The Evolutionary Tree Continues to Fall: Falsified Predictions, Backpedaling, HGTs and Serendipity Squared

_{Cornelius Hunter

July 27, 2011

Intelligent Design}

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Charles Darwin’s theory of evolution states that the species arose from earlier species. Slight changes accumulating over long time periods resulted in one species giving rise to a new species, over and over. Read more

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Exactly. In fact even that is an understatement – every living thing and every record of every living thing is the explanadum – that to be explained. I realize I'm being repetitious, which is a bit lame. But I'm pointing out that each living this is evidence of [non-specific ever changing] evolutionary causes because only those causes could have produced them. Take away the assumption that the [non-specific ever-changing] evolutionary causes are responsible, and living things are no longer evidence of them. It's circular.ScottAndrews_{July 30, 2011
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Even Shubin understood the place to look for evidence of the transition is between two periods- the period in which there weren't any tetrapods and the period in which there are tetrapods. Tiktaalik was found after tetrapods existed.Joseph_{July 30, 2011
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Elizabeth, Have you read Shubin's book "Your Inner Fish"?
Let's return to our problem of how to find relatives of the first fish to walk on land. In our grouping scheme, these creatures are somewhere between the "Everythungs" and the "Everythings with limbs". Map this to what we know of the rocks, and there is strong geological evidence that the period from 380 million to 365 million years ago is the critical time. The younger rocks in that range, those about 360 million years old, include diverse kinds of fossilized animals that we would recognize as amphibians or reptiles. My colleague Jenny Clark at Cambridge University and others have uncovered amphibians from rocks in Greenland that are about 365 million years old. With their necks, their ears, and their four legs, they do not look like fish. But in rocks that are about 385 million years old, we find whole fish that look like, well, fish. They have fins. conical heads, and scales; and they have no necks. Given this, it is probably no great surprise that we should focus on rocks about 375 million years old to find evidence of the transition between fish and land-living animals.- Neil Subin pages 9-10
But anyway, the point is had the new data been available to Shubin- the data that puts the transition back to before 390 million years ago- that whole set up would be meaningless and wrong. Meaning he would not have been looking where he did.Joseph_{July 30, 2011
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ScottAndrews:
Every living thing and every fossil are relevant to evolution, because their very existence is evidence of the various evolutionary processes (some blanks to be filled in later) which must have produced them.
Exactly. In fact even that is an understatement - every living thing and every record of every living thing is the explanadum - that to be explained. To say that tiktaaliks are irrelevant to evolution is like saying that calcium is irrelevant to chemistry! And evolutionary theory, inter alia, posits that all living things can be placed on a hierarchical tree diagram by means of phenotypic characters and that this tree that will tend to be deeply nested. Tiktaaliks can be placed on the tree, together with the Zachelmie footprints, as below: http://talkrational.org/showthread.php?p=755320#post755320 Also, a good cautionary paper here: http://rspb.royalsocietypublishing.org/content/early/2010/08/21/rspb.2010.1321 (Not open access, but the abstract is good). Casey Luskin writes:
New scientific discoveries are exciting because they force us to revise, rethink, and improve our scientific explanations. In fact, neo-Darwinian evolution is certainly not refuted by these newly discovered tetrapod tracks. However, it's clear that evolutionary thinking led some researchers to make a prediction here. They claimed this prediction was a great confirmation of evolutionary theory. But this prediction is now known to be false. Neo-Darwinism lost an important argument.
