed more than 30,000 pieces of 19 bird genes, yielding a family tree of unprecedented detail, said Scott Edwards, a bird specialist and professor of evolutionary biology at Harvard University.

"The great thing about this molecular data is that you can compare species that don't share any obvious traits," said Edwards, who was not one of the study authors.

The new lineage helps showcase how evolution works, experts said. Although falcons do not appear closely related to hawks, each species developed similarly shaped beaks and talons to hunt prey"an evolutionary process that biologists call convergence.

Working the new results into the guidebooks that birders use could take years, but many experts said some change is likely. Such books normally take their cue from the American Ornithologists' Union, which releases an updated checklist of bird species each year.

Carla Cicero, curator of birds at the University of California-Berkeley's museum of ornithology and a member of the committee that decides on changes to the checklist, said the committee typically waits for many teams to duplicate new findings before changing its bird classifications.

Still, "there are going to be a lot of changes, I can tell you that," Cicero said.

For Hackett, who led the group along with Field Museum researcher Sushma Reddy and University of Florida zoologist Rebecca Kimball, the genetic study is the fulfillment of daydreams she had as a child while leafing through picture books of birds.

"For me this is the grown-up, scientific equivalent of looking through those picture books and speculating why those birds looked the way they did," Hackett said.

Although conclusions like the falcon-parrot link may rattle some bird specialists, Joel Greenberg, an expert bird-watcher and editor of an anthology of Chicago nature writing, said such surprises can deepen the delight of studying birds.

"This may be one more of God's little jokes," Greenberg said.

As for your second author, a creationist, he can't offer any evidence of "creationism" no matter how hard he tries, so he tries to challenge evolution that is without any support or evidence - just opinion.
Good try, but no cuppie doll for you!
cicerone imposter
 
  2  
Reply Sat 6 Sep, 2008 01:07 pm
@cicerone imposter,
gunga, Here's another "study" provided by the National Geographic Society. Please show evidence to refute their findings.

http://www.pbs.org/wgbh/evolution/library/03/4/l_034_01.html
gungasnake
 
  3  
Reply Sat 6 Sep, 2008 02:36 pm
@cicerone imposter,
PBS's entire stock in trade on this sort of topic is basically agenda-driven ideological bullshit. I've just given you (above) the real reasons why flying birds could not evolve. If you have any real love for PBS you might want to direct them to this thread as a way of upgrading their educations.
rosborne979
 
  1  
Reply Sat 6 Sep, 2008 02:45 pm
@gungasnake,
Too bad your reasons why birds could not evolve are all wrong and your sources are all crap. PBS wins. You lose. Next.
0 Replies
 
gungasnake
 
  2  
Reply Sat 6 Sep, 2008 03:10 pm
I'm going to simply have to declare myself the winner in this one and move on. I posted a well reasoned analysis of the impossibility of flying birds evolving from anything else on the planet now or in past ages, and all I see in response is insults and demands that I refute a number of ignorant evolution screeds from PBS or National Geographic.

One final thought for anybody who cares to read it is the question of how a velociraptor or therapod, having none of the features needed by flying birds, evolved into one when non-flying birds and badly flying birds like chickens cannot even re-evolve the tiny bit of whatever they'd need to fly decently:

http://able2know.org/topic/121646-1

parados
 
  2  
Reply Sat 6 Sep, 2008 03:20 pm
@gungasnake,
Quote:
Since 1990, more than three times as many bird fossils dating from the Cretaceous have been discovered than were found in the previous two centuries.


And you quoted stuff from the 70's.

Maybe you should catch up with the times gunga.

Or are all your arguments "basically agenda-driven ideological bullshit"?
0 Replies
 
parados
 
  2  
Reply Sat 6 Sep, 2008 03:26 pm
@gungasnake,
Actually, your argument wasn't well reasoned and you failed to answer my 2 questions about your argument.

1. What evidence do you have that something "de-evolves" if it serves no purpose? Tell us why most animals have tails and some do not. What is the purpose of the tail on the elephant? What purpose does the lack of tail serve on the chimpanzee?
2. You failed to explain how you know feathers have no purpose so would have de-evolved. Colored plumage is not necessarily without purpose even if the creature having such plumage does not have the ability to fly.
gungasnake
 
  2  
Reply Sat 6 Sep, 2008 03:41 pm
@parados,
I said "de-evolve or become vestigial" and if you were to believe Darwin's view that all life forms are in a perpetual state of flux, you could add "turn into something else" to the other two. One good example of "become vestigial" is the wings on kiwis and ostriches.
cicerone imposter
 
  1  
Reply Sat 6 Sep, 2008 03:45 pm
gunga doesn't want to admit that the science of bird evolution is an on-going effort to find answers. With recent technologies to find and analyze more information about bird evolution, it continues to seek how they evolved. That's what science does - just the opposite of creationism which assumes god created them "that way."

