Dolphin, or modified modern descendent of the air-breathing, warm-blooded, live-birthing dolphin-like Ichthyosaurs?
– Jean-Baptiste Lamarck –
(Translation by Hugh Elliot 1914)
In the same climate, significantly different situations and exposures at first simply induce changes in the individuals who find themselves confronted with them. But as time passes, the continual difference in the situation of the individuals I’m talking about, who live and reproduce successively in the same circumstances, leads to changes in them which become, in some way, essential to their being, so that after many generations, following one after the other, these individuals, belonging originally to another species, find themselves at last transformed into a new species, distinct from the other.
For example, if the seeds of a grass or of any other plant common to a humid prairie are transported, by some circumstance or other, at first to the slope of a neighbouring hill, where the soil, although at a higher altitude, is still sufficiently damp to allow the plant to continue living, if then, after living there and reproducing many times in that spot, the plant little by little reaches the almost arid soil of the mountain slope and succeeds in subsisting there and perpetuates itself through a sequence of generations, it will then be so changed that botanists who come across it there will create a special species for it.
— Lamarck (1809, 39)
– ICHTHYOSAURS –
The exceptional level of preservation in German specimens has allowed highly accurate reconstructions of early Jurassic ichthyosaurs. This has revealed a striking morphological similarity to modern dolphins. ..
— University of Bristol (2002-2015) ‘Palaeobiology Research Group’ webpage
‘INTRODUCTION TO THE ICHTHYOSAURIA’
Ichthyosaurs were not dinosaurs, but represent a separate group of marine vertebrates. Because ichthyosaurs were so specialized and modified for life in the ocean, we don’t really know which group of vertebrates were their closest relatives. They might have been an offshoot of the diapsids — the great vertebrate group that includes the dinosaurs and birds, the pterosaurs, the lizards and snakes, and many other vertebrates. On the other hand, some have suggested that the ichthyosaurs were descended from a distant relative of the turtles.
— Waggoner (1995, Introduction)
UCMP (University of California Musuem of Palaeontology) Berkeley Education
FOSSIL SAVED FROM MULE TRACK REVOLUTIONIZES UNDERSTANDING OF ANCIENT DOLPHIN-LIKE MARINE REPTILE
Scientists have revealed a new species of ichthyosaur (a dolphin-like marine reptile from the age of dinosaurs) from Iraq, which revolutionizes our understanding of the evolution and extinction of these ancient marine reptiles…..Fischer and his colleagues retraced the evolutionary history of Cretaceous ichthyosaurs. In fact, the team was able to show that numerous ichthyosaur groups that appeared during the Triassic and Jurassic ichthyosaur survived into the Cretaceous. It means that the supposed end of Jurassic extinction event did not ever occur for ichthyosaurs
— University of Southampton (2013)
‘Science Daily’ published May 14th
– NATIONAL GEOGRAPHIC –
‘GIANT SEA REPTILES WERE WARM-BLOODED?’
Prehistoric predators could control their body temperatures, study says.
“These marine reptiles were able to maintain a high body temperature independently of the water temperature where they lived, from tropical to cold-temperate oceanic domains,” said study co-author …
— Choi (2010) ‘National Geographic News’ published June 12th
‘OLDEST FOSSIL OF REPTILE LIVE BIRTH FOUND’
Most air-breathing marine creatures that bear live young, such as whales and dolphins, birth their babies tail-first, so the newborns don’t suffocate during labor. But on land, babies tend to come out headfirst. And the earliest whales, which also evolved from land mammals, birthed their newborns headfirst.
The new fossil confirms that the first ichthyosaur babies came out headfirst, the study reports. The ichthyosaur mother died with three young: one outside the mother, one half-emerged headfirst from her pelvis and one still inside, waiting to be born.
— Oskin (2014) ‘Live Science’ published Feb., 12th
– Jean-Baptiste Lamarck –
…in order to grasp her procedure, her laws and operations, and to gain an idea of what she actually brings into existence. This, in short, is the kind of knowledge which constitutes the true naturalist. Those who approach the subject from this point of view are naturally few; they are interested impartially in all natural productions that they can observe.
