Another Just-So Story
One of the most fundamental evidences for evolution is the similarities between the species. Evolution calls for the species to have evolved via a process of common descent leaving them with similarities inherited from their common ancestor. But there are several problems with this idea. One problem is that there are a great many similarities between species that could not have been inherited from a common ancestor. In such cases evolutionists say the similarities evolved independently. Evolution repeated itself because of a similar environment. But another problem is that there are many similarities between species with key environmental differences. One example is the vision system in humans and squids. Their respective environments could hardly be more different. Now a new study provides yet another example: venomous snakes of North America and Australia, which occupy different ecological niches. As one evolutionist explained:Most biologists tend to assume that convergence in body form for a group of organisms implies that they must be ecologically similar. But our study shows that there is almost no overlap in diet between many of the snakes that are morphologically very similar.
Evolutionists explain these examples of convergence in different niches with ad hoc mechanisms. For one reason or another, similar designs arose independently, in spite of different environments. This highlights how flexible evolution is. It can explain a great variety of outcomes. But this also means that similarities between species are not the strong evidence evolutionists claim them to be. In fact what these data reveal is how difficult it is to falsify the theory.
CH: But another problem is that there are many similarities between species with key environmental differences. One example is the vision system in humans and squids.
ReplyDeleteSee this post that contrasts significant differences between both systems.
For example, squid eyes move the lens to focus like a camera, while human eyes change shape. There are also significant differences at the level of the retina, such as where image processing occurs, whether they are light facing, etc.
So, as usual, when we actually look at the data, they are similar, but at a superficial level.
In regards or the snake study, a link to the actual paper is conspicuously absent. The details matter.
However, good ides are good regardless of their source.
In biological Darwinism, Variation is random to any particular problem to solve, including problems present in their environment, and those that are not. Not only are they not guaranteed to solve local problems an organism might have, but there is no guarantee it will not solve similar problems in some other environment.
For example, bird wings work just as well in North America as they do in Australia. As they would on some complexly different planet with an atmosphere similar to ours, even though they didn't evolve there.
"For example, bird wings work just as well in North America as they do in Australia. As they would on some complexly different planet with an atmosphere similar to ours, even though they didn't evolve there."
DeleteDo you have any empirical criticism to back up those claims? Without other systems, those birds wings don't do anything, at least not on earth.
No Scott, the similarities between human and squid eye are not superficial. Thanks for pointing out the "missing link," it is in there now.
DeleteThe problem with these various examples of convergence is they reveal that evolution is merely a tautology. Evolution is taken as a given, and whatever we find in biology, evolution must have created it, whether or not it accords with the theory. There are always more explanatory mechanisms that can be brought to bear. So from a scientific perspective, the theory has little explanatory value.
"No, it's not", isn't an argument.
DeleteDo I really have to point this out to you?
Marcus,
DeleteThere are obvious caveats, such as if gravity on the planet was 10x stronger, etc. Nor would bird wings continue to work for long if no compatible food supply was present. But my point still stands.
Perhaps your objection would be clearer if you elaborated on why you think bird wings *wouldn't* work on another planet with a comparable atmosphere?
Is there some magical barrier that would prevent it?
Scott, the function of a birds wing is dependent upon more than the atmosphere, things that are not obvious. Its part of a complete system, designed for specific circumstances. I think all of the systems would have to be in place for the statement to be correct.
DeleteI've already provided a few caveats. Beyond those already given, it's unclear why they wouldn't work.
DeleteSo, it would be helpful if you elaborated beyond, "They weren't designed to work there", which wouldn't necessarily follow even if that were true.
That's like saying human designed airplanes wouldn't work on some other planet with a similar atmosphere and gravity as earth because "they weren't originally designed to work there."
I'd also point out that, without further elaboration, Marcus' objection is an example of judging an idea by its source, not it's contents.
DeleteScott: In regards or the snake study, a link to the actual paper is conspicuously absent. The details matter.
ReplyDeleteThis is probably the paper: Grundler & Rabosky, Trophic divergence despite morphological convergence in a continental radiation of snakes, Proceedings of the Royal Society B: Biological Sciences 2014.
http://rspb.royalsocietypublishing.org/content/281/1787/20140413.abstract
Haven't read the paper yet, but from the abstract, researchers found that "Much of the convergence appears to involve the recurrent evolution of stereotyped morphologies associated with foraging mode, locomotion and habitat use" even though the prey differs.