Long-held Assumptions Of Flightless Bird Evolution Challenged By New Research

ScienceDaily (Sep. 7, 2008) " Large flightless birds of the southern continents " African ostriches, Australian emus and cassowaries, South American rheas and the New Zealand kiwi " do not share a common flightless ancestor as once believed.

Instead, each species individually lost its flight after diverging from ancestors that did have the ability to fly, according to new research conducted in part by University of Florida zoology professor Edward Braun.

The new research, which appears this week in the online edition of the Proceedings of the National Academy of Sciences, has several important implications.

First, it means some ratites, like the emus, are much more closely related to their airborne cousins, the tinamous, than they are to other ratites, Braun said.

Second, it means the ratites are products of parallel evolution " different species in significantly different environments following the exact same evolutionary course.

Braun and his fellow researchers began closely studying this group of flightless birds, known collectively as ratites, after a discovery made while working on a larger-scale effort to better understand the evolution of birds and their genomes by analyzing corresponding genetic material sampled from the tissue of many different bird species and determining how they relate to one another.

As they analyzed the genetic material, they noticed that the ratites did not form a natural group based on their genetic makeup. Rather, they belonged to multiple related but distinct groups that contained another group of birds, the tinamous, with the ability to fly.

Previously, the ratites were used as a textbook example of vicariance, a term that describes the geographical division of a single species, resulting in two or more very similar sub-groups that can then undergo further evolutionary change and eventually become very distinct from one another.

Scientists assumed that a single flightless common ancestor of the ratites lived on the supercontinent of Gondwana, which slowly broke up into Africa, South America, Australia and New Zealand; once divided, the ancestor species evolved slightly in each new location to produce the differences among the present-day ratites, Braun said.

But in light of this new information, he said it's more likely that the ratites' ancestors distributed themselves among the southern continents after the breakup of Gondwana, which began about 167 million years ago, in a much more obvious way.

They flew.

Although these new revelations teach evolutionary scientists a great deal, they also pose a great many new questions. For example, why did these birds evolve into such similar organisms in such different environments?

"To know for sure, we'll have to go into the lab and really study the genetics underlying the ratites' developmental pathway," Braun said. "But nobody would have asked that question without the type of data we've collected, which raises the question in the first place."

The scientists' effort to analyze such a tremendous amount of genetic material collected from birds across the globe is in turn just a single part of a program called Assembling the Tree of Life, funded and organized by the National Science Foundation, which aims to assemble a body of similar research for every group of organisms on the planet, including animals, plants, fungi, algae and bacteria.
Adapted from materials provided by University of Florida.
0 Replies
 
parados
 
  1  
Reply Sat 6 Sep, 2008 04:10 pm
@gungasnake,
No answer for my questions?

Hmmm.. one almost gets the impression you don't have a grasp of the topic.
0 Replies
 
parados
 
  1  
Reply Sat 6 Sep, 2008 04:21 pm
@gungasnake,
Quote:
I said "de-evolve or become vestigial"

No, you didn't say that.. What your post said was this..

Quote:
would have DE-EVOLVED and either disappeared altogether or become vestigial



Both disappearing and becoming vestigial are your evidence of "de-evolving". The tail in chimpanzees is vestigial and you didn't explain why it disappeared for them but remains on an elephant.

Of course that doesn't explain how something that never had a function like you claim can become vestigial. If anything the kiwi and ostrich refute your argument. Certainly the wings on a Kiwi or ostrich are still there. They just don't have the previous function of flying. Your claim was that the feathers wouldn't be around to evolve into something else. Since the wings are there but not used it shows that they don't disappear if not used.
0 Replies
 
rosborne979
 
  1  
Reply Tue 6 Jan, 2009 12:39 pm
@gungasnake,
gungasnake wrote:
One final thought for anybody who cares to read it is the question of how a velociraptor or therapod, having none of the features needed by flying birds...

Even though they DID have feathers, just not specialized for flight (because they didn't use them for flight).
gungasnake wrote:
... evolved into one when non-flying birds and badly flying birds like chickens cannot even re-evolve the tiny bit of whatever they'd need to fly decently

How do you know they can't re-evolve flight. Give them time (and incentive) and evolution says they just might.
0 Replies
 
Setanta
 
  1  
Reply Tue 6 Jan, 2009 12:41 pm
Everybody knows that dinos didn't evolve into birds . . . they sent away for the kit they saw advertised in the back of the comic books . . .
0 Replies
 
 

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