This is an equivocation wrt the word "prediction". The extraordinary prediction referred to by Shubin was that tetrapod fossils, showing transitional features between extant fossil tetrapods, would be found in a particular stratum, that was known to be exposed in a particular place on the earth's surface, namely, late Devonian river sediments on Ellesmere Island,Canada. Far from their prediction being "now known to be false" - they found them! The prediction Luskin is claiming is "now known to be false" is not clear, but it clearly isn't Shubin's because Shubin's was successful. In fact, what Luskin is complaining about is that tiktaalik isn't "transitional", although he tries to rebut claims that this is what he is doing, extremely unsuccessfully. The prediction was absolutely correct - they predicted where the Tiktaaliks would be, and there they were. The did not predict that they would find the earliest tetrapods at that location in the geologic column, but that they would find tetrapods with transitional features at that location. As Luskin correctly notes, this hoohah is all about rhetoric, not about science. There is a perfectly good phylogeny on which both Tiktaalik and the other early tetrapods, including the Zachelmie footprint-makers, can be placed, and the features of Tiktaalik remain as transition as ever. Just as modern tarsiers have transitional features between modern lemurs and new world monkeys, yet all are extant species.Elizabeth Liddle_{July 30, 2011
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The theory of evolution does not expect nor predict a tree of life because the theory of evolution is silent on the origin of living organisms and it is the origin that determines how many trees there will be. (it is a given that basic fact will be lost on evos)Joseph_{July 30, 2011
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There isn’t any way to test the claim that a prokaryote can “evolve” into anything but a prokaryote. Doveton:
Sure there is: http://www.ncbi.nlm.nih.gov/pubmed/12446813 and http://www.bacterialphylogeny.info/eukaryotes.html as examples.
Except there isn't any evidence that endosymbiosis took place other than "it looks like it did". Your first link doesn't help.Joseph_{July 30, 2011
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the footprint finding AND Tiktaalik are both hugely relevant to evolution Every living thing and every fossil are relevant to evolution, because their very existence is evidence of the various evolutionary processes (some blanks to be filled in later) which must have produced them.ScottAndrews_{July 30, 2011
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BTW, Chris:
You then mention Tiktaalik which is the only specific reference you make to substantiate your third, fourth and fifth piece of evidence. But, we now know that Tiktaalik is irrelevant to evolution.
No, we certainly do not! More on that later, but the short answer is that the footprint finding AND Tiktaalik are both hugely relevant to evolution, specifically fish-tetrapod transition! There's an old creationist canard, much mocked in evolutionary circles, that goes "then why are there still monkeys?" Casey Luskin is making the exact same error - "then why were there still Tiktaaliks?" I actually know Per Ahlberg, who has worked on both, and I'll try to dig out what he wrote about them. It's fascinating work!Elizabeth Liddle_{July 30, 2011
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Chris, thanks, and I will watch that video. Also respond in more detail to your post, and try to check the links as well. However, I will say that the "pick one piece of evidence" approach is problematic. What matters, so often, in huge domains of science like evolutionary theory, or the age of the earth, is the consilience of multiple pieces of often independent evidence. Any one piece may have multiple possible explanations. But a good theory will cover lots of pieces of evidence. It may not be the neatest, or even the most intuitive, explanation for any one piece, but the model we want is one in which all the explanations for all the pieces hang together. But I'll try to explain what I mean in more detail with respect to your post above later, hopefully having had time to watch the video! Thanks. LizzieElizabeth Liddle_{July 30, 2011
