Tuesday, June 15, 2004

The world goes round and round...

Over at the Panda’s Thumb there is a recent post by P. Z. Myers titled, Pre-Cambrian coelomate! One point I should make here is that it is refreshing to see that the post is not simply another diatribe against maniacal creationists. Here’s an excerpt (beginning with a quote from a Science article):
Ten phosphatized specimens of a small (<180 µm) animal displaying clear bilaterian features have been recovered from the Doushantuo Formation, China, 40 to 55 million years before the Cambrian. Seen in sections, this animal (Vernanimalcula guizhouena gen. et sp. nov.) had paired coeloms extending the length of the gut; paired external pits that could be sense organs; bilateral, anterior-posterior organization; a ventrally directed anterior mouth with thick walled pharynx; and a triploblastic structure. The structural complexity is that of an adult rather than larval form. These fossils provide the first evidence confirming the phylogenetic inference that Bilateria arose well before the Cambrian.
This is exciting news, not because it revolutionizes our understanding of evolutionary history, but precisely because it is nothing surprising at all—we expect, from molecular/phylogenetic evidence, that complex animal life arose long before the Cambrian 'explosion', and what these fossils represent is a satisfying confirmation of that expectation (and they neatly fit predictions about bilaterian evolution that Erwin and Davidson made in 2002). It is actually expected, though, that bilaterian coelomates are even older than the 570 million years of the Doushantuo Formation; the last common ancestor of protostomes (arthropods and others) and deuterostomes (vertebrates and others) is estimated to have lived somewhere between 600 and 1200 million years ago.
This is a cross-section of the coelomate. Continuing the thread over at Pharyngula, Myers writes,
The important point is that this animal possesses the rudiments of morphological characters that are going to erupt into a wide range of diverse specializations in the Cambrian, and it has them roughly 50 million years before the Cambrian 'explosion'. The phyletic innovations we have first seen so clearly in the Cambrian did not come out of nowhere, but have a solid evolutionary foundation in simpler animals.
For those who don’t know what the Cambrian Explosion was, here is a brief explanation. About 540 million years ago, in a span of time only a few million years wide (with some estimates at 2-3 million years), between approximately 45% and 85% of the body plans we see in the animal world today, appeared. Between 19 and 35 phyla were introduced. What is enigmatic about this event is that there is no known reason as to why it should have occurred the way it did. Why should simple life suddenly burst forth (evolve?) into scores of complex phyla in so short a duration? Now, a few million years is a long time if you’re waiting for a table at a local restaurant, but in terms of morphological change, it is but a tick of the clock. Some creationists, such as Hugh Ross, argue that the empirical evidence supports the idea that God has a grand plan in which humans are the ultimate goal. Given the laws of physics, instituted by God, it takes billions of years to prepare a suitable environment for our solar system and, consequently, it takes millions of years to prepare a suitable environment on Earth for complex, advanced life. That such an explosion of diversity takes place at such an opportune time in Earth’s history is a hallmark of a purposeful plan. Consider the comments of Dr. Paul Chien, chairman and professor of biology at the University of San Francisco, in an interview he had with Reasons to Believe:
RTB – So, are you saying that the Cambrian explosion shows evolution “going the wrong way?” Chien – Yes. In fact, one of the most respected scientists in the West, James Valentine at the University of California-Berkeley, is writing a book on this by the title of Origin of Animal Phyla, instead of The Origin of Species. I think when the book is finished it will greatly help people understand what’s going on. Creation is going on. - “Exploding” with Life!, Facts for Faith, Quarter 2, 2000 (emphasis added)
This brings us to how evolutionists tend to view the Cambrian Explosion event. One mistake you will typically see is that of circular reasoning. The very fact of finding older, fossilized life forms that are simpler than those found at the time of the Cambrian Explosion is sometimes seen as “money in the bank” for evolution. This is one reason why a ruckus is raised whenever fossils are found that pre-date the Cambrian Explosion. Notice the inherent evolutionary assumptions, with regards to pre-Cambrian fossils, in the following excerpt from Donald Brownlee and Peter Ward’s book, Rare Earth:
