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Author Topic:   fossils
ogon
Member (Idle past 6129 days)
Posts: 70
Joined: 05-13-2007


Message 1 of 18 (401142)
05-18-2007 2:18 PM


From what I have read so far about evolution, fossils play a major part in backing up the theory of evolution. yes?
I am guessing fossils of animals have been found with no wings and animals/birds have been found with full wings BUT have animals been found with half wings? This would certainly go some way towards confirming the theory of evolution.
I have a couple more questions about the evolution of birds but this will do for now!
ogon

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AdminNosy
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From: Vancouver, BC, Canada
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Message 2 of 18 (401146)
05-18-2007 2:38 PM


Thread moved here from the Proposed New Topics forum.

  
AZPaul3
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Posts: 8513
From: Phoenix
Joined: 11-06-2006
Member Rating: 5.3


Message 3 of 18 (401157)
05-18-2007 3:46 PM
Reply to: Message 1 by ogon
05-18-2007 2:18 PM


What's a Half Wing?
I am guessing fossils of animals have been found with no wings and animals/birds have been found with full wings BUT have animals been found with half wings?
Evolution does not work by half measures AND does not work by going from none to all in one giant step. The development of a wing is a slow continuum with each species along the way fully formed and capable of survival/reproduction. Do not think the wing was developed specifically for flight. Feathered arms are seen, longer feathered arms are seen, long feathered arms with/without digits are seen, etc.
Arm to Wing Evolution - from Dinosaur to Bird Evolution
But you are right. The fossils do indeed lend such a preponderance of evidence for evolution that it is now beyond question, except by those who are truly blind or just plain stupid.
Edited by AZPaul3, : Stil kant spel.

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Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 4 of 18 (401165)
05-18-2007 4:13 PM
Reply to: Message 1 by ogon
05-18-2007 2:18 PM


I am guessing fossils of animals have been found with no wings and animals/birds have been found with full wings BUT have animals been found with half wings? This would certainly go some way towards confirming the theory of evolution.
It depends exactly what you mean. As you can see from AZPaul3's link, there are anatomical intermediates between dinosaur forelimbs and modern bird wings.
If you mean, is there some known feathered dinosaur which we can identify as a glider but not a flyer, then I think that's a "no". (I suppose it's possible that such a species has been found, but that the feathers were not preserved.)

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NosyNed
Member
Posts: 8996
From: Canada
Joined: 04-04-2003


Message 5 of 18 (401171)
05-18-2007 4:24 PM
Reply to: Message 1 by ogon
05-18-2007 2:18 PM


Historically speaking
From what I have read so far about evolution, fossils play a major part in backing up the theory of evolution. yes?
Today they are more important to tell us about the history of life on earth and how evolution has unfolded. They are a part of the backup for the ToE but not so major (though that is hard to quantify).
Historically they supplied a important impetus. Long before Darwin the fossils forced the recognition that life on Earth had not always been the same. In fact, it had undergone many changes over a long (but unknown how long) period of time.
Explaining how that could happen was one thing that a ToE had to do.
The fossils offer one line of support for the ToE in that the pattern apparent in them fits with what you'd expect from the ToE and fits other patterns uncovered in life forms (biogeography -- where living types are now and DNA patterns are two major examples).

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Parasomnium
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Message 6 of 18 (401179)
05-18-2007 4:30 PM


Fossilization is a rare occurrence
To add to what others have said about the role of fossils in the theory of evolution, it is worth noting that fossilization is actually quite rare. A number of circumstances need to be just right for it to happen, and some kinds of creatures will almost never be found as a fossil. Hence the sketchy nature of the fossil record.

"Ignorance more frequently begets confidence than does knowledge: it is those who know little, not those who know much, who so positively assert that this or that problem will never be solved by science." - Charles Darwin.
Did you know that most of the time your computer is doing nothing? What if you could make it do something really useful? Like helping scientists understand diseases? Your computer could even be instrumental in finding a cure for HIV/AIDS. Wouldn't that be something? If you agree, then join World Community Grid now and download a simple, free tool that lets you and your computer do your share in helping humanity. After all, you are part of it, so why not take part in it?

