The Cambrian Explosion, No Help To I.D.
Even as an I.D. dissenter I agree that the members of each phyla that first “exploded” onto the scene 500 million years ago look very different from one another… today. But viewed way back then at the beginning of the Cambrian “Explosion” it looks more like bilaterian worms radiated into more complex and diverse worms over the tens of millions of years prior to the “explosion,” because in general the earliest Cambrian relatives of the living phyla tend to be a lot more wormlike or sluglike than most modern day representatives of the living phyla. Even many of the living phyla are basically still worms, and the more complex living phyla (e.g. molluscs, chordates) have early–representatives or relatives that are rather more wormlike than the better–known modern representatives with more complex body plans.
Way back in the Cambrian era even the earliest members of the “vertebrate” phylum (of which humans are members!) resembled filter–feeding worms that happened to swim. The earliest vertebrates in the Cambrian didnʼt have jaws, scales, a boney skeleton, or anything else that most readers would associate with the word “fish!” They looked like the first two pics on the right:
And the process of their development from the Cambrian onward, before they had evolved jaws, when they still had rounded sucking mouths, looked like the third and fourth pics down on the right:
In fact, the earliest identifiable representatives of Cambrian “phyla” were preceded by millions to tens of millions of years of small shelly fossils [see fifth pic down on right], i.e., organisms that had already been evolving and diversifying. Also, deposits like the Chenjiang have dozens and dozens of trilobite–like and arthropod–like organisms that preceded the Cambrian "explosion" which fall cladistically outside of these respective clades—these are transitional forms! How can I.D.ists ignore the plain evidence that the Cambrian “explosion” did not come out of nowhere?
It is not much of an evolutionary mystery that the fossil record looks like this, from single–celled organisms up to the little shellies that preceded the Cambrian Explosion:
The Sequence of Fossils in the Geological Record
Before 700 mya, maybe well before: Single–celled eukaryotes (acritarchs)
Earlier Ediacaran: Multicellular animal eukaryotes, but simple, SPONGE–grade organisms
Later Ediacaran: Multicellular animal eukaryotes with more complexity, i.e. cnidarian–grade organisms
Very late Ediacaran: Simple SLUG–grade/WORM–grade organisms (at least their tracks and burrows) – the first ones only making surface tracks and lacking burrowing ability. Making tracks suggests that the organisms have at least a front end and a back end, a mouth, anus, and gut connecting them. These are almost certainly bilaterians.
Very late Ediacaran: The very first biomineralized “skeletons”, e.g. Cloudina, basically a WORM secreting a tube, as well as the first evidence of predatory boring. Cloudina gets no mention at all in Meyerʼs book.
At the beginning of the Cambrian, we start to see more complex burrowing – e.g., vertical burrowing through sediment, clearly indicating WORM–grade organization and an internal fluid skeleton, i.e. a coelom. The burrows gradually increase in complexity over 10 my.
SMALL SHELLY fauna: The shells, which started very small and very simple, gradually diversify and get more complex, radiating especially in the Tommotian. By the end of the Tommotion, some of the “small shellies” can be identified as parts of larger, “classic” Cambrian animals. The Tommotian is an utterly key period for any serious discussion of the Cambrian Explosion. Unfortunately, the word “Tommotian”, or any equivalent terminology does not even appear in the book! The Small Shelly Fauna (SSF) gets just one (one!) mention in the book, buried in endnote 27 of Chapter 4.)
Further Questions For I.D. Regarding the Known Phyla
Maybe an I.D.ist can explain why we need 33–40 phyla when merely 9 of those phyla constitute about 95% of all animal life? The remaining 26–31 phyla have fewer than about 2,000 known members—the rarest with just three members (Cycliophora: odd sacs represented by Symbion pandora), two members (Xenoturbellida: strange flatworm) or one species (Micrognathozoa: tiny jawed animal, and Placozoa, an animal that resembles a multicellular amoeba). Most are simple marine organisms, often referred to as worms or nanoplankton.
