iouae
Well-known member
You are a real sweet talker.
You employ the Socratic tactic of appearing to be ignorant in order to solicit a response. But unlike Socrates, you just may be ignorant.
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Evolutionists: How did legs evolve?
- Thread starter Clete
- Start date
You are a real sweet talker.
You employ the Socratic tactic of appearing to be ignorant in order to solicit a response. But unlike Socrates, you just may be ignorant.
iouae
Well-known member
I clicked on the first link, and yes, fringe science trying to explain away real science.
Find me your best YEC site which explains the geologic column.
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That's why I pointed out that they evolved later.
As noted above, we see lots of transitional forms between fish and tetrapods. Acanthostega seems to be pretty close to perfectly poised between the two. It's got internal gills, lateral line system, fish tail fin, and could not have moved about on land.
On the other hand, it has the legs of a tetrapod, with femur, tibia, fibula, tarsals, metatarsals, and phalanges.
All it needs is more robust connection to the spine, and you have a tetrapod. Notice also that genetic data supports evolution of tetrapods from the lobed-fin fishes.
(PhysOrg.com) -- A collection of new fossil finds in Scotland that date back to the 15 million year period between 345 and 360 million years ago are helping to fill the almost blank fossil record during a period that had until recently been considered to be essentially devoid of life except for that which lived in the seas. The discovery of the fossils by a team led by Jennifer Clack of the University Museum of Zoology at Cambridge and paleontologist Stanley P. Wood, is forcing archeologists the world over to do some rewriting of the history books. They have published a paper describing their discoveries in the Proceedings of the National Academy of Sciences.
Prior to these recent fossil finds, archeologists had taken to thinking of the time that came after a mass extinction some 359 million years ago, as very nearly empty regarding land biology due mainly to the almost complete lack of fossil evidence (only a single skeleton and a few bones had ever been found). Because of this, some theorists had suggested that there was likely too little oxygen in the air during this period to support such life. Now however, because of these new finds, those theories will be tossed to the wind.
https://phys.org/news/2012-03-fossil-romer-gap.html#jCp
As you see, there's an abundance of genetic, anatomical, and fossil evidence to support it. So three independent sources make for very strong evidence.
As YE creationist Kurt Wise admits, it's very good evidence for evolution of legs.
Although spiders have six joints, not all chelicerates have six joints. Sea spiders, for example, have nine, IIRC. And not all arachnids have four pairs of legs. There are mites with three pairs and even some with two pair. Spiders are just characterized by having four pair.
As you see in the case of vertebrate legs, considerable work has been done in the last few decades to document how they evolved. The fact that the same genes mediate fins and legs is powerful support for the fossil record showing numerous transitional forms between fins and legs.
Facts are stubborn things. They don't go away, even if we object to them.
Would you like some more detail on the way genetics has shown how fins evolved into legs?
Fossil finds help fill in Romer's Gap
Pederpes ("Peter's Foot") is an extinct genus of early Carboniferous tetrapod, dating from 348 to 347.6 Ma in the Tournaisian age (lower Mississippian). Pederpes contains one species, P. finneyae, 1 m long.
Life reconstruction of Pederpes finneyae
This most basal Carboniferous tetrapod had a large, somewhat triangular head, similar to that of later American sister-genus Whatcheeria, from which it is distinguished by various skeletal features, such as a spike-like latissimus dorsi (an arm muscle) attachment on the humerus and several minor skull features. The feet had characteristics that distinguished it from the paddle-like feet of the Devonian Ichthyostegalia and resembled the feet of later, more terrestrially adapted Carboniferous forms. Pederpes is the earliest-known tetrapod to show the beginnings of terrestrial locomotion and despite the probable presence of a sixth digit on the forelimbs it was at least functionally pentadactyl.
https://en.wikipedia.org/wiki/Pederpes
All together, 37 different specimens (including isolated limb bones, skull bones, and even a handful of specimens with multiple bones from the same individual) were studied by Anderson and colleagues. The fossils could be referred to six or seven different groups of early tetrapods, showing that tetrapods were going strong even in the middle of Romer’s Gap. Some of these (closely related to Ichthyostega, shown below) are forms that are most closely associated with earlier times in earth’s history; one way or another, they made it through a big extinction just prior to Romer’s Gap. Maybe, then, the extinction didn’t hit tetrapods as hard as previously thought.
