Wednesday, October 25, 2006

Ancient fish [Gogonasus andrewsae] was advanced for its age

Ancient fish was advanced for its age, ABC, October 19, 2006, Anna Salleh ... Graphic: Gogonasus andrewsae, National Geographic.

Fish developed features characteristic of land animals much earlier than once thought, researchers say.Also at: Independent Online, Livescience, National Geographic, The Age, The Australian.

Dr John Long of Museum Victoria and his colleagues base their conclusions on an uncrushed 380 million-year-old fish fossil found in Western Australia. My home State! At ~380 mya, this is ~20 myr earlier than tetrapods Ichthyostega and Acanthostega, both ~360 mya, ~10 myr earlier than Eusthenopteron, and ~5 myr earlier than Tiktaalik (see time chart, Wikipedia):

The problem for `blind watchmaker' evolution is that "the invasion of land required modification in almost every system in the vertebrate body" and therefore it required extensive preparation in advance while the ancestral line of all land animals was living underwater, i.e. "the tetrapods evolved [sic] their legs underwater and only then, for reasons unknown, began to pull themselves onto land" (my emphasis):

"The movement from water to land is perhaps the most dramatic event in animal evolution, because it involves the invasion of a habitat that in many respects is more hazardous for life. ... the invasion of land required modification in almost every system in the vertebrate body ... Although fish fins at first appear very different from the jointed limbs of tetrapods, an examination of the bony elements of the paired tins of the lobe-finned fishes shows that they broadly resemble the equivalent limbs of amphibians. In Eusthenopteron, a Devonian lobe-fin, we can recognize an upper arm bone (humerus) and two forearm bones (radius and ulna) as well as other elements that we can homologize with the wrist bones of tetrapods ... Eusthenopteron could walk more accurately flop-along the bottom mud of pools with its fins, since backward and forward movement of the fins was limited to about 20-25 degrees. Acanthostega, one of the earliest known Devonian tetrapods, had well-formed tetrapod legs with clearly formed digits on both fore- and hindlimbs, but the limbs were too weakly constructed to enable the animal to hoist its body off the surface for proper walking on land. Ichthyostega, however, with its fully developed shoulder girdle, bulky limb bones, well-developed muscles, and other adaptations for terrestrial life, must have been able to pull itself onto land, although it probably did not walk very well. Thus, the tetrapods evolved their legs underwater and only then, for reasons unknown, began to pull themselves onto land." (Hickman, C.P., Jr., Roberts L.S. & Larson, A., "Animal Diversity," [1995], McGraw-Hill: Boston MA, Second Edition, 2000, p.311).

This has the appearance of a far-sighted plan by an Intelligent Designer, rather than the meanderings of a "blind, unconscious, automatic process which ... has no purpose in mind. ...has no mind and no mind's eye. ... does not plan for the future. ...has no vision, no foresight, no sight at all... the blind watchmaker":

"Natural selection, the blind, unconscious, automatic process which Darwin discovered, and which we now know is the explanation for the existence and apparently purposeful form of all life, has no purpose in mind. It has no mind and no mind's eye. It does not plan for the future. It has no vision, no foresight, no sight at all. If it can be said to play the role of watchmaker in nature, it is the blind watchmaker." (Dawkins, R., "The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe Without Design," W.W. Norton & Co: New York NY, 1986, p.5)

and Dawkins is clearly puzzled by the question, "Why did fish first develop the changes that permitted the move out of water onto the land?" including "Lungs ... And fins that you could walk on." And his "It wasn't that they were trying to initiate the next big chapter in evolution!" shows that even he sees that it looks like a far-sighted plan:

"The tetrapods probably evolved from an otherwise extinct group of lobefins called the osteolepiforms. Among osteolepiforms are Eusthenopteron and Panderichthys, both dating from the late Devonian, about the time when the first tetrapods were starting to emerge onto the land. Why did fish first develop the changes that permitted the move out of water onto the land? Lungs, for example? And fins that you could walk on rather than, or as well as, swim with? It wasn't that they were trying to initiate the next big chapter in evolution!" (Dawkins, R., "The Ancestor's Tale: A Pilgrimage to the Dawn of Evolution," Houghton Mifflin Co: Boston MA, 2004, p.298).

