Missing Link?

[Not-son-of-fish]

How do evolutionists account for the lack of living transitional lifeforms? :huh: There should be hundreds right outside my window right?

Thanks

[DivineOb]

I suppose it depends on how you define 'transitional form'. So, how do you define it?

[Minnesota]

I believe most evolutionists would posit that YOU are most likely a transitional form. Can't be proven of course, but considering the vast amount of evidence showing that all current life forms are the result of evolution, there is no reason to think that Homo sapiens have reached a dead end---other than the possibility that they may obliterate themselves through their own carelessness.

[Woman]

fish:

How do evolutionists account for the lack of living transitional lifeforms? There should be hundreds right outside my window right?

Thanks

How do you know there aren't? Would you know a transitional lifeform if it bit you?

[Dr.GH]

The closer to the Cambrian, the easier it is to point to tansitionals.

The notion of equivalency means that the same point doesn't need to be proven over and over and over. Once a general princple is demonstrated, we can move on to the next important issue.

If you agree, we can proceed.

[djnoz]

How do evolutionists account for the lack of living transitional lifeforms? There should be hundreds right outside my window right?

Natural selection is part of the evolution process. Those transitional species have probably all become extinct, because they were unsuited to their environment.....

Of course, if your a Nazi, there are plenty of transitional life forms out there....

[DunnySaze]

How do evolutionists account for the lack of living transitional lifeforms? :huh: There should be hundreds right outside my window right?

Thanks

There is no lack of living transitional forms. In fact, ALL living organisms are transitional forms. Transitional between what existed in the past, and whatever will exist in the future. Assuming of course something radical doesn't happen the near future like the extinction of all life.

We can't say what those future forms will be. For example, consider the seal. This animal cannot be described as fully terrestrial, nor can be described as fully aquatic. It's a mix of both. In the future, will seals become entirely aquatic, entirely terrestrial, or have some other destiny? There's no way to tell, since there appears to be no 'direction' to evolution.

Now if your definition of 'transtional lifeform' differs considerably from what evolutionists mean by that term, then that's a whole different matter.

:ahem:

[WinAce]

There are always bizarre animals like the Walking Catfish (http://www.flmnh.ufl.edu/fish/Gallery/Descript/WalkingCatfish/WalkingCatfish.html) if digging up fossils isn't your preferred hobby...

[Not-son-of-fish]

Today @ 04:37 AM post located here (http://www.theologyweb.com/forum/showthread.php?s=&postid=89544#post89544)
DivineOb:

I suppose it depends on how you define 'transitional form'. So, how do you define it?

The kind of transitional form I am referring to here would be a visible transition between living species. (i.e. A fish with legs, a horse with wings, or something similar) I am referring to a living lifeform not a fossill.

[Socratism]

This thread will go nowhere as long as the common definition of transition is used by one set of posters and the evolutionary meaning of it is used by others.

All it means to many is that there are some forms that have characteristics of more than one classification grouping, where the groupings were originally established because some characteristics seemed to belong almost exclusively to that grouping.

To others the term refers to a "lineage", that is a continuous line of descent that supposedly branched off slowly over time to create separate lineages that at some point could be recognized as different by their differing characteristics.

Thus there are dilemmas, one if a particular characteristic can not be distinguished as binary (it is either there or it isn't), and another if consideration of multiple charactistics simultaneously does not show consistency, i.e. one characteristic shows a trend in one direction but a different characteristic shows a trend in another. In this latter case there is no identifiable ancestor and specimens are thought to be only cousins (speaking loosely).

In fact, many if not most (or all) citings of transitional forms in the literature are of this latter type.

[DunnySaze]

This thread will go nowhere as long as the common definition of transition is used by one set of posters and the evolutionary meaning of it is used by others.


Couldn't agree more.



In this latter case there is no identifiable ancestor and specimens are thought to be only cousins (speaking loosely).

In fact, many if not most (or all) citings of transitional forms in the literature are of this latter type.


Again, I think you hit it right on the head. Archeaopteryx for example is considered transitional between dinosaurs and birds because it has features attributed to, and diagnosic of, both groups. It is however not considered a direct ancestor to birds, but rather a closely related offshoot of whatever the actual ancestor was. To determine true ancestory you'll need genetic data that doesn't get recorded in the fossil record.

In fact, recent evidence suggests that rather than thinking of modern birds as a separate group in themselves, it may be more accurate to consider them the last surviving branch of the dinosaur group. Depends where you want to draw the line. That's the problem with a continuum of species, the line is obscure sometimes. New evidence leads to re-evaluation.

[Duvenoy]

Today @ 03:03 PM post located here (http://www.theologyweb.com/forum/showthread.php?s=&postid=89952#post89952)
Not-son-of-fish:



The kind of transitional form I am referring to here would be a visible transition between living species. (i.e. A fish with legs, a horse with wings, or something similar) I am referring to a living lifeform not a fossill.

Fish with legs: Mudskippers.Their pectoral fins, short and stout, are used more as legs than fins. they spend a lot of tine ashore. This can also be found in some angler fish and sea robins, that spend no time ashore, but crawl or hop along the sae bottom.