Blue Beach isn’t the only locality to plug Romer’s Gap–another recently described set of fossils from Scotland shows a similarly rich tetrapod ecosystem. Together, these localities in disparate parts of the world suggests that the purported gap in the fossil record is more a collecting artifact than the result of genuine rarity of these animals during their time. Anderson and colleagues perhaps summarize it best:
“It now seems that, whenever we discover rare windows into this time period, we find numerous fossil tetrapods reflecting a rich diversity of forms.” — Anderson et al. 2015
In other words, Romer’s Gap probably isn’t a real phenomenon! With more fossils, it’s getting shorter and shorter. This is so often the case in paleontology–and that’s a good part of what keeps us all out looking for fossils. A “gap” in the fossil record is just a challenge to overcome.
http://blogs.plos.org/paleo/2015/04/29/romers-gap-four-limbed-fish-novia-scotia/
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Clete asked reasonably for information, and didn't respond unreasonably. While I disagree with him on how convincing three sources of evidence are, he's not being dishonest or offensive about it.
I can respect that.
iouae
Well-known member
Clete said "I already know the answers to the questions I'm asking, moron."
I look forward to him receiving the Nobel prize for solving the mystery of where all legs originate.
Or maybe he is just a YEC with a mouth. Who knows.
There is MICRO evolution and there is MACRO evolution. The Bible teaches that God made (speaking in this case of animals) He created them male and female after their kind, that is male and female fully formed "adults" capable of reproducing after their kind. So, an extreme example so you understand what I'm referring to, fruit flies can't mate with elephants. So MICRO evolution is consistent with Gods word. Now, MACRO evolution (major evolutionary change. MACRO evolution applies mainly to the evolution of whole taxonomic (organisms) groups over long periods of time.) No ... Gods word does not teach this and MACRO evolution is not consistent with Gods word and is totally dismissed and NOT believed. We see and recognize, MICRO evolution such as in different breed of dogs, cats, etc ..... but they are still within their kind and were created by God within their kind fully formed "adults". Let's go to a main point regarding "life", in the beginning ... how did "life" itself start in the first place? And if one believes in MACRO evolution then where is proof of the major the major transitions within the various groups? Regarding your chart ... I understand it represents a evolution theory ... looking at the chart ... and if the chart theory you provided is in the context of MICRO evolution and it is within it's own kind ... then yes ... possible and biblically supported .... but this is already "accepting" in this the example provided, this "animal" existed in the first place and "fully formed" beginning at the bottom of the chart". So in your chart .... what took place from the bottom of the chart downwards back to the very beginning? Where are the transitions from "organisms" into the various "groups of things resulting over long periods of time "fully formed" "things"? Actually,using just the chart you provided as an example supports what Gods word says .... "adult" fully formed, after their kind. So, MICRO versus MACRO .... recognizing MICRO evolution does not mean at all then a person must or does support MACRO evolution belief. It does not, we do not believe in MACRO evolution and it is not biblically supported.
6days
New member
iouae said:
Your heretical beliefs are not science. Your false belief system is what has lead to many shoddy conclusions in 'real science'.
I don't think you know what real science is iouae? It seems as soon as we discuss something you don't understand, such as our chat on genetics, your only response is ad hominem. (In our discussion on genetics, you were tossing the same phrase 'fringe science's against secular geneticists,in secular journals, instead of truth g to address the argument)
6days
New member
We have already established your dishonesty on that issue. Mr Wise says the evidence is often a better fit for the Biblical account. Perhaps this would help you represent Mr. Wise more honestly... You could say something like 'Mr Wise says it's very good evidence of common ancestry within the evolutionary framework. He says it is an interpretation, and he rejects those interpretations.'The Barbarian said:
Considerable work has been done 'documenting' many things witlin the common ancestry belief system. Fortunately science often exposes the shoddy conclusions.The Barbarian said:
God documented this... "For in six days God created the heavens, and the earth and everything g in them."