Also, how about an I.D.ist explaining why, among multi–cellular organisms, beetles and mites proliferate so much, producing hundreds of thousands of species, while other phyla produce far fewer? The number of species of mites might even reach 1 million according to some estimates, as more beetles and mites continue being discovered all the time. Wow, the Designer or Natureʼs innate design abilities really seem focused on mites.
13 phyla of multi–cellular animals appear during the Cambrian Explosion.
20 phyla of multi–cellular animals appear AFTER the Cambrian. Neither is the number of phyla into which all the worldʼs species can be divided agreed upon among systematicists. Under the most frequently used classification scheme there are 38 animal phyla, but some systematicists claim there are between 35 and 40 phyla. Three new phyla were discovered in the last century, the most recent in 1993.
Meyerʼs Creationist Hero, Louis Agassiz
Meyer idolizes Agassiz, a creationist who opposed even the evolutionary idea of common descent. Here is how Agassiz argued for creationism in his day [SOURCE: Agassiz, Evolution and Permanence of Type, The Atlantic Monthly, 1874, pages 92–101]:
“…the earliest known Vertebrates” [from the fossil record when Agassiz was writing] “…are Selachians (sharks and their allies) and Ganoids (garpikes and the like), the highest of all living fishes, structurally speaking.”
“It shall be answered that these belong to the Silurian and Devonian periods, and that it is believed [by evolutionists] that Vertebrates may have existed before that time. It will also be argued that Myzonts, namely Amphioxus, Myxinoids [Hagfish], and Lamper–eels [Lampreys], have no hard parts and could not have been preserved on that account. I will grant both these points, though the fact is that the Myzonts do possess solid parts, in the jaws, as capable of preservation as any bone, and that these solid parts, if ever found, even singly, would be as significant, for a zoologist, as the whole skeleton.”
In other words Agassiz was mocking evolutionists for not finding fossil evidence of the earliest jawless eel–life vertebrates in the fossil record prior to the Devonian. He was also mocking them for not finding fossil evidence of Amphioxus–like early vertebrates prior to jawless eel–like vertebrates in the fossil record. But both were found, and they were found in the places where the Evolutionists expected them to be found.
Agassiz also wrote loads that argued in favor of the idea that different races of humanity were each created separately and could be classified on the basis of specific climatic zones (just as he viewed the separate creations of animal and plant species), and that the different races of humanity were accordingly endowed with unequal attributes by their Creator.
Agassiz came from a line of ministers, and during his natural science studies he favored Cuvier the creationist over Lamarck the transformationalist/evolutionist. Does Meyer mention that?
In a recent short radio debate with a specialist in the Cambrian who pointed out developments in the “little shellies” pre–Cambrian, Meyerʼs even backed away from his claim that the lack of fossils prior to the Cambrian explosion did much if anything to provide evidence for “I.D.”
Meyer should be embarrassed concerning how closely his charts of the major phyla resemble the charts creationists used in the 1980s when they tried to argue that each phyla was created independently. He should have used more detailed charts such as these.
Meyer also needs to consider that species have to spread widely in order to increase their chances of even being fossilized. Some species are going to be far more successful at reproducing and invading new environments and they are going to spread widely and have a much greater chance of being fossilized. While branches of those species, their “cousins” so to speak, may go extinct far sooner, with little chance of the remains of such extinct cousins being fossilized at all. To suggest an analogy, the fossil record resembles a car park garage buried sometimes slowly, and sometimes by a catastrophe (thatʼs what todayʼs geologists believe about the fossil record, their view is called Actualism, which leaves room for both Uniformitarianism and local Catastrophic burying events). There are cars on each level of the parking garage, but the cars undergoing transitions are on the ramps between levels and havenʼt reached the point where their descendants cover a large part of any one level of the car park garage yet. So when the garage is buried the cars on the ramps are naturally less numerous. (And many of those side ramps simply lead off a cliff, leaving little to no remains, i.e., all those cousin species that go extinct for each species that makes it to a different level of the car park garage and expands its brood there, and increases its chances of leaving fossils behind. If you donʼt know where to look for the ramps, your odds of finding transitional fossils are minimal.
