Saturday 14 January 2012

The Cambrian Explosion and Being Thwarted by Blocking

You will have to forgive me for this post, it is simply me not wanting to feel like my time was wasted. I was posting on an anti-evolution discussion group and spotted someone making bizarre claims about theism and materialism in one long post, whilst also having another post on the Cambrian explosion. So I had two tabs open; one for discussing with him on the materialism thread, the other with the Cambrian explosion stuff so that I could critique it in more detail. During that time it appears he has blocked me on Facebook, meaning I cannot see the post any more and cannot post my response. Fortunately, the page is still open. So here I will copy his post and below will be my response.

Philip Cunningham wrote the following:

Darwin's Dilemma - Excellent Cambrian Explosion Movie
http://www.youtube.com/watch?v=WUkLKZjJuU0

Exotic Cambrian Animals and Plants and Ediacaran biota - Animated videos
http://www.lightproductionsvideo.com/Cambrian-Animals.html

Fossil Gallery - images of species from Cambrian period - Main Gallery
The Main Gallery is a comprehensive source of information based on the latest scientific research covering the majority of species so far described from the Burgess Shale. It contains a growing collection of over 500 high resolution images representing 184 species in 135 genera. In addition, dozens of scientifically accurate drawings and breathtaking digital animations will allow you to visualize these organisms in three dimensions and see how they lived.
http://burgess-shale.rom.on.ca/en/fossil-gallery/list-species.php

Anomalocaris - The largest predator of the Cambrian (3D Animation)
http://burgess-shale.rom.on.ca/en/fossil-gallery/intro_1.php

Virtual Sea Odyssey; Observe the creatures who lived in the Burgess Shale community from a "virtual submarine". - video
http://burgess-shale.rom.on.ca/en/sea-odyssey/

"Darwin's Dilemma examines some of the most important fossil discoveries ever made and with them, a mystery deeper than Charles Darwin ever imagined. For the fossil record of the Cambrian Explosion does not reveal the gradual development of life forms as Darwin posited in his work, but a period in which compound eyes, articulated limbs, sophisticated sensory organs and skeletal frames burst into existence seemingly out of nowhere." -
Anika Smith - Discovery Institute

Deepening Darwin's Dilemma - Jonathan Wells - Sept. 2009
Excerpt: "The truth is that (finding) “exceptionally preserved microbes” from the late Precambrian actually deepen Darwin’s dilemma, because they suggest that if there had been ancestors to the Cambrian phyla they would have been preserved."
http://www.discovery.org/a/12471

Deepening Darwin's Dilemma - Jonathan Wells - The Cambrian Explosion - video
http://www.metacafe.com/watch/4154263

Challenging Fossil of a Little Fish
What they had actually proved was that Chinese phosphate is fully capable of preserving whatever animals may have lived there in Precambrian times. Because they found sponges and sponge embryos in abundance, researchers are no longer so confident that Precambrian animals were too soft or too small to be preserved. “I think this is a major mystery in paleontology,” said Chen. “Before the Cambrian, we should see a number of steps: differentiation of cells, differentiation of tissue, of dorsal and ventral, right and left. But we don’t have strong evidence for any of these.” Taiwanese biologist Li was also direct: “No evolution theory can explain these kinds of phenomena.”
http://www.fredheeren.com/boston.htm
Punctuated Equilibrium and Patterns from the Fossil Record - Casey Luskin
Excerpt: “The Cambrian Explosion is by no means the only “explosion” in the fossil record. One evolutionist concedes that for the origin of fishes, “this is one count in the creationists’ charge that can only evoke in unison from paleontologists a plea of nolo contendere [no contest].” Plant biologists have called the origin of plants an “explosion,” saying, “the … radiation of land (plant) biotas is the terrestrial equivalent of the much-debated Cambrian ‘explosion’ of marine faunas.” Vertebrate paleontologists believe there was a mammal explosion because of the few transitional forms between major mammal groups: “There are all sorts of gaps: absence of gradationally intermediate ‘transitional’ forms between species, but also between larger groups — between, say, families of carnivores, or the orders of mammals.” Another study, “Evolutionary Explosions and the Phylogenetic Fuse,” found a bird (as well as a mammal) “Early Tertiary ‘explosion’” because many bird and mammal groups appear in a short time period lacking immediately recognizable ancestral forms. Finally, others have called the origin of our own genus Homo, “a genetic revolution” where “no australopithecine (ape) species is obviously transitional” leading one commentator to call it, like others called the Cambrian Explosion, a “big bang theory” of human evolution."
http://www.ideacenter.org/contentmgr/showdetails.php/id/1232

