On Transitional Species (SUMMATION MESSAGES ONLY)

"In looking for the gradations by which an organ in any species has been perfected, we ought to look exclusively to its lineal ancestors; but this is scarcely ever possible, and we are forced in each case to look to species of the same group, that is to the collateral descendants from the same original parent-form, in order to see what gradations are possible, and for the chance of some gradations having been transmitted from the earlier stages of descent, in an unaltered or little altered condition."--Origin of Species, Chapter 6Since it is impossible to tell without DNA the exact relationship between fossils it is always assumed that they are collateral descendants (as described by Darwin) who have preserved characteristics found in the common ancestor. With this understanding, one can not draw a non-arbitrary line beyond which a species is too distantly related to the common ancestor in order to evidence a transition. For that reason, the duck billed platypus is as transitional between reptiles and placental mammals as H. erectus is transitional between modern humans and our common ancestor with chimps.

The problems here are two fold. How do you determine that a fossil is directly in the lineage of another? The short answer is that you can not determine this. As Henry Gee says, fossils don't come with birth certificates.Secondly, even Darwin stated that the collateral ancestors of those transitional forms can preserve features that evidence a transition."In looking for the gradations by which an organ in any species has been perfected, we ought to look exclusively to its lineal ancestors; but this is scarcely ever possible, and we are forced in each case to look to species of the same group, that is to the collateral descendants from the same original parent-form, in order to see what gradations are possible, and for the chance of some gradations having been transmitted from the earlier stages of descent, in an unaltered or little altered condition."--Origin of Species, Chapter 6So what we are really talking about is the transitional form, and the species who carry this transitional form are transitional species.Edited by Taq, : No reason given.

Context is of the utmost importance here, as you mention. In fact, without context you simply can't talk about transitions.As an analogy, let's say I am driving down the road. Someone calls me and asks where I am. I tell them "I'm half way there"."Half way to where?" they ask.I tell them "Since I am always moving in the car I am always half way to somewhere".It becomes quite apparent that I have not answered the original question of "Where are you?". If I would have said "Half-way between Overland and Kootenai on Vista" my friends would know exactly where I am. That is how it is with species. You need to know the origination and destination before a half-way point can be established. You need context.If I had said, "Half way between Overland and Kootenai near Vista" my friends would still have a pretty good idea where I was. That is how it is with transitional fossils. They may not be in the direct flow of the lineage (or Vista Ave. in my analogy), but they give the general trend.

Really? I would say that shared characteristics transmitted from common ancestry tend to dwarf derived characteristics that evolved in each lineage. Humans, birds, lizards, fish all have backbones just as their common ancestor did. We all share the same basal embryonic developmental patterns. We all still use iron based hemoglobin to transport oxygen and carbon dioxide. The list goes on and on and on.On top of that, all of these shared and derived characteristics fall into the predicted nested hierarchy. We don't see species, living or dead, that have a mixture of mammalian and avian features, as one example. We don't see fish with vestigial patches of fur. We don't see birds with atavistic mammary glands. We don't see bats with feathers. All of these shared and evolved characteristics fall into the precise pattern predicted by the theory of evolution, and is inexplicable by creationism. That is the conclusion drawn from the objective morphology of fossils and living species. We conclude that these mixture of traits are due to evolution and common ancestry because the theory predicts the very pattern of shared characteristics that we observe. One does not have to assume shared ancestry in order to conclude that Archaeopteryx has dinosaur features not found in any living bird and avian features not found in any non-avian dinosaur. Those are simply the facts. From those facts we conclude that evolution occurred. And they do. Can you name a single body part that humans have but chimps do not?Can you name a single body part that humans have but whales do not? Compare that to the body parts that humans and whales share. One of the few differences I can think of is baleen. Whales and humans share the same mammalian lungs, liver, stomach, vertebrae, ulna, radius, humerus, cranium, brain, etc, etc, etc. Whales even nurse their young just like humans. If whales had vestiges of feathers it would disprove evolution. The simple existence of vestiges by themselves does not indicate evolution. It is the fact that the vestiges fall into the predicted nested hierarchy that points to evolution. I would disagree with "special cases" but the adaptation was relatively quick if you count 10's of millions of years as quick.

It is more than that. There is also the fact that shared features fall into a nested hierarchy as predicted by the theory of evolution. A common designer is not limited to a nested hierarchy, therefore there is no reason that one should exist. If mammals and birds have a common designer then what was stopping the designer from designing a species with a combination of mammalian and avian features? There is simply no reason that we should see a nested hierarchy if shared features were due to a common designer.On the other hand, a nested hierarchy is the only pattern that evolution can produce, at least for species that do no participate in horizontal genetic transfer. Therefore, evolution is the best explanation for the pattern of homology that we observe. Why should they still be there? For example, should lions still have gills according to your view of evolution? Why?

