Over at Evolution News and Views, an article by Dr. Cornelius Hunter titled, Irony Alert: Michael Shermer on “When Facts Fail”, accuses evolutionists (and especially Shermer) of intransigence in the face of awkward facts which spoil their case. Shermer recently authored an article in Scientific American, in which he noted that “people seem to double down on their beliefs in the teeth of overwhelming evidence against them” because revising these beliefs threatens their worldview. Dr. Shermer proposed that the best way to persuade people to revise their erroneous beliefs is to convince them that dropping these beliefs will not require them to change their worldview. When people are reassured that their fundamental worldview is not at stake, they can them examine the evidence dispassionately. Dr. Hunter was not impressed: he maintains that evolutionists are leading offenders, when it comes to refusing to revise their beliefs.
Dr. Hunter points to trilobites as his star example of “facts that fail” to square with the alleged “evidence for evolution.” However, a recurring failing of Dr. Hunter’s criticisms is that they reveal a lack of familiarity with the scientific literature – especially the most recent writings on the issues he raises.
Dr. Hunter cites several sources to back up his contention that trilobites are a stumbling block for evolution. Curiously, though, he never even mentions the leading online resource for information about trilobites: the award-winning Website, www.trilobites.info, which is maintained by Dr. Sam Gon III, a biologist (PhD, Animal Behavior; MA, Zoology [Ecology, Behavior and Evolution]) who is greatly intrigued by the expression of ancient biodiversity that trilobites represent. Dr. Gon is also the Senior Scientist for The Nature Conservancy’s Hawai‘i Field Office in Honolulu.
Instead, Dr. Hunter cites Wikipedia, a 43-year-old article on trilobite eyes, and a 37-year-old article by Niles Eldridge on the absence of fossil transitional forms in the evolution of trilobites. If I were trying to mount a case against evolution, I would want better sources than that.
The evolutionary origin of trilobites
Let’s begin with the Wikipedia article on trilobites, cited by Dr. Hunter:
Early trilobites show all the features of the trilobite group as a whole; transitional or ancestral forms showing or combining the features of trilobites with other groups (e.g. early arthropods) do not seem to exist. (Bolding is Dr. Hunter’s.)
The article lists various alleged transitional forms, declaring them “far from compelling,” but argues that it is “still reasonable to assume… that trilobites share a common ancestor with other arthropods.” It continues:
Evidence suggests that significant diversification had already occurred before trilobites were preserved in the fossil record, easily allowing for the “sudden” appearance of diverse trilobite groups with complex derived characteristics (e.g. eyes).[8], [18]
I’ll say more about trilobite eyes in a moment, but first, let’s go back to the original quote. It doesn’t say that there are no fossils of transitional forms; instead, what it says is that there are none “combining the features of trilobites with other groups.” In other words, no mosaics. That’s quite different from saying trilobites have no fossil ancestors.
And now let’s compare what Wikipedia says with Dr. Sam Gon III’s carefully-researched article, Origins of Trilobites. It turns out that a highly plausible sequence of transitional forms leading to trilobites exists in the fossil record:
So where did trilobites come from?
The likely scenario is that trilobites arose from Precambrian bilaterians, arguably arthropods, that gave rise to Cambrian arachnomorphs, among them trilobites. The evidence is neither clear nor unambiguous. The fossil record is spotty, but suggestive, and only some remarkable sites such as Chengjiang, Kaili, and the Burgess Shale reveal the rich diversity of non-calcified arachnomorph arthropods. The fossils of the Precambrian reveal some bilaterian diversity, among them a few species that might be candidates for trilobite ancestors. Perhaps it is the simple, dorsally unsegmented Precambrian fossil, Parvancorina, that offers the most reasonable link to arachnomorphs. Lin et al, 2006 strongly linked Parvancorina to an unambiguously arthropodan Cambrian creature, Skania sundbergi, closely related to Primicaris larvaformis. Similar taxa have been documented in Australia, Chengjiang, Kaili, and the Burgess Shale (see image of Skania fragilis, left). If neither Skania nor the protaspid stage of trilobites were preserved, it would have been difficult, if not impossible, to make the link between Parvancorina and trilobites. As it is, both Parvancorina and Skania/Primicaris can be placed in a relationship that might look something like the sequence below…
There follows a diagram, titled, From Parvancorina to Trilobite in Four Easy Steps. Dr. Gon continues:
The figure above is a series of ontogeny diagrams to demonstrate the sequential steps between Parvancorina and trilobites:
In the ontogeny of Parvancorina (red path on left edge above), ontogeny is simple, and there is little change in the structure of the animal as it grows. The adult animal is a large version of the immature, except with more pairs of legs under a large, undifferentiated dorsal carapace. In a stylized Primicaris (magenta path), there is likewise little change in the animal during ontogeny, but there is incipient dorsal tagmation [segmentation of the back – VJT]; a hint of distinction between the cephalic [head] region and the rest of the body, indicated by a change in the curvature of the lateral margin (and genal spines in Skania), as well as the truncation of lateral (presumed digestive) branches. In Naraoia, (purple pathway) separation of the cephalon from the rest of the body is clear even in early ontogeny (purple arrow), but otherwise the similarity of ontogeny to Primicaris is easily seen. In the Helmetiidae (indigo path), there is a pygidium [tail], and thoracic segments are added to the developing body from the pygidium forward (indigo arrow).Finally, in a typical trilobite (rightmost path), the protaspid stage [an early stage prior to the development of segments – VJT] resembles Parvancorina, the earliest meraspid [segment added] is defined by a single suture between cephalon and pygidium (as in Naraoia), and as growth occurs, segments are added from the pygidium to the thorax, as in helmetiids. What sets trilobites apart are a set of synapomorphies (blue arrow) – such things as calcification of the exoskeleton (from the protaspis onward in advanced trilobites, but only from meraspis forward in Agnostida and Olenellida, as far as is known), dorsal eyes with sutures, specialized hypostomal features, etc.
When examined comparatively, as above, it is fairly easy to see how separation of cephalon from body, and then addition of additional tagmata (segments) during growth are the key developmental character additions that take us from Parvancorina to a trilobite form. Taken in sequence, and with legs added to accentuate their underlying shared arthropod heritage, the links between Parvancorina, Primicaris, Naraoia, Kuamaia (a helmetid), and trilobites seem easier to visualize in the sequence below… (Bolding of phrases is mine – VJT.)
Now, it is quite true that the status of the unsegmented fossil Parvancorina as a trilobite ancestor remains the subject of controversy (but see here for a defense of their place in trilobite evolution). However, a much stronger case can be made for Naraoia, and I would invite skeptical readers to check out Dr. Sam Gon’s Web page on this fossil and make up their own minds. Wikipedia evidently agrees with Dr. Gon, for it declares:
When Harry B. Whittington began dissecting some specimens (Naraoia was among the most populous of the Burgess Shale animals), he discovered that the legs (and gills) of the beasts were very similar, if not identical to those of trilobites, thus the current placement of Naraoia in class Trilobita.
Let me remind readers that if Dr. Hunter wishes to argue that the appearance of trilobites in the fossil record cannot be explained by the modern theory of evolution, then the onus is on him to prove that. In order to undercut Dr. Hunter’s case, all a paleontologist needs to do is to point to a plausible series of fossil ancestors.
Did trilobites evolve?
Dr. Hunter would also have us believe that there are no instances in the fossil record of one species of trilobite evolving into another. To bolster his case, he cites the paleontologist Dr. Niles Eldredge, writing on the difficulties of the standard evolutionary theory:
If this theory were correct, then I should have found evidence of this smooth progression in the vast numbers of Bolivian fossil trilobites I studied. I should have found species gradually changing through time, with smoothly intermediate forms connecting descendant species to their ancestors.
Instead I found most of the various kinds, including some unique and advanced ones, present in the earliest known fossil beds. Species persisted for long periods of time without change. When they were replaced by similar, related (presumably descendant) species, I saw no gradual change in the older species that would have allowed me to predict the anatomical features of its younger relative.
However, Dr. Hunter’s citation from Eldredge is decades old: it dates back to 1980. Dr. Sam Gon’s 2008 online article, Evolutionary Trends in Trilobites, tells quite a different story:
Through the 300 million years that trilobites existed, prior to their extinction in the Permian, there were many opportunities for diversification of form, starting from the presumed primitive morphology exemplified by a species such as Redlichia (left). This typical primitive morphotype had a small pygidium, well developed eye ridges, a simple, lobed glabella, several thoracic segments, and a rather flattened body form. The first trilobites were characterized by this primitive form…
…An analysis of morphological diversity of trilobite forms showed that increasing from the Cambrian, there was a peak in morphological diversity in the Ordovician (which parallels a peak in overall diversity of trilobites families) that decreased only as overall trilobite diversity decreased toward their extinction in the late Permian.