ReplyDeleteZ: Haven't read the paper yet, but from the abstract, researchers found that ....
DeleteJ: ... After assuming that all the millions of assumptions, that no one can even articulate during their life time, required for the "finding-methodology" to be valid, yes ... But you can't apply inductive criteria to that approach. The same kind of thing can be done for tons of UCA and SA histories. But no one can even articulate all the assumptions to "show" us the explanation when you're limited to the data set in question.
Jeff: But no one can even articulate all the assumptions to "show" us the explanation when you're limited to the data set in question.
DeleteWhy don't you start out by articulating why that would even be necessary. Let me guess, some axiom that is beyond criticism requires it?
If the Evolution Theory were graphically represented, I think it would look like an amorphous polymer entanglement, or a hair ball.
ReplyDeleteactually Marcus, evolution is like The Blob. Remember that flick?
DeleteIt consumes all...nothing escapes the EvoBlob.
It is fazed by no thing.
It emulsifies irreducible complexity, digital codes, detect and repair mechanisms and so much more design elements and tools into a palatable elixer.
The EvoBlob..........you've been waaaaarrrrnnnnned.
..........a behemoth....crushing itself under the weight of its own hedge bets....
DeleteAnd it feeds best on zombies ;)
DeleteWhistling past the graveyard
DeleteAnd it is just a matter of time before the whole of creation(ism) is assimilated.
DeleteResistance is futile
Deletevelikovskys,
Delete"Resistance is futile."
Tell that to Data.
Marcus said:
ReplyDelete“If the Evolution Theory were graphically represented, I think it would look like an amorphous polymer entanglement, or a hair ball.”
So something like this.
Germanicus, your link shows a beautiful artistic rendering of the imaginary theory of evolution where one life form leads to another. I was thinking the true state of the theory would be better represented by something like the hair ball in the picture. http://www.sciencebuzz.org/blog/sure_it_s_magic_gross_magic_hairball_magic
DeleteThanks Dr. H.
ReplyDelete"Evolution is taken as a given, and whatever we find in biology, evolution must have created it, whether or not it accords with the theory."
There would be no "must have" if Evolution where not religious in nature. Evolution is a faith based religion--the first tenet of this religion is that Evolution is the Almighty Creator of all biological things.
The venomous snakes "must have" evolved independently because Evolutionists "know" (i.e. their faith-based belief system dictates) that both snakes evolved (they don't know how, but they are certain of it). Since the snakes were too far separated to have "converged", they must have evolved independently.
But, this flexibility weakens the convergence epicycle. If snakes can evolve independently at a distance, then how could anyone know whether they didn't evolve independently in proximity. Proximity make it easy to throw "convergence" around and put a stop to questions.
"Evolution did it." Case closed.
I have a very basic question regarding the theory of evolution. This post highlights the problem I have and that is I really don’t understand how the environment operates to bring about all the morphological novelty that has been created throughout the centuries.
ReplyDeleteThe problem of similar body plans evolving from different ancestors is apparently solved by a label: convergent evolution.
I can understand how changes in the environment bring about minor variations. As a climate becomes colder for example, I can accept that animals that develop thicker coats of fur will have a better chance of surviving and will come to dominate the population.
What I cannot understand is how the environment can effect any major morphological changes. The environment paints with such broad strokes that it cannot “tinker” with anything other than very minor – I would say non-morphological – changes.
For example, what changes in the environment created the hammer head shark, when sharks without a hammer head survive just as well? What about butterflies or any organism that goes through multiple morphological stages during its life cycle. Some environmental variables changed such that a caterpillar builds a cocoon and later emerges with a completely different body plan – really?
Let us not forget the four stage life cycle of the liver fluke.
Why did the artic tern learn to fly between poles when many birds survive without flying from pole-to-pole?
Why did starlings learn to create murmurations when many birds survive without learning to fly in such beautiful patterns?
Evolution did all this - of course.
Doublee: The problem of similar body plans evolving from different ancestors is apparently solved by a label: convergent evolution.