"In virtually all cases a new taxon appears for the first time in the fossil record with most definitive features already present, and practically no known stem-group forms."
Fossils and Evolution, TS Kemp - Curator of Zoological Collections, Oxford University, Oxford Uni Press, p246, 1999

"Every paleontologist knows that most new species, genera, and families, and that nearly all categories above the level of family appear in the record suddenly and are not led up to by known, gradual, completely continuous transitional sequences.”
George Gaylord Simpson (evolutionist), The Major Features of Evolution, New York, Columbia University Press, 1953 p. 360.

"No wonder paleontologists shied away from evolution for so long. It seems never to happen. Assiduous collecting up cliff faces yields zigzags, minor oscillations, and the very occasional slight accumulation of change over millions of years, at a rate too slow to really account for all the prodigious change that has occurred in evolutionary history. When we do see the introduction of evolutionary novelty, it usually shows up with a bang, and often with no firm evidence that the organisms did not evolve elsewhere! Evolution cannot forever be going on someplace else. Yet that's how the fossil record has struck many a forlorn paleontologist looking to learn something about evolution."
Niles Eldredge , "Reinventing Darwin: The Great Evolutionary Debate," 1996, p.95

"Enthusiastic paleontologists in several countries have claimed pieces of this missing record, but the claims have all been disputed and in any case do not provide real connections. That brings me to the second most surprising feature of the fossil record...the abruptness of some of the major changes in the history of life."
Ager, D. - Author of "The Nature of the Stratigraphical Record"-1981

"The extreme rarity of transitional forms in the fossil record persists as the trade secret of paleontology."
Stephen Jay Gould

"Why, if species have descended from other species by fine gradations, do we not everywhere see innumerable transitional forms? Why is not all nature in confusion, instead of the species being, as we see them, well defined? But, as by this theory innumerable transitional forms must have existed, why do we not find them embedded in countless numbers in the crust of the earth? But in the intermediate region, having intermediate conditions of life, why do we not now find closely-linking intermediate varieties?"
Charles Darwin - Origin Of Species

My response was as follows:

Ah, a favourite topic of mine. If anyone would like a good, accessible look into this topic, I recommend Darwin's Lost World by Martin Brasier.

I watched some of the Cambrian animals videos and rather enjoyed them, but where were the Ediacaran videos? I also enjoyed looking at the Burgess Shale animals, but that makes me wonder, why did you present Middle Cambrian organisms without presenting Early Cambrian beasties as well? You will find that fauna of the Early Cambrian differs from that of the Middle (no trilobites until the Atdabanian for starters). A gallery of Tommotian or Nemakit-Daldynian fauna would be informative. Was this omission deliberate or accidental?

In addition to that, why did none of the links you presented discuss the Ediacaran forms? Most sources would admittedly do a poor job of presenting them, not demonstrating the faunal changes within the group, but they should at least highlight the presence of terminal Ediacaran biomineralisation (Cloudina and Namacalathus).

"Darwin's Dilemma examines some of the most important fossil discoveries ever made and with them, a mystery deeper than Charles Darwin ever imagined. For the fossil record of the Cambrian Explosion does not reveal the gradual development of life forms as Darwin posited in his work, but a period in which compound eyes, articulated limbs, sophisticated sensory organs and skeletal frames burst into existence seemingly out of nowhere."

It certainly is a fascinating puzzle, but overstated in this case. These things coming "out of nowhere" is actually referring to millions of years. Conservative calculations for the evolution of an eye actually puts them as able to evolve so quickly that the fossil record would be expected to show it in a single step. Additionally, taphonomic experiments appear to highlight that the features we might want to observe evolving (usually the more complex and often soft ones, such as the eye) decay first.

"The truth is that (finding) “exceptionally preserved microbes” from the late Precambrian actually deepen Darwin’s dilemma, because they suggest that if there had been ancestors to the Cambrian phyla they would have been preserved."