Paleontologists dig up transitional fossils by traveling to exactly those places on earth where the strata is dated to the time period where such transitions most likely existed, and finding an outcropping there that is exposed and that is also known to contain fossils. That is exactly how the discovery of the first mammal–like reptile fossil was made. Some brave paleontolgists traveled way up north to a particular outcropping that was dated to a particular time period between reptiles and mammals and known to contain fossils, and they found the first mammal–like reptile fossils (with double–jaw joints and other transitional features). Some of those intrepid paleontologists also died as a result of the harsh weather they experienced during their digs up there. A more recent case was the discovery of the amphibian–like fish, Tiktaalik. The paleontologist leader of the expedition knew the geologic record and where such transitions would had taken place and obtained funding to visit particular strata from that period that was exposed and known to be fossiliferous. In other words they trekked to the “ramp of the parking garage” and found on that ramp the remains of Tiktaalik, a fish with an amphibian–like skull, eyes on the top, a distinct neck, finger bones, and other amphibian–like characteristics, but in a fish. They also got lucky in that it was near the time when they would have had to retreat because winter was coming and the ground was beginning to refreeze and would have remained frozen most of the year too.
Does Meyer mention how important it is to look in the right places, geologically speaking, for transitional fossils? Does he mention that that is exactly how transitional species have been successfully discovered? Does he mention that the “Pre–Cambrian” is not really a geologic period at all due to the enormous upheavals that took place during that period? Itʼs simply rock that has no name for a period all its own, other than being “pre”Cambrian, like a heavily erased black board that you hope to discover some scribbles on that nature has not yet erased.
Also, paleontologists realized after more fossils of each species were discovered that if there was a “design” to the way organisms continued to change and spread out on the earth, that design was not straightforward. It began to look more like nature was trying everything, experimenting, trial and error–wise, tinkering, and failing a huge amount of the time. The discovery of an increasing number of ancient horse–like species led to them co–existing at different intervals and most dying out like leaves on a bushy tree when autumn comes, not following a straight path that might imply an intended plan of “design.” The fact that most species simply go extinct doesnʼt exactly cry out “intelligent design.” Vast numbers of cousin species simply go extinct, often leaving behind Nothing But A Wide Diversity Of Teeth (enamel is one of the hardest of natural substances). Meyers in his book mentions such things as the Permian extinction, which was the largest known mass extinction event. Was the Designer shaking his etch–i–sketch?
I read that the most complete T. Rex is only about 85%. Most evidence for T. Rex was quite fragmentary until that special fossil was finally found. That same is true of fossils of other species from horses to hominids to cetacea. Often only the teeth have survived and been discovered that bear silent witness to the existence of endless cousin species that once existed but exist no more.
“Itʼs tempting to build this story like a totem pole, with trotting Pakicetus at the base, Ambulocetus laying its humming jaw on top of it, and Rodhocetus, the earliest whale to swim like a whale, sitting above the two. It seems like such a smooth progression toward todayʼs cetaceans that it must be right. But such a version would only be a vertical slice of the story. Life doesnʼt proceed from one point to another — it forks and radiates like the cladograms that represent it. Paleontologists have found many other whale bones in Eocene rocks of Pakistan and India. Mostly They Are Teeth — the rock surrenders A Few skulls as well — but even teeth clearly show that their owners were Not Clones of Pakicetus or the other better–known whales. Ambulocetus kept to brackish deltas and coastal water, but Thewissen has found whale teeth from about the same age in what at the time was the open ocean. Gingerich has found at least three contemporaries of Rodhocetus a few million years younger than Ambulocetus: Takracetus, with a wide, flat head; Gavinocetus, with a slender skull and loose hips; and Dalanistes, a whale with a head as long and narrows as a heronʼs set on a long neck, with hips cemented firmly enough to its spine to walk on land. If this is a confusing picture, it should be. As time passed, certain whale species emerged that were more and more adapted to life in the water, but other species simultaneously branched away in many directions. Walking and swimming whales lived side by side, or in some cases traded homes as the buckling birth of the Himalayas shuffled their habitats. Some were only a minor variation on a theme that would carry through to modern whales, but others — heron–headed Dalamistes, for example — belonged to strange branches unlike anything alive today.”