Don't know of any flying or gliding horses, but how 'bout flying squirrels and sugar gliders? What might evolution be doing with these?

Hmm. Blind cave fish. These, no longer needing eyes, are in the process of losing them.

There's a species of rattlesnake, one of the viridis complex, that commonly preys upon a species of ground squirrel, in the south west. The squirrel is in the precess of becoming partially resistant to the snake's venom and the snake must get a pretty good hit to kill one. At the same time, the snake's venom is becoming 'hotter'. A great example of two animals evolving together, as this has been going on for milinia, with no end in sight.

This is just fast and dirty, off the top of my head. If I weren't so lazy, I'd hit the books and make a longer list, but, I'm sure you can see what I mean. They're all around us.

Edited to add that none or all of these creatures might be 'transitional'. It is not possible to predict the future of a species. One can only observe the evidence of the past.

doov

[Socratism]

If you want to consider adaptation to be "evolution by random mutations plus natural selection" that is your choice, but adaptation seems to occur a bit faster than that.


It is not possible to predict the future of a species. One can only observe the evidence of the past.

Which might be taken to say that evolution is not a theory that can predict the future but only a subjective explanation of the past.

Isn't there a saying that "Hindsight is 20-20"?

[DunnySaze]

If you want to consider adaptation to be "evolution by random mutations plus natural selection" that is your choice, but adaptation seems to occur a bit faster than that.


There is no rate inherent in the definition you give: "evolution by random mutations plus natural selection". What makes you think the process described this way is 'slow'?



Which might be taken to say that evolution is not a theory that can predict the future but only a subjective explanation of the past.


One might take it that way, but that would be a misunderstanding. Prediction in science is not about predicting the future, it's about predicting that something will be observed (like the result from an experiment) or predicting the sorts of things you might see if your theory were correct; as well as the sorts of things you would not expect to see.

For example, evolutionary theory predicts that similarity between organisms will show the same relationships and in the same degree; to a high statistical probability; in molecular and in anatomical details. Special creation makes no such prediction. The observations support the evolutionary view.

[Duvenoy]

Today @ 04:58 PM post located here (http://www.theologyweb.com/forum/showthread.php?s=&postid=90053#post90053)
Socratism:

If you want to consider adaptation to be "evolution by random mutations plus natural selection" that is your choice, but adaptation seems to occur a bit faster than that.



Which might be taken to say that evolution is not a theory that can predict the future but only a subjective explanation of the past.

Isn't there a saying that "Hindsight is 20-20"?



Hind sight is indeed 20/20, which is why we've come to understand a lot about transitionals species.

http://www.gcssepm.org/special/cuffey_05.htm

I've worded some of my statement poorly. I should have said that it is impossible to predict the future of a modern species, such as the mudskippers, that you can readly observe alive, in the field.

Why? Very simple. They might get a new predator, as the 'skippers have. The tropical fish trade is proceeding to decimate them, and when ashore, they're not hard to catch. To my knowledge, there is yet no captive, breeding program for them, as there is for a great many, other species. And, wild-caught are always cheaper on the market.

So, what does this mean for the mudskippers? Will their populations become so thin that extinction is right around the corner? Or will they, through natural selection, become harder to catch? They concievably could even return to wholly aquatic life.

I don't know, although adding destruction of habitat to the first option, I'd tend to think that that's what's going to happen. As it will with many, modern species, ultimatly including ourselves.

Doov

[Not-son-of-fish]

05-07-2003 @ 03:39 PM post located here (http://www.theologyweb.com/forum/showthread.php?s=&postid=89983#post89983)
Socratism:

This thread will go nowhere as long as the common definition of transition is used by one set of posters and the evolutionary meaning of it is used by others.



Good point, sorry for wasting everyones time. Thanks for the info though.

-Fish

[Roy]

05-07-2003 @ 01:38 PM post located here (http://www.theologyweb.com/forum/showthread.php?s=&postid=89877#post89877)
DunnySaze:



There is no lack of living transitional forms. In fact, ALL living organisms are transitional forms.

Um, most living forms aren't transitional, since they'll become extinct. A few lucky living forms won't, and they're the transitional ones. In most cases there's no way of telling which are which.*

Roy

*Giant pandas are more likely to be dead ends than transitional forms; cockroaches are more likely to be transitionals than a dead end. Most things in between could go either way.

[Roy]

05-07-2003 @ 03:03 PM post located here (http://www.theologyweb.com/forum/showthread.php?s=&postid=89952#post89952)
Not-son-of-fish:



The kind of transitional form I am referring to here would be a visible transition between living species. (i.e. A fish with legs, a horse with wings, or something similar) I am referring to a living lifeform not a fossill.

Horses with wings? You are very confused. I think you should learn what evolution implies will exist before you claim that it doesn't.

Though if you really want evidence for the cartoon version of evolution, try Disney's 'Hercules'. There's a horse with wings in that.