  
Chiroptera
Inactive Member


Message 7 of 18 (401183)
05-18-2007 4:43 PM
Reply to: Message 1 by ogon
05-18-2007 2:18 PM


Welcome to EvC, ogon.
As Ned pointed out, fossils provide good evidence for evolution, but they are not a major part of the evidence. In fact, the theory of evolution was pretty much fleshed out and accepted long before the major transitional series were discovered. The evidence for evolution exists in all the branches of biology, not just paleontology. In fact, the relative timing and sequencing of important evolutionary events can often be determined in embryology and through cladistical analysis.
That said, paleontology does provide good evidence for evolution (and does help in the absolute timing of key events, as well as elucidating details not obvious through other methods), but it is now a matter that there is so much evidence in other fields of biology that the fossils are just one more bunch of evidence added to a whole heap of evidence.
The main importance of fossils is not that they offer evidence for evolution per se, but that they provide details about specific events in evolutionary history.
-
I am guessing fossils of animals have been found with no wings and animals/birds have been found with full wings BUT have animals been found with half wings? This would certainly go some way towards confirming the theory of evolution.
Huh. Confirm how? That such a thing is possible? But we already know such a thing is possible: animals with half-wings exist now:
To confirm that birds evolved as a branch of theropod dinosaurs? But we already know that through cladistical analysis, which provides much stronger evidence for the evolutionary origins of birds than any fossil ever will.
To provide easy to understand evidence to confirm the theory of evolution? No one seriously doubts that theory of evolution, and very few people doubt that birds evolved as a branch of theropod dinosaurs, except for creationists, and they will simply dismiss any fossil find as they have dismissed all other fossils showing "half-features".
It would really, really be neat to find dinosaurs with half-wings, but the main interest would really be to answer some questions that remain about when and how flight evolved.

Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine

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NosyNed
Member
Posts: 8996
From: Canada
Joined: 04-04-2003


Message 8 of 18 (401198)
05-18-2007 5:09 PM
Reply to: Message 1 by ogon
05-18-2007 2:18 PM


What are "half-wings"?
Hello again, ogon.
I hope you are getting the answers you need. You are asking good questions and deserve to get good answers.
Generally, you should follow up for clarification if there is any confusion. There is bound to be some since several people are answering and we all have our own -- non-expert -- opinions.
To answer the "half-wing" question we should ask you to define what you mean by a "half-wing".
Is my arm with more-or-less the bones of a birds wing (but solid) but with no feathers at all a "half-wing". That is are feathers "half"?
Is a chicken's forelimb that allows for some flight but much, much less than half the flight of an eagle a "half-wing"?
You've seen some drawings of various developments in fore limbs that have varying degress of "wingness". Where is the half way point?
One issue that must be clear is that no animal has a "half" anything. They may not be as good at something as an animal that comes 20 million years later but they still have at least adequately functional parts. If they don't there is a technical term for it: dead

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PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


Message 9 of 18 (401228)
05-18-2007 5:44 PM
Reply to: Message 4 by Dr Adequate
05-18-2007 4:13 PM


Microraptor gui was probably a glider.

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Nighttrain
Member (Idle past 3994 days)
Posts: 1512
From: brisbane,australia
Joined: 06-08-2004


Message 10 of 18 (401290)
05-19-2007 3:03 AM
Reply to: Message 8 by NosyNed
05-18-2007 5:09 PM


Re: What are "half-wings"?
One issue that must be clear is that no animal has a "half" anything. They may not be as good at something as an animal that comes 20 million years later but they still have at least adequately functional parts. If they don't there is a technical term for it: dead
Hang on, Ned. we have humans wandering around with half a brain. Even on this forum. Whether they are a negative mutation from our strand, or a divergent species from our parent line, has yet to be determined.:-p

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ogon
Member (Idle past 6129 days)
Posts: 70
Joined: 05-13-2007


Message 11 of 18 (401294)
05-19-2007 3:28 AM
Reply to: Message 9 by PaulK
05-18-2007 5:44 PM