ReplyDeleteConvergence isn't merely a label, but a consequence of natural selection. Observations of convergence is what is known in science as evidence.
Doublee: What I cannot understand is how the environment can effect any major morphological changes.
Because the major morphological changes aren't major morphological changes on short time scales, e.g. limbs evolved from bony fins, and you would probably see little difference between generations.
Doublee: For example, what changes in the environment created the hammer head shark, when sharks without a hammer head survive just as well?
Why would some people be plumbers when electricians survive just as well? Niche specialization is the key. Hammerheads have a number of advantages, including greater binocular perception, and increase maneuverability when hunting benthic prey.
Doublee: What about butterflies or any organism that goes through multiple morphological stages during its life cycle.
Metamorphosis is just part of an extended development. It's just that the larvae can also feed. Before about 280 million years ago, insects hatched as miniature adults. After that time, the young of some species hatched as worm-like organisms.
Doublee: Why did the artic tern learn to fly between poles when many birds survive without flying from pole-to-pole?
Niche specialization.
But how did the wormlike larva know how to turn into adults? How did they knowhow to go to sleep as a pupa, and wake up as an adult?
DeleteShevi S: But how did the wormlike larva know how to turn into adults?
DeleteIt's not a matter of knowing, but evolution. Some larvae are born early before development is complete.
Okay, how did they evolve the ability to survive as early born larva? How did they evolve they abilty to go to sleep and wake up as adults?
Deletenatschuster: Okay, how did they evolve the ability to survive as early born larva?
DeleteThey don't have to be that early born, just a bit early at first. It's not known for sure, but one hypothesis is that they started by ingesting the remaining yolk.
natschuster: How did they evolve they abilty to go to sleep and wake up as adults?
Many insects don't go to sleep, but got through an incomplete metamorphosis from pronymph to nymph stage. Metamorphosis is just a variation in the process of development.
Zachrei:
Delete…[B]ecause the major morphological changes aren't major morphological changes on short time scales,…
I know that major morphological changes aren’t major morphological changes on short time scales.
I am trying to understand the nature of the environment and what variables in that environment would result in the evolution of one form rather than another.
For example, what are the specific variables in the environment that would result in the evolution of the hammer head shark? At the same time there are many another species of shark in the same environment I would assume.
To put the question another way, what are the components of natural selection that would select those incremental changes that would eventually result in the hammer head shark?
It seems that Richard Dawkins and David Berlinski have said it best. “What survives, survives.”
Doublee: I am trying to understand the nature of the environment and what variables in that environment would result in the evolution of one form rather than another.
DeleteIt takes two factors; variation and selection. When a variation occurs that allows for niche specialization cladogenesis can result.
Doublee: To put the question another way, what are the components of natural selection that would select those incremental changes that would eventually result in the hammer head shark?
With hammerheads, there is still some uncertainty. However, as we pointed out above, the adaptation seems to have evolved for hunting on the seabed for shrimp, rays, and small fish. Hammerheads sacrifice some power in swimming for maneuverability and a greater sense capability, including binocular vision, and a refined electrical sensitivity suitable for finding prey hidden in the seabed.
Doublee: “What survives, survives.”
Unless reproductive success is linked to heritable traits, there is no evolution.
Zachriel:
DeleteIt takes two factors; variation and selection
You continue to supply labels with no substance. Am I not making myself clear or do you really have no answers to my questions? Please tell me what you don't understand about my questions and I'll try one more time to make myself clear.
Doublee: You continue to supply labels with no substance.
DeleteVariation and selection are directly observed. Have no idea why you consider the answer insufficient, especially as the terms variation and selection are not without substance.
Doublee: “What survives, survives.”
That's not the claim, of course. It's that certain variation have a greater chance of reproductive success. You have sharks. Some have wider heads which give them advantages when hunting benthic prey, but disadvantages them when hunting fast moving fish.
"Convergence isn't merely a label, but a consequence of natural selection. Observations of convergence is what is known in science as evidence."
ReplyDeleteIf your religion is evolution then you can label it evidence. Heck, you can call it what ever you want.
Marcus: If your religion is evolution then you can label it evidence. Heck, you can call it what ever you want.
DeleteWe assure you, it's not our religion. In any case, Darwin posited convergence as a consequence of natural selection in the nineteenth century.