Okay, that post took some effort and time to put together and I thank you for doing that.Sorry, had to go out of town last week. Didn't do much here, and missed this.
Genetic, because evo-devo has shown the same homeobox genes responsible for fins are also responsible for vertebrate legs.
Here's just one, which is striking:
So now we have anatomical and genetic information showing the evolution of limbs. As I think I mentioned, the first walking vertebrate didn't walk on land. Acanthostega was a fish, with a lateral line system, internal gills, rayed fin tail, and limb connections to the spine too weak to let it walk on land. It walked on the bottom of ponds.
Because someone in this thread mentioned coelacanths as a putative human ancestor, it's important to note that they aren't. They are lobed-fin fish, and land vertebrates did evolve from lobed-fin fishes, but not coelacanths. And Coelacanths living today are much evolved from their ancient ancestors anyway.
The lungfish are much closer to our line, and not surprisingly, lungfish are more closely related genetically to us than they are to a bass. BTW, lungs in fish seem to have evolved before swimbladders. Lungs aren't modified swimbladders, swimbladders are modified lungs. That's a bit of a diversion, but we can talk about it separately, if you'd like to know how we know.
Other branches of lobed-fin fish developed more interesting structures.
Having found the right strata, paleontologists are pulling all sorts of half-fish/half-tetrapods out of the rocks, and it seems that there was a lot of selective pressure toward walking.
Limbs in fish have evolved at least twice since. Mudskippers have modified fins to "walk" and even climb trees.
The sargassum fish lives in "forests" of sargassum seaweed, and have evolved "hands" from their fins to climb around in the weed.
Edit: Apparently it's happened at least three times. Frogfish use fins to walk along the bottom.
It looks weird, because it's the same bones, using the same motion as we see in tetrapods.
Any thoughts on other creators that have legs like insects and spiders and crabs, et al. I just watched a youtube video last night that happened to mention a piece of amber that is supposedly 100 million years old and has a spider in it. Do evolutionary theorists have any idea how spiders evolved - what they evolved from and whether they ever had something other than four pairs of legs with six joints each? Where there ever any with four joints or two? Why is six better than five?
I don't really mean to be focusing on spiders. It just so happens that spiders have caught my attention after having mentioned them earlier in the thread. I never realized that there are tens of thousands of spider species in the world and every single one of them have exactly four pairs of six jointed legs. I find that astounding but it's just a particular point of curiosity on my part. It isn't me trying to move the thread in that particular direction.
There is one other direct question I'd like to ask that might help move things toward where I'm thinking of going with this thread...
Do you suppose that legs could just form in one step? Sure, going from fins to stiff crutch like appendages is a sort of a single step, right, but I mean real legs that have joints and feet and can be used to walk with. Would evolutionary theory accept the notion that such a thing could happen in a single evolutionary step or would that be way too complex and require the organism to take advantage of slight successive variations, as Darwin put it?
Thanks again for spending the time it took to write that post.
Clete
You're still angry because you got caught in a lie. You denied that Wise called intermediate forms "transitional forms", when you knew that's what he called them in the title of his paper. Let it go. You thought no one would know, and so you were exposed. Learn from it.
It's "Dr. Wise" and he says as you also know that the existence of the transitional forms he referred to is "strong evidence" for evolution. Instead of trying to revise what he said, learn from it.
Perhaps this would help you represent Dr. Wise more honestly... You could say something like "Dr. Wise admits that the evidence at present favors evolution, but that he expresses hope that in the future, a creationist interpretation might be found."