Responding to some posts I have to say is impossible for me because they are full of words I just don't understand. But I am picking up bits and I've just posted on my other thread (fossils)what I hope is a sensible conclusion to what I have picked up so far.
I shall explain why I started this fossil/bird thread.
Out of all life you have to admit that birds are one of the biggest wonders. Especially in terms of that at one time there were no birds. These guys are animals that have developed/evolved wings and took to the sky, amazing.
In my naivity I thought that in the beginning we must have had creatures climbing trees. Now creatures wouldn't climb trees for no reason so I thought the reason could be to escape predators or to reach food. Some of the food could be airborn. So I got this vision of an animal jumping out from a tree trying to catch an airborn piece of food and splat! The animal ends up dead on the floor!
My problem then was. Somehow this creature has to grow wings in order to catch food. Perhaps predators are increasing in numbers and it just isn't safe to be wandering around the forest floor anymore. My understanding was, animals adapted to a new or changing environment through changing genes. Genes literally made changes in the physical appearance of an animal in order to survive.
That might sound so naive but I must have picked the notion that this was correct from somewhere. This I believe is a common notion among lots of people. But, if the changing genes to suit the changing environment was how things happened then my question was going to be, if these animals were jumping to their deaths out of trees then they wouldn't be able to change their genes and pass them on cause they were dead!
SO, my problem now is I can't quite get a clear picture in my head, knowing what I now know about true evolution, of how we can have an animal with no feathers, then an animal with feathers, I've changed my wording to feathers because reading earlier responses has made me realise I too have wings but no feathers. It's the feathers in order to fly that cause me a problem now. The case of the hairiest animals surviving in an icreasingly cold environment works in my head. BUT, I'm having problems with animals jumping out of trees. The animals that jumped out of trees and flew would survive and so reproduce. BUT, no animals are gonna jump out of trees, fly, and survive.
I think I've just got a puncture!
ogon

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Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 12 of 18 (401299)
05-19-2007 4:48 AM
Reply to: Message 9 by PaulK
05-18-2007 5:44 PM


Dino-gliders
Thanks.
Semper aliquid novi ex China, eh? I can't keep up.

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PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


Message 13 of 18 (401300)
05-19-2007 5:10 AM
Reply to: Message 11 by ogon
05-19-2007 3:28 AM


quote:
BUT, I'm having problems with animals jumping out of trees. The animals that jumped out of trees and flew would survive and so reproduce. BUT, no animals are gonna jump out of trees, fly, and survive.
Have you never observed an ordinary squirrel ? They jump out of trees all the time, and they don't (often) get killed doing it. And they can't fly at all. Flying squirrels, as shown above can do even better because of the skin flaps joining their arms and legs, which allow them to glide.

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Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 14 of 18 (401301)
05-19-2007 5:19 AM
Reply to: Message 11 by ogon
05-19-2007 3:28 AM


Jumping Out Of Trees
If you look at creatures which live in trees, they don't jump out of trees, they jump from tree to tree.
Now anything which increases the animal's surface area in the direction of the ground as it jumps gives it a bit of air resistance in that direction, meaning that it can take longer, flatter jumps. (This is why squirrels have bushy tails and rats don't.)
This is an ideal situation for evolution, because any improvement, no matter how small, is an improvement.
Many lineages of gliders, such as the one pictured above, get stuck as gliders and never go on to develop flight, because their surface area is increased by means of skin stretched between their front and hind limbs. This is fine for gliding, but it can't develop into a wing that the creature can flap.
Bats have increased surface area because of skin stretched between their fingers. It's easy to see how to get from a gliding to a flying form here.
And birds have feathers. Now, so do some dinosaurs which don't have forearms adapted for flight in the slightest, such as Caudipteryx. Feathers serve at least two other purposes --- insulation and display --- this is why flightless birds still have them. So it is not beyond belief that feathers came first and flight came later, when feathered dinosaurs started leaping from tree to tree and surface area became important.
---
Footnote on scaling laws: the value of suface area falls off with size, because of the square-cube law. This is why there are no gliding monkeys, and why you can't fly by tying artifical wings onto your arms.
Edited by Dr Adequate, : No reason given.

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jar
Member (Idle past 394 days)
Posts: 34026
From: Texas!!
Joined: 04-20-2004


Message 15 of 18 (401357)
05-19-2007 11:41 AM
Reply to: Message 11 by ogon
05-19-2007 3:28 AM


reuse and cooption
One of the remarkable things about the evidence for evolution is that what we see in the record is old stuff being recycled for new uses.
Feathers are a great example.
First, they seem to be just another form of what makes scales. They also seem to serve multiple functions. Look at any bird and you find that most of the feathers are NOT involved in flight. Birds have feathers on parts that do not play a functional role in flight. There are also birds that do NOT have feathers in places other birds do (look at the head of a vulture) and birds that do not even fly, yet still have feathers.
One big use for feathers is insulation. We have a whole industry based on "Down Jackets" and down is still one of the best insulators known.
Feathers also provide padding, and a shield. They can be display items, sexual signaling devices, camouflage and perhaps other functions we have not documented yet.
So step one is the evolution of feathers in general. It might have given one group of creatures better adaptation to temperature ranges, or better camouflage, or made them look more sexually attractive or provided padding or helped them avoid predation with the predator coming away with a mouthful of fluff instead of meat or any number of other functions.

Aslan is not a Tame Lion

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