The answer to this seeming conundrum is that the animals were indeed present, but they were so small as to be essentially invisible to the fossil record. A recent and spectacular discovery of microscopic fossil animal embryos seems to confirm this view. Using newly developed techniques of searching for tiny (but complex) animals in minerals called phosphates, paleontologist Andy Knoll and his colleagues have uncovered a suite of tiny but beautifully preserved fossils interpreted to be the embryos of 570-million-year-old triploblasts – animals with three body layers, like most of those found today. These fossils tell us that the ancestors of the modern phyla were indeed present at least 50 million years before we find any conventional fossil record of them. The combination of genetic information and new discoveries from the fossil record now give us a robust view of the rise of animals: They did not exist 1 billion years ago, and perhaps not 750 million years ago. Animals are indeed very late arrivals on the stage of life on Earth. Thanks to these new discoveries and interpretations, the question of “when” has been answered to most people’s satisfaction: The emergence of animals was a two-stage event. The initial stage seems to have occurred less (and perhaps much less) than the billion years ago proposed by Wray and his colleagues. But even recalibrated, the Wray group’s finding has given us yet another tantalizing insight into the potential incidence of animal life in the Universe. The Wray work confirms that there were indeed two “explosions.” The first was the actual differentiation of the various body plans; the second was the differentiation and evolution, in these various phyla, of species large and abundant enough to enter the fossil record. This leads us to ask a crucial question: Even if the evolve, do animals necessarily, or inherently, go on to diversify, enlarge, and survive? Does the second flowering of animal life – the Cambrian Explosion event so long known to geologists – inevitably follow the first diversification, or is it yet another threshold of possibility that may be (but is not necessarily) attained? (emphasis in original)
Since they already accept naturalistic evolutionary transformation as a given, they see finding fossils prior to 540 million years ago as evidence in favor of the evolutionary paradigm. Of course simply finding fossils does not tell us that those particular ancient creatures actually evolved into the diversity of complex phyla we find at the Cambrian event. To be fair to Brownlee and Ward, I doubt that they are thinking in such a limited manner. If pressed, they would probably state that earlier fossils should exhibit morphological characteristics that would appear as predecessors to the more complex Cambrian fossils. Additionally, they might say that one should expect to find earlier fossil forms that are molecularly related to later forms. Enter the recent find where evidence is shown of pre-Cambrian coelomates. Yes! Here is additional evidence required to substantiate the evolutionary paradigm! But is it really? Again we see a bit too much eagerness on the part of the evolutionist. To repeat, finding a simpler form of an animal that existed prior to an advanced form of an animal does not tell us that the one evolved into the other. At most it tells us that one existed prior to the other. From Brownlee and Ward,
Whether the Cambrian event included the diversification of body plans or consisted simply of the first evolution, by these various body plans, of skeletons and large size is a moot point. Something stimulated the evolution of many large animals with skeletons in a brief period of geological time. (emphasis in original)
Notice how the question of whether evolution was capable of performing the event is ignored. Something stimulated the event… we must simply assume that it was evolution. From The Cambrian Explosion Biology's Big Bang, by Stephen C. Meyer, Marcus Ross, Paul Nelson and Paul Chien,
…even on the most optimistic interpretation of these remains, Precambrian strata account for no more than four animal body plans (including some of largely unknown characteristics). Thus, neither the peculiar Ediacaran fauna nor the Precambrian fossil record taken as a whole establishes the existence of the wide variety of transitional intermediates that neo-Darwinism and punctuated equilibrium require. The Cambrian explosion attests to the first appearance of organisms representing at least nineteen phyla. Yet, Vendian organisms represent ancestral forms for, at most, four Cambrian phyla (granting ancestral status to a worm phylum and Kimberella as a mollusk). This leaves between 80 and 90 percent of the Cambrian phyla with no ancestors in the Precambrian rocks. Further, even if one grants that representatives of four phyla existed in the Precambrian, it does not follow that these forms were actually transitional intermediates. Some were, or may have been, representatives of known Cambrian phyla such as sponges (phylum Porifera), thus demonstrating not a gradual transformation but instead only the earlier appearance of a previously known phyla.