Leading paleontologist Robert L. Carroll is also puzzled because these "Changes in the structure of the fins of fish and the limbs of tetrapods are ...among the most difficult evolutionary phenomena to explain" because "Darwinian selection theory can account for the modification of particular structures so that they are better suited for a given environment, but it is much more difficult to understand how the limbs of early tetrapods could have evolved from the fins of a fish ... since these changes involve radical shifts in function between completely different selective regimes":

"Changes in the structure of the fins of fish and the limbs of tetrapods are among the most striking aspects of vertebrate evolution. They directly reflect changes in habitat and ways of life both within and between each major group. They are also among the most difficult evolutionary phenomena to explain. Darwinian selection theory can account for the modification of particular structures so that they are better suited for a given environment, but it is much more difficult to understand how the limbs of early tetrapods could have evolved from the fins of a fish or how the wings of birds could have evolved from the forelimbs of dinosaurs, since these changes involve radical shifts in function between completely different selective regimes. Paradoxically, an equally serious problem is to explain the stability of limb structure within individual groups or lineages, which may retain an extremely stereotyped pattern for hundreds of millions of years." (Carroll, R.L., "Patterns and Processes of Vertebrate Evolution," Cambridge University Press: Cambridge UK, 1997, pp.227-228).

"The specimen is the most perfect complete three-dimensional fish of its kind ever discovered in the whole world," says Long, who reports the team's findings online today in the journal Nature. "It looks like it died yesterday. You can still open and close the mouth." Dr Long says the preserved remains of a Gogonasus fish from the Devonian period were found last year in the remote Kimberley area at the Gogo fossil site, once an 'ancient barrier reef' teeming with fish.

Graphic: Windjana Gorge, where the Fitzroy River cuts the Napier Range, an ancient Devonian coral barrier reef that these fossils were found in (I lived `near' here at Derby from 1983-1986 and I know this area well).

He says previous analyses based on limited material suggested Gogonasus had relatively primitive features. But when his team used a CT scanner at the Australian National University to analyse this new fossil, it found the fish had a number of features common to land animals. "It's hiding a lot of deceptively advanced features that were not recognised before until we had such a perfect specimen," Dr Long said. Again, these "deceptively advanced features" were being prepared about ~20 million years in advance of them being needed!

For example, Dr Long says Gogonasus had hole in its skull similar to that found in the first land animals. He says this hole eventually became the Eustachian tube in higher vertebrates. Dr Long's team's analysis also revealed the fish's pectoral fin had the same pattern of bones as the forelimbs or arms of land animals, called tetrapods. "It's definitely a fish. It's got gills, it swims in water, it's got fins," Dr Long said. "But it's a fish that is showing the beginnings of the tetrapod's advanced body plan that would eventually carry on to all living land animals." Dr Long says Gogonasus also had a cheek bone structure similar to early amphibian and a single pair of nostrils, like humans. See above! Here are some more quotes which show that prior to the discovery in the 1980s that Acanthostega was fully aquatic, Darwinism expected that fins gradually evolved into feet as an adaptation for living on land:

"There's only one problem with this familiar version of how our distant ancestors emerged from the sea: it's probably wrong. ... newly assembled fossils-in particular, a 360 million-year-old salamander-like aquatic animal called Acanthostega- strongly suggest that toes and feet were developed before the first relatives of fish climbed onto land, not after:"

"It is one of those fixed images of evolution: adventurous fish managing to hoist themselves onto their stubby fins and crawling clumsily out of the swamps to forage for food. Once these primeval creatures were on terra firma, their offspring began to adapt to their new environment, natural selection (over tens of millions of years) favoring those that developed features well suited to life on land: paws, hooves, knees, joints, fingers and thumbs. Thus, as generations of schoolchildren have learned, did these marine creatures give rise to frogs, birds, dinosaurs and all the rest. There's only one problem with this familiar version of how our distant ancestors emerged from the sea: it's probably wrong. For one thing, the first creatures to waddle ashore were arthropods with well-developed legs and pincers. For another, newly assembled fossils-in particular, a 360 million-year-old salamander-like aquatic animal called Acanthostega- strongly suggest that toes and feet were developed before the first relatives of fish climbed onto land, not after. Moreover, in shape and function, Acanthostega's fully jointed toes bear no resemblance to the spiky, fanlike fins of a fish. Scientists believe they understand how a fish's gills evolved into an amphibian's lungs. But how did fins turn into feet like these?" (Nash, J.M, "Where Do Toes Come From?" Time, August 7, 1995, p.68)

