If this is true then they should not be used as examples of evolutionary precursors to existing phyla. Stop lawyering! If archaeopteryx is, oversimplifying but slightly, a run-of-the-mill dromaeosaur skeleton with a covering of luxurious flight-capable feathers, then it's evidence that birds arose from theropod dinosaurs. Why? Because it has so many features of both things.
It could be a dead-end, but that would only be because it's a cousin branch of whatever the species the real ancestral line runs through. That you really can't tell one way or the other about that question does not change what I just said about birds coming from dinosaurs. Had you read the link I gave you in the previous post with any attention, you would not still be arguing fallaciously unless it were your intent to deceive.
Look here:
Figure 2. The effects of an incomplete fossil record on the reconstruction of evolutionary relationships. (A) This branching tree (phylogeny) represents the actual pattern of evolutionary relationships. (B) The actual preserved record of species in the fossil record might look something like this. (C) This branching tree represents a possible reconstruction of the evolutionary tree based on the fossil evidence. Note that the general pattern of relationships is preserved, but that errors have been made with regard to specific ancestor-descendant relationships.
Creationists take the real data, picture B, and draw vertical parallel lines from each point. That's done for lawyering purposes, and its done in studied ignorance of all the obvious evidence for relationship between fossils.
And when a fossil of "something related" is found, it can be plugged in on the tree at the appropriate point of divergence. There is little or no evidence that either Spriggina or Anomalocaris should be plugged in at the points your post suggests.
Both are like Archaeopteryx in showing intermediate characteristics between earlier and later forms. You aren't explaining why the obvious inference is not allowed here. It looks especially funny to me that creationists argue that nothing is an ancestor of anything else, draw the chart of initial appearances as various items floating on air (vertical parallel lines), then use the chart as evidence to support their malfeasance in drawing it that way in the first place (i.e, as proof that there are no transitional forms).
Doesn't sound like a very viable candidate for ancestor to multile phyla, as your posting seems to suggest.
Anomalocaris has several features of worms (circum-oral ring, lobopods), as well as features of arthropods (the segmented, plated specialized appendages). It is evidence that some line of worms somewhere gave rise to arthropods. It is but one of many lines of evidence pointing that way, all of which tend to support and confirm each other. Did you know, for instance, that hatchling insects look like little lobopod worms? Why should that be? Sort of reminds you of how hatchling frogs look like little fish.
So why aren't we allowed to infer that what looks like a duck, quacks like a duck, walks like a duck, lays eggs and flies isn't a duck? Does it have something to do with your religion? And why should the findings of science be required to have something to do with your religion?
Stop lawyering! If archaeopteryx is, oversimplifying but slightly, a run-of-the-mill dromaeosaur skeleton with a covering of luxurious flight-capable feathers, then it's evidence that birds arose from theropod dinosaurs. Why? Because it has so many features of both things. Again, I’m not trying in one swoop to dispute the entirety of evidence put forth in favor of evolution, just pointing out that the particular cases of anomalocaris and spriggina that you cited as evidence of extant phyla precursors are not nearly as clear as you assert.
For example, from this,
The high degree of anatomical detail preserved in specimens of Chengjiang anomalocarids attests to the quality of Chengjiang fossils. If the criticisms of Hou and Bergstrom (1997) are accepted at face value, it is arguable that the apparently smooth, featureless surface of the soft-cuticle of Collins' Burgess Shale A. canadensis is an artefact resulting from comparably inferior preservation associated with fossils from the Burgess Shale biota. The small size of reported Chengjiang anomalocarids correlates with the assumption that their remains represent juveniles, while Collins' described A. canadensis specimens represent adult organisms. Whether the preservational environments or different ontogenetic stages account for the differences in visible anatomical details is unclear. end quote
It seems as though much work need to be done before you can state with any confidence that anaomalocaris is halfway between worms and arthropods, as opposed to all arthropod.
It could be a dead-end, but that would only be because it's a cousin branch of whatever the species the real ancestral line runs through. That you really can't tell one way or the other about that question does not change what I just said about birds coming from dinosaurs. Had you read the link I gave you in the previous post with any attention, you would not still be arguing fallaciously unless it were your intent to deceive. Look here:
I understand the overall concept you are asserting. The problem, however, is whenever a closer investigation is done of any of the examples cited, there is no uniform opinion in the scientific community, as seen above with anomalocaris, or with dinosaur to bird evolution, which is a continuing area of hot debate. It is not lawyering to point this out. Every example cited by one defender of evolution is a bone of contention with someone else in the evolution community. The devil is in the details. This sort of thing doesn’t happen in the physical sciences---no chemist disputes the ordering of the Periodic Table.
Here’s a little “lawyering” for you:
Figure 2. The effects of an incomplete fossil record on the reconstruction of evolutionary relationships. (A) This branching tree (phylogeny) represents the actual pattern of evolutionary relationships.
No, it doesn’t. It represents a hypothesis about the possible pattern of evolutionary relationships.
Creationists take the real data, picture B, and draw vertical parallel lines from each point. That's done for lawyering purposes, and its done in studied ignorance of all the obvious evidence for relationship between fossils.
My pointing out the lack of unanimity in the evolution community concerning the taxonomic classification of two fossil types is just that, nothing more, nothing less (I’m not advocating creation science, see below). You cited them as evidence of transition while the jury is still out. You’re using fossils that are the subject of contention (as they all seem to be) to advocate your position. Is that a form of lawyering on your part?
So why aren't we allowed to infer that what looks like a duck, quacks like a duck, walks like a duck, lays eggs and flies isn't a duck?
It is never that clear cut once you go from generalities to specifics. That has nothing to do with my religion.
Does it have something to do with your religion? And why should the findings of science be required to have something to do with your religion?
I have not to this point referred to anything not from scientists. But in the end, you are, of course, correct. I am a Biblical creationist, not a scientific creationist. I put my faith in scripture. Some others put their faith in natural science. The two are opposed, at least one is wrong. Neither can prove their fundamental axioms, no one can. One can only demonstrate the internal self-consistency of one’s beliefs and point out the self-contradictory nature of others' beliefs. Rephrasing:
Does it have something to do with your science? And why should the findings of religion be required to have something to do with your science?
Although it’s interesting to follow their efforts, I can’t conceive how scientific creationists will ever put forth a cogent theory without pulling in information from scripture. Their real value is in keeping the evolution community honest, which is most definitely needed since there is no way to conduct controlled experiments as in other fields.
But for most, this whole crevo debate is just one battle in the larger war: who will control the government schools? But most Christians aren’t seeing the bigger picture. If they would learn their Bible, they wouldn’t be fighting to get alternative theories into the public schools, they would be calling for the elimination of all government involvement with schools (see here) . Many defend evolution so as to maintain a tool which is used to knock Christianity in the government schools. It’s all part of a larger battle, into which I jump into on various threads as I have time and am able. My religion convinces me that evolutionary theory is wrong, as are government schools. I will fight both and hope to expose an internal flaw or two as I am able.
If government ever got out of the school business, then these crevo debates would in my opinion have no place on Free Republic. Until then, en garde.