Evolutionists will sometimes respond to this line of reasoning by asking something along the lines of, “well then why does it look like evolution?” Unfortunately, a question such as that assumes that the mechanism of evolution is in place and operational. This is tantamount to committing Berra’s Blunder, in which the theory is being forced onto the data, as opposed to letting the data support the theory. Since the evolutionary mechanism is assumed to be operational, the fossil evidence is interpreted as supporting the mechanism. Also, note how the discussion will typically move into the subjective, for the words that need to be added to the previous question are “to me” (i.e., Why does it look like evolution [to me]?). Along those lines, one could justifiably ask, “Why does it look like Design [to me]?” Venturing even further into the realm of subjectivity the evolutionist may ask, “Why would a mythical designer do such and such (as opposed to so and so)?” Yet even they should understand that, apart from completely knowing the intentions of a designer, one cannot completely know the reasons why a designer acted as he did. Again, they stumble over the Blunder. However, the objective arguments about supposed ancestors to the Cambrian fossils ignore the critical characteristic regarding the Cambrian Explosion’s eruption of diversity – that of time. In their paradigm there simply isn’t enough of it. Recall that the Cambrian Explosion evidence indicates that a diversity of complex phyla burst onto the scene in a matter of only a few million years. Life forms that were large and advanced entered the scene within fully functional ecosystems. The best that an evolutionist can offer is to acknowledge that the explosion occurred, and that the diversity recorded in the fossil record really did appear in a brief geologic instant (ref. Brownlee and Ward’s quote above). That such high speed activity runs completely contrary to the paradigm is conveniently ignored or, in a classic example of circular reasoning, it is sometimes posited that such an event must be part of the evolutionary process itself! I guess since evolution is considered to be fact, and since the simpler fossils predate the Cambrian fossils, then it only follows that the simpler life forms evolved into the Cambrian life forms? The most that an evolutionist can hope for is that fossil evidence will eventually be uncovered that will not only refute the current Cambrian evidence, but that will conclusively demonstrate how simple, teeny-weeny creatures such as the one shown above transformed so quickly into the complex, large life forms shown below. It’s difficult to see past a notion that is entrenched within your paradigm. In The Privileged Planet, Guillermo Gonzalez and Jay Richards describe the lack of acceptance with which the astronomical community gave to the idea of a finite age for the universe, despite the findings of astronomers such as Edwin Hubble:
Like Einstein, most astronomers of the early twentieth century, including the young Hubble, believed in a static and eternal universe. Even after Einstein conceded his error in the late 1920s, many scientists would not accept the implications of an expanding universe – namely, that it came into existence sometime in the finite past. …For example, consider the account C. F. von Weizacker gives of a discussion he had with the physical chemist Walther Nernst in 1938:
He said, the view that there might be an age of the universe was not science. At first I did not understand him. He explained that the infinite duration of time was a basic element of all scientific thought, and to deny this would mean to betray the very foundations of science. I was quite surprised by this idea and I ventured the objection that it was scientific to form hypotheses according to the hints given by experience, and that the idea of an age of the universe was such a hypothesis. He retorted that we could not form a scientific hypothesis which contradicted the very foundations of science. He was just angry, and thus the discussion, which was continued in his private library, could not lead to any result.
Old habits die hard. At the core of the debate, though, is the notion that the evolutionary paradigm is based on the scientific method and uses methodological naturalism as its mode of operation with which to discover the truth about the natural realm. Yet how committed are adherents of naturalism to discovering the truth? I’ll discuss that in an upcoming post… Additional resources: Hominid Jewelry? (RealPlayer) – Creation Update webcast, Reasons to Believe, April 27, 2004 The Cambrian Explosion Biology's Big Bang (PDF), by Stephen C. Meyer, Marcus Ross, Paul Nelson and Paul Chien

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