"But Acanthostega['s] ... tetrapod anatomy evolved while our ancestors lived exclusively underwater and it evolved for life underwater. The first vertebrate that walked onto land didn't crawl on fish fins, it had evolved well-turned legs millions of years beforehand":

"Jenny Clack ... who works at the University of Cambridge's Museum of Zoology, discovered the bulk of Acanthostega's skeleton in 1987 and has been carefully reconstructing it ever since with fellow paleontologist Michael Coates. They are just finishing up their monographs on the creature, and some of the conclusions they've drawn from its body are surprising other paleontologists. For a long time it was assumed that our limbs and feet, which work so well for walking on land, evolved for that exact purpose. But Acanthostega has convinced Clack and Coates otherwise; tetrapod anatomy evolved while our ancestors lived exclusively underwater and it evolved for life underwater. The first vertebrate that walked onto land didn't crawl on fish fins, it had evolved well-turned legs millions of years beforehand." (Zimmer, C., "Coming Onto the Land," Discover, Vol. 16, June 1995, pp.118-127, p.120).

"The big surprise, however, is that this creature would have spent most of its time in the water. `We didn't expect to find Acanthostega having such a fish-like gill apparatus,' says Coates, who described the material with Clack. `While it had lungs, it may not have been obliged to use them. The gill skeleton is an important part of our interpretation of Acanthostega as primarily, and primitively, aquatic':

"Given all these obstacles, how on earth did anything emerge from the water to roam dry land? Until quite recently, the evolution of land animals was seen as a matter of necessity. In an increasingly arid world, so the thinking went, fish were forced to haul themselves out of pools that were drying up and go in search of new ponds. In the process of coping with drought, these resourceful creatures evolved the limbs, lungs and senses that made a permanent move to land possible. ... But in 1987, [Per] Ahlberg and Jenny Clack of the University of Cambridge discovered some remarkably complete fossils on the barren shores of Greenland. Acanthostega is around the same age as Ichthyostega and is also a very primitive tetrapod, forcing the palaeontologists to rethink. Years of painstaking laboratory analysis have revealed that Acanthostega looked similar to the panderichthyids, except that it had limbs with digits instead of lobe-fins. The big surprise, however, is that this creature would have spent most of its time in the water. `We didn't expect to find Acanthostega having such a fish-like gill apparatus,' says Coates, who described the material with Clack. `While it had lungs, it may not have been obliged to use them. The gill skeleton is an important part of our interpretation of Acanthostega as primarily, and primitively, aquatic,' he adds." (McLeod, M., "One small step for fish, one giant leap for us," New Scientist, Vol 167, 19 August 2000, p.28).

.... Earlier this year scientists reported the discovery of Tiktaalik roseae, a 375 million-year-old species of fish that filled the evolutionary gap in the transition between water and land animals. While Tiktaalik had a skull that was identical to an amphibian, Dr Long says Gogonasus looks much more like a fish. "This particular fish is a bit like a wolf in sheep's clothing," he said. In fact, Dr Long says Gogonasus is more closely related to land animals than a fish called Eusthenopteron, which until recently was considered the common ancestor of all land animals. "It's replaced Eusthenopteron as the best fish to use when studying the ancestry of the first tetrapods," Dr Long said. Dr Long says there are still many unsolved questions about the evolution of land animals, such as how fin rays evolved into digits. The real question is why "fin rays evolved into digits"!

Graphic: The fin-foot (actually fins-arm/leg) transition, Brian Choo.