Within this diversification, there were a number of evolutionary trends in morphology that developed in unrelated clades, creating homeomorphy (attainment of similar forms in unrelated groups). These homeomorphic trends, such as effacement, increased spinosity, reduction in body size, streamline shape, and loss of eyes, can not be reliably or consistently used to assess higher systematic relationships. Instead, these features can tell us about selective pressures on trilobites and how similar solutions were derived in parallel by different evolutionary lineages.
And for readers who would like more detail of an actual lineage of trilobites evolving over a period of millions of years, here’s one from Russia that should convince even the most hardened skeptic (see here and here for the family tree):
The trilobite fossil record is among the best of all the animal groups. It is not surprising then that it sometimes reveals sequences of evolutionary transition, recording the adaptation, or descent with modification, to new selective pressures as a matter of survival, or perhaps record failure to adapt, leading to extinction. One great example is the radiation of Baltic asaphid trilobites of family Asaphidae from the region that is now Saint Petersburg, Russia from late in the lower Ordovician and into the middle Ordovician. A hundred years of collecting of these strata has provided tremendous data set for cladistics analysis. The region that has long yielded a tremendous diversity of trilobites is believed to have been an inland sea during the earlier Ordovician that was cut off from the ocean to the west. At some point toward the late Ordovician the inland sea again became connected to the ocean. The resulting flow of sediment (turbidity) clouded the water and settled on the seafloor. Through some 50 foot of limestone encompassing some two million years, some Asaphidae lines of descent developed stalked eyes of ever increasing height, ostensibly to enable them to better spot either prey or predators, or both. The figure shows selected species and lines of descent. Not all lines produced elevated eyes. The figure below depicts the two best known: 1) Asaphus lepidurus to Asaphus expansus, which branches into Asaphus cornutus with moderate stalked eyes, and then to Asaphus kowalewskii, with very high eye stalks that almost seem unnatural. The other branch from Asaphus expanses leads to three species with successively higher eyes, Asaphus kotlukovi, Asaphus punctatus and Asaphus intermedius. (Bolding mine – VJT.)
Another Web page, owned by www.fossilmall.com and titled, About Russian Trilobites, fills in the gaps:
Selective pressures due to salinity and turbidity led to adaptations of Asaphus genus Russian Ordovician Trilobites (see figure below). Asaphus expansus branched into two Asaphidae lines of descent, one ultimately leading to Asaphus kowalewski with high eyestalks, and the other branching into two lines, one leading to Asaphus plautini with its large, sharp genal spines genal, and the other leading to another sequence of ever higher eye stalks in Asaphus kotlukovi, then Asaphus punctatus, followed by Asaphus intermedius and finally Asaphus convincens. These observed evolutionary trends are supported by a century of cladistics research that document about two million years of adaptive radiation within the Asery horizon that is more than 50 feet thick. (Bolding mine – VJT.)
Once again, I would urge readers to have a look at this family tree. You be the judge: does this look like “no gradual change in the older species”? By the way, Dr. Eldredge is a thoroughgoing evolutionist, who happens to be an outspoken proponent of the theory of punctuated equilibrium. He describes his work on trilobites here.
I think we can fairly conclude that: (i) trilobite evolution is an established fact, and that it occurs gradually on at least some occasions; and (ii) while Dr. Niles Eldredge knows an awful lot about trilobites, he never went digging for them in Russia.
Trilobite eyes
Next, Dr. Hunter argues that trilobite eyes pose a special conundrum for evolution, since these animals’ eyes “were perhaps the most complex ever produced by nature.1” The citation for this assertion is a 1974 paper by Lisa J. Shawver, titled, “Trilobite Eyes: An Impressive Feat of Early Evolution” (Science News, Vol. 105, p. 72), but curiously, no quotation from the paper is given. However, it seems that back in 1976, evolution-skeptic Randy L. Wysong, author of The Creation-Evolution Controversy (Inquiry Press, Midland, Michigan), quoted Shawver (p. 345) as claiming that trilobites “possessed the most sophisticated eyes ever produced by nature” – a quote that has been mined dozens of times since. Trouble is, similar claims have also been made for the eyes of the mantis shrimp – only to be roundly debunked a few months later, when more evidence came to light. An online article at the Virtual Fossil Museum cautions that there is a lot we don’t know about even the finest examples of trilobite eyes: “As incredible as the Phacops crystal eyes that appeared much later in the Ordovician were, we cannot know what the trilobites could see with them.”