…These … devices, commonly used in natural sciences, are purely artificial aids which we have to use in the arrangement and division of the various observed natural productions; to put us in the way of studying, comparing, recognising and citing them. Nature has made nothing of the kind: and instead of deceiving ourselves into confusing our works with hers, we should recognise that classes, orders, families, genera and nomenclatures are weapons of our invention. We could not do without them, but we must use them with discretion and determine them in accordance with settled principles, in order to avoid arbitrary changes which destroy all the advantages they bestow.
— Lamarck (1809, 19-20) Elliot’s 1914 Translation
Uncommon Descent from Ancestral Common Condition
Karl Ernst von Baer
Drawing a number of conclusions from his work on developing embryos, von Baer emphasized that development is epigenetic, proceeding from homogeneous to heterogeneous matter…
Karl Ernst von Baer
von Baer held that the animal kingdom could be separated into four distinct archetypes: the radiata (e.g., starfish and sea urchins), the mollusca (e.g., clams and octopus), the articulata (e.g., insects and crabs), and the vertebrata (e.g., fish and human beings). He denied recapitulation theory—the idea that the embryos of more complex animals passed through morphological stages comparable to those of the adult forms of organisms lower in the hierarchy of life. He maintained that the embryo of an animal exemplified from the beginning of its gestation only the archetype or Urform of that particular organism “The embryo of the vertebrate,” he asserted, “is already at the beginning a vertebrate” (1828-1837, 1: 220).
So a human fetus, he held, would move through stages in which it would take on the form of a generalized vertebrate, a generalized mammal, a generalized primate, and finally a particular human being. The form of the growing fetus moved from the general to the specific. The human embryo, in its early stages, therefore, never assumed the mature form of an invertebrate or of a fish.
Richards (nd. 2)
Von Baer’s concept of principle (his laws) are reflected in recent research involving the study of brain development in vertebrates and its implication for our simplistic linear and continuous view of evolutionary development by A.B. Butler and others The quotes below are taken from ‘Evolution of Vertebrate Brains:
EVOLUTION OF VERTEBRATE BRAINS
….The simplistic … concept of evolution ranks organisms on an ascending scale that is presumed to reflect evolutionary history … While this concept is unfortunately widely and deeply embedded in the public consciousness, it is completely unsupported by the massive amount of data on evolution, not only for the brain but for all characters across the board.
…That brain enlargement and elaboration has occurred four times independently presents a very different reality of how brain evolution has operated than is perceived in the widely held folk-belief…
Butler (2009, 57)
… reptiles did not give rise to mammals any more than mammals gave rise to reptiles. In regard to embryological development, it likewise generally proceeds from the general (common ancestral features) to the specific (specializations of the taxon) … What is clearly established is that all taxa have their own specializations. Each taxon has a mix of primitive features.
Butler (2009, 64)
Basically, as you can see above, this brain study really begins to support a theory proposed over 180 years ago in a pre-molecular/genetic age and strongly supports the concept that species converge on ancestral features (shared ancestral condition) and then, later become specialists and they diverge from a shared (common) ancestral CONDITION, not a literal descent as the independent origins of brain types strongly suggests.
Karl Ernst von Baer
The first law says that the general features of a large group of animals appear earlier in the embryo than the special features. The second law says that less general characters are developed from the most general, and so forth, until finally the most specialized appear. The third law is that instead of passing through the stages of other animals, each embryo of a given species departs more and more from them. Finally, the fourth law concludes from the previous three that the embryo of a higher animal is never like the adult of a lower animal, but only like its embryo.
The quote above also highlights the independent evolution of brains and essentially a non-linear model which also dovetails very well with D’Arcy Thompson’s discontinuous scales of complexity model from many different worm-like origins (See first five chapters of forthcoming book: Evolution by Other Means…?). This begins to open up an alternative, less literal form of evolutionary development of the actual species and of course begins to support older principles of development and evolution by epigenetic modification according developmental conditions during speciation of shape and form according to natural scales of complexity (ibid).
What made Von Baer’s model distinct from the Darwinian perspective was the means by which these commonly associated ancestral organisms had changed so dramatically through time. The Neo-Darwinian perspective sees it as a fishy-pod to walking amphibian/reptile to mammal progression as highlighted above in Butler’s study, whereas, Von Baer seen the complex patterning of embryological development as a scaled down version (not a literal recapitulation) of species formation itself (ibid).
