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Member (Idle past 1433 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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Author | Topic: Aquatic Origin of All Modern Birds? | |||||||||||||||||||||||
RAZD Member (Idle past 1433 days) Posts: 20714 From: the other end of the sidewalk Joined: |
It's a boat, it's a plane ... it's AQUABIRD!!!
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U.S. and Chinese geologists dug up several nearly complete three-dimensional fossil imprints of uncrushed, loon-like birds called Gansus. They are named for the Gansu region, 2,000 kilometers west of Beijing, where they were found in rocks that used to be the muddy bottom of an old lake. Only the fossils' heads and upper necks are missing. The remains show their structure in rich detail, leading one of the scientists to say that the birds' features are strikingly modern for 110-million years of age. "No other fossil bird of this age, and even some fossil birds that are much younger than Gansus, has this same suite of modern style features," said Jerald Harris of Dixie State College in Utah, speaking at a Washington news briefing held by the journal Science, in which the study appears. "Gansus is, therefore, the oldest known bird that is this modern in its anatomy," he said. "It helps us fill a gap in the evolutionary progression towards modern birds." The bird skeletons, although headless, offer plenty of evidence for an amphibious life. Their upper body structure shows that Gansus could take flight from water like a modern duck. The webbed feet and bony knees are clear signs that Gansus swam. "This observation significantly strengthens a long-standing hypothesis that the origins of all modern birds - every one of the 10,000 bird species living today - probably took place in aquatic environments," said Matthew Lamanna. "Every bird living today, from ostriches to eagles to hummingbirds, probably evolved from a Gansus-like ancestor." Long standing? Anyone know some background on this hypothesis? And does it have anything to do with the evolution of feathers before flight? EnjoyBio\Evolution or links we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
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kuresu Member (Idle past 2541 days) Posts: 2544 From: boulder, colorado Joined: |
THe only thing I can think of is that birds, the current ones, that is, are much older than we (or at least I) thought. This puts it in around the time of the raptors (which I know someone will soon correct me on this date) that were around then, like Velociraptor, Utah-raptor, and Deinonychus. Which puts them as cousins, as a quick observation (either that, or my whole post is total bull, which it probably is, 'cause I'm not too familiar with dinosaurs).
All a man's knowledge comes from his experiences
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arachnophilia Member (Idle past 1372 days) Posts: 9069 From: god's waiting room Joined: |
i guess it had to happen here sooner or later. they've already posted this article to t.o. a few times.
gansus is not a new find. not even close. we had gansus fossils in the early 80's. this is just a very well preserved, and more complete find.
quote: i would call neornithes "modern birds." thats actually what the name means, after all. last i checked, gansus is still in basal ornithurae. unless they've moved it, due to the new find, this is basically a lot of hot air.
quote: helped. past tense. in 1981. there were a half dozen good specimens dug up about 2 or 3 years ago.
Long standing? Anyone know some background on this hypothesis? well, we've had a good idea that modern birds evolved from aquatic birds for a while -- the non-aquatic birds of the time, enantiornithes or "opposite birds" all died out. gansus is a close candidate for the ancestor of modern birds. but to say that all modern birds were once aquatic is a bit, uh, wrong. came from an aquatic form? maybe.
And does it have anything to do with the evolution of feathers before flight? no. feathers were around long before gansus. he's much, much closer to what we'd call a modern bird, and well within everyone's definition of a bird. feathers evolved in dinosaurs, long before they were anything close to birds.
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arachnophilia Member (Idle past 1372 days) Posts: 9069 From: god's waiting room Joined: |
This puts it in around the time of the raptors (which I know someone will soon correct me on this date) that'll be me, i guess. archaeopteryx: 150 myagansus: 110 mya velociraptor: 80 mya Which puts them as cousins, as a quick observation (either that, or my whole post is total bull, which it probably is, 'cause I'm not too familiar with dinosaurs). archaeopteryx may be a basal deinonychosaur. that would put the relationship (kind of) like this, leaving out a bunch: dienonychosaurs|-archaeopteryx | |-gansus | `-modern birds |-troodon `-velociraptor
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Modulous Member Posts: 7801 From: Manchester, UK Joined: |
"Gansus is the oldest example of the nearly modern birds that branched off the trunk of the family tree that began with the famous proto-bird Archaeopteryx," said Peter Dodson of the University of Pennsylvania. The remains were dated to about 110 million years ago, making them the oldest for the group Ornithurae, which includes all modern birds and their closest extinct relatives
Another news item Fossils of those avians that gave rise to the modern bird lineage "are relatively rare in the Cretaceous," explains Matthew Lamanna of the Carnegie Museum of Natural History, co-author of a paper detailing the finds, published today in Science. But "when we mapped ecology onto our evolutionary tree, a pattern became apparent that species leading up to modern birds are mostly aquatic," Lamanna notes... During Gansus's time, a group of birds called the Enantiornitheans--known as opposite birds because their wing joints are reversed compared to their modern relatives--dominated the skies. But the opposite birds perished along with the dinosaurs 65 million years ago. SciAm The Article in science can be found here, I think.
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arachnophilia Member (Idle past 1372 days) Posts: 9069 From: god's waiting room Joined: |
quote: they're known as "opposite birds" because their metatarsels fuse in the opposite direction from modern birds. as far as i know, their arms are not on backwards. but the rest is pretty valid. the enantiornithes were the flying birds, and modern birds seem to have come from birds like gansus.