Eric Warrant, of Lund University in Sweden, sums up the debate over the pros and cons of insect versus vertebrate eyes: “In some ways we’re better, but in many ways, we’re worse,” he says. “There’s no eye that does it all better.” Among vertebrates, birds of prey appear to have the best eyes, while squid and octopus have arguably the best eyes in the invertebrate world.
In any case, it seems that the compound eyes of the Cambrian predator Anomalocaris, the first animal known to have eyes, were superior even to those of trilobites: they were able to sense night and day, and were 30 times stronger than those of trilobites, making them on a par with most modern insects’ eyes. (I should point out, however, that there is some doubt as to whether some recently discovered fossil eyes that were ascribed to Anomalocaris really belonged to this animal, after all.)
In his article, Dr. Hunter also cites a 1993 text by Professor Riccardo Levi-Setti, declaring trilobite eyes to be “an all-time feat of function optimization.” No page reference is given; apparently the quote is taken from page 29 of the second edition of Professor Levi-Setti’s best-selling book, Trilobites (University of Chicago Press, 1993). Once again, I found out via a quick Google search that this quote is frequently copied and pasted by evolution skeptics.
It might interest Dr. Hunter to know that Dr. Sam Gon, in his online article, The Trilobite Eye , actually cites Professor Levi-Setti’s book in his bibliography. That’s very curious, if (as Dr. Hunter implies) Professor Levi-Setti views the evolution of the trilobite eye as a genuine problem for evolution.
In his highly informative article, Dr. Gon points out that there were actually three different types of trilobite eyes: holochroal, schizochroal (pictured above, for the trilobite Phacops rana) and abathochroal. The most complex of the three was the schizochroal eye, found in just a single suborder of trilobites, which appeared in the early Ordovician period, about 36 million years subsequent to the emergence of trilobites in the Cambrian, 521 million years ago. Funny, that. So much for the claim that Nature’s “most sophisticated eye” appeared in the early Cambrian. Dr. Gon succinctly describes what scientists know about trilobite eyes:
Three types of trilobite eyes
There are three recognized kinds of trilobite eyes: holochroal, schizochroal, and abathochroal. The first two are the major types, with the great majority of trilobites bearing holochroal eyes, and the distinctive schizochroal eye a recognized innovation of the Phacopida. Holochroal eyes are characterized by close packing of biconvex lenses beneath a single corneal layer that covers all of the lenses. These lenses are generally hexagonal in outline and range in number from one to more than 15,000 per eye! Schizochroal eyes on the other hand are made up of a few to more than 700 relatively large, thick lenses, each covered by a separate cornea. Each lens is positioned in a conical or cylindrical mounting and is separated from its neighbors by sclera (cuticular exoskeleton material) that extends deeply, providing an anchor for the corneal membrane, which extends downward into the sclera, where it is called intrascleral membrane.The abathochroal eye is seen in only a few Cambrian trilobites and is somehat similar to the schizochroal eye, but differs in some important respects: the sclera is not thick, and the corneal membrane does not extend downward, but ends at the edge of the lens…
An excellent description of the complexity of schizochroal eyes can be found here. At first sight, the complexity of these eyes looks daunting:
In contrast to the holochroal eye, each lens in the schizochroal eye, which are much larger in size (typically 250 to 500µm) but significantly fewer in number (up to 770 in Dalmanites pratteni Roy, sp. nov.), is separated from its neighbours by a pillar of exoskeletal material known as the interlensar sclera. Lenses are typically packed hexagonally, forming vertical dorso-ventral files and diagonal rows, but square packing is evident in a few rare cases. Each lens is covered by its own individual cornea, appearing as an eye in its own right (Figs. 8 and 9).
To complicate matters further, each lens in the schizochroal eye is formed by a number of components, which differ in composition (Lee et al., 2007). The incorporation of magnesium in the lower part of the lens (intralensar bowl) creates what is known as an ‘aplanatic’ surface, as it differs in refractive index from the upper part of the lens (upper lens unit) – such a surface results in the bending (or refraction) of light helping to bring light rays into focus at some point beneath the lens. This type of lens – known as a ‘doublet’ – was independently designed by mathematicians Descartes (1637) and Huygens (1690), both unaware that they had been beaten by nature by a few hundred million years. (Bolding mine – VJT.)
The schizochroal eye found in some trilobites is so remarkable that it has even inspired valuable work in the field of biomimetics, as scientists attempt to develop ever-thinner video cameras. They’ve now developed one that sees like a trilobite.
