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Experimental evidence for evolution

Discussion of everything related to the Theory of Evolution.

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Re: Experimental evidence for evolution

Postby jevg » Sat Oct 02, 2010 10:43 pm

I asked a simple question “what do you think?

You raise an interesting scenario.
Maybe it makes it easier to crawl into small holes/spaces, or maybe something else that cannot be seen but was advantageous for the snake's ancestor.


May I refer you to Richard Ellisin’s book AquaGenesis where he puts it this way on page 158

“Although the fossil record is too sparse to make any definitive statements (always dangerous in paleontology anway), many paleontologists have done exactly that. After two groups of scientists examined fossil snakes from the same area, two scenerios emerged. Scanlon, Lee, and Caldwell have proposed that snakes are derived from water-dwelling lizards (mosasaurs), and emerged from the water to become the terrestrial species that we know today. “
“the other group of scientists, Tchernov et al. (2000), believe that modern snakes are the descendants of small, burrowing, terrestrial lizards.

. . . As for the legs, which Scanlon et. al. cited to demonstrate that snakes are descended from lizards, all they mean to Tchernov's group is that ancestral lizards lost their legs, became snakes, evolved into snakes with legs, and as of now have become (mostly) snakes without legs. They acknowledge that this is a less parsimonious explanation, but it nevertheless "remains a possibility, given the incompleteness of the fossil record of snakes and the recognition of multiple loss of limbs among squamates in general."

This excerpt simply highlights the different views.

Notice that with the “land hypothesis”, the originators Tchernov et.al. acknowledge that their explanation is “a less parsimonious” one, the hypothesis that you appear to be supporting.

Excerpts from Page 155
. . . None of this discussion addresses what to many is the fundamental question about snake evolution in the first place: Why should an animal with legs evolve into one without them? Legs seem to be quite a useful bit of equipment; every other terrestrial vertebrae has them. Only the fishes are legless; the whales, to adapt to the fishes watery environment, have lost their hind limbs completely and their forelimbs have evolved into paddles. Perhaps the sea snakes are a more advanced form of snake, for only in aquatic animals does leglessness confer an advantage -- or at least, it does not handicap the animal. . .

You will notice that my question is a direct lift from Ellisin’s book. So it is Ellisin who does not see the advantage of loss of limbs. In fact he goes further and states that “only in aquatic animals does leglessness confer an advantage -- or at least, it does not handicap the animal. . .

My guess is he knows more about this subject than you or I and it could even include Geokinkladze


You suggest I use Occams razor and I am very happy to apply that principle.

Here is the principle http://pespmc1.vub.ac.be/occamraz.html
“The principle states that one should not make more assumptions than the minimum needed. This principle is often called the principle of parsimony. It underlies all scientific modelling and theory building. It admonishes us to choose from a set of otherwise equivalent models of a given phenomenon the simplest one. In any given model, Occam's razor helps us to "shave off" those concepts, variables or constructs that are not really needed to explain the phenomenon. By doing that, developing the model will become much easier, and there is less chance of introducing inconsistencies, ambiguities and redundancies.”

So which idea do I apply Occams razor to
The aquatic hypothesis
The land hypothesis
Or the “someone removed the legs intentionally” hypothesis. :)

Well since I have played “devil advocate” by introducing the creation or “someone removed the legs intentionally” hypothesis I will apply occam’s razor to it.

Remember one should not make more assumptions than the minimum needed.

We know that during the late 50’ and early 60’s thousands of women took the drug Thalidomide to combat morning sickness. This resulted in the terrible tragedy of thousand’s children being born with deformed or missing limbs.

So it proved that direct intervention (whether intentional or not) during the embryo stage of development can produce loss of limbs.

The only assumption that therefore needs to be made is that the cell mechanism can be directly altered to make this change heritable.
Therefore just one assumption is required.
Less than one could make it a fact.

How many assumptions are needed for the “land hypothesis” ?
How many for the “aquatic hypothesis” ? http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1626205/

Please read just the Conclusion of the paper and count the number of assumptions. Also remember that the land hypothesis is less parsimonious than the aquatic hypothesis.