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Hi Lizzie, You asked: So can you give me some actual examples (of evolutionists as the true Spin Doctors)? The Cambrian Explosion, for starters. Asking for 75 minutes of your time is unreasonable, I know, but please try and watch the Darwin’s Dilemma documentary if you want to discuss this further. And then every instance of “convergent evolution” (ie. between placental and marsupial mammals) and “divergent evolution” (ie. between the Y chromosome in humans and chimps). Convergent evolution is a term evolutionists use to simply explain away the problem of supposedly distantly related species being uncomfortably similar. Divergent evolution glosses over the opposing problem of supposedly closely related species being uncomfortably dissimilar. Now then, onto your evidence: Your first piece, biological classification/common descent has been dealt with here. Your second piece is actually another example of evolutionists as true Spin Doctors: using HGT to magic away exceptions to the tree of life where none are permitted. You then mention Tiktaalik which is the only specific reference you make to substantiate your third, fourth and fifth piece of evidence. But, we now know that Tiktaalik is irrelevant to evolution. So much for the first category. Next we have the second category. You first of all cite “all the examples” I mentioned. I honestly don’t know what you’re referring to there. You add Lenski’s e-coli experiments which have been dealt with here (in a comment addressed to Ellazimm originally, but one that I’ve referred you to before today). You mention fruitflies: mere sub-specific variety (within a pre-existing, unevolved gene pool), at best. A failure to recognise the fact that fruitflies also demonstrate genetic homeostasis, at worst. GAs: intelligent designers using intelligently designed systems to achieve intelligently designed goals. IOW, irrelevant. Replication with variance has been dealt with here. Then yet more spinning when you mention “irreducible complexity”. Evolutionists have this notion that the IC argument (like Paley’s watch argument) has been dealt with when it hasn’t. All we see are gross misunderstandings of the argument or lack of awareness of the obstacles to overcoming IC. Behe himself answers most of your objections here. What you call “novel functions” in bacteria, I call missing the point. If you read the post I referenced earlier , you will see why. Finally, antifreeze in arctic fish: the Edge of Evolution, at best. Sub-specific variety (within a pre-existing, unevolved gene pool) at worst. So, by moving onto actual specific evidence for evolution, we are definitely moving in the right direction and I applaud and encourage that, Lizzie. However, as I’ve demonstrated above, the one-liner scattergun approach to evidence for evolution is weak and ineffective (although it did allow me to highlight some unanswered posts!) Can I please request a more practical and focused approach instead? Pick one piece of evidence, preferably one that is particularly important and significant to you personally, and use the entire post to detail why that piece of evidence supports evolution. I will then respond in full (avoiding reliance on links which are frankly no substitute for debate). I think that is the most productive way forward in this discussion.Chris Doyle_{July 30, 2011
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Chris: I'm not sure whether you perhaps missed my point, or making a more subtle one. You wrote:
Everybody here would grant the assumptions that you’ve listed precisely because we’re all interested in “Finding Out Stuff.”
My point is that science is not, primarily (or at least methodologically) about "Finding Out Stuff". It's about fitting models to data. Now, finding a well-fitting model may be a kind of "Finding out" of a kind of "Stuff" but not, I suggest, in the way it's commonly understood. So we get headlines like "scientists find the ancestor of the whale". What the scientists have actually found is a model of whale evolution that is a good fit to the data (and that data may be fairly sparse). And while some "findings" may be such overwhelmingly well-fitting models that we regard them as "facts", actually there are no "facts" in science. Everything is always up for grabs. It's just that if we regarded everything as equally up for grabs, we'd never make any progress. Hence Asimov's point about "the relativity of wrong". We know that the curvature of the earth is near zero. We have always known that. We have always know that we do not live on a tiny spherical asteroid like The Little Prince. But we can probe that value to find it more and more precisely. Nonetheless, the dimensions of the earth, and its shape, will never be an an challengeable "fact". It will always be subject to refinement (ditto for the age of the earth, of course).
However, there’s another assumption that evolutionists take for granted and that is: evolution is true. And the problem with this assumption is that it is detrimental to “Finding Out Stuff”.
Two questions: what do you understand by the phrase:"Evolution is true"? Second: can you give me an example of where this assumption has been detrimental to "Finding Out Stuff"? Thanks!
It closes minds and swamps us with dogma. If you removed that evolutionist assumption, I think you would see the huge gulf close very quickly.