Remarkable as it may appear, it seems that the developmental process of paedomorphosis can account for the evolution of the complex schizochroal eye from a simpler, ancestral holochroal eye. To quote from Dr. Gon’s article once again:
How did schizochroal eyes evolve?
All early trilobites (Cambrian), had holochroal eyes and it would seem hard to evolve the distinctive phacopid schizochroal eye from this form. The answer is thought to lie in ontogenetic (developmental) processes on an evolutionary time scale. Paedomorphosis is the retention of ancestral juvenile characteristics into adulthood in the descendent. Paedomorphosis can occur three ways: Progenesis (early sexual maturation in an otherwise juvenile body), Neoteny (reduced rate of morphological development), and Post-displacement (delayed growth of certain structures relative to others). The development of schizochroal eyes in phacopid trilobites is a good example of post-displacement paedomorphosis. The eyes of immature holochroal Cambrian trilobites were basically miniature schizochroal eyes. In Phacopida, these were retained, via delayed growth of these immature structures (post-displacement), into the adult form.
Schizochroal eyes were once thought to be unique to trilobites, but scientists now know that these kinds of eyes can also be found in the insect, Xenos peckii.
Finally, scientists have powerful evidence for the evolution of animal vision. It turns out that the same master gene — called Pax6 — controls eye development in virtually every creature with eyes. Although advanced eyes evolved independently in different lineages of animals on several occasions, the most basic eye (a simple light-detector) evolved just once. An article by Ed Yong in National Geographic (“Inside the Eye: Nature’s Most Exquisite Creation,” February 2016) handily summarizes the evidence for the common ancestry of animal vision:
We know this because all eyes are constructed from the same building blocks. Nothing that sees does so without proteins called opsins — the molecular basis of all eyes. Opsins work by embracing a chromophore, a molecule that can absorb the energy of an incoming photon. The energy rapidly snaps the chromophore into a different shape, forcing its opsin partner to likewise contort. This transformation sets off a series of chemical reactions that ends with an electrical signal. Think of the chromophore as a car key and the opsin molecule as the ignition switch. They turn, and the engine of sight whirs to life.
There are thousands of different opsins, but they are all related. A few years ago, Megan Porter, now at the University of Hawaii at Manoa, compared the sequences of almost 900 genes, coding for opsin proteins from across the animal kingdom, and confirmed that they all share a single ancestor. They arose once and then diversified into a massive family tree. Porter draws it as a circle, with branches radiating outward from a single point. It looks like a giant eye. (Bolding mine – VJT.)
And now, a team of scientists led by Dr. Roberto Fueda has even figured out when vision originated: around 700 million years ago. Lucas Brouwers explains their reasoning in an article in Scientific American titled, Animal vision evolved 700 million years ago (November 20, 2012):
Opsin is a member of large family of detector proteins, called the ‘G-protein coupled receptors’ (GPCRs)… Most GPCRs detect the presence of certain molecules… But opsin is different. It doesn’t bind molecules physically. Instead, it senses the presence of a more delicate and ephemeral particle: the photon itself, the particles (and waves) that light is made of…
First of all, Feuda confirmed the existence of three distinct opsin types within bilateria (bilaterians are animals with left-right symmetry)…
The first animal to carry three opsins was not the bilaterian ancestor, but the last common ancestor of Bilateria and Cnidaria (jellyfish, anemones, corals and their kin). Feuda found all cnidarian opsins belong to one of three different groups, each of which correspond to the three basic opsin types in Bilateria…
Feuda’s team leapt to another branch of the family tree, and scoured the genomes of two sponges, Oscarella and Amphimedon, for opsin sequences. No dice. Apparently, opsins only evolved after sponges had diverged from other animals, but before the split between Bilateria and Cnidaria… Fortunately for Feuda, there exists one animal lineage in this sweet spot between sponges on one side and cnidarians/bilaterians on the other. Meet the placozoans.
…[T]he placozoan genome harbours two opsins. But here’s the catch: these opsins cannot detect light.
…[O]ur opsins really had two origins. One is the birth of opsin itself, the other is the mutation that turned opsin into a light sensing protein. The opsin lineage itself arose between 755 and 711 million years ago, from the duplication of a single GPCR. The last common ancestor of Bilateria and Cnidaria lived between 711 and 700 million years ago. This leaves a short window of time (evolutionary speaking) in which opsin acquired the light sensing mutation and split into the three opsin families we still carry today.
