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Author | Topic: The Definition and Description of a "Transitional" | |||||||||||||||||||||||||||||||||||
Robert Byers Member (Idle past 4396 days) Posts: 640 From: Toronto,canada Joined: |
It is true evolutionists will present transitionals here and there.
BUT when one surveys the whole animal kingdom living now or in the past.WHERE are the transitions as they must of existed?! If your right they should be numerous and more in thier connections, or reasonable interpretation that there is a connection, diversity and examples of each turn on ther road. Yet this is not so and we creationists think we know why.(Anyone not paying attention because they never existed) Rob
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Loudmouth Inactive Member |
quote: This is a very good start. The other possibility may be that a transitional species could live successfully in both environments. For instance, a species that is able to live both in water and on land. One such species alive today is the mudskipper. Here is a description from iiNet | naked dsl - broadband - adsl - phone - voip:
Long Jumper By curling its body to one side and suddenly staightening it, a Mudskipper can flip itself as far as 60cm in one movement. Fantastic FinsThe mudskipper's fins are adapted so that it can walk, jump, swim, and even climb. The front pair of fins, called pectoral fins look like little arms. The fish uses them for moving about on land, they are so muscular they can support the fish's weight. The second pair, called pelvic fins, are shorter and joined together underneath the body to make a kind of sucker. This sucker helps the Mudskipper to cling on to mangrove roots when it climbs. Funny Looking Little FaceThe strangely shaped mouth is good for snapping up insects, spiders and even small crabs. It also has sharp teeth for grabbing prey. Its nostrils are called nares. Its bulging eyes make it look primative. Oxygen TanksLike all fish, the mudskipper breathes with its feathery gills. It moves water over them with its gill covers, and absorbs oxygen from the water into its blood. Before climbing out of the swamp, the Mudskipper fills its large gill chambers with water. These act like oxygen tanks, keeping the fish's blood supplied with oxygen while it is on land. Mudskippers can breathe through their skin as well. Pop-up PeepersThe Mudskipper's bulging eyes are close together on top of its head. They stick up so that the fish can see all around itself. When the Mudskipper swims its eyes pop out of the water. They can move up and down like the periscopes of a submarine, and allow the Mudskipper to see above and below the water at the same time. When the Mudskipper is out of water, it keeps its eyes moist by rolling them back into their into their sockets every so often. Torpedo-shaped Body.Although the Mudskipper is considered to be a clumsy swimmer compared with other fish, its torpedo-shaped body helps it to swim through the water quite fast. Even today we can see species that are in transition from aquatic to terrestrial environments. This is exactly what we would expect to see in the fossil record. And we do:
The above is a painting of the fossil species Acanthostega. It had both internal lungs and external gills. It's limbs can be classified as both fins and legs. It's head is obviously fishlike, as is it's tail. This is a perfect example of what we would expect from a transitional species, a species that it is adapted to two different environments. This species (Pederpes) is also a transitional, and it displays bone structures that are preserved in tetrapodian terrestrial species today, including a femur, tibia, ulna, radius, humerus, etc.
This is exactly what we would expect to find, since evolution builds on previous body types instead of creating new structures all at once. Does this fit what you would call transitional? This message has been edited by Loudmouth, 07-26-2004 02:30 PM {Fixed large quote box - AM} This message has been edited by Adminnemooseus, 07-26-2004 03:01 PM
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RRoman Inactive Member |
quote:How about a kangaroo that was able to climb trees, but did not spend all it's time in trees? "Knowledge is Power" - Francis Bacon
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NosyNed Member Posts: 9004 From: Canada Joined: |
For example for sure there was no intermediate kind between a tree kangaroo and a kangaroo. What does that mean? Does it mean that all kangaroos are the same kind so of course, there can be none between. Or does it mean that they are separate kinds and there would have to be a transitional which you don't think exists. In that case you still haven't said what that transitional would look like.
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NosyNed Member Posts: 9004 From: Canada Joined: |
Jeafl, perhaps you could add your definition for a transitional here.
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Darwin Redux Inactive Member |
I really don't like talk of transitionals as discrete entities. Every organism that has ever existed (including us) is a transitional form. Except of course, those lineages that became extinct without producing descendents...But a very good transitional anyway is Archaeopteryx, or perhaps Ambulocetus...
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NosyNed Member Posts: 9004 From: Canada Joined: |
Robert found it inconventient to support his claims. When confined to Boot Camp to get a chance to understand how to he left. Not a huge loss but unfortunate for him.