At this point in time, the largest challenge from the stratomorphic intermediate record appears to this author to come from the fossil record of the whales. There is a strong stratigraphic series of archaeocete genera claimed by Gingerich 60(Ambulocetus, Rhodocetus, and Prozeuglodon[or the similar-aged Basilosaurus]61) followed on the one hand by modern mysticetes,62 and on the other hand by the family Squalodontidae and then modern odontocetes.63 That same series is also a morphological series: Ambulocetuswith the largest hind legs;64-66 Rhodocetus with hindlegs one-third smaller;67 Prozeuglodon with 6 inch hindlegs;68 and the remaining whales with virtually no to no hind legs: toothed mysticetes before non-toothed baleen whales;69 the squalodontid odontocetes with telescoped skull but triangular teeth;70 and the modern odontocetes with telescoped skulls and conical teeth. This series of fossils is thus a very powerful stratomorphic series. Because the land mammal-to-whale transition (theorized by macroevolutionary theory and evidenced by the fossil record) is a land-to-sea transition, the relative order of land mammals, archaeocetes, and modern whales is not explainable in the conventional Flood geology method (transgressing Flood waters). Furthermore, whale fossils are only known in Cenozoic (and thus post-Flood) sediments.71 This seems to run counter to the intuitive expectation that the whales should have been found in or even throughout Flood sediments. At present creation theory has no good explanation for the fossil record of whales.
Kurt Wise Toward a Creationist Understanding of Transitional Forms
You tried to shade what he said, and you got caught. Learn from it.
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"Microevolution" is change within a species. "Macroevolution" is the evolution of new species. This has been directly observed. In some cases, such as ring species, a microevolutionary change could retroactively become macroevolutionary, by the extinction of a linking population. There's no magical difference between the two.
That's not part of evolutionary theory. Darwin just assumed that God created the first living things. Research seems to indicate that it began naturally, from the Earth, as God says in Genesis.
If you see a perch and a man as being the same "kind", that's pretty inclusive. But in a real sense, genetics and the fossil record shows that all known life on Earth is the same "kind."
The first living things were prokaryotes, and they were here for an extremely long time before eukaryotes(organisms with nucleated cells) appeared. More than half of the history of life has only prokaryotes. Would you like to learn about the evolution of eukaryotes?
Could you give us an example of an organism that is not "fully formed?" Even transitional forms are fully formed. They just have characteristics of two groups. And since we've been at it for a while, there aren't many major groups for which transitional forms aren't known. Can you think of one?
Protons and sold-state electronics aren't Biblically supported either. There is much that is true, that is not in the Bible. The Bible itself says so.
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But there is no evidence that spiders evolved from mites or vise versa. There are no vestigial legs hiding inside the body of a mites left over from when they used to be spiders. What differentiates a spider from another arachnid isn't so much their legs since nearly all arachnids have four pairs of legs but rather it's their waste size, which is really small in spiders and way bigger (realtive to their body size) in other arachnids.
Well, I'm tempted to engage this directly but I don't want to send this off on a tangent just yet. Suffice it to say that I see no such thing - and neither do you really. What you call transitional forms, I call question begging, unfalsifiable non-sense but that's a debate for another day.
That wasn't the point.
The argument was made that suggested a false dichotomy. If I agreed with A then C. If I agreed with B then still C. I had already explained that I rejected A and my rejection of B didn't need explanation and so I just stated that I rejected it. The point was that the conclusion C didn't apply.
HOW? Yes!
I doubt very strongly that you'll be able to give any detail at all about HOW they evolved. Evolutionist never explain HOW anything evolved. They only explain THAT it evolved, HOW never comes into it. Well, almost never. I'm sure there must be a rare exception where someone somewhere postulated some theory about the HOW rather than the WHETHER but its usually just the sort of thing like your longer post about legs from fins, where one supposed prior form magically turns into the next and then the next and you guys call that evolution. The slight successive variations that Darwin theorized have been morphed into quantum leaps over the years, (through slight successive variation, of course).
- I was just proofreading this post and wanted to clarify that the last paragraph there wasn't intended to be insulting. It's just an observation. I'd rewrite it if I had the time. -
Clete
The evidence is that they evolved from a common ancestor, an early chelicerate. The Arachnomorpha (which includes spiders and mites) go back a long way. Trilobites are a branch from the Arachnomorpha.
DNA analysis of existing Arachnids sorts out like this:
And we know it's a valid method, since it can be tested on organisms of known descent.