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RAZD Member (Idle past 1433 days) Posts: 20714 From: the other end of the sidewalk Joined: |
i guess it had to happen here sooner or later. they've already posted this article to t.o. a few times. gansus is not a new find. not even close. we had gansus fossils in the early 80's. this is just a very well preserved, and more complete find. Gotta love overstatement eh?
well, we've had a good idea that modern birds evolved from aquatic birds for a while -- the non-aquatic birds of the time, enantiornithes or "opposite birds" all died out. gansus is a close candidate for the ancestor of modern birds. When did the enantiornithes die out? With the dinosaurs? Book I am reading suggests that being aquatic or able to burrow (small mice like mammals) was what led to survival of the KT event. The meteor hit rock with high sulfer content that may have resulted in very acidic rains.
no. feathers were around long before gansus. he's much, much closer to what we'd call a modern bird, and well within everyone's definition of a bird. feathers evolved in dinosaurs, long before they were anything close to birds. Do we know if the first birds were terrestrial or aquatic? I look at cormorants taking off and think ground effect plus high surface speed 'running' on water could have evolved to avoid predators. This is also how flying fish would have evolved their wings. Oh yeah, add fish to the types of organisms that separately evolved wings. Enjoy. we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ... to share.
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arachnophilia Member (Idle past 1372 days) Posts: 9069 From: god's waiting room Joined: |
i guess it had to happen here sooner or later. they've already posted this article to t.o. a few times. gansus is not a new find. not even close. we had gansus fossils in the early 80's. this is just a very well preserved, and more complete find. Gotta love overstatement eh? i've read a few things on t.o. that seem to suggest that this article is about the five specimens they found a few years ago, in which case there is cause for some (belated) excitement. the previous gansus fossils (a leg and not much else) were fairly paltry poultry. if that's the case, i'm glad the newspapers and magazines are waiting until the actual study hits the journals.
When did the enantiornithes die out? With the dinosaurs? i think so, yeah.
Book I am reading suggests that being aquatic or able to burrow (small mice like mammals) was what led to survival of the KT event. The meteor hit rock with high sulfer content that may have resulted in very acidic rains. i highly suspect that being aquatic is equally as good of an argument. many of the animals that did survive either lived in the water (fish) or spent a lot of time in the water (crocodiles). of course, most of the mammals of the time were burrowers. but this would be a good explanation why all of the earlier relatives of modern birds are aquatic.
Do we know if the first birds were terrestrial or aquatic? define "first birds." most people consider the first bird to be archaeopteryx.
I look at cormorants taking off and think ground effect plus high surface speed 'running' on water could have evolved to avoid predators. the first relatives of birds we have that could fly were all pretty much predatory themselves. thought this would be a good usage for a partial ability to fly, it appears that flight evolved first.
This is also how flying fish would have evolved their wings. Oh yeah, add fish to the types of organisms that separately evolved wings. lol, there is a slight difference though. flying fish are running from predators in the water. the longer they stay out of it, the less likely they are to be eaten. instant selection factor.
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RAZD Member (Idle past 1433 days) Posts: 20714 From: the other end of the sidewalk Joined: |
i highly suspect that being aquatic is equally as good of an argument. many of the animals that did survive either lived in the water (fish) or spent a lot of time in the water (crocodiles). of course, most of the mammals of the time were burrowers. but this would be a good explanation why all of the earlier relatives of modern birds are aquatic. Well the book also has some hooey in it too. It's "A Short History of Nearly Everything" by Bill Bryson. Obvious (to me anyway) that he doesn't know much about anything and is reporting based on interviews with who will talk to him on the subject. Not sure what he does to 'vet' the information.
ol, there is a slight difference though. flying fish are running from predators in the water. the longer they stay out of it, the less likely they are to be eaten. instant selection factor. But that's what I was thinking for the early birds. I was thinking of some of the more 'predatory' waterfowl - cormorants and the like catch and eat fish, and the "flightless" cormorant uses its wings underwater (as do penguins, another fish predator). Plus the insulation value of feathers for a warmblooded diver ... call it the aquatic bird concept. Were the other fossils found with archy terrestrial? I would think they would have to be or much more would have been said about aquatic birds.
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arachnophilia Member (Idle past 1372 days) Posts: 9069 From: god's waiting room Joined: |
Were the other fossils found with archy terrestrial? I would think they would have to be or much more would have been said about aquatic birds. yes, quite a lot were terrestrial, and quite a lot were arboreal. there's actually some argument regarding "ground up" v. "trees down."
I was thinking of some of the more 'predatory' waterfowl - cormorants and the like catch and eat fish, and the "flightless" cormorant uses its wings underwater (as do penguins, another fish predator). Plus the insulation value of feathers for a warmblooded diver ... call it the aquatic bird concept. well, those specific adaptation, insulating feathers, and flight (penguis "fly" underwater) both appeared prior to gansus and the aquatic ornithurae, so they aquatic lifestyle was not what caused them. though it probably helped shape birds into their modern forms. for instance, i would image that long feathery tails wouldn't do well in the water, but shorter pygostle tails would. and it actually wasn't a large step to go into the water. archaeopteryx was a shore-bird. the place in germany it comes from, solnhofen, was a lagoon. it might have even spent some time in the water, or hunting very small fish with its feet.
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