It's a gulf I'd gladly see closed, Chris! But I suggest that what really needs removing is the assumption that evolutionists make the assumption you assume they make! That's why I'd like you to unpack the assumption you think they make!Elizabeth Liddle_{July 30, 2011
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Hiya Lizzie, Everybody here would grant the assumptions that you've listed precisely because we're all interested in "Finding Out Stuff." Furthermore, those assumptions allow us to keep an open mind and prevent dogma arising. However, there's another assumption that evolutionists take for granted and that is: evolution is true. And the problem with this assumption is that it is detrimental to "Finding Out Stuff". It closes minds and swamps us with dogma. If you removed that evolutionist assumption, I think you would see the huge gulf close very quickly. I don't know if you checked out either of the links I mentioned to Doveton in relation to whale evolution: but, in direct response to the PDF you referenced, here is another one. Incidentally, browsing the many articles in the www.scienceagainstevolution.org website will give you an insight into the roots of my skepticism.Chris Doyle_{July 30, 2011
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Chris, I'm sort of intrigued by your skepticism vis a vis whale evolution. I mean skepticism is healthy and all that, but I think Doveton's point - though somewhat tactlessly expressed! - references this gulf that I know I've talked about here as well (possibly just as tactlessly) between the kind of assumptions we take for granted so much in science that they are rarely made explicit, namely, that all conclusions are provisional, and that science is about fitting models to data, not proof, and the way science is perceived by those outside the field - Finding Out Stuff. That's why I posted the link to Asimov's essay - but, curiously, your interpretation of it was itself an illustration of the gulf! There's a paper here about whale phylogeny that you might find interesting: http://webh01.ua.ac.be/funmorph/raoul/fylsyst/Thewissen2007.pdf On the other mind you might dismiss it as more Just So stories. I'd be interested to know whether you do! This is not meant to be patronising at all - I think there really is a huge gulf, and scientists bear primary responsibility for it IMO (and science journalists a little of it as well). I've had interesting arguments with lawyers about science, and lawyers are pretty smart people. But a lawyer's take on evidence is so different from a scientist's, it is hard to bridge the gulf. And then there are engineers....Elizabeth Liddle_{July 30, 2011
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Doveton and ScottAndrews:
ScottAndrews,
Birds and bats fly while dogs and snails do not because the flight traits gained in the former two groups of organisms by luck were selected while the flight trait was either not available or not selected in the latter two groups of organisms.
Just going off on a tangent here based on what you wrote Lizzie. Why are you substituting “by luck” in the above? Such implies that you think that those organisms that gained flight were in some way more fortunate than those who did not gain flight. I really don’t think that most (if any) organisms that get flight are more lucky than those who didn’t. Looking strictly at the lineage of cormorants and turkeys, for example, those two groups seem to show that at least some organisms are perfectly successful giving up the trait.
Scott is correct - I wasn't using "luck" in the sense of "good luck" - I should have said "chance" I guess. My point really is that which path a population starts going down at the beginning may be mostly chance (even drift), but if that direction turns to be pushing on an open door, the population will keep going in that direction,which may in turn close other doors. In my hypothetical example, a tree-dwelling population might find itself getting lighter and fluffier because smaller and fluffier means better survival from a fall; another might find itself getting stronger at clinging, because being good at clinging stops you falling, but can no longer move in the direction of ligher and fluffier because of the muscles it has found effective for clinging with. But the door a population starts pushing on may be largely a matter of chance.Elizabeth Liddle_{July 30, 2011
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Lizzie, post 50, that's much more like it (from a proper scientist, too)! I will respond to that fully sometime this weekend, hopefully. Have a good one!Chris Doyle_{July 29, 2011
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Morning Doveton, While the fossil record may not show changes taking place – it is after all a series of snapshots – it does show distinct morphological incremental changes across closely related species. This just isn't true and this is plainly obvious from the fact that you claim that: The fossil evidence we have for cetaceans is one of the better examples. If that's the best you can do (and given that it was the first example you gave, it probably is) then your beliefs are literally in a whale of trouble. If you require any further confirmation of that fact, just re-read what you wrote here: I suppose we in science see a bit more nuance in the fossil record that you do not. Are you serious, Doveton? Do you know how ridiculous that statement makes you sound? You can't substantiate your disagreement with me so you have to make an appeal to authority instead: always a bad sign. But then lumping yourself in with that authority, well, you can't expect to be taken seriously after a move like that.Chris Doyle_{July 29, 2011
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Doveton, For example, you’ve presented the ability to fly as post-hoc evidence for the selection of said trait, which is fine, but that’s just oversimplification of what genetics and breeding demonstrate. Evolutionary evolutionary presents the explanation for how that relationship works There is no basis in breeding to show how a change such as gaining flight would occur. Genetics offers nothing in this respect either. Countless research papers describe the difference in genes and proteins between two organisms but leave the pathway between them hanging as something assumed and yet omitted. In the historical sense no evidence is provided for selection besides the variation it explains.ScottAndrews_{July 29, 2011
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Doveton, Just going off on a tangent here based on what you wrote Lizzie. Why are you substituting “by luck” in the above? I was quoting her. But she was referring to element of chance, not good fortune.ScottAndrews_{July 29, 2011
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Doveton, We know that specific incremental characteristic changes that ultimately could support flight were selected in the former two groups because we have the fossil evidence that indicates such. We hold that selection is the cause of the variation in fossils, and the evidence is that the fossils are varied. What's mind-straining is that each case of circular reasoning is used to bolster the other case of circular reasoning in a similarly circular manner. It's employed with regard to living things and to fossils, and either case can and is used to support the other. The variations are held as evidence of selective pressure as a result of understanding that the mechanisms of heredity, competition, reproductive success, offspring relative success and mortality rates, etc. lead to variation. That's exactly what I've been saying. The variations are the evidence of the selective pressure, which in turn is used to explain the variations. You can use "X" - anything at all - to explain variations if the variations, which clearly exist, are accepted as evidence of X.ScottAndrews_{July 29, 2011
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ScottAndrews,
Birds and bats fly while dogs and snails do not because the flight traits gained in the former two groups of organisms by luck were selected while the flight trait was either not available or not selected in the latter two groups of organisms.