Von Baer extrapolated the patterns of development to infer that evolution had preceded from the unorganised cellular world, to the undefined generic (generalist) forms and from fundamental forms, diversified into a myriad of species (specialists) from these commonly shared templates, to put his theory in more modern language.
A LITTLE PIECE OF LESSER KNOWN HISTORY REGARDING VON BAER’S MODEL
Darwin had fundamentally missed the point of Von Baer’s model of embryology and how it could explain evolution on another scale. He was rather enthusiastic to employ embryological evidence to support the theory of common descent from a single origin in a branching pattern according to gradual natural selection, as becomes apparent when you read the different editions of Origin. And this is supported in the quote below: taken from Individual Development and Evolution: The Genesis of Novel Behaviour, by Gilbert Gottlieb (2001):
Charles Darwin on the Evolution of Species and the Role of Embryological Development
Jane Oppenheimer (1967, 338) “Darwin got his wrongheaded idea about the testimony of embryology from the naturalist Louis Agassiz, and he could not be dissuaded from it even by the arguments of Thomas Huxley, one of his most ardent and dedicated supporters” as quoted in page 25 individual development… “As Oppenheimer points out, Darwin did not have any of von Baer’s works in his library at the time of his death in 1882. We also know from various sources that Darwin did not read German easily or with great understanding, thus von Baer’s writings would have been quite a chore in the original. But German was Ernst Haeckel’s mother tongue and still he managed to stand von Baer on his head,…”
Gottlieb (2001, 25)
Thomas Henry Huxley (Darwin’s so-called Bull Dog and greatest defender of the theory of selection) as detailed in Barnes’ 2014 in Scientific Memoirs verbatim was fully acquainted with Von Baer’s embryological laws in the original German as reiterated below:
Karl Ernst von Baer’s Laws of Embryology
… the more general characters of a large group appear earlier in the embryo than the more special characters. From the most general forms the less general are developed, and so on, until finally the most special arises. Every embryo of a given animal form, instead of passing through the other forms, rather becomes separated from them. Fundamentally, therefore, the embryo of a higher form never resembles any other form, but only its embryo.
Anyway, the Darwinists went with the Haeckel model and Von Baer’s theory fell into obscurity. So it didn’t matter that Haeckel was a little over artistic in his representations or literal in his concept of linear descent, for by this time, the Darwinist version took hold and their linear descent is the one we adhere to dogmatically to this day. They also dismissed everything epigenetic and therefore Darwin’s own views on the matter as you will see if you read anything about epigenetics on this site or in any of the books written by this present author on the subject. And another dimension to all of this is the fact that: “Following the publication of Darwin’s Origin of Species, in 1859, biologists were eager to apply the theory of evolution to the paleontological record.” as noted by Aulie (1975, 21) in The American Biology Teacher, 1975, National Association of Biology Teachers [Link].
See another article on this site relating to the whole misapplied terminology and how we and other mammals may not be as related to reptiles as you think (Link)
Haeckel’s form of common descent became the Darwinian doctrine, helped by a whole plethora of fossil hunters who had a particular passion for giant lizards (dinosaurs) and used the Weismannian (pre-formationist belief that everything required to make a functioning organism is pre-written in the genes) view to guide their interpretation.
To-day we are categorically told without a doubt that we shared a common ancestor between fish and a fishy-pod species that gave rise to amphibians, the reptiles and then, somehow mammals emerge from these reptilian ancestors and so on and so forth. Yet these proposed ancestors remain entirely illusive in the fossil record as it happens when you drill down to it.
A More Modern Evolutionary Developmental Model and Revisiting Von Baer’s Alternative
Von Baer’s alternative model of evolutionary development akin to D’Arcy Thompson’s view, are however, beginning to find support, but I doubt with all the wrongheadedness and the anti-Von Baerean views regarding the theory, that even our modern embryologists/evolutionary developmental biologists, as they are referred to in modern times, are grasping the full implications of Von Baer’s laws. For instance, the following excerpt explains how many of Von Baer’s concepts are beginning to be supported by more recent studies as seen below:
Von Baer’s law for the ages: lost and found principles of developmental evolution
With advances in multiple fields, including paleontology, cladistics, phylogenetics, genomics, and cell and developmental biology, it is now possible to examine carefully the significance of von Baer’s law and its predictions…185 years after von Baer’s law was first formulated, its main concepts after proper refurbishing remain surprisingly relevant in revealing the fundamentals of the evolution–development connection, and suggest that their explanation should become the focus of renewed research.