This claim is rather jejune. Preservation of microbes does not mean everything else will be preserved as well; different processes preserve different organisms and sometimes it is even based on size. Fossilisation is often a biased process, preserving some organisms and not leaving a trace of others, even when they are equally abundant. Additionally, what is there to say that we would even be able to recognise ancestors to Cambrian phyla? We base our classifications on derived characters which the ancestors are unlikely to possess. What we should expect really is confusion and difficulty. Guess what we find.

This might be a good point to mention another overlooked piece of evidence - trace fossils. Trace fossils from the end Proterozoic to the Phanerozoic show a steady increase in complexity, highlighting a steady increase in the complexity of organismal behaviour. Burrows in the Ediacaran are very simple, yet steadily become more complex and diverse in the Cambrian. Some can even be used for stratigraphy, for example, Diplocraterion (a U shaped burrow which shows signs of periodical adjustments in depth) appears in the late Tommotian and can be used to tell if a particular rock is of that age. Before Diplocraterion, simpler burrows such as Skolithos and Arenicolites are found (and persist throughout the fossil record). The majority of end Ediacaran and Early Cambrian trace fossils have unknown causative organisms, yet those organisms were certainly around. They weren't preserved, but we know that they were there because their burrows are preserved.

Watching the Wells video, it is interesting that they seem to provide predictions which Darwin never made. His theories were compatible with a number of potential predictions with regards to how evolution progresses and Darwin even briefly seemed to suggest that it might be a jerky process. Throw in our modern understanding of speciation and that should be expected.

He thankfully did mention Ediacaran forms, but there seems to be some dishonesty here. Half of the issue is that we cannot classify a lot of the organisms we find, they are justifiably termed "problematica". So to turn around and say "there are gaps in the fossil record at the origins of phyla" is rather premature considering we don't know where most fit.

“I think this is a major mystery in paleontology,” said Chen. “Before the Cambrian, we should see a number of steps: differentiation of cells, differentiation of tissue, of dorsal and ventral, right and left. But we don’t have strong evidence for any of these.”

I found this an interesting claim, as differentiation of cells and tissues appears in some Ediacaran forms (Spriggina, Charniodiscus, Kimberella for example), the origin of bilateral symmetry is debatable, though potentially found in Kimberella and Parvancorina for example. What we find are blurred lines, which we should expect.

"Punctuated Equilibrium and Patterns from the Fossil Record - Casey Luskin Excerpt: “The Cambrian Explosion is by no means the only “explosion” in the fossil record. One evolutionist concedes that for the origin of fishes, “this is one count in the creationists’ charge that can only evoke in unison from paleontologists a plea of nolo contendere [no contest].” Plant biologists have called the origin of plants an “explosion,” saying, “the … radiation of land (plant) biotas is the terrestrial equivalent of the much-debated Cambrian ‘explosion’ of marine faunas.” "

Why is this a surprise? Adaptive radiations are to be expected, especially when new niches open up. Many, if not most, of those radiations occurred after mass extinction events, which open up numerous niches. These radiations occurring rapidly should not surprise us. The claims of no gradational intermediates is not correct. What we find at the diversification events is that the fossils found are difficult to classify with ease (the whole Ida fiasco is testament to that) which is exactly what we should expect from evolution.

You quote a few palaeontologists, many as out of date statements, others worth addressing. Take Gould and Eldredge for example, as they can also both be quoted as stating that gradualistic evolution is observable in the fossil record (albeit uncommon due to major change occurring around speciation events in isolated populations) and can both be quoted declaring that there are some superb transitional forms that are widely known (see Hooking Leviathan By Its Past by Gould for example).

Since Darwin, his dilemma has been cleared up in many ways, but it does still remain a puzzle. It is not a puzzle which causes problems for evolution, but simply one which will prove difficult to explain accurately (so many factors are in play, such as environment, biotic interactions, changes in taphonomic processes, genetic changes and so on).

I resisted temptation to make this even longer by throwing in a few references, quotations and links. I was also tempted to discuss a couple of aspects of my dissertation which were applicable, but decided not to. 

I will try to get back to my posts on flood geology, as it appears I have a challenger (who so far has made an unsupported claim and nothing more). 

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