Just going off on a tangent here based on what you wrote Lizzie. Why are you substituting "by luck" in the above? Such implies that you think that those organisms that gained flight were in some way more fortunate than those who did not gain flight. I really don't think that most (if any) organisms that get flight are more lucky than those who didn't. Looking strictly at the lineage of cormorants and turkeys, for example, those two groups seem to show that at least some organisms are perfectly successful giving up the trait.Doveton_{July 29, 2011
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ScottAndrews,
I’m being a bit facetious, obviously, but I must add the final piece:
Oh I know. And perfectly good facetiousness imo. :)
We know the above because the flight traits gained by the former two groups of organisms was selected while the flight trait was either not available or not selected in the latter two groups of organisms because the former group flies while the latter group does not.
Mmm...not quite. We know that specific incremental characteristic changes that ultimately could support flight were selected in the former two groups because we have the fossil evidence that indicates such. We also suspect that no specific incremental characteristic changes for flight came up for the latter to organisms because thus far none of the closely related fossilized ancestors show any such traits.
What I’m demonstrating is the circular nature of the explanation.
Well no...you're demonstrating the circular nature of your particular phraseology by presuming that evolution relies upon the understanding of variations show selection. However, we only think in terms of variations show selection because we understand evolution (or at least genetics). Your explanation relies upon a post-hoc conclusions based upon an understanding of the principles of evolutionary relationships rather than focusing upon the principles that evolutionary theory actually studies and describes. In other words, your confusing the conclusions drawn from evolutionary theory with the phenomenon of evolution being studied. For example, you've presented the ability to fly as post-hoc evidence for the selection of said trait, which is fine, but that's just oversimplification of what genetics and breeding demonstrate. Evolutionary evolutionary presents the explanation for how that relationship works, and that explanation provides the evidence for the selection of given traits that leads to a given ability, hence the focus on hereditary mechanisms, competition for resources and breeding, relative offspring success (against those offspring without a given trait), fossil records of trait development through related organisms, and so on.
In other words We don’t actually know which selective pressures applied to birds or bats but not to dogs or snails. We infer that those pressures were part of the cause from the existence of the traits we credit them with helping to produce. We can make occasional wild guesses at what those selective pressures might have been, but are at a loss to explain why other organism were not affected. This shows that we know little or nothing of the proposed cause, only of the effects.
Sort of - we know some of the selective pressures for trait adoption in some cases - hence the reason we can surmise others with a certain degree of accuracy - hence the reason we can breed dogs and horses and other organisms with certain traits. But that's neither here nor there. The real point is that we don't need to know the specific selective pressures to answer your question. Here's the answer again reworded to take selection out: Birds and bats fly while dogs and snails do not because the flight traits gained in the former two groups of organisms were selected neutral or advantageous to the overall survival of bird's and bat's offspring while the flight trait was either not available or not selected a non-hereditary neutral anomaly in the latter two groups of organisms. I won't argue that it would be interesting to know them and that they would certainly fill in a good deal of understanding on the mechanics of the process, but one can still know enough about the mechanics of the process to answer the question you've posed without knowing the selective pressures.