— Carl Zimmer, At the Waterʼs Edge
Does Meyers really believe that lamenting that Darwinʼs views overshadowed those of Louis Agassiz (Meyerʼs creationist hero), is going to get him or the I.D. movement anywhere? As I said concerning the parking garage analogy, tons of cousin species went extinct, and species that had not succeeded to the point of spreading far and wide have far less chance of being fossilized.
The Impatience of Intelligent Design Advocates
If I.D. is simply the assertion that intelligence created biological structures then any discussion of I.D. will be quite short. More to the point is how did “intelligence” do it? Via what stages and via what particular acts of intervention was each change in biological structures accomplished?
A curious scientist would also want to ask “the Designer” how He came to this or that decision, conclusion, or ask what connections existed inside the divine mind that led to choosing this change instead of that change in particular being made, and what did the Designer do to effect each such and such a change? Did God utilize mutagenic chemicals that already exist inside each cell and move them telekinetically toward the right spots in the DNA chain to effect this or that point mutation? Or did the Designer effect a whole genome duplication event in some cases and whittle things down from there, or what not? Did God bend and focus mutagenic cosmic rays so that they penetrated the germ cells of the organism and effected the right mutations? And if the Designer could make all of those miraculous changes one by one, then why not just pop whole new species into existence instead of all that wrangling with the tiny stuff over eons to make it look like they evolved? Indeed, why not just pop the whole cosmos into existence in a matter of days?
And if the Designer accomplished his purposes via endless tiny mutation events over eons of time did the Designer also have to keep a watchful eye on DNA Heʼd just changed, to ensure no more mutagenic chemicals or cosmic rays touched this or that part of the DNA to reverse such changes? And to ensure the fetus was carried safely to term? Did The Designer also have to monitor each animal born with such new mutations to ensure it was not taken by diseases or predators or natural disasters or crippled, so it would remain alive at least long enough to reach the age of sexual reproduction and pass along such changes?
Curious scientists continue to search for connections in nature, how things are related to one another, not how they are discontinuous from one another as I.D.ists seem to be concluding rather impatiently. Most scientists are not impatient when it comes to continuing to asking questions concerning how things in nature are connected to one another, how they all fit together. Questions like…
How does something in the biological world work?
But letʼs not stop there.
What are all the known analogues in the biological world that resemble how that one thing works?
How flexible is this one thing? What are the most probable natural changes/alterations this one thing or its earliest ancestors might have undergone?
What are some hypothetical natural changes/alterations this one thing or its earliest ancestor might have undergone?
Lastly, based on all our knowledge of 1) to 4), how might they be related in an evolutionary sense?
I.D.ists start at 1) like Behe who regurgitated what we found out from other scientists about how the flagellum works, and continued to harp on how it all fits together. Yes it does. Now it does. But did it always fit together exactly like that over the billions of years in the past when the earth had nothing but single–celled life forms on it? The flagellum most probably arose at a time when bacteria were exchanging DNA actively—and also absorbing any DNA they came across passively—for probably over a billion years. And to trace all possible changes in the DNA of such ancient bacteria over that length of time is impossible at present. Nor do we have fossils from that early period, certainly nothing like the fossils we possess for the bones of ancient vertebrates and how their modes of transportation changed over time, i.e., from fins to limbs among vertebrates.Labels:Cambrian explosion, creationism, Discovery Institute, flagellum, intelligent design, Louis Agassiz, Michael Behe, Stephen C. Meyer
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