Roy

[DunnySaze]

Today @ 05:39 PM post located here (http://www.theologyweb.com/forum/showthread.php?s=&postid=151045#post151045)
rthearle:



Um, most living forms aren't transitional, since they'll become extinct. A few lucky living forms won't, and they're the transitional ones. In most cases there's no way of telling which are which.*

Roy

*Giant pandas are more likely to be dead ends than transitional forms; cockroaches are more likely to be transitionals than a dead end. Most things in between could go either way.


Possibly I'm a tad confused or confusing on this.

I don't think extinction necessarily means an organism still cannot be a transitional form. True, it no longer contributes to future generations, but the concept of transitional form does not necessarily imply a direct ascedent-descendent relationship, although it may. For example, my uncle could be considered a transitional form between my paternal grandfather and myself, even if he never leaves offspring of his own. My father is also transitional of course, but in addition to that he participates in the direct ascendent line.

Perhaps I should have said if we could compared say, organisms from 3,000,000 years ago and those from 3,000,000 years in the future, we may find transitional forms between them which represent organisms living today. For example we may look at humans 3 Ma into the future and determine that humans today are intermediate between them and Australopethicus afarensis.

But in that case wouldn't Neanderthals also be intermediate between them and the Australos?

Maybe I'm wrong.

[Barron]

05-06-2003 @ 08:12 PM post located here (http://www.theologyweb.com/forum/showthread.php?s=&postid=89524#post89524)
Not-son-of-fish:

How do evolutionists account for the lack of living transitional lifeforms? :huh: There should be hundreds right outside my window right?


There probably are. Afterall, one can only identify as "transitional" by having two others to compare it to. Since we can't see the future for the second form, it's hard to judge what will be transitional and what won't. You might also want to look up a little on "ring species" for a pretty good example of a "living transitional".

I don't know if this applies to you at all, but sometimes think that creationists are stuck with a weird idea of what a transitional is. And I blame computers. Yep. My theory is that these folks have something akin to computer morphing in their minds, with the transitionals as the "tweened" frames. Thus when they don't see weird "what if they mated" sorts of animals they assume transitionals don't exist. It takes an extreme example of that like Archy to even get on their radar.

Barron

[Roy]

Today @ 06:27 PM post located here (http://www.theologyweb.com/forum/showthread.php?s=&postid=151102#post151102)
DunnySaze:




I don't think extinction necessarily means an organism still cannot be a transitional form. True, it no longer contributes to future generations, but the concept of transitional form does not necessarily imply a direct ascedent-descendent relationship, although it may. For example, my uncle could be considered a transitional form between my paternal grandfather and myself, even if he never leaves offspring of his own. My father is also transitional of course, but in addition to that he participates in the direct ascendent line.

Perhaps I should have said if we could compared say, organisms from 3,000,000 years ago and those from 3,000,000 years in the future, we may find transitional forms between them which represent organisms living today. For example we may look at humans 3 Ma into the future and determine that humans today are intermediate between them and Australopethicus afarensis.

But in that case wouldn't Neanderthals also be intermediate between them and the Australos?

Maybe I'm wrong.

No, you're right. But for a modern species to be a transitional form in this sense means it has to be descended from a species which branched off, where the other branch evolved into something different, without there being substantial evolution on its own line. There aren't many examples I can think where this might apply. Of all the extant species of birds, for instance, the only one that comes to mind it the hoatzin.

Roy

[John Boy]

I wonder if Not-son-of-fish would accept an egg-laying mammal with a cloaca and lack of nipples as a living transitional between reptiles and mammals?

Of course, given that about 95%-99% of every lifeform that has ever lived on Earth is extinct, we shouldn't be too surprised that there aren't too many to be found. The fossil record, however, is rich with them. For instance, just ask yourself if Diarthrognathus is a reptile or a mammal and how you came to that conclusion (to give a hint: it has diagnostics that are half-mammal/half-reptile and could be classified as either reptile or mammal, or both for that matter).

Here's a link to help you:
http://www.gcssepm.org/special/cuffey_05.htm

And here's Gish's failed response to reptile/mammal transitions:
http://www.gcssepm.org/special/cuffey_08.htm

Good luck!

Take care. :smile:

[DunnySaze]

Yesterday @ 10:54 PM post located here (http://www.theologyweb.com/forum/showthread.php?s=&postid=151275#post151275)
rthearle:



No, you're right. But for a modern species to be a transitional form in this sense means it has to be descended from a species which branched off, where the other branch evolved into something different, without there being substantial evolution on its own line. There aren't many examples I can think where this might apply. Of all the extant species of birds, for instance, the only one that comes to mind it the hoatzin.

Roy

Yes, you're right.

Extinct forms can be transitional, but they may not necessarily be if they evolved along a line which itself ended. It was too strong of a generalization for me to say that all extant organisms are transitional. Just so you know, I was also considering transitional not just in terms of speciation and higher, but below that level too. For example, if we compare modern Homo sapiens with those of 25,000 years ago and those of 50,000 years ago, there is no speciation, but the form of those 25,000 years ago is intermediate between the other two. The skull slightly larger, the skeleton slightly more gracile than their 50,000 year old counterparts and less so than modern examples.