Abzhanov (2013 Summary)
Von Baer’s laws are coming into clearer focus in the light of our more modern understanding of embryological development and how it may relate to species development. This is perhaps best illustrated via what has come to be described as the hourglass model. The developmental hourglass model is summarised in the excerpt below. (note embryogenesis means the origin of the embryo as a species and phylotypic means the phylo type where phylo refers to the shape and form of an organism):
The developmental hourglass model: a predictor of the basic body plan?
The hourglass model of embryonic evolution predicts an hourglass-like divergence during animal embryogenesis – with embryos being more divergent at the earliest and latest stages but conserved during a mid-embryonic (phylotypic) period that serves as a source of the basic body plan for animals within a phylum. Morphological observations have suggested hourglass-like divergence in various vertebrate and invertebrate groups, and recent molecular data support this model. However, further investigation is required to determine whether the phylotypic period represents a basic body plan for each animal phylum, and whether this principle might apply at higher taxonomic levels.
Naoki and Shigeru (2014, Abstract)
Part of diagram sourced from: Naoki, I., and Shigeru, K., 2014, The developmental hourglass model: a predictor of the basic body plan? Development, Vol. 141, , Fig. 2, p. 4651 (adapted from Wang et. al. 2013) http://dev.biologists.org/content/develop/141/24/4649.full.pdf
Below is another excerpt relating to the hourglass model and directly links recent molecular investigations to the pattern predicted specifically in Von Baer’s third law that corresponds with the latter phase of the embryological developmental hourglass model.
In search of the vertebrate phylotypic stage: A molecular examination of the developmental hourglass model and von Baer’s third law
In 1828, Karl von Baer proposed a set of four evolutionary “laws” pertaining to embryological development. According to von Baer’s third law, young embryos from different species are relatively undifferentiated and resemble one another but as development proceeds, distinguishing features of the species begin to appear and embryos of different species progressively diverge from one another.
..According to the hourglass model, ontogeny is characterized by a starting point at which different taxa differ markedly from one another, followed by a stage of reduced intertaxonomic variability (the phylotypic stage), and ending in a von-Baer-like progressive divergence among the taxa. …The molecular evidence for the later parts of the hourglass model, i.e., for von Baer’s third law, was stronger than that for the earlier parts.
Hazkani-Covo, et al (2005 Abstract)
The hourglass model is idealised to show the type of convergence (on a shared ancestral condition, I would like to stress, rather than a literal ancestral common ancestral form) and this is where the following excerpt becomes interesting.
There is no highly conserved embryonic stage in the vertebrates: implications for current theories of evolution and development
Embryos of different species of vertebrate share a common organisation and often look similar. Adult differences among species become more apparent through divergence at later stages…Our survey seriously undermines the credibility of Haeckel’s drawings, which depict not a conserved stage for vertebrates, but a stylised amniote embryo. In fact, the taxonomic level of greatest resemblance among vertebrate embryos is below the subphylum.
Richardson et al (1997, Abstract)
This bottleneck of the hourglass does not therefore correspond to the ‘conserved stage’ employed by the literal and linear model of common genetic descent, but to a stylised amniotic embryo stage, which is important as this describes not only a more primitive and less defined stage in the amniotic organisms (these include all vertebrates that are not fish or amphibian types), but it implies a much earlier stage in evolutionary development akin to when Butler’s study established a fundamental ancestrally shared generalist shared condition amongst the vertebrate groups .
This corresponds much more closely with Von Baer’s actual laws of going from the generic generalist forms (archetypes) and diverging into increasingly independent and more specialised forms that we might call an adult species, than I believe even the scientists re-examining his model realise.
This model in turn, supports D’Arcy Thompson’s view of the same (different primitive generalist form becoming increasingly diversified and ultimately becoming specialised species). And of course reflects the study carried out by Butler on the evolution of vertebrate brains where the results suggest independent evolution of the brains within the broader vertebrate groups and descent from a commonly shared ancestral condition rather than the simplistic linear model of fish to amphibian, to reptile and mammal etc we currently employ today, even if we say it was from a common ancestor that then split.