Good point. The process in arthropods is known as "tamosis." Arthropods are very obviously arranged in a series of body segments. In most arthropods today, they aren't identical, but are modified or reduced in various ways. The mouthparts of arthropods, for example, are modified legs, which are still controlled by genes for legs, but modified by other genes. In some circumstances, they can be reverted to legs.
Actually the distinguishing mark for spiders is five abdominal segments, much modified with the last two being evolved into spinnerets.
Barbarian asks:
Would you like some more detail on the way genetics has shown how fins evolved into legs?
The first step is the normal fish fin. As in teleosts, small basal bones, with bone-like rays enclosed in thin epithelium.
Among modern-day vertebrates, paired appendages (fins and limbs) vary widely in their form and function (Fig. 1; Goodrich, 1930; Coates and Cohn, 1998). According to the current interpretation of the phylogeny, much of the differences among various types of vertebrate paired appendages largely result from differential losses of skeletons that were present in the common ancestor of jawed vertebrates (Fig. 1; Coates, 1994, 1995). In archetypal paired appendages, skeletal supports consisted of several large endoskeletal bones (pro-, meso-, and metapterygium of Gegenbaur, 1878) lying at the base, which articulate proximally with pectoral or pelvic girdles and distally with numerous smaller bones supporting dermal fin rays. In the fins of most sharks and primitive ray-finned fishes of today (Fig. 1A), this basic pattern has been retained with little modification, while in paired appendages of the teleosts and tetrapods, which together comprise the vast majority of modern-day vertebrate species, only portions of the ancestral skeletons remain. In the paired fins of teleosts, skeletal supports now consist mostly of the pro- and mesopterygial components of endoskeletons plus the dermal fin rays (Fig. 1B), while in limbs of tetrapods only the metapterygium and its distal branches can be seen (Fig. 1C) (Coates, 1994).
Fig. 1. Diversity in vertebrate appendicular skeletons. (A) Dogfish shark (Squalus acanthias), a chondrichthyan. In most cartilaginous fishes, the bauplan of pectoral fins consist of three large cartilages lying at the base of the fin which articulate proximally with the pectoral girdle and distally with numerous smaller cartilages (“distal radials”) supporting the fibrous fin rays known as ceratotrichia. (B) Zebrafish (Danio rerio), a teleost. In most teleosts, the skeletons of paired appendages (“fins”) consist of five basal bones and variable number of smaller, more distally-lying nodular bones (distal radials) articulating with the segmented fin rays. (C) Mouse (Mus musculus), a tetrapod. In tetrapods, paired appendages (“limbs”) are characterized by the presence of several large, proximo-distally arranged series of endochondral bones which are organized into the three major segments known as the stylopod (upper arm/leg), zeugopod (lower arm/leg), and autopod (wrist/ankle and digits). In all panels anterior is to the top and proximal is to the left. Only pectoral appendages are shown. Homology of pro- (blue), meso- (green), and metapterygium (yellow) is based on Mabee (2000). A: after Shubin and Alberch (1986). B: after Grandel and Schulte-Merker (1998). C: after Williams et al. (2006). d.r.: distal radials. cer.: ceratotrichia. f.r.: fin rays. sty.: stylopod. zeu.: zeugopod. aut.: autopod.
https://www.sciencedirect.com/science/article/pii/S0012160608010166
Functional analysis of these appendages show that some fish evolved highly simplified control fins, analogous to the diving planes of submarines, while others retained bones that make them useful for a variety of things. In lobed-fin fishes, the metapterygium enlarged and in several lines became useful for movement by pushing along the bottom of ponds.
Lungs having been evolved long before legs, only a more robust connection with the spine was necessary to permit movement on land. As I mentioned, this has happened twice since the first event. (actually, three times, if you count the very primitive "leg" of the "walking catfish.")
The key is that each change could not be harmful to the organism. Hence, we could certainly do better with an additional set of hands, but there is apparently no way they could be produced de novo. So we see the fins becoming simpler and more robust, but nothing really new. Just modifications of things already there.