Tens of millions of years from now whales may very well lose these vestigial characteristics. What then? That evidence is found in the developmental patterns of all tetrapods. The recurrent laryngeal nerve loops under the aorta and then connects to the larynx. This is due to our fish heritage as seen here:Just a moment... Why is it impossible for these vestiges to completely go away? Why would a designer need to use a common design? Why would a designer be limited to a nested hierarchy? You haven't explained this at all. Also, some creatures have more than two eyes which falsifies your model. Edited by Taq, : No reason given.

What criteria are you using to determine if a fossil is intermediate or not? Evidence please. No one claims that they came from each other. What we claim is that they share a common ancestor. They would all be found in the same strata since they are all living at the same time, so they would not be said to be a fossil sequence.

Yes, they do. The human vermiform appendix is a vestige left over from an ancestor that was an herbivore. I can point to an anatomical feature in any species that evidences their ancestral lineage. They aren't that hard to find. I named one for humans in this very post. I can also point to the recurrent laryngeal nerve found in all tetrapods that evidences their ancestral origin in fish. Do you want more examples?

It is the PATTERN of shared body plans that evidences common ancestry. That PATTERN is a NESTED HIERARCHY. Each and every time I bring this up you ignore it. It is time to start facing the facts. We have shown you these anatomical remnants and yet you still reject the theory. We have shown you those remnants. You ignore them. And yet the recurrent laryngeal nerve is a remnant of the developmental pathway established in fish that we inherited from them. You ignore it. It is present in all tetrapods. So your argument is that there should be vestigial parts if evolution is true. Since there are vestigial parts we can then conclude that evolution is false. Is that your argument?Edited by Taq, : No reason given.

So you ask for examples of these features that have been passed on from our common ancestry with other species, and when presented with these examples you reject them as speculation.Can you be more dishonest? Last I checked, the theory of evolution states that the majority of features should be adapted to work in the new environment. That's how evolution works, by modifying features to increase the fitness of the species.

That is your own assertion, not one made by the theory of evolution. A nested hierarchy is more than a common blueprint. You can have a common blueprint and still have NO NESTED HIERARCHY. When will you start understanding this? Please, read up on what a nested hierarchy is, and then explain why one would expect a nested hierarchy if creationism is true.So why don't we see any species with a mixture of bird and mammal features? Why do bats have fur and teats while birds have feathers and regurgitation? Why is there a lack of common blueprint between the bird and bat adaptations for flight? Why is it that we see certain intermediates but not others?

I will actually disagree with this. The only requirement for being transitional is having a mixture of characteristics from two divergent taxa. The platypus is a transitional species because it has a mixture of characteristics from mammals and reptiles.Transitional does not mean ancestral. Those are two different concepts.

I would argue that "close" is completely arbitrary. At what point is a species too distant from the common ancestor to no longer be considered transitional?Also, the transitional nature of a species has nothing to do with ancestry. It only has to do with the morphology of the species. Ancestry is a conclusion derived separately from the transitional nature of the species. A species with a mixture of mammalian and avian features would be transitional, but this fossil would also falsify common ancestry.Edited by Taq, : No reason given.

Evolutionary distance is a conclusion. The transitional features of a fossil are the observations. They are different steps in the scientific method. Using the same criteria, one could label the platypus to as a proto-mammal and therefore transitional. The only distinction you are making is the time period in which the fossils are found.What I am trying to stress is the need to keep the observation (transitional morphology) separate from the conclusion (shared ancestry and evolution). A fossil can still be transitional/intermediate even if evolution is false. The theory of evolution is so widely accepted because it is able to accurately predict which transitionals we should see and which we should NOT see. I think that is an important point that can be missed if you start to mix the observations with the conclusion.

I'll give it one more try and see if it helps.For all intents and purposes the terms transitional and intermediate are one in the same. When these terms are put together with the theory of evolution then you can also include evolutionary distance. In this respect there is a tendency to label species close to the common ancestor as transitional and those further away as intermediate. However, it is an arbitrary line just as there is an arbitrary line between being short and tall. They are all shades of grey, if you will.The proper usage of transitional is in relation to the observations, which is what I was trying to stress. You don't observe evolutionary distance, that is the conclusion from analysing the observations. You observe the morphology. Therefore, a transitional fossil must be described in terms of direct observations that are independent of theory.Does that make sense?