Indeed, why would a `blind watchmaker' start preparing one line of fish having "fins with well-formed limbs, like a human arm" (my emphasis):

Fossil fish a missing link, The Australian, October 19, 2006 ... Preserved in three-dimensional form, the fossil is the first complete and perfect skeleton of the types of fish that gave rise to the first land animals. The Gogonasus fossil shows the ancient marine fish had large holes in its skull for breathing, and also had muscular front fins with well-formed limbs, like a human arm. Dr John Long, who led the expedition, said the transition from a fish living in water to an air-breathing land animal with arms and legs was one of the most dramatic transitions in the history of evolution. ...

complete with, "the beginnings of a wrist joint and a complete front fin, consisting of the same arm bones found in humans and four-legged animals-the humerus, radius and ulna":

Discovery Points to Our Fishy Heritage, Livescience, Jeanna Bryner, 18 October 2006 ... The fossil also showed the beginnings of a wrist joint and a complete front fin, consisting of the same arm bones found in humans and four-legged animals-the humerus, radius and ulna. ...

This is obviously far-sighted design (and not a "blind, unconscious, automatic process which ... has no purpose in mind. ...has no mind and no mind's eye. ... does not plan for the future. ...has no vision, no foresight, no sight at all... the blind watchmaker") to those whose minds are not closed to that possibility!

As I said in a post of 07-Apr-06, commenting on Tiktaalik roseae,this fish-amphibian (including fins-arm/foot) transition "is evidence for my "Construction Project Design Argument," which I have argued for in discussion groups (e.g. Calvin Reflector 03-Dec-00, 30-Dec-00 1/2 & 2/2 and intend to present in my future book, "The Design Argument".

See also my comments (which I had forgotten about) in 1998 on the Calvin Reflector when the first Gogonasus fossil was found:

Re: fossil fish with fingers, Stephen Jones. 24 Jan 98 .... What a "coincidence". The only line of fish that developed the beginnings of arms and legs, also just happened to have an "advanced nasal system with a nostril opening in the roof of the mouth", ready for when its descendants did finally get pelvis and shoulder joint connections to their spinal column millions of years later, they would be able to walk on land! Sounds like a far-sighted (not a blind) Watchmaker to me! ... Actually, the fin-hand/foot transition is IMHO one of the best examples of intelligent design, and an insuperable problem for the blind watchmaker, because it had to happen twice [i.e. in both arms and legs] in the putative common ancestor, and in no other animal before or since ... The fin-hand/foot transition is really just another example of the component-by-component assembly over millions of years of a series of unrelated structures which are of no immediate use to the organisms possessing those structure, but which will form essential part of a larger coordinated system in the distant future. The same "conceptual bankruptcy" that applies to Darwinist explanations of the development of the human complex, applies also to the development of the land animal complex ..."

Stephen E. Jones, BSc (Biol).
Genesis 7:13-16. 13 On that very day Noah and his sons, Shem, Ham and Japheth, together with his wife and the wives of his three sons, entered the ark. 14 They had with them every wild animal according to its kind, all livestock according to their kinds, every creature that moves along the ground according to its kind and every bird according to its kind, everything with wings. 15 Pairs of all creatures that have the breath of life in them came to Noah and entered the ark. 16 The animals going in were male and female of every living thing, as God had commanded Noah. Then the LORD shut him in.

2 comments:

Anonymous said...

The limbs were used by the gogonasus to launch itself at prey underwater. It did not just grow these arms for no reason waiting to become a human. They evolved for a useful reason. The fact this arm-like structure might later become useful for humans to type on computer keyboards was irrelevant to the gogonasus and its evolution, and you're looking the wrong way down the telescope if you think it was. Pengo.

Stephen E. Jones said...

Thanks for both comments.

As for "anonymous'" comment, it commits the Fallacy of False Alternative that a far-sighted long-range plan can have short-range elements.

That _Gogonasus_ may have had some immediate use for its emerging "beginnings of a wrist joint and ... the same arm bones found in humans and four-legged animals-the humerus, radius and ulna" does not preclude them being part of an Intelligent Designer's long-range plan that they were ultimately for "humans to type on computer keyboards" and generally manipulate tools, etc.