The result? The variations are held as evidence of the selective pressure, while the selective pressure in turn is used to explain the variations.
No. The variations are held as evidence of selective pressure as a result of understanding that the mechanisms of heredity, competition, reproductive success, offspring relative success and mortality rates, etc. lead to variation. The two understandings are not, however, used to explain each other.Doveton_{July 29, 2011
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Elizabeth, Allow me to revise again (borrowing some text from Doveton): Birds and bats fly while dogs and snails do not because the flight traits gained in the former two groups of organisms by luck were selected while the flight trait was either not available or not selected in the latter two groups of organisms. We know the above because the flight traits gained by the former two groups of organisms by luck were selected while the flight trait was either not available or not selected in the latter two groups of organisms because the former group flies while the latter group does not. For example if hanging on stops baby monkeys dying, being strong, and therefore dense may be advantageous (hang on better) but not much use for saving you if you do let go. So the monkeys that survive to breed are the strong clingers, and they won’t evolve to fly. The trouble is, you're inventing this selective pressure to fit the evidence. You can't do that and follow the evidence to a cause at the same time. What evidence do we have that there was ever a time when monkeys or their predecessors were dropping off trees left and right and that this caused them to cling rather than fly or gallop? The only evidence is that monkeys cling instead of flying or galloping.ScottAndrews_{July 29, 2011
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Joseph,
There isn’t any way to test the claim that a prokaryote can “evolve” into anything but a prokaryote.
Sure there is: http://www.ncbi.nlm.nih.gov/pubmed/12446813 and http://www.bacterialphylogeny.info/eukaryotes.html as examples.
Relationships? Based on common design or common descent?
The relationships illustrated in the links I provided.
As for the link supporting my claim see comment # 31
Oh...the New Scientist quotes. Here: http://www.texscience.org/reports/sboe-tree-life-2009feb7.htm http://sandwalk.blogspot.com/2009/01/darwin-was-wrong.html http://scienceblogs.com/evolutionblog/2009/01/the_trouble_with_science_journ.php http://scienceblogs.com/pharyngula/2009/01/new_scientist_says_darwin_was.php http://scienceblogs.com/evolvingthoughts/2009/01/darwin_was_wrongish.php And so on and so forth... In the immortal words of several evolutionary biologists who wrote back to the New Scientist about the cover story: "First, it's false, and second, it's inflammatory." So no, "evolutionary biologists" (plural) have not said that there is no evidence for the tree of life even according to New Scientist article (which the Telegraph repeated). Graham Lawton, the writer, merely took a bunch of quotes out of context, exaggerating and misrepresenting them. In any event, if this is the reference you are relying upon then I feel quite secure that I and my colleagues can continue to rely the evidence for the Tree of Life.Doveton_{July 29, 2011
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ScottAndrews - another factor, of course is just - luck. Good old stochastic processes. Critters that acquired wings were those for whom some slight mutation started to push them in that direction. Now, before you say, "what use is half a wing", consider tree-dwelling critters. Tree dwellers live with one heck of a hazard - falling out of trees. And what kills you when you fall out of a tree is the deceleration as you hit the ground hit the ground times your mass. And what affects the deceleration is your terminal velocity, also if you are lucky, any shock absorbers you happen to have. So baby animals in trees that are light, and fluffy will have a better chance of reaching maturity and having offspring than baby animals that are heavy and bald. And baby animals that can spread something out, however small, as they fall, are more likely to survive than baby animals that don't. So potentially we have flying snakes, flying squirrels, sugar gliders, and fruit bats. But whether we get them or not, and what we get, depends no only on the environment (being born up a tree) but on what marginally advantageous traits happen to show up, because there is more than one way of not falling out of a tree, including being able to hang on. And once a population starts down a particular "solution path" then other "solutions" may become irrelevant, or even conflict with other things. For example if hanging on stops baby monkeys dying, being strong, and therefore dense may be advantageous (hang on better) but not much use for saving you if you do let go. So the monkeys that survive to breed are the strong clingers, and they won't evolve to fly. Of course fruitbats both cling and fly - clever things! There is more than one way to skin a cat.Elizabeth Liddle_{July 29, 2011