Now I am only playing “devils advocate” here, but the creation hypothesis wins, simply on the basis of the occams razor principle which you have introduced into this discussion.

I have studied Gould’s essay on the Panda’s thumb and I would ask you to count the number of assumptions he has had to make before he arrived at where he wished to go.

We are dealing here with belief systems not with the scientific method.
The boundary between belief and science is being blurred to the point that beliefs are being presented as fact and that, I strongly argue, is not good science.
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Re: Experimental evidence for evolution

Postby canalon » Mon Oct 04, 2010 5:57 pm

jevg wrote:Notice that with the “land hypothesis”, the originators Tchernov et.al. acknowledge that their explanation is “a less parsimonious” one, the hypothesis that you appear to be supporting.


I would not call a "top of my head hypothesis" a support for any hypothesis. I have absolutely no clue about what made the loss of limb useful to be honest. I was just trying to point out that the fact that you (or anyone else for that matter) do not see the advantage does not mean that there are none.

jevg wrote:Please read just the Conclusion of the paper and count the number of assumptions. Also remember that the land hypothesis is less parsimonious than the aquatic hypothesis.

Now I am only playing “devils advocate” here, but the creation hypothesis wins, simply on the basis of the occams razor principle which you have introduced into this discussion.

Actually you were the first one to bring it in, and I will once again repeat what I told you: the implicit complexity of the creator is much higher than any hypothesis that we could do based on that event happened randomly, and that one, and that other... because if you take the thalidomide example to get there you needed the full evolution of human, the development of a civilization and of a chemical industry etc to get to that molecule. So one little pill/step with a lot more hidden complexity than a series of mutations by mechanisms that are known and do not require external forces.
This is in this hidden complexity that you have consistently refused to acknowledged that lies the opposition to any external creator in modern science.
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Re: Experimental evidence for evolution

Postby Geokinkladze » Tue Oct 05, 2010 1:31 am

jevg wrote:
You appear to be (and I would conclude unintentionally) blurring the distinction between variation within species (ie darwin@s finches) and speciation.


Ok give me YOUR universally accepted definition of a species. In other words YOUR definition of a species, that is also universally accepted as THE definition of species. Now I'm not interested in your definition that is accepted by the people who read the same books as you, I'm talking about THE universally accepted definition. I could be asking the impossible, maybe miracles happen?

jevg wrote: Now a biblical scholar pointed me to the Genesis account Chapter 3 verse 14, which reads in reference to the serpent.
“Because you have done this you are accursed more than all the cattle and all wild creatures. On your belly you shall crawl……”

So the account states that all the animals were put into a state of disadvantage (cursed) but the snake more than the rest, in that it lost it’s limbs.

Now I may not be a creationist, but this explanation has more logic to it than Darwinian selectivity.


jevg wrote: What do you think?


Firstly I think you're a creationist. Now that's not meant as an insult so please don't take it as one. I guess that's just my opinion. The only reason I say it is that you say you're not, but it's become fairly obvious to me that you are.

Secondly, with regard to the snake: Limbs have a resource cost that requires maintenance. Limbs would adversely affect digestion. Limbs would snag on twigs and branches. They would provide an easier target for predators and prey. In return what advantages would they provide? I guess that as random mutation and natural selection have led to them disappearing then the advantages must have been outweighed by the disadvantages.
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Re: Experimental evidence for evolution

Postby StevePush » Tue Oct 05, 2010 7:48 am

I am just now joining this long and interesting thread, so please forgive me if I'm repeating information others have already covered.

jevg says "the Darwinian mechanism does not explain speciation." This statement is true if by "Darwinian" jevg means the theory as explicated in Darwin's On the Origin of Species in 1859. Darwin did a good job of explaining adaptation, but despite his ambitious title, he didn't provide much insight into the process of speciation.