Anonymous' focusing only on "arms" ignores that the same pattern of bones were not only emerging within the *pectoral* fins but also within the *pelvic* fins. But the latter were less developed than the pectoral fins and so may not yet have been ready for "gogonasus to launch itself at prey underwater."

The `blind watchmaker' theory has therefore to explain not just *one* pair of fins transforming into arms but *two* pairs, transforming into both arms *and legs*, when there may have been little, if any, immediate benefit in their earliest stages.

Indeed, when considering _Gogonasus'_ sister taxon _Eusthenopteron_, Carroll says of its "… forelimb ... More distally, there are no large endoskeletal supports for the fin and one must suppose that the metacarpals and phalanges of tetrapods developed as almost, if not entirely, new structures." (Carroll, R.L., "Vertebrate Paleontology and Evolution," W.H. Freeman & Co: New York NY, 1988, p.145). IOW, the *forward* support structures also may not have been yet in place for "gogonasus to launch itself at prey underwater."

Even the late agnostic Gordon Rattray Taylor realised that "the step from sea" required "an impressive array of coordinated changes" that was "quite inconsistent with the slow accumulation of imperceptible changes upon which Darwin based his theory" and raised the question whether they "could have taken place by chance":

"When we survey the evolutionary story, from the first multicellular creatures up to man we soon get the feeling that from time to time there was a dramatic change of plan - and indeed of lifestyle - that is quite inconsistent with the slow accumulation of imperceptible changes upon which Darwin based his theory. ... The most obvious and striking of these major steps was the step from sea to land, a step taken some 360 million years ago. Suddenly, four-legged air-breathing creatures appeared - quite unlike the scaly, limbless, water-breathing fishes which had been the most prolific creatures up to this time. ... So why did the fishes invade the land? No one knows. The real obstacles to such a move were the massive structural changes needed to make life on land worthwhile. To begin with, the fish would need legs simply in order to relieve the pressure of its body on the ground, which would compress the lungs. Equally importantly, the land animal needs a strong pelvic girdle. The fins of fishes are attached only to bony plates beneath the skin and could not support the weight of the body until a link had been provided to transmit their support to the spine. There were problems with the front suspension too, for in fishes the forward fins are firmly linked to the skull. Turned into legs, the animal would have to move its head from side to side with each step, so a new system of suspension had to be provided. Finally, since the weight of the body was no longer taken by the water, the spine itself needed strengthening. ... And so on to the next step, because land animals must also protect their body from drying out, by swapping scales for an impervious skin. Actually, the skin of some modern amphibians is quite sophisticated: it admits water when the creature returns to that element, the increased permeability being under hormonal control. We do not know if anything of the kind occurred in primitive amphibians. Land animals also need to protect their eyes from drying by a flow of tears and need an eyelid to protect it from dust particles. Similarly the nose must be protected by a supply of mucus. The land animal must also change its sense organs. It no longer needs the curious organ which runs along its side called a lateral line, and this is converted, by an amazing series of steps… into the ear. The eye, too, changes, since the refractive index of air is different from that of water and no doubt there are modifications in the sense of smell ... And then, of course, there is the problem of the legs themselves. Before ever the fish reached the land the structure of its fins began to change. Instead of rays, a series of bones corresponding to the tibia, radius and ulna of the arm appeared. Digits, tarsals and metatarsals evolved (so it is now generally conceded) as wholly new structures, though the point - unwelcome to Darwinians - was hotly contested in the 1930s. The fish which decided to remain fish very sensibly, converted their lungs into swim-bladders with which they could regulate the depth at which they swam. ... The earliest definitely four-footed creatures known were found in strata some 370 million years old in Greenland, which at that time was not icy but had a mild climate. Known as Ichthyostegids, they possessed a five-toed foot but retained the fishy tail and the lateral line of their fishy ancestors. ... All that need concern us is the larger question of whether such an impressive array of coordinated changes could have taken place by chance ...." (Taylor G.R., "The Great Evolution Mystery," Harper & Row: New York NY, 1983, pp.55-57, 59-61).

BTW apologies for the delay in moderating these comments. I had given Blogger my email address to notify me when there were comments awaiting moderation, but on just now checking it was not there. I have now redone it and checked that it *is* there.

Stephen E. Jones