In the meantime, I think the important point is to arrive at as good a definition of transitional as possible. Otherwise the discussion goes no where. It seems that Jeafl is another poster who doesn't like being expected to support his claims. So we'll leave this thread until someone else comes bombing in with the "no transitionals" claim. They won't know one if they trip over it either mind you.
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Darwin Redux Inactive Member |
Ok...It would be good to define a transitional - perhaps with respect to character states? A transitional could be defined as an organism that has a synapomorphy of an ancestral taxa as a plesiomorphy, and a plesiomorphy of a descendent taxa as a synapomorphy. How does that sound?
Easier description: Transitional exhibits as an ancestral character state what is a derived character state in the the 'older' form, and exhibits as a derived character state was is an ancestral character in the later form. I think we may be onto something here...
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NosyNed Member Posts: 9004 From: Canada Joined: |
LOL, but what?
I don't even understand the simpler description.
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arachnophilia Member (Idle past 1372 days) Posts: 9069 From: god's waiting room Joined: |
For example, what are the defining characters of birds? It's not feathers... this is some nice circular logic here, and it needs to be pointed out. why are feathers not a defining characteristic of a bird? no other animal today has them. do reptiles have them? mammals? amphibians? fish? if you ask any biologist the single most defining feature of a bird what will they say? now, according to you:
quote: for something to be partway between a bird and something else, wouldn't it have to feathers? why should that rule out feathers as a defining feature? it is, afterall, what we're looking for. but you can't say it's not a defining characteristic of a bird because the transitional form that led up to birds also had feathers. that just makes no sense.
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NosyNed Member Posts: 9004 From: Canada Joined: |
It doesn't matter what Mark says. It may well be that taxonimists don't use feathers as a characteristic of birds (though I would be surprised). It is what is used by those who have done the defining that we need to see a source for.
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Darwin Redux Inactive Member |
Sorry, I'm using too much jargon...
Here's maybe a simpler definition. We have Lineage A and Lineage B. Lineage A/B is postulated to be a 'transitional form'. A 'unique/derived' character in Lineage A can be noted to be an ancestral, primitive character in Lineage A/B, and an ancestral, primitive character in lineage B is a 'unique/derived' character in Lineage A/B.
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Itachi Uchiha Member (Idle past 5643 days) Posts: 272 From: mayaguez, Puerto RIco Joined: |
DSo you have any pictures of the original fossils so that I could check them out.
Loudmouth writes: The other possibility may be that a transitional species could live successfully in both environments. For instance, a species that is able to live both in water and on land. Let me see if I got this. You're saying then that the transitional species has more information than the present one because it went from being able to live in both enviroments (land - water) to living in only one. Hmmm wasn't information supposed to increase. A cat can walk, jump, swim and climb just like the mudskipper. So i guess a cat is also in a transitional state.
Loudmouth writes: This is exactly what we would expect to find, since evolution builds on previous body types instead of creating new structures all at once. Does this fit what you would call transitional? Yes but in order to believe you I need to see the original fossil and not a drawing. I can draw a picture of God from what I read in the bible but will it be enough to convince you of his existence. Ponlo todo en las manos de Dios y que se joda el mundo. El principio de la sabiduria es el temor a Jehova
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NosyNed Member Posts: 9004 From: Canada Joined: |
oh, I almost have it now.
Let me try? We have to separated higher taxa (today). For example, reptiles and mammals. (A and B). A transitional (A/B -- a reptimammal) would have a specific characteristic that we now associate only with A (reptiles) AND some other specific characteristic that we now associate only with B (mammals). I think this has already been put forward upthread.
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NosyNed Member Posts: 9004 From: Canada Joined: |
We'll have to start finding pictures.
It is not always easy to find good ones.dinosaur to bird Geoscience Research Institute | I think we need more research on that... for a poor one of archeopterix (and some description of how they are transitional (it is not just feathers). I'll add others by edit.Reptile to Mammal http://www.mathematical.com/dinodviniaprima.html this whole site has many pictures of the fossils. Not all of them are reptile to mammal transitions, some are reptile to dinosaur. Others are not what we think of as transitionals with our current taxa bias. This sitehttp://rainbow.ldeo.columbia.edu/courses/v1001/9.html supplies a discussion of the times and give drawings and names. If you google the names you will find pictures of the original fossils for some. The only problem I can see you having with the drawings is that you think someone is making them up. They are done very carefully indeed from the fossils to allow them to be shown clearly. Something that is difficult if you don't have the actual fossil in front of you for some of them. This message has been edited by NosyNed, 11-30-2004 12:01 AM This message has been edited by NosyNed, 11-30-2004 12:02 AM
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