Therefore, I have retained the principle of the hourglass model as it corresponds to Von Baer’s Third Law and the latter phase in particular, with the narrower waist (bottleneck) showing convergences prior to divergence. The earlier phase of the hourglass may represent diversity amongst types, but this would not necessarily show in a molecular (gene) study, but we might assume that organisms were diverse and perhaps fundamentally distinct with independent origins as D’Arcy Thompson indicated, as the evidence seems to support. This model when applied at every scale of species development, would therefore imply that each major group emerged from fundamental archetype forms which were undifferentiated generic forms and later developed along these established trajectories their more specific and specialised forms. See preview chapters of forthcoming book for more detail on this nested scales of complexity model (the Matryoshka principle akin to nested Russian dolls). Conceptually, it is a bit like nested hourglasses, within ever-increasingly larger houglasses.
Essentially, the hourglass model, if applied in accordance with Von Baer’s actual laws and principles, gives us a fairly major piece of the evolutionary puzzle where, if Nature does operate on increasingly sophisticated scales of complexity using the same fundamental method of self-similar patterns of growth and form as outlined in the preview chapters, then Von Baer’s developmental model for vertebrates can be easily scaled up to an evolutionary level of speciation and when restated in the light of our most up-to-date understanding of epigenetics, this becomes a very dynamic model indeed and has the potential to unlock the otherwise unknown course of the evolutionary past.
The model followed for assessing or reassessing the fossil record, is as outlined above. Now we will look at some more examples below with this generalist primitive to specialised species – scaled levels of complexity upon the same fundamental templates/themes of life model in mind.
Spot the Difference: The Trilobite & Modern Horse-shoe Crabs???
Below are a few excerpts on the similarities between trilobites and horseshoe ‘crabs’. The latter form isn’t technically a crab, but unlike the former: is believed to be a living fossil. I’m proposing that trilobites are also ‘living fossils’ as it can be argued that horseshoe crabs are simply the epigenetically modified versions (modernised model) of the common ancestral body-form of a primitive trilobite:
Trilobites were ancient arthropods. They appeared in the Cambrian era, 540-million years ago. The nearest thing to a trilobite today is the horseshoe crab with a very similar exoskeleton…
(By the way, the hardy cockroach, still with us today, once coexisted with trilobites)
Trilobites, horseshoe crabs and sea scorpions have similar spine rows along the inner margin of their legs. The lamellae on the outer leg branch of trilobites are similar (and thought to have the same evolutionary origin) as the filaments of the book gills of horseshoe crabs …
The eyes of trilobites penetrate the dorsal surface of the head shield as in horseshoe crabs. Nonetheless, trilobites are not the direct ancestors of horseshoe crabs … All trilobites share certain unique features (like the calcite mineralogy of the exoskeleton and calcified eye) to indicate that they are a separate branch of Arthropoda.
It could be argued that the earlier trilobites (who turned up in the Cambrian as soft-bodied and more developed forms) got their exoskeleton armour and special calcite (crystal) composite eyes long before the emergence (less than a million years later) of a much more sophisticated and specialist model in the form of a ‘living fossil’ horseshoe crab?
A trilobite (left) and horseshoe crab (right), which on the basis of their similar appearance were traditionally considered related.
Returning to the seeming distinction between horseshoe crabs and the trilobites – based upon the calcite material of their exoskeleton and eyes noted in the previous study, and of course the remodelling of the fundamental body plan, recall the article linked to the formation of skeleton structures (exoskeleton and the formation of the first vertebrates – FISH), with the changing chemistry of water (biomineral – shell & skeleton building influx) leading up to the Cambrian explosion and possibly, along with rise in oxygen levels, being the cause of the vast diversity of complex life. Just to remind you, here is an excerpt below:
The oceans teemed with life 600 million years ago, but the simple, soft-bodied creatures would have been hardly recognizable as the ancestors of nearly all animals on Earth today.,,
Then something happened. Over several tens of millions of years — a relative blink of an eye in geologic terms — a burst of evolution led to a flurry of diversification and increasing complexity, including the expansion of multicellular organisms and the appearance of the first shells and skeletons…
The amazing lens and ingenuity of trilobite eyes and their experimental characters as trilobites developed as a species, originated with the calcium dump into the shallow primordial waters. Their soft-bodied forms that can trace their ancestral CONDITION, to embryonic forms in the Pre-Cambrian period perhaps – as proposed in a recent article on this site
Below are more related and pertinent excepts:
The many lenses of its eyes were tiny calcite crystals. Fortey talks about the evolution of sight in general, and how trilobites evolved this wholly unique form of sight. He quotes Shakespeare:
…Of his bones are coral made:
Those are pearl that were his eyes:
Well, calcite is exactly the material of pearl, but trilobites used its perfectly clear crystalline form to see.