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Doveton, Birds and bats fly while dogs and snails do not because the flight traits gained in the former two groups of organisms were selected while the flight trait was either not available or not selected in the latter two groups of organisms. I'm being a bit facetious, obviously, but I must add the final piece: We know the above because the flight traits gained by the former two groups of organisms was selected while the flight trait was either not available or not selected in the latter two groups of organisms because the former group flies while the latter group does not. What I'm demonstrating is the circular nature of the explanation. We don't actually know which selective pressures applied to birds or bats but not to dogs or snails. We infer that those pressures were part of the cause from the existence of the traits we credit them with helping to produce. We can make occasional wild guesses at what those selective pressures might have been, but are at a loss to explain why other organism were not affected. This shows that we know little or nothing of the proposed cause, only of the effects. The result? The variations are held as evidence of the selective pressure, while the selective pressure in turn is used to explain the variations.ScottAndrews_{July 29, 2011
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Elizabeth Liddle:
No, I’m talking about evidence... evidence that Darwin’s mechanism actually works, can be observed to work, and that its prerequisites are present.
Great! That's what you've been asserting and we've been asking for since you first showed up here, and what we are still waiting for. Time to put up or shut up, as they say.Mung_{July 29, 2011
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ScottAndrews,
According to your explanation, your second statement is an assumption. Perhaps some specimens of dogs and snails did make small changes in the direction of flight, but they weren’t advantageous.
Fair enough. I sit corrected. For snails and dogs, at the very least flight was not a selected trait.
I’m going to get this right if I keep trying:
Well, from my point of view the catch above is good indicator you are on the right track. :)
Why do birds and bats fly while dogs and snails don’t? Birds and bats gained changes that allowed flight, which under the circumstances and environments at the time were an advantage. And how do we know that birds and bats gained changes that allowed flight, which under the circumstances and environments at the time were an advantage, but dogs and snails did not? Because birds and bats fly while dogs and snails do not. Is that better? :)
Hmmm...well, you are closer, however the evolutionary explanation you provided answers a different question than the one you are asking. Try this instead: I’m going to get this right if I keep trying: From an evolutionary perspective, why do birds and bats fly while dogs and snails don’t? Birds and bats fly while dogs and snails do not because the flight traits gained in the former two groups of organisms was selected while the flight trait was either not available or not selected in the latter two groups of organisms. Pretty straight forward explanation. Now, if you want to know how the two groups gained the flight trait, that's a different question. Still further different is the question of how the two other groups did not gain said trait, a question I might add that I certainly have no way to answer since there are many possible explanations (as you pointed out above) how an organism might not come up with a given trait. I'm reminded here of a joke I heard some time ago - why don't snakes have legs? They are against wearing leather shoes. Not a very good joke imo, but it does illustrate a point - why questions can be answered in a variety of ways and many times the answers are informative, but not very useful. How questions, otoh, tend to be both informative and useful.Doveton_{July 29, 2011
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When Lizzie notes above, “there is no reason to change further”, what she means is that there is no selective pressure or rather nothing advantageous to select when a population reaches an optimum balance with its environment.
And yet, according to Darwin, there is always selective pressure. It's core to his theory.Mung_{July 29, 2011
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Doveton, There isn't any way to test the claim that a prokaryote can "evolve" into anything but a prokaryote. Relationships? Based on common design or common descent? As for the link supporting my claim see comment # 31Joseph_{July 29, 2011
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I certainly see evidence of a tree and common descent. Good for you. Unfortunately that point of view is still untestable. You could test it by following the links and either acknowledging the relationships that the studies (and tests) show or you could follow the links and report on what you see as errors in the testing methods used.
Also evolutionary biologists have said there isn’t any evidence for a tree of life. Strange…
Would you be so kind as to site a reference for this please? Thanks in advance.Doveton_{July 29, 2011
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