But current evolutionary theory -- called the "modern synthesis" because it integrates Darwin's theory with Mendelian genetics -- explains speciation quite well. And evolutionary biologists have amassed considerable evidence to support this view.

For an excellent review of this evidence I refer you to Chapter 7 of Why Evolution Is True by Jerry A. Coyne. Because speciation generally takes millions of years, it cannot be observed directly. But the fossil record, embryology, and genetic analysis show that species diverged from common ancestors.

The most common type of speciation involves geographic isolation. The theory of geographic speciation predicts that species on either side of a geographic barrier will be more closely related to each other than to species on the same side of the barrier. This is exactly what evolutionary biologists have found. Coyne writes:

Each side of the Isthmus of Panama, for example, harbors seven species of snapping shrimp in shallow waters. The closest relative of each species in another species on the other side. [Emphasis in original.]

Evolutionary theory also predicts that after a period of geographic isolation, diverging species will become reproductively isolated. This reproductive isolation has been shown many times in nature. And using flies, which have short generation times, scientists have been able to produce reproductively isolated populations in the lab.

Coyne also describes another type of speciation that can be studied directly. Polyploidy, or the production of extra copies of chromosomes, can cause speciation in as little as two generations. This type of speciation happens often in plants and occasionally in animals. In some plants, biologists have been able to reproduce these speciation events in the lab, to the extent that the lab varieties can mate successfully with the species that evolved in nature.

Thus Darwinian theory, as it is currently understood by evolutionary biologists, is extremely well supported by scientific evdience.
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Re: Experimental evidence for evolution

Postby jevg » Tue Oct 05, 2010 8:40 pm

canalon
Your honesty is very refreshing, and this is in no way a patronising comment.

I agree that because I don’t see an advantage does not mean there is none.

What I disagree with is the a priori position that speciation is a product of some Darwinian mechanism and that position is a scientific fact. If it were a fact then the evidence would point to it.

I have been consistent in pointing out that the experimental evidence does not point in that direction. In fact it contradicts that position.

Now nobody has managed to refute that evidence and with good cause because this controversy is not about science but about two opposing belief systems.

Neither of these belief systems can be supported by science.

Science by it’s very nature, must operate within the realms of natural law, and natural law does not and indeed cannot explain the arrival of the cell or life or species.
This is the situation whether we like it or not.

Let me explain ( Please think about this)

All known life depends upon genetic instructions. No hint of metabolism has ever been observed independent of an oversight and management information/instruction system.

We use the term "bioengineering" with good reason.

Genes are literal programs. They are sent from a source by a transmitter through a channel within the context of a viable cell. They are decoded by a receiver and arrive eventually at a final destination.
At this destination, these messages catalyze the needed biochemical reactions.

The cell is in fact a biochemical communication system.

Genes have undeniable "meaning" which is shared between source and destination. (Fact)
Noise pollution of this "meaning" is greatly minimized in the cell by ideally optimized redundancy coding and impressive biological repair mechanisms. (Fact)

A noisy channel is one that produces a high corruption rate of the source's signal.
Now signal integrity is greatly compromised during transport by randomizing influences. (Fact)
In molecular biology, various kinds of mutations introduce the equivalent of noise pollution of the original instructive message. (Fact)

Communication theory goes to extraordinary lengths to prevent noise pollution of signals of all kinds. (Fact)

So given this longstanding struggle against noise contamination of meaningful algorithmic messages, does it not seem curious to you that the central dogma of biology today attributes genomic messages themselves solely to "noise."?

Without algorithmic programming to control options, the number of possible paths in sequence space for each needed biopolymer is truly enormous.

But when multiple biopolymers must all converge at the same place at the same time to collectively interact in a controlled biochemically cooperative manner, I argue that faith in this "self-organization" becomes "blind belief."
No empirical data exists for such a metaphysical leap.

Darwinism (in all its forms) and Creationism (in all its forms) are both belief systems, trying to explain this arrival with both claiming theirs is truly scientific. The fact is that neither of them is.

Isn't it about time a start is made to at least acknowledge this.
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Re: Experimental evidence for evolution

Postby Geokinkladze » Tue Oct 05, 2010 10:01 pm

StevePush wrote: I am just now joining this long and interesting thread


You are half right, it's certainly long. It's been fun while it lasted but unfortunately I shall have to take my leave and do other things. I'll hope to check back now and again to see if there's an answer to the question: why are leaves green? see: http://www.biology-online.org/biology-forum/about675-48.html which is originally what brought me here.

Hopefully if anything comes of this thread then it will be that viewers will realise it's better to prevent your religious views from clouding your rational ones. Science is attempting to answer the big questions via a series of small incremental steps, sometimes there are periods of stasis, other times there are periods of rapid discovery, quite a lot of theories become extinct (sound familiar anyone?) :wink:

Stephen Hawkings is currently doing the rounds with his new book, he says that God isn't necessary to explain the creation of the universe. I agree wholeheartedly with that one. Anyone who tries to prove or disprove the existence of God by scientific means should be treated with caution.
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Re: Experimental evidence for evolution

Postby StevePush » Wed Oct 06, 2010 4:23 am

jevg wrote:Darwinism (in all its forms) and Creationism (in all its forms) are both belief systems, trying to explain this arrival with both claiming theirs is truly scientific. The fact is that neither of them is.

I agree with regard to creationism. It is not falsifiable and thus not scientific.

Darwinism, on the other hand, is scientific, and your own posts prove as much. You claim to have presented experimental evidence that cotradicts Darwinian theory. I disagree that the studies you cite contradict Darwinism, but the fact you can articulate such an argument proves that Darwinism is falsifiable.

The fact that Darwinists are unconvinced by your arguments does not in itself render their views to be blind faith. As long as they can make predictions that can potentially be proven false, their views are scientific.
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Postby canalon » Wed Oct 06, 2010 10:18 pm

JEVG

The theory of evolution as we know it is scientific as it lays hypothesis on how it work, makes predictions and allow verification of them, or falsifications. Creationism is based on faith only. That is the main difference.
Now in light of your analysis of facts, I hope you won't mind if I ask whether you are an engineer. For curiosity's sake...
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Re: Experimental evidence for evolution

Postby jevg » Mon Oct 11, 2010 7:17 am

canalon

Sorry for the delay but have been otherwise occupied. Life outside this forum you know :)

I am a Radio/Radar Engineer (now retired).

I agree with your last comment. Creationism is based on faith and cannot be subjected to scientific enquiry. Where I would add to your comment is that Darwinism which was and could have been regarded as null hypothesis originally has now, in my view, taken on the mantra of a faith based system.

Darwin tried to explain the origin of Species scientifically and indeed put forward a plausible hypothesis while honestly recognising it's flaws. Those flaws have in the light of evidence turned out to be quite profound and that is why I argue the way I do.
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Re: Experimental evidence for evolution

Postby jevg » Mon Oct 11, 2010 7:46 am

StevePush

I hope my response to canolan explains more my position.
My whole point is that Darwinism is falsifiable and the evidence is showing it to be so. Since it is being falsified with evidence, and at the same time still being regarded as a scientific theory (indeed as fact) this is what has turned this hypothesis into a belief system.

You referred me to Jerry Coyne's book.
I have read a lot of it though not all and would be very happy to discus it further. This book actually proves my point and I will be quite happy to demonstrate it.
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Re: Experimental evidence for evolution

Postby StevePush » Tue Oct 12, 2010 6:32 am

jevg wrote:You referred me to Jerry Coyne's book.
I have read a lot of it though not all and would be very happy to discus it further. This book actually proves my point and I will be quite happy to demonstrate it.

I would be pleased to read your thoughts on why you believe the theory of evolution has been falsified.
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Postby JackBean » Tue Oct 12, 2010 8:42 am

jevg:
you're saying, that darwinism/theory of evolution was disproved, but these are not equal. The theory of evolution was here even before Darwin, he just came up with the mechanism.
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.
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