The trilobites’ calcite eyes
“Trilobites could see their immediate environment with amazingly sophisticated optical devices in the form of large composite eyes, the first use of optics coupled with sensory perception in nature.” – Riccardo Levi-Setti
Our fossilized arthropods show some peculiar characteristics and one of the most astounding of them can be found in the construction and capabilities of their eyes. Even in the early stages of their development, being one of the first classes of marine invertebrates that we know of, they had already developed a very advanced visual system. Most trilobites owned a sort of multi-facetted composite eyes, situated at either side of the glabella – the emphasis is placed on the wording “sort of” as they are not entirely identical to the kind of eyes that we see in recent insects and the like. In at least one of the nine orders we find trilobites showing a primary blindness, i.e. they never developed eyes in their evolutionary progress in the first place, among them the representatives of the suborder Agnostina within the order of the Agnostida. Furthermore, numerous species show a secondary blindness, i.e. a “devolution” of eyes developed at earlier stages of their evolution, in some cases leading to the complete disappearance of the visual system they previously owned. The latter can be attributed to the adaption to changing environments or specific feeding habits. Devolution can be found even in trilobite orders that are well known for their highly developed eyes like the Phacopida…
The following images once more portray the superficial, clearly visible differences between the holochroal and schizochroal trilobite eye.
left: holochroal eye from CLARKSON, 1975, right: schizochroal eye from LEVI-SETTI, 1993
Note: How trilobites managed to develop such highly complex eyes has not been entirely explained. I think it is beyond dispute that they built their lenses from the same amorphous calcium carbonate that is found in abundance in the world’s oceans and which they used to build and harden their entire exoskeleton in the first place. The exact method of constructing and transforming this material into transparent individual lenses with a predefined shape has not been described to a satisfactory level. Hints may have been given by a recent study into some of today’s sea urchins featuring spines built from single calcite crystals. These sea urchins enclose amorphous calcium carbonate in an envelope of living cells and shape it into its desired form prior to crystallization. How exactly they are able to do this is yet unclear, but the solution to this problem could have a significant effect on how we can explain the secrets of the trilobite eye.
For an entire discussion on crystaline origins of proteins, the genetic code etc, see chapter three of forthcoming book ‘Evolution: By other means…?‘ awaiting final edits.
To understand the epigenetic mechanism for loss of eyes according to environmental factors, which might explain the de-evolution aspect of trilobite eyes discussed above, see e-book or paperback version summary in the following link http://www.amazon.com/Lamarck-And-Tale-Blind-Cave-Fish/dp/178280465XI
Furthermore, epigenetic modification via environmental conditions can also help to explain how Nature managed this feat of engineering of trilobite eyes (in the early types that did develop them) and explicable via the conversion of available resources during evolutionary development which I have written about regularly on these blogs and elsewhere in books. The result being: perfectly adapted species according to their needs and evolutionary experience and inherent genetic/epigenetic complexity. In other words, epigenetic mechanisms express, turn on or off, and general regulate existing genes. “Epigenetic mechanisms are the competent users of the genetic tool-kit” as the book description for Nelson Cabej’s epigenetic evolutionary publication, ‘Building the Most Complex Structure on Earth: An Epigenetic Narrative of Development and Evolution of Animals’ states.
The summary of Cabej’s book describes the epigenetic role in this genetic toolkit as follows:
Building the most complex structures on Earth…
This is a novel theory that describes the epigenetic mechanisms of the development and evolution of animals and explains the colossal evolution and diversification of animals from a new post-genetic perspective. Modern biology has demonstrated the existence of a common genetic toolkit in the animal kingdom, but neither the number of genes nor the evolution of new genes is responsible for the development and evolution of animals. The failure to understand how the same genetic toolkit is used to produce millions of widely different animal forms remains a perplexing conundrum in modern biology. The novel theory shows that the development and evolution of the animal kingdom are functions of epigenetic mechanisms, which are the competent users of the genetic toolkit.