And if Dr. Hunter were to ask me why I trust these evolutionary trees, I would simply answer: because they make testable predictions, because they explain a lot, and because they fit the known data.
Readers with a strong background in science can find out more about the evolution of opsins here.
Conclusion
We have seen that there is excellent genetic and biochemical evidence for the evolution of all animals’ eyes from a common ancestor, 700 million years ago. We have also seen that there are plausible fossil precursors for trilobites, and several examples of trilobite evolution in the fossil record. Finally, we saw that the most sophisticated trilobite eye, which is confined to a single lineage, did not appear until 36 million years after the first trilobites emerged, and that it seems to have originated from a simpler trilobite eye via the process of paedomorphisis. Whatever one might think of the case for evolution, I do not think that trilobites constitute any special difficulty for the theory.
Say what now?
I can certainly see why. Do you also avoid phylogenetics altogether?
Off to a good start
TristanM,
Haha! I like it! No room for ‘protein space too large’, ‘no/too many theories’, ‘Nobel Laureate X says’, or ‘No Single Tree’.
Nice!
So you lie by ommission.
Proverbs 12:22: Lying lips are an abomination to the LORD, but those who act faithfully are his delight.
(That shoots down your Pascal’s Wager position, too.)
That atheists and “skeptics” like Shermer are two-faced hypocrites.
Quite the cowardly response, Tristan. Nice job
The alleged theory of evolution fails because it makes untestable claims.
Accusations of lying, Patrick? Unbecoming of a moderator.
I explained, fossils aren’t very informative. Unless we have access to the soft tissue and the details at the molecular level, we can say one thing looks like another, therefore they are phylogenetically related.
Here is a rock. It looks kind of transitional to a human face.
Nonsense. Morphology can provide clues to phylogeny, and in fact was all we had until the last 50 years or so, and we didn’t do so badly. It just isn’t done in the crude manner you claim. I think we’ve previously established that you know nothing about phylogenetic analysis, and care less. So don’t pontificate.
Just curious with a young earth, why is there not an abundance of soft tissue?
I was referring to soft tissue in a living context where you can even take some cells out of the tissue and possibly even grow them.
The issue with pseudo fossils highlights a problem with real fossils having too little detail. But first regarding pseudofossils:
Below is an example of pseudo fossil “tree” or dendrite.
The problem with fossils is that unless we know the molecular details of how a shape is arrived at, we really don’t know how credible a transition is. We know the pseudo fossil below isn’t a tree because we have molecular details, but what about other fossil for which we have no molecular details about the development of the structure. For example, the pentadactyl form is arrived at through different developmental mechanisms. How does on know when it is convergence (a euphemism for common design) or common descent.
We have the infamous case of Nebraska Man
https://en.wikipedia.org/wiki/Nebraska_Man
Which would have been settled quickly if we had actually access to molecular details.
I think Nelson and Wells (who is a developmental biologist) have better arguments than the Trilobite example. Nelson got his PhD under Wimsatt, so Nelson has some first rate stuff.
Wells and Nelson I think deliver a pretty good case agains von Baer’s law, which has relevance to arguing the evolution of trilobites in the total absence of any data on developmental mechanisms and embryology!
http://www.arn.org/docs/nelson/pn_darwinianparadigm061593.htm
Where do trilobites go in the above? No one knows, hence that’s why paleontologists like dealing with fossils, they can avoid details that might otherwise call into question their claims of common descent with modification.
To pile on here, what I find objectionable to “fossil record proves evolution” is that the molecular details. Just because the shells look similar, does that mean they had a common ancestor. What about the Orphan Gene’s involved in making shells in different creatures?
Below is a depiction of orphan genes involved in the formation of shells in oysters (the non-paralogous genes). If we just looked at the shells of various species, we might think, “no problem”, but when we actually look at the orphan genes involved in making the oyster shell, it is different than the shells of any other species. Superficial looks are deceiving. And proof of evolution by paleontology is superficial.
The authors are amazed at how unique the gene list is for the oyster shell. The same could be true for other species.
One might be awestruck at the number of authors involved in the study that generated the diagram below. It goes to show, some paleontologist simply looking at similarity of shapes and making an evolutionary inference is pretty shallow in his analysis by comparison.
http://www.nature.com/nature/journal/v490/n7418/full/nature11413.html
Are you saying fossils support common descent with modification is why you avoid discussing fossils in your teaching?