Week in and out, Dr. Hunter proves evolution is a religion. I'm grateful he continues to publish on this blog.
DeleteWeek in, week out, Dr Hunter calls science a religion. But calling it one doesn't make it one. I can call a dog "a cat" but it doesn't make it a cat.
DeleteIf Dr. Hunter is making a mockery, why would you of sound mind read his work every week and comment on his blog continuously? I think you are drawn to all of his compelling arguments and you can't help yourself Ian.
DeleteDon't most people around here think religion is a good thing, and that religion is an important part of their lives? So saying evolution is a religion is really a compliment?
DeleteSo saying evolution is a religion is really a compliment?
DeleteNot if it's a heretical religion. Heretics preach falsehood and must be destroyed lest their lies lead the faithful to hell.
This comment has been removed by the author.
ReplyDeleteWhat Darwin postulated is similar to what is used above to counter Dr Hunter’s assertion that squid and human eyes have many similarities. The argument against that was on a morphological/ phenotypical scale whereas phenotype is largely driven by genotype therefore the molecular similarities and differences are what really matter.
ReplyDeleteDarwin posited convergence on the morphological scale, not necessarily on the molecular scale. Equally, the argument used here that squid eyes operate differently to human eyes is less relevant than what are the main genes and proteins involved in eye function and in human function where they evolved separately, apparently. Typically, we find strong similarity between the various genes involved in similar functional processes, such as vision/ the eye.
Equally, although we might expect the necessity for evolution to come to the same solution to a necessary environment-induced adaptation phenotypically (if you need to fly, you need wings, these are a common known efficient structure that allow flight, therefore it seems that different adaptations could be expected to converge to this “function”), there is no reason to expect that they will come to the same solution on the molecular basis. This is due to the sequence search space and random probabilities needed to generate a functional protein from a gene, where say the average protein is 300aa in length and would require multiple components to make a successful pathway to generate the phenotype observed. Not to mention the need for specialised cells to also undergo morphological changes themselves to enable them to perform this role, from differences in membrane composition to differences in shape, size, cell-cell contacts and organelle composition among other changes. Therefore, it could be viewed as a surprise that convergence at the molecular level is such an observed phenomenon (hence why in many publications where convergence is found, it is often described as "surprisingly").
Further, it is a fallacy to argue that convergence is “strong” evidence for evolution as this does not understand what “strong” evidence truly is. Strong evidence would be evidence that supersedes or outweighs opposing theories (or in this case an opposing theory[singular]). Yet clearly, convergence does not do that – far from it (for reasons outlined above why expectations of evolution might be different to what we find here). For example, if I take a 4x4 Ford car and compare it to a coupe Ford car would I say that the 4x4 evolved from the coupe because although it is different in many ways, it converges in the various instruments, engine, and mechanical parts and layouts it uses? Or would I infer that because of these similarities, they are from the same designer? That is an obvious answer and it is plain to see that similarity strongly implies a similar designer.
Therefore to say that convergence is strong evidence for evolution when it is at best equal as evidence for a common designer is a misunderstanding of what strong evidence constitutes and is quite frankly very wrong. Equally, if things are dramatically different (for example if there was quite a different genetic code in existence in one set of organisms than in another), evolution would welcome this evidence as strong support for the theory as this different code arose from divergence and evolved differently as a result. So if both scenarios can be accommodated by the theory, it is a theory of everything and a theory of everything is a theory of nothing as famously said (by whom I forget).
So if you wish to hold onto your faith of evolution you can continue to use convergence as a piece of strong evidence for your worldview but it is only strong evidence where there is no other theory (i.e. you exclude intelligent design as a valid scientific approach which much of modern science seems determined to do) and therefore it is the only theory for life and divergence and therefore everything you find is strong evidence for your theory as there is no other alternative.
Thus, a theory of nothing.
Dr JDD: Darwin posited convergence on the morphological scale, not necessarily on the molecular scale.
DeleteMost of the same rules apply. If you have similar environmental pressures, then the adaptations may converge, especially if they start from similar beginnings. Nevertheless, as Darwin said, we will not generally see them "converge so closely as to lead to a near approach to identity throughout their whole organisation."
If you disagree, you might want to post specifics.