I value bluntness. You've been honest and forthright about your ideas, and that's enough.
On the diagram showing the spider family tree, what's supposed to be off the left side of the page and what sits at the first two branches? Where's the creature that's sort of a horse shoe crap and sort of a sea spider but not really either one? Was there ever a creature that didn't have eight legs and slowly but surely turned into a creature that does have eight legs?
Again, I really am not trying to focus on spiders here. It's just turned into a convenient avenue to go down toward the final destination.
Also, notice that there is DNA for legs or there isn't, right? I mean, where did the DNA code for legs come from? How long is the DNA code for legs, hundred of base pairs, thousands? Is it longer or shorter than the DNA code for fins, or is it just different (i.e. not longer or shorter just different)? How much different is it? Is it a lot different or just a little incy-wincy bit different. (See what I did there! "incy-wincy spider" - get it?
)
Clete
Again, I really am not trying to focus on spiders here. It's just turned into a convenient avenue to go down toward the final destination.
Also, notice that there is DNA for legs or there isn't, right? I mean, where did the DNA code for legs come from? How long is the DNA code for legs, hundred of base pairs, thousands? Is it longer or shorter than the DNA code for fins, or is it just different (i.e. not longer or shorter just different)? How much different is it? Is it a lot different or just a little incy-wincy bit different. (See what I did there! "incy-wincy spider" - get it?
)Clete
iouae
Well-known member
Hey 6days, at least learn the geologic column. Here is a mnemonic...
The Pre-Cambrian Order Seems Devoid of Carbon Permanent Traces. Its Just a Creche Type Quagmire.
Pre-Cambrian, Cambrian, Ordovician, Silurian, Devonian, Carbon, Permian, Triassic, Jurassic, Cretaceous, Tertiary, Quaternary
Right Divider
Body part
Please provide your Biblical evidence for this claim.
iouae
Well-known member
Thanks for the comprehensive post Barbarian.
I have no axe to grind one way or the other whether there are fossils in Romer's gap or not.
I personally do not believe the taphonomy excuse, that fossils just did not preserve well in Romers gap, or the fossils are yet to be found.
I have a few doubts about Pederpes, since the link you gave says "Pederpes was discovered in 1971 in central Scotland and classified as a lobe-finned fish." Maybe they were right the first time and it is a lobe-finned fish.
All later land tetrapods have pentadactyly or 5 toes, this one 6.
This is what https://en.wikipedia.org/wiki/Evolution_of_tetrapods has to say.
"Carboniferous tetrapods[edit]
See also: Carboniferous tetrapod
Until the 1990s, there was a 30 million year gap in the fossil record between the late Devonian tetrapods and the reappearance of tetrapod fossils in recognizable mid-Carboniferous amphibian lineages. It was referred to as "Romer's Gap", which now covers the period from about 360 to 345 million years ago (the Devonian-Carboniferous transition and the early Mississippian), after the palaeontologist who recognized it.
During the "gap", tetrapod backbones developed, as did limbs with digits and other adaptations for terrestrial life. Ears, skulls and vertebral columns all underwent changes too. The number of digits on hands and feet became standardized at five, as lineages with more digits died out. Thus, those very few tetrapod fossils found in this "gap" are all the more prized by palaeontologists because they document these significant changes and clarify their history."
My belief is that there were certain times in the geologic column, that God experimented, whenever there would be a big change and the new organisms might need a tweak. For instance I see the Ediacarans, possibly those in the Romer Gap, and certainly Pleistocene Hominids as God experimenting to get some new animal functioning correctly. Not a person on this forum agrees with me that God needs to experiment, or believes that God is a Scientist, and sometimes learns from failures too. What others think does not trouble me.
In the end, I believe John 1:3 that every plant and animal was created by Jesus. I differ from YEC in that I add "not just 6000 years ago, but at different times in the geological past". To me, every fossil just adds to the glory of God. If this present biome was not great enough, 99% has died out and can only be admired as fossils.
There isn't any which is the point. God's creation allows for adaptation and that is what we see in evolution. Animals adapting to changing conditions.