Is that what paleontologists do, simply look at shapes? What is the creation science methodology for determining inferences?
stcordova,
Should one be surprised that there are genomic differences between divergent taxa?
According to Patrick, his ill will towards creationists is “well deserved.”
LoL! Science is not done by consensus. What evidence supports evolution via blind and mindless processes?
You have a tiny little bit of a point here, but you’re trying to make it big enough to cast doubt on paleontology. Most pseudofossils are easily recognizable and bear only a superficial resemblance to real fossils. The rare exceptions are generally hundreds of millions of years old and are sometimes mistaken for early microorganisms, which have little recognizable structure.
Do you have any idea how small that dendrite is? Probably not, or you wouldn’t imagine it could be mistaken for a tree. No professional would ever mistake it even for a plant.
None of this is true. Credible transitions happen in phylogenetic context, and are frequently seen in small steps. It’s that phylogenetic analysis, the stuff you ignore, that provides evidence. Some phylogenetic analysis uses molecular characters, some of it doesn’t. Nor are “molecular details” necessary to distinguish dendrites from fossils.
It was settled quickly without access to “molecular details”. Your example argues against your claim, as is so often the case with you.
Argument by credentials again. Imagined credentials at that. Let’s see those better arguments.
You are accusing paleontologists of dishonesty, though I suppose you will deny doing so. All that is in your imagination. And in fact there are a fair number of fossils showing many ontogenetic stages, trilobite exuviae among them. Stop pontificating on subjects about which you are completely ignorant.
stcordova,
Sal, the oyster was the only mollusk in the comparison. These are not genes unique to oysters. These are genes for which no homolog could be found in various sequenced non-molluscan genomes. The way you conduct your Gish Gallop makes you find a lot of examples that aren’t what you think they are. First the dendrites, now this, and of course many, many others in the past. You are an embarrassment to creationists. Or should be.
Only to a complete moron. I bet you though that grilled cheese sandwich really had the face of the Virgin Mary on it too, right?
But science becomes consensus among those educated in the topic by the quality and quantity of the positive evidence. That’s why you IDiots don’t even attempt do science.
“Science isn’t done by consensus” has been stupid ever since non-scientist michael crichton came up with it. It tries to confuse the process of science with the status of scientfic knowledge. Basic science textbooks exist to convey the dread Scientific Consensus on a topic. Crichton’s argument would throw them all out, because crichton was a dumb douchebag.
While science is done by research and not be consensus (however that might be done), it is noteworthy that science produces one consensus after another, because there is only one objective reality. Contrast with religion, which has splintered into many thousands of mutually exclusive “truths” because religion doesn’t deal with objective reality, it deals with subjective superstition – and there is no end to these.
Every scientific consensus today was at one time a single hypothesis competing with many other equally possible hypotheses, based on the theory and instrumentation of the time. Gradually, both theory and instruments improved to the point where it became irrational to disagree. Contrast, again with religion, where it is irrational to agree.
adapa:
And what is the positive evidence for evolutionism?
That’s what you want people to believe but given the scientific status of evolutionism that just isn’t so. The only rational thing to do in light of evolutionism is to disagree.
The instruments haven’t helped- they just unlocked a myriad of systems and subsystems unexplainable via blind and mindless processes.
What orphan genes? Point them out. Nowhere in the article you link is orphan genes mentioned.
Even that is actually not true. If you look in the supplementary information, they write that of all the genes in the oyster genome, about 7000 did not have functional annotations, yet of these roughly 7000, 96.2% of them still have detectable homology in Lophotrochozoa. That leaves roughly 250 genes with unknown histories out of a 28.000 gene genome. Not that many, particularly considering as you point out, oysters are the only mollusc in the comparison.
Which basically means we are simply not in a position to claim that any of them, not even a single one, is an orphan. Once other molluscs are sequenced, we can start to give estimates.
That’s fantastically dumb. Rocks don’t reproduce by making copies of themselves with mutations in their genomes (rocks don’t have genomes at all), organisms do. This simple undeniable and basic fact immediately predicts a diverging branching process with accumulating changes, leading to morphological transitions over geological time for biological organisms. Not for minerals.
Comparative morphology for creationists/IDists.
Glen Davidson
The lack of necessary details that get erased by the fossilization process allows common descent to build its case on ignorance rather than knowledge. A theory that relies so heavily on distorted and unclear and uncertain data isn’t very good.
A good example is all the reversals of Nebraska man, lucy, tiktaalic, and last but not least the coelacanth.
Is the “lung” in the coelacanth a primitive lung or a vestigial lung. Who knows?
I seem to recall once we got a hold of living coelacanth, we revised its status to living fossil, and we also revised its status of lung to vestigial. Goes to show how much credence we can put on imaginative paleontological stories that go way beyond the data actually available to us.
How many orphans will mean “evidence that strongly support” evolution? and How many will “falsify” evolution?
Blas,
All the genes had to be orphans at some point in time. How did blind and mindless processes find them? Oh, that’s right, evolution gets to start with the very thing that requires an explanation. And that is why they can’t say if evolution proceeds via blind and mindless processes or by means of intelligent design. They can only put their personal bias on it and say it proceeds via blind and mindless processes- no science involved
Comparative morphology is meaningless in the era of the modern synthesis. Evolution now has to be unpacked at the genetic level and you guys are still stuck in Darwin’s world
This is a strawman version of paleontology. You’re the only one distorting data here. But let’s see your examples:
“Nebraska man” was misidentified, made much of briefly in the press, and quickly fixed. It’s actually a good example of self-correcting paleontology, as well as the dangers of seeing what you want to see, since Osborn was attached to the idea of human ancestors living in North America. You should take heed. Not sure how Lucy or Tiktaalik presents any sort of problem. You will have to elaborate.
“I seem to recall” is the operative clause here. Clearly, Latimeria has vestigial lungs. Makes sense considering that it’s a deep water fish. Since evolution happens, this doesn’t tell us that all coelacanths, not to mention other ancient sarcopterygians, had vestigial lungs. How that contradicts anything from paleontology is unclear to me. Perhaps you can explain. But I doubt it. You still haven’t responded to the tropical mammoth thing, or the pseudofossil thing, or anything else. The Gish Gallop is strong in this one.
John Harshman,
How does evolutionism explain the existence of lungs? What genetic changes produced them?
Blas,
How about you say what the limits should be?
Yeah tell us what the limits are, Blas. And show your work. Try to explain why that would be the limit.
Neither do languages. Neither do solar systems. Nor universes.
And, Blas, why don’t you come up with an explanation for the many more genes that aren’t orphans at all?
I’ll note that “common design” is a crock, as the patterns are those of inheritance, not of intelligent choosing.
Glen Davidson
You first
That is only your opinion and it isn’t science. You need something more than that
GlenDavidson,
A major feature going extinct and then re appearing 200 million years later is evidence for descent?
Didn’t really answer the question, did you?
But gee, I’d like to see an actual argument that similar solutions shouldn’t evolve more than once. Show that they’re the same genetic material (sans some sort of lateral transfer) doing the same thing, and then you’ll have something that would be improbable in the extreme.
I see that you’re avoiding the lack of evidence for creation/ID like usual. Because, well, that evidence simply isn’t appearing, is it? Not that it matters to you…
Glen Davidson
Assuming you conclusion, the details that exist may be sufficient
All knowledge is finite, fossils provide data. Combined with other evidence from other fields the best explanation at this time is common descent. So is your position we should just ignore fossils?
How do you know how heavily distorted it is, by virtue of your never specified theory? Newton seemed to do OK with uncertain data. Better instruments ,better data, better theories.
John Harshman has discussed Nebraska man, could you specify the reversals of the others and how it pointed toward separate descent?
No one absolutely but I would guess that other features of the fossil might provide data, the strata that it was found in might ,you seem to assume all doubt is evidence in favor of your unknown position.
What kind of imaginative paleontological stories do you prefer? Was that a prediction of creationism that the lung should be vestigial? Just trying to get a feel for how useful your theory is.
What’s “distorted and unclear and uncertain” about something like Archaeopteryx. Or Tiktaalik, for that matter?
That they’re great evidence for evolution and against creationism or any sort of design that we could recognize (adaptations of hereditary information, not of more intelligently-chosen information) is a problem for you, and I suspect that’s the main reason you avoid it.
Glen Davidson
How they came to be is very unclear and very uncertain.
Mere evolution isn’t being debated. What is the evidence that evolution by means of blind and mindless processes can produce vision systems?
That doesn’t exist. There is plenty of supporting evidence for ID- living organisms and their systems and subsystems making up at least part of that support.
Did the feature go extinct or did the organism?
That isn’t even what the text you quoted says. Try reading for comprehension rather than scanning for gotchas that you then cut and paste here. You make up the inference that a major feature went extinct and reappeared. The text supposes that it evolved once. Take off the creationist goggles.