Cabej (2013, Synopsis of book)
See also recent article on epigenetic evolution for more info and links:
Now returning to the proposed remodelling via epigenetic means of our horseshoe crab, (which is not a crab), the creature which has remained virtually unchanged for over 400 million years… and therefore often referred to as a ‘living fossil’. I wonder what some people would think of this rather radical suggestion that the trilobites did not go extinct, but are actually represented by the ‘living remodelled descendants from an ancestral condition’ (or body plan shared by many arthropods) – the horseshoe crab!?
- For the counter argument, to even horseshoe crabs having become extinct and the so-called living fossils aren’t really living fossils, see the article below which takes a Darwinian stance for explaining evolution at Jerry Coyne’s website. It is titled: Horseshoe crabs aren’t Living Fossils
Horseshoe crabs are famous for having changed little in morphology since they first show up in the fossil record over 400 million years ago (!): they are thus called “living fossils”…Well, living species are remarkably similar in general external features to their long-dead (and extinct) relatives, but there are distinct differences, and of course we know nothing about the difference in their internal features, nor in the structure of the DNA of ancient species … Nevertheless, there is surprising “stasis” of morphology over a very long period of time, and we’re not sure why that is.
Of course you will make up your own mind (hopefully after you have fully acquainted yourself with the revolution and evolutionary implications of epigenetics) as to whether, trilobites ever really went extinct, or just converged on a more efficient and modified body-plan; a highly adapted and matured species of arthropod and came to dominate their niche as modernised versions as seen in the living fossil or horseshoe ‘crab’; Or, whether you want to knit-pick the miniscule variants on the same fundamental theme and call it a distinct species, proclaiming that the superficial difference between a horseshoe (crab) in its slightly modernised form, is proof-positive that its ancestors went instinct as Darwinism tells us as it wasn’t the survivor in life’s great game of Russian Roulette. I wonder what Gerry would think of the concept that trilobites never went extinct either and instead modernised their form and converged on the more streamlined version of a real living fossil – what we call today: a horseshoe crab???
Moreover, there are lots of example for the status of ‘living-fossil’ if we apply the scaling complexity principle (going from the generalist to the specialist) and understand evolution by epigenetic modification. These species (modified descendents of the their former selves?) raise the tantilising prospect of bringing a whole plethora of presumed extinct species back from the dead! But perhaps it is a good thing that most of them have become shrunken over the millennia, or we might be looking at something along the lines of the following depiction!
Starship Troopers (1997)
Just when you thought it was safe to leave the water
Info graphic taken from article by Richard Macey
December 1, 2005 http://www.smh.com.au/news/science/just-when-you-thought-it-was-safe-to-leave-the-water/2005/12/01/1133311132842.html
And there’s more…
Idea & actual photo comparison courtesy of:Comparison of T. rex and emu feet (i.imgur.com) submitted by Smoke_Me_When_i_Die
And if you thought like I did, (until I read up on epigenetic modification & reactivation of ancestral programs), that birds don’t have teeth, so how did big dinos become little dinos & lose their ferocious teeth, read the article links below and it will all begin to make more sense.
As rare as hen’s teeth? Not any more, say scientists
Yes, the way we depict Neanderthals has changed!
The story goes, or at least how I was told when I was an archaeology undergrad, But now, .. Click on link for article on our relationship to Neanderthals
Nearly the final spot the difference
Above is a typical timeline given for all of evolution. Compare this with the alternative timeline and its course of events below. This was developed from the research over the last few years into scientific alternatives to Darwinism by the author of this blog.
A Spooky Spot the difference
Spot the difference with a difference…..
It could be just a matter of Scale….Something Universal is going on
See articles on scaling laws on this site and don’t forget to share…Pleaseeeeeeeeeeeeee
P.S. The evolutionary model based upon the best scientific minds of the past 200 years is also seemingly fractal (self-similar patterns at every scale, where the smallest parts are reflected in the whole and the whole reflects even the smallest scale).
Synopsis of fothcoming book on going beyond Darwinism
and in the meantime, something facinating to watch & think about below: