Questions about Evolution

[iNow]

For instance, your point (3) about the evolution of the eye is incomplete. From what did the eye evolve in 364000 generations? And really, an eye can be described in 3640-ish bits? You must be kidding. Describing an eye, with all its intricaties, its interactions with other subsystems, its chemical composition, etc. etc. would take millions, probably hundreds of millions of bits. Books full of texts are written about the eye... and still, all these books together only capture a tiny fraction of what the eye really is.

 

You know, the mammalian eye isn't even really that great. This may help you understand its evolution.

 

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Evolution: Library: Evolution of the Eye

Evolution of the Eye:

When evolution skeptics want to attack Darwin's theory, they often point to the human eye. How could something so complex, they argue, have developed through random mutations and natural selection, even over millions of years?

 

If evolution occurs through gradations, the critics say, how could it have created the separate parts of the eye -- the lens, the retina, the pupil, and so forth -- since none of these structures by themselves would make vision possible? In other words, what good is five percent of an eye?

 

Darwin acknowledged from the start that the eye would be a difficult case for his new theory to explain. Difficult, but not impossible. Scientists have come up with scenarios through which the first eye-like structure, a light-sensitive pigmented spot on the skin, could have gone through changes and complexities to form the human eye, with its many parts and astounding abilities.

 

Through natural selection, different types of eyes have emerged in evolutionary history -- and the human eye isn't even the best one, from some standpoints. Because blood vessels run across the surface of the retina instead of beneath it, it's easy for the vessels to proliferate or leak and impair vision. So, the evolution theorists say, the anti-evolution argument that life was created by an "intelligent designer" doesn't hold water: If God or some other omnipotent force was responsible for the human eye, it was something of a botched design.

 

Biologists use the range of less complex light sensitive structures that exist in living species today to hypothesize the various evolutionary stages eyes may have gone through.

 

Here's how some scientists think some eyes may have evolved: The simple light-sensitive spot on the skin of some ancestral creature gave it some tiny survival advantage, perhaps allowing it to evade a predator. Random changes then created a depression in the light-sensitive patch, a deepening pit that made "vision" a little sharper. At the same time, the pit's opening gradually narrowed, so light entered through a small aperture, like a pinhole camera.

 

Every change had to confer a survival advantage, no matter how slight. Eventually, the light-sensitive spot evolved into a retina, the layer of cells and pigment at the back of the human eye. Over time a lens formed at the front of the eye. It could have arisen as a double-layered transparent tissue containing increasing amounts of liquid that gave it the convex curvature of the human eye.

 

In fact, eyes corresponding to every stage in this sequence have been found in existing living species. The existence of this range of less complex light-sensitive structures supports scientists' hypotheses about how complex eyes like ours could evolve. The first animals with anything resembling an eye lived about 550 million years ago. And, according to one scientist's calculations, only 364,000 years would have been needed for a camera-like eye to evolve from a light-sensitive patch.

 

Approach the world with open eyes...

[foodchain]

Although I do believe that evolution occured, I don't think this is a good explanation. I have to believe that evolution occured, simply because of the overwhelming evidence, but mathematically speaking, I simply cannot understand it.

 

For instance, your point (3) about the evolution of the eye is incomplete. From what did the eye evolve in 364000 generations? And really, an eye can be described in 3640-ish bits? You must be kidding. Describing an eye, with all its intricaties, its interactions with other subsystems, its chemical composition, etc. etc. would take millions, probably hundreds of millions of bits. Books full of texts are written about the eye... and still, all these books together only capture a tiny fraction of what the eye really is.

 

Now look at the human genome, how many bits are needed for describing it (using the best available compression techniques available)? Still many billions of bits. Assume, that initially, appr. 3.5 billion years ago, there was no information or just a few tens of bits of information (e.g. simple organic molecules), then it would take zillions of years to evolve to human beings, much more than the universe exists now (appr. 14 billion years) and even more than earth exists and could sustain life after its initial very hot period (3.5 to 4 billion years).

 

In some way, I have a feeling that this reasoning is flawed. I do not have the expertise to pinpoint what is wrong, but given the tremendous complexity of current life forms, this mechanism simply is too slow.

 

It is remarkable that evolution has gone so fast. In just a few billions of years it has resulted in what we see now. I personally think that there still remains a lot to be explained and that no definite answers are found. We can fairly well do descriptive evolutionary science, but the underlying mechanisms still are far from being understood near 100%. Selection most likely is an important part of the underlying mechanism, but there must be more than that. I don't believe in a single silver bullet, which explains it all. Probably many different mechanisms are working (have been working) "cooperatively".

 

One thing you can also look at today is the simple fact that you can look at the complexity of the eye in reference to more simpler versions, such as on a crab compared to say a human eye. Or the evolution of the eye is still around today. Its not as if one day in one specie appeared a perfect eyeball or something. Insect vision is also a bit different from peoples I would say, and how the eye works and related anatomy varies considerably taking into account all the various species that posses such.

[immortal]

 

For instance, your point (3) about the evolution of the eye is incomplete. From what did the eye evolve in 364000 generations? And really, an eye can be described in 3640-ish bits? You must be kidding. Describing an eye, with all its intricaties, its interactions with other subsystems, its chemical composition, etc. etc. would take millions, probably hundreds of millions of bits. Books full of texts are written about the eye... and still, all these books together only capture a tiny fraction of what the eye really is.

 

Now look at the human genome, how many bits are needed for describing it (using the best available compression techniques available)? Still many billions of bits. Assume, that initially, appr. 3.5 billion years ago, there was no information or just a few tens of bits of information (e.g. simple organic molecules), then it would take zillions of years to evolve to human beings, much more than the universe exists now (appr. 14 billion years) and even more than earth exists and could sustain life after its initial very hot period (3.5 to 4 billion years).

 

In some way, I have a feeling that this reasoning is flawed. I do not have the expertise to pinpoint what is wrong, but given the tremendous complexity of current life forms, this mechanism simply is too slow.

 

 

Evolution works by cumulative selection, it preserves good changes and eliminates the rest. Yes without selection organisms would just mutate or change and it would take zillions of years to evolve into humans but if you add selection you can easily evovle into humans within 3.5 billion years. It does'nt mean that it was designed to create us it is just an emergent property of the systems no one is intending to create us not even god.

 

For example:- Tell a monkey to write the eleven letters in the word 'shakespeare' on a typewriter it would take millions of years for a monkey to write the word with one go. Now you add selection keep the letters which are on the right place (for example if a monkey types the letter 'a' on the third box ) and jumble the rest and you would see that it does'nt take millions of years to type the word. This is how evolution works. And also you will see that at the begining there will be a sudden burst of mutations and selection pressures acting which accerelates evolution.

[shadowacct]

Approach the world with open eyes...

Yes, with open eyes, but also with a critical mind. If they mention that according to one scientist's calculations, a camera-like eye can form in 364000 years from a very simple structure, then I would like to see more detail on this. Any more references? Links? I simply don't believe this, without further evidence than someone referring to "one scientist's calculations".

 

 

One thing you can also look at today is the simple fact that you can look at the complexity of the eye in reference to more simpler versions, such as on a crab compared to say a human eye. Or the evolution of the eye is still around today. Its not as if one day in one specie appeared a perfect eyeball or something. Insect vision is also a bit different from peoples I would say, and how the eye works and related anatomy varies considerably taking into account all the various species that posses such.

I agree that evolution of the eye still is happening and sure, eyes of future species will differ from eyes of current species. But this does not answer my questions.

 

 

For example:- Tell a monkey to write the eleven letters in the word 'shakespeare' on a typewriter it would take millions of years for a monkey to write the word with one go. Now you add selection keep the letters which are on the right place (for example if a monkey types the letter 'a' on the third box ) and jumble the rest and you would see that it does'nt take millions of years to type the word. This is how evolution works. And also you will see that at the begining there will be a sudden burst of mutations and selection pressures acting which accerelates evolution.

I see the analogue and I like it (it at least partially answers my question). But still, I have an important question about this. In the 'shakespeare' analogon, the outcome already is known and so we can keep letters at the right place. I also see that in this case, the process of typing the correct word boils down to 11 parallel processes, one process for each letter. As soon as all 11 processes have finished, we have the desired result. This is much better than having a single process with 26^11 possibilities, which have to be fulfilled.

In evolution, however, the outcome is not known and we have no criterion, on which we can decide in the right direction or not. Also, intermediate steps can be less fit than both the starting point and the end point. The 'shakespeare' analogon has a nice property, that it is monotonous with repsect to fitness. The closer to the desired word, the more fit. In evolution, I really think that this monotonous function of fitness is not a correct assumption. There may be local minima of the fitness function, and I would expect it to be VERY hard to overcome such local minima, especially if the steps, taken by the process are small.

I'll keep this analogon in mind, however, and think about it, and see if it can be adapted to solve the problem of non-monotonous fitness and unknown outcome.

[Paralith]

In evolution, however, the outcome is not known and we have no criterion, on which we can decide in the right direction or not. Also, intermediate steps can be less fit than both the starting point and the end point. The 'shakespeare' analogon has a nice property, that it is monotonous with repsect to fitness. The closer to the desired word, the more fit. In evolution, I really think that this monotonous function of fitness is not a correct assumption. There may be local minima of the fitness function, and I would expect it to be VERY hard to overcome such local minima, especially if the steps, taken by the process are small.

 

The criterion that you are looking for is determined by the environment. A trait in the "right direction," as you say, in the context of the environment, gives it's owner more reproductive success than other individuals who do not have that trait. That trait may not be perfect, but that doesn't matter - what matters is that it is better than other traits for conferring reproductive success in that environment. This trait will then be maintained in the population at a greater frequency than the other, less fit traits.

[iNow]

Yes, with open eyes, but also with a critical mind. If they mention that according to one scientist's calculations, a camera-like eye can form in 364000 years from a very simple structure, then I would like to see more detail on this. Any more references? Links? I simply don't believe this, without further evidence than someone referring to "one scientist's calculations".

 

Curious you read my post that way. I was simply giving one example to illuminate just how easily possible this actually is. However, you critical mind is worthy of respect, and I offer you the following 26,300 examples to help you "believe" this. If the above examples and those linked below STILL aren't enough, then I'd suggest you will never accept that the mammailian eye could EASILY have been formed via evolution by natural selection, despite what evidence is put forth for your review.

 

http://scholar.google.com/scholar?q=mammalian+eye+evolution&hl=en&lr=

[foodchain]

I agree that evolution of the eye still is happening and sure, eyes of future species will differ from eyes of current species. But this does not answer my questions.

 

 

Well I don’t know what would convince you. Evolution is present physically in evidence, in life basically. If you would just study why science makes the claim of evolution you would see this. As for the math and the generation bit, well, I would think that’s not exactly the reality of it. I mean what’s the typical lifespan of a rat in the woods, how many offspring does it produce, how many of them survive, is it always the same number? Is it like this for all mammals, what about fish, how about reptiles, or for any specie or organisms period?

 

I mean if you don’t accept vision or the organs and related biology for such to come about from natural selection then I don’t know what aspect of evolution as understood by biology you would accept really. Vision most likely made it in a macro and micro sense or in time, it was successful and thusly successful aspects of biology sticks around. It does not have to be perfect, nothing in biology is perfect in regards to what is the best trait, that’s typically Hitler like vision really, not saying you do that. What allows something to survive today may not be what it takes in X time for such.

 

Lastly again from the molecular scale to the ecological scale there is a massive amount of evidence physically for evolution, this includes vision also. Simply put like in my earlier post more "primitive" versions of such are still alive today, you have to go and take the theory as put forward in the books though to life itself, as in you actually have to go and study organisms and what’s related to them such as behavior to understand where the theory comes from.

[shadowacct]

If you would just study why science makes the claim of evolution you would see this.

My problem is not acceptance of evolution, I hardly doubt that this occurred and still occurs. But I am wondering about the underlying mechanisms.

 

I mean if you don’t accept vision or the organs and related biology for such to come about from natural selection then I don’t know what aspect of evolution as understood by biology you would accept really.

It is not a matter of acceptance, there is evidence for evolution (geological track, DNA). But it is more a matter of the how.

 

A similar thing I have with other sciences, such as the theory of gravity. I perfectly understand this (and even did a lot of computations with it), but it still does not explain it to me. What is gravity? What is it really? We can describe it very accurately (in fact, amazingly accurately) but still, we are struggling about its precise nature. A similar thing is true for evolution. We have quite good descriptions of what happened and about the time scale on which things happened. But these are descriptions, just like we have for gravity. But what is the driving force? Selection most likely is part of it, but I have the strong feeling there must be more. We don't have the full answer (yet), and that also is something a good scientist always must keep in mind. There remains a lot more to be discovered.

 

Finally, there is the question of the 'why'. But this is not the realm of science. Then we go to philosophy, ethics, religion. From a scientists point of view, I would already be very happy with a deep understanding of the 'how' question. We solved the 'what' question to a fair extent, and we are just touching upon the 'how' question. The 'why' question is a deeper question and I have personal ideas about that, but on a scienceforum I don't want to bother you with that .

[CDarwin]

But I am wondering about the underlying mechanisms.

 

Selection, genetic drift, gene flow, and mutation primarily.

 

It is not a matter of acceptance, there is evidence for evolution (geological track, DNA). But it is more a matter of the how.

 

Selection, genetic drift, gene flow, and mutation primarily.

 

A similar thing I have with other sciences, such as the theory of gravity. I perfectly understand this (and even did a lot of computations with it), but it still does not explain it to me. What is gravity? What is it really? We can describe it very accurately (in fact, amazingly accurately) but still, we are struggling about its precise nature. A similar thing is true for evolution.

We have quite good descriptions of what happened and about the time scale on which things happened. But these are descriptions, just like we have for gravity. But what is the driving force? Selection most likely is part of it, but I have the strong feeling there must be more. [/Quote]

 

This is based on your "strong feeling" that selection is insufficient. You misrepresent it when you say "we" like you're speaking for humanity, because scientists do have a very good idea of the nature of evolutionary change.

 

We don't have the full answer (yet), and that also is something a good scientist always must keep in mind. There remains a lot more to be discovered.

 

Meaningless truism.

[Paralith]

My problem is not acceptance of evolution, I hardly doubt that this occurred and still occurs. But I am wondering about the underlying mechanisms.

 

It is not a matter of acceptance, there is evidence for evolution (geological track, DNA). But it is more a matter of the how.

 

A similar thing I have with other sciences, such as the theory of gravity. I perfectly understand this (and even did a lot of computations with it), but it still does not explain it to me. What is gravity? What is it really? We can describe it very accurately (in fact, amazingly accurately) but still, we are struggling about its precise nature. A similar thing is true for evolution. We have quite good descriptions of what happened and about the time scale on which things happened. But these are descriptions, just like we have for gravity. But what is the driving force? Selection most likely is part of it, but I have the strong feeling there must be more. We don't have the full answer (yet), and that also is something a good scientist always must keep in mind. There remains a lot more to be discovered.

 

Finally, there is the question of the 'why'. But this is not the realm of science. Then we go to philosophy, ethics, religion. From a scientists point of view, I would already be very happy with a deep understanding of the 'how' question. We solved the 'what' question to a fair extent, and we are just touching upon the 'how' question. The 'why' question is a deeper question and I have personal ideas about that, but on a scienceforum I don't want to bother you with that .

 

I disagree that the " 'how' question" is just barely being touched upon. The "what" of evolution was accepted by mainstream science quite a while ago, and ever since then the "how" has been the main focus of research. Especially the eye, an example you've seized upon - this is an organ about which a lot of the "how" has in fact been answered, especially since it's a favorite example of IDers and creationists. If you have trouble accepting this "how," then you're going to have trouble accepting the rest of the "how" that evolutionary biologists have further described - and I think that's the main point that foodchain was trying to make.

 

You'll have to forgive me for being somewhat skeptical about your acceptance of evolution. A new tactic being favored by many IDers today is to outwardly accept evolution as a changing of species - but to still question that the mechanisms of evolution can exist independently of a designer. Which of course, they can, and the eye is just one of the examples supporting that fact.

[foodchain]

My problem is not acceptance of evolution, I hardly doubt that this occurred and still occurs. But I am wondering about the underlying mechanisms.

 

It is not a matter of acceptance, there is evidence for evolution (geological track, DNA). But it is more a matter of the how.

 

A similar thing I have with other sciences, such as the theory of gravity. I perfectly understand this (and even did a lot of computations with it), but it still does not explain it to me. What is gravity? What is it really? We can describe it very accurately (in fact, amazingly accurately) but still, we are struggling about its precise nature. A similar thing is true for evolution. We have quite good descriptions of what happened and about the time scale on which things happened. But these are descriptions, just like we have for gravity. But what is the driving force? Selection most likely is part of it, but I have the strong feeling there must be more. We don't have the full answer (yet), and that also is something a good scientist always must keep in mind. There remains a lot more to be discovered.

 

Finally, there is the question of the 'why'. But this is not the realm of science. Then we go to philosophy, ethics, religion. From a scientists point of view, I would already be very happy with a deep understanding of the 'how' question. We solved the 'what' question to a fair extent, and we are just touching upon the 'how' question. The 'why' question is a deeper question and I have personal ideas about that, but on a scienceforum I don't want to bother you with that .

 

Well to cut a long story short I would say the "why" is survival basically. I think it gets shrugged off by humanity at large because it appears ugly, its not very romantic. I mean what cant survive typically dies, or really it goes extinct. If life was not mutable, had no way to adapt, it would have never survived. The reason its called natural selection is you have a genotype, a phenotype and its relation to the environment. I think that’s it in short order really. Now if you want to say natural selection is just an operator on genes, well, you are still agreeing with me really:D

 

Now if you want to get into exact mechanisms, such as mutation rates, types of mutations, epigenetic networks and so on like evo-devo, go ahead, but it all trails back to that somewhat simple model. Mutations typically appear to be nothing short of random really. In that really genetic models go one way, such as genes--> proteins. So chiefly you have DNA repair mechanisms, or really many mechanisms basically to support keeping DNA the way it is for transcription and such. Typically then you have a low mutation rate. Then when a mutation occurs there a few things that can happen to it after the mutation, such as being negative or positive, or neutral in regards to fitness(environment). This I think derives from basically the mutation, some mutations are null, as in don’t do anything themselves, but would still hold some impact as a gene, such as being neutral or negative again. That whole area in itself is a great deal of research and reading, but overall mutations are random, and in time get selected for or against. This is why rapid environmental change is devastating to life overall.

 

Then you have it in reproduction being passed off as a genotype. Everyone has a genotype. Now how the genotype basically comes to be expressed along with environment to cut it short in large is a phenotype. Though the phenotype can express a degree of plasticity, it is highly thought of as next to impossible for two organisms of different species to have identical phenotypes with different genotypes. An example of this is a person, who without any exercise looks like a professional body builder, such does not happen in reality right? Genes can get switched on and off and in general again you run into a huge block of information not suitable for a single post really, or in large I could not explain it all to you, simply I don’t hold all that information, yet... Now the relationship of the phenotype and genotype along with environment is not perfectly understood, such as epigenetic networks and reproduction, novel roles of RNA are also being discovered, along with so much other discovery that’s almost hopeless to try to keep up with. The point again is that life evolved over time, and via natural selection is really how this works, such is present in all the physical evidence you can want. Having holes in the record here and there is not a failure of the theory as much as it may be simply a failure of not having enough specimens to study. The opposite of natural selection would be what, and what would evolution look like then?

[pioneer]

The discontinuity of evolutionary data should not be glossed over, because it can lead to interpretation problems. For example, say you decided to keep a journal of a child's life from birth to age 21. Each day you enter the important things that happened. This is continuous data. Ask somone to randomly pick 100 pages from this journal, distributed over the 21 years of records, and from only this data, explain why the person is like he is. If he had a car accident at age 15 and you don't happen to pick this, it would not be part of your equation. Maybe his girfriend left him at june 6, on his 18tth years. This is also important data that may be chosen during random data selection.

 

The theory one might come up with, would be consistent with the data that was chosen, but it may or may not be the reality of the situation. The data may suggest the environment was not a factor. But in reality, the environmental affects that were overlooked by the data, may have been the primary reasons for why he is what he is. One may then decide it must be some type of chemical imbalance due to his genetics. Genetics sort of gets used like a trump card, to answer any type of mystery.

 

Selective advantage does a little better, since the young man had to adapt to the environmental changes, which in turn, induced changes in him. This was his best way he could cope. If you look at this in terms of thermodynamics, selective advantage sort of amounts to the lowest energy state with respect to the new environment. In other words, it is the most stable state, thereby allowing it to remain.

 

If we scale this up to include mutations, in the light of stable selective advantage, the only mutations worth their weight in gold, are the most stable states, dictated by the environment in which they evolve in. If it is not stable in an environment, it will expire due to the potential of the environment, i.e., lion appearing in north canada. It sort of amounts to the environment setting the parameters for selective advantage. This determines which mutations can stick. What sticks has an impact on the environment setting new environmental parameters. This then determines which mutations have a shot at the next round of selective advantage. For example, if a human had mutated during the dinosaurs, even though it is more advanced in most ways, it might not survive. The bandwidth is tight so the process bulids up in a way that is like a continuous evolution. We can see this with bacteria as the medicine environments change. Big environmental changes opens the door wider for selective mutations.

 

The whole thing amount to an esculating thermodynamic potential. If you sort of bottom line life, plants absorb energy from the sun and animals use oxygen, induced because of the sun, to burn solar energy that has been stored on the earth within the plants. If you consider what humans do, we not only burn food, but fossils fuels. Or the sun got way ahead of the equation on earth, accumulating solar potential as fossil fuel, until human's finally turned the tide in the earth's direction. We may have gone too far on the side of the earth. Now we are trying to reach a balance. This balance will then be the potentials for selective mutations.

 

There is a big jump from solar energy and the earth's oxidation potential to genetics. Yet these two potentials sort of dictate what is possible. For example, the solar energy at the equator is very high tending to slant the equation a little more in the direction of the solar energy storage. Then we have weather, which is another solar and earth equilibrium. If there is not enough rain, then the solar energy sort of loses its edge due to forest fires or due to animals eating the sparse plants until deserts begin to appear. That is now the local sun-earth balance for further selective mutations.

[Billy Ray]

The first life did not "evolve". Instead, it resulted from chemistry. Start here --http://www.theharbinger.org/articles/rel_sci/fox.html -- and we can discuss it further if you wish.

I want to discuss it further, this is something I've been wondering about.

 

So, I understand it resulted from chemistry, but what is the possibility of that? I googled a little and found some websites where it said the possibility is extremely small, is it really so? If it is then how come life still emerged?

[Dak]

I see the analogue and I like it (it at least partially answers my question). But still, I have an important question about this. In the 'shakespeare' analogon, the outcome already is known and so we can keep letters at the right place. I also see that in this case, the process of typing the correct word boils down to 11 parallel processes, one process for each letter. As soon as all 11 processes have finished, we have the desired result. This is much better than having a single process with 26^11 possibilities, which have to be fulfilled.

 

In evolution, however, the outcome is not known and we have no criterion, on which we can decide in the right direction or not.

 

evolution only works to push things from A --> G if at least one step along the way is an improvement.

 

a simplified model of evolution:

 

#taking the progression A-->B-->C-->D-->E-->F-->G

 

#assuming that each step in the progression has a 1/10 chance of occouring

 

#assuming that our evolving mechanism simply retains improvements and abandons non-improvements (eg, A-->better-than-A is kept, whilst A-->not-better-than-A is abandoned)

 

#letting the maths be a bit wonky

 

 

 

if A<B<C<D<E<F<G, then evolution will drive the change from A to G.

 

as each step has a 1/10 chance of happening, then we could expect each step to occour after ~5 attempts, and then be kept. overall, then, with each step taking 5 attempts, a reasonable estimate is A-->G occouring in about 30 attempts.

 

for each bit thats not advantageous, evolution works less well. eg:

 

if A<B<C=D<E<F<G (and C<E), then:

 

A --> B is an improvement, so will be retained (and so on), BUT

C --> D is not an improvement, so will NOT be kept.

 

to proceede, the information will have to jump directly from C to E for there to be an improvement, and thus retention. if the chance of C-->D = 1/10 and D-->E is 1/10, then going strait from C-->E is 1/100, and could be expected to happen in about 50 tries. so, then, we have A-->B, B-->C, E-->F and F-->G taking ~5 tries each, and C-->E taking ~50 tries: it now takes about 70 tries to go from A to G.

 

if A=B=C=D=E=F<G, then there will be no retention at any step untill G is reached, and all the changes will have to happen at once.

 

this gives a 1/10^6 chance, so we can expect it to take ~500,000 tries to go from A-->G.

 

so, yes, non-viable intermediatory forms lessen evolutions effectiveness at driving a change, and it is required that the intermediatory forms be somehow advantageous in their own right in order for evoultion to take effect.

 

a few notes:

 

whilst the above is an implimentation of evolution, it is not natural evolution, which is a different 'implimentation' of evolution. natural evolution doesn't keep improvements and abandon all others and revert to what was there previously; rather, it retains changes at a rate proportional to their improvement. this complicates things alot, but the principle is still the same

 

Also, intermediate steps can be less fit than both the starting point and the end point.

 

in which case evolution will specifically lower the chances of the progression A --> G by stalling it at the 'disimproving' step.

 

note that it can still be gotten around, it just takes time, and, depending on many variables, it can take just one disadvantageous step to halt a progression.

[shadowacct]

You'll have to forgive me for being somewhat skeptical about your acceptance of evolution. A new tactic being favored by many IDers today is to outwardly accept evolution as a changing of species - but to still question that the mechanisms of evolution can exist independently of a designer. Which of course, they can, and the eye is just one of the examples supporting that fact.

This is unbelievable! So, asking critical questions is not allowed anymore? Who is the scientist over here? But it doesn't matter. If this is the way to go over here, then I'm done with this thread! Arrogance is reigning here!

[Paralith]

This is unbelievable! So, asking critical questions is not allowed anymore? Who is the scientist over here? But it doesn't matter. If this is the way to go over here, then I'm done with this thread! Arrogance is reigning here!

 

haha, I never said that you weren't allowed to ask critical questions. Critical questions are fine. But what I suspect that you're doing is asking the same questions that have been asked and answered already, many times over by many different people. Which is also allowed, but tiresome. And though you've chosen to focus on one statement of mine, I hope you did notice the many and detailed answers to your questions that you also received from me and several other forum members.

 

besides, are you really going to let one random internet person tell you what you are and aren't allowed to do?

[shadowacct]

I am not an expert at all in this subject, and I am willing to look into this in more detail, but I have severe questions. But if you think you have answered my questions, then that is your good right. No need to discuss this further, my conclusion is that I have to find better places to search for answers. This is my last post in this thread.

 

besides, are you really going to let one random internet person tell you what you are and aren't allowed to do?

As I said before, arrogance reigns over here.

[lucaspa]

I think you misunderstand what he is saying. He is saying that the reason why life exists at all is due to the fact that it allows energy to be dispersed more effectively. Thusly, life is the side effect (of the 2nd law of Thermodynamics).

 

If that is what Sampson is saying, then it is wrong. Life doesn't "disperse" energy, but concentrates it. Remember, life is a DECREASE in entropy: it is an INCREASE in the energy available to do work.

 

For instance, your point (3) about the evolution of the eye is incomplete. From what did the eye evolve in 364000 generations? And really, an eye can be described in 3640-ish bits?

 

From light sensitive proteins via a light sensitive spot such as are seen in Paramecium.

 

I didn't say the eye could be described by 3640 bit. I said, using the hypotheticals, that it would represent an increase of that amount. Let's look at what I said again:

 

"3. Let's take a less severe example. A selection pressure such that of 100 individuals, 99 survive to reproduce. -log(2) (99/100) = -log(2) (.99) = - (-0.01) = 0.01.

So now we have only an increase of 0.01 "bits" in this one generation due to selection. But remember, selection is cumulative. Take this over 1,000 generations and we have an increase of 10 "bits". Now, Nilsson and Pelger have estimated, using conservative parameters, that it would take 364,000 generations to evolve an eye. D-E Nilsson and S Pelger, A pessimistic estimate of the time required for an eye to evolve. Proceedings of the Royal Society of London, B. 256: 53-58, 1994. Taking that over our calculations shows that the eye represents an increase of 3,640 "bits" of information."

 

Notice I picked a very low selection coefficient -- 0.01. In nature, many selection coefficients are 10-50 times greater than that.

 

Now look at the human genome, how many bits are needed for describing it (using the best available compression techniques available)? Still many billions of bits. Assume, that initially, appr. 3.5 billion years ago, there was no information or just a few tens of bits of information (e.g. simple organic molecules), then it would take zillions of years to evolve to human beings, much more than the universe exists now (appr. 14 billion years) and even more than earth exists and could sustain life after its initial very hot period (3.5 to 4 billion years).

 

1. The DNA itself is not, strictly speaking, information described in "bits". Instead, it represents instructions for building an organism.

 

2. Your assumption of "no information" or just a few tens of bits is not accurate. First there is selection involved in forming elements in that all combinations of protons, neutrons, and electrons are not possible. So just having carbon involves having quite a bit of information. Then you get more information in that carbon cannot form all possible chemicals, so there is selection and increase in information when amino acids are made.

 

3. More information is generated when you make proteins by chemistry. It turns out that not every amino acid can be adjacent to every other amino acid; they are not playing cards. Fox and co-workers did an experiment using 3 amino acids -- glutamic acid, glycine, and tyrosine. With 3 amino acids you would expect 3^3 or 27 possible tripeptides. Instead, they got 6. So, if you put that in the information equation, it would be -log(2)(6/27) = -log(2)(2/9) ~ 3 bits of information added just to get those tripeptides.

 

It is remarkable that evolution has gone so fast.

 

Actually, evolution has gone much slower than it is capable of going.

Evaluation of the rate of evolution in natural populations of guppies (Poecilia reticulata). Reznick, DN, Shaw, FH, Rodd, FH, and Shaw, RG. Science 275:1934-1937, 1997. The lay article is Predatory-free guppies take an evolutionary leap forward, pg 1880.

 

This is an excellent study of natural selection at work. Guppies are preyed upon by species that specialize in eating either the small, young guppies, or older, mature guppies. Eleven years ago the research team moved guppies from pools below some waterfalls that contained both types of predators to pools above the falls where only the predators that ate the small, young guppies live. Thus the selection pressure was changed. Eleven years later the guppies above the falls were larger, matured earlier, and had fewer young than the ones below the falls. The group then used standard quantitative morphology to quantify the rate of evolution.

 

So we have a study in the wild, not the lab, of natural selection and its results. The rate of evolution was *very* fast. Evolution is measured in the unit "darwin", which is the proportional amount of change per unit time. The fish evolved at 3700 to 45,000 darwins, depending on the trait measured. In contrast, rates in the fossil record are typically 0.1 to 1.0 darwin. This means that evolution can happen 10,000 times faster than seen in the fossil record. Instead of 3.8 billion years, that rate would produce all the evolutionary change seen in just 380,000 years! The question has become: why has evolution gone so slow!

 

I personally think that there still remains a lot to be explained and that no definite answers are found. We can fairly well do descriptive evolutionary science, but the underlying mechanisms still are far from being understood near 100%.

 

Very few things are known in science at 100%. Every time you answer a question, 3 or 4 new questions pop up out of the answer. However, overall evolutionary mechanisms are known: natural selection, sexual selection, genetic drift, gene flow, mutation, recombination, etc.

 

Selection most likely is an important part of the underlying mechanism, but there must be more than that.

 

Why "must" there be more to get the designs we see in nature? That's what natural selection is: an algorithm (unintelligent process) that is guaranteed to give design. Now, will natural selection account for every feature of every organism? No. But it does account for what we are most interested in: the adaptations (designs).

 

I want to discuss it further, this is something I've been wondering about.

 

So, I understand it resulted from chemistry, but what is the possibility of that? I googled a little and found some websites where it said the possibility is extremely small, is it really so? If it is then how come life still emerged?

 

The possibility of getting protocells by chemistry is VERY high: close to 1 or virtual certainty. The websites that claim very small possibility are making some very bad assumptions:

 

1. That amino acids are like playing cards and are thus interchangeable within a protein. That is, ALL amino acid sequences are possible. That simply isn't so.

2. That only ONE particular amino acid sequence will do the job. We know that isn't so because different organisms have different versions of the protein (different amino acid sequences) to do the same thing. Think of cytochrome c -- essential for using oxygen to "burn" food. http://members.aol.com/SHinrichs9/descent/denton.jpg

 

3. If you combine amino acids by chemistry, you don't have to get one particular protein. Instead, what you want are the odds of getting A biological activity. Not a specific one. And the odds of getting a protein with A biological activity = 1. You don't know which activity, but it will have one.

 

So those calculations showing a small probability are examples of GIGO: garbage in, garbage out.

 

Instead of low probability, DATA indicates that the formation of life by protein first would be very high probability.

[swansont]

If that is what Sampson is saying, then it is wrong. Life doesn't "disperse" energy, but concentrates it. Remember, life is a DECREASE in entropy: it is an INCREASE in the energy available to do work.

 

I disagree. I think you need to distinguish between the process and the entity.

 

Without getting into the details of what life is, the processes of living beings increase entropy. View the body as an engine: it does work and rejects heat. It definitely increases entropy. The being itself, i.e. all of the molecules that comprise it, represents a decrease in entropy. But it took a lot of work to create that being, so the entropy increased elsewhere.

[lucaspa]

Yes, with open eyes, but also with a critical mind. If they mention that according to one scientist's calculations, a camera-like eye can form in 364000 years from a very simple structure, then I would like to see more detail on this. Any more references? Links? I simply don't believe this, without further evidence than someone referring to "one scientist's calculations".

 

Then why don't you go to a library and look at the paper?! I did! Here's the reference again:

D-E Nilsson and S Pelger, A pessimistic estimate of the time required for an eye to evolve. Proceedings of the Royal Society of London, B. 256: 53-58, 1994.

 

Here's a web article by one of the authors describing the paper: http://www.talkreason.org/articles/blurred.cfm#lund

 

In evolution, however, the outcome is not known and we have no criterion, on which we can decide in the right direction or not.

 

Yes, the "outcome" is "known" in evolution: designs that will perform well in that particular environment. In the Dawkins' example, Dawkins picked the environment. In evolution, physics, chemistry, and interactions with other life picks the outcome. And yes, we have an objective criteria to decide the "right" direction in evolution: frequency of traits or alleles that are greater than the Hardy-Weinberg equilibrium predicts.

 

Mendelian genetics predicts that the frequency of traits/alleles in a population will remain constant. It comes directly from the equations of Mendelian genetics and is known as the Hardy-Weinberg principle. Most loci do, in fact, conform to a Hardy-Weinberg equilibrium. So, if you follow a population for generations (by taking a good sized sample of that population) and looking at the frequency of a trait or allele, you can see if a population is going in the "right" direction -- adaptation -- by 1) seeing that the overall population is stable and 2) observing that the frequency of some traits or alleles are increasing.

 

Also, intermediate steps can be less fit than both the starting point and the end point.

 

Please document this. If you are referring to a changing environment between two stable points (starting and end points), then the intermediate steps will be less fit with regard to those points. BUT, the intermediates will be more fit than the preceding forms for that particular environment.

 

There may be local minima of the fitness function, and I would expect it to be VERY hard to overcome such local minima, especially if the steps, taken by the process are small.

I'll keep this analogon in mind, however, and think about it, and see if it can be adapted to solve the problem of non-monotonous fitness and unknown outcome.

 

The reason people question you is that you are repeating the flawed arguments we have seen written by IDers and other creationists. It's apparent that you are not reading textbooks of evolutionary biology. For instance, what you refer to as a fitness "valley" only occurs in the situation of heterozygous disadvantage or underdominance. This is where both the homozygotes are more fit than the heterozygote. Figure 13.12 D in Futuyma's Evolutionary Biology, 1999, pg 379. The text on page 402 is clear. Fitness landscapes can get more complicated if there are interactions between loci, but even here "evolution may be envisioned as the movement of a point (representing the population) on the surface. The point moves steadily upslope until it arrives at the peak -- the allele frequency at equilibrium".

 

The being itself, i.e. all of the molecules that comprise it, represents a decrease in entropy. But it took a lot of work to create that being, so the entropy increased elsewhere.

 

The way you have phrased this, you have that entropy increased elsewhere BECAUSE of life. Instead, the entropy was increasing ANYWAY, thus allowing life to decrease in entropy without violation of the 2nd Law.

 

For instance, plants decrease entropy by using the energy of sunlight to combine carbon dioxide and water to make sugars. It takes a lot of work to create glucose from carbon dioxide and water. The way you stated it, "so the entropy increased elsewhere" that would mean that the decrease in entropy in plants causes the solar system to increase in entropy. That's the "so" in the sentence. Instead, as you well know, the solar system increases in entropy due to the nuclear fusion in the sun. The solar system would increase in entropy whether there were any plants or other life or not.

 

"the processes of living beings increase entropy. View the body as an engine: it does work and rejects heat. It definitely increases entropy."

 

Not ALL the processes of living beings increase entropy. As we noted, the photosynthesis of sugars by plants decreases entropy and does NOT "reject heat". In heterotrophs, there is conversion of foods to energy. Synthesizing proteins and DNA decrease entropy. This is more than balanced by the increase in entropy due to the combustion of the food.

 

I would view this as life tests the validity of the 2nd Law of Thermo. Since life never exists in a system where the TOTAL entropy is not increasing, then the 2nd Law is not challenged by the existence of life.

[Billy Ray]

The possibility of getting protocells by chemistry is VERY high: close to 1 or virtual certainty. The websites that claim very small possibility are making some very bad assumptions:

 

1. That amino acids are like playing cards and are thus interchangeable within a protein. That is, ALL amino acid sequences are possible. That simply isn't so.

2. That only ONE particular amino acid sequence will do the job. We know that isn't so because different organisms have different versions of the protein (different amino acid sequences) to do the same thing. Think of cytochrome c -- essential for using oxygen to "burn" food. http://members.aol.com/SHinrichs9/descent/denton.jpg

 

3. If you combine amino acids by chemistry, you don't have to get one particular protein. Instead, what you want are the odds of getting A biological activity. Not a specific one. And the odds of getting a protein with A biological activity = 1. You don't know which activity, but it will have one.

 

So those calculations showing a small probability are examples of GIGO: garbage in, garbage out.

 

Instead of low probability, DATA indicates that the formation of life by protein first would be very high probability.

But is it certain that if we have proteins we will definitely get a real cell?

[lucaspa]

But is it certain that if we have proteins we will definitely get a real cell?

 

Define "real cell". We will get a living cell. It will be made entirely of proteins without DNA or RNA.

 

The reason is due to the side chains of the amino acids in the proteins. Most amino acids have side chains that are "hydrophobic" or "water-hating". They are like oil and don't mix with water. Some side chains are hydrophilic or "water-loving" and mix with water. Think of soap with a hydrophobic tail and a hydrophilic head: they form small spheres with the tails in and the heads out with the water. Or think of oil droplets.

 

Proteins tend to fold so that the hydrophobic side chains are in the center and the hydrophilic ones on the outside. When there are lots of proteins together in water, they tend to aggregate so that the hydrophobic parts are together and the hydrophilic ones out. This ends up making a cell.

 

If you look at Figure 2 at http://www.theharbinger.org/articles/rel_sci/fox.html you can see cells forming as water hits proteins formed by dry heating of amino acids.

 

The cell membranes of modern cells are over 50% protein. So all you need is protein to make a cell membrane. And there is your cell! Proteins to form the cell membrane and other membranes inside the cell and some proteins dissolved in the water inside the cell -- serving as the cytoplasm. The cells 1) metabolize, 2) grow, 3) reproduce, and 4) respond to stimuli.

 

By metabolize I mean that they will break down molecules for energy and also make new proteins and DNA or RNA. They will even photosynthesize!

[Billy Ray]

Define "real cell". We will get a living cell. It will be made entirely of proteins without DNA or RNA.

 

The reason is due to the side chains of the amino acids in the proteins. Most amino acids have side chains that are "hydrophobic" or "water-hating". They are like oil and don't mix with water. Some side chains are hydrophilic or "water-loving" and mix with water. Think of soap with a hydrophobic tail and a hydrophilic head: they form small spheres with the tails in and the heads out with the water. Or think of oil droplets.

 

Proteins tend to fold so that the hydrophobic side chains are in the center and the hydrophilic ones on the outside. When there are lots of proteins together in water, they tend to aggregate so that the hydrophobic parts are together and the hydrophilic ones out. This ends up making a cell.

 

If you look at Figure 2 at http://www.theharbinger.org/articles/rel_sci/fox.html you can see cells forming as water hits proteins formed by dry heating of amino acids.

 

The cell membranes of modern cells are over 50% protein. So all you need is protein to make a cell membrane. And there is your cell! Proteins to form the cell membrane and other membranes inside the cell and some proteins dissolved in the water inside the cell -- serving as the cytoplasm. The cells 1) metabolize, 2) grow, 3) reproduce, and 4) respond to stimuli.

 

By metabolize I mean that they will break down molecules for energy and also make new proteins and DNA or RNA. They will even photosynthesize!

By real cell I mean a cell that can evolve into a human being(and everything else).

 

As I said I've read stuff which said the probability for the first cell assembling was basically 0 and I had some ideas(non-creationist) to still "explain" the emerging of life against all odds. But if the probability is in fact nonzero than my ideas are irrelevant.

[iNow]

As I said I've read stuff which said the probability for the first cell assembling was basically 0 and I had some ideas(non-creationist) to still "explain" the emerging of life against all odds. But if the probability is in fact nonzero than my ideas are irrelevant.

 

I was pretty pleased with the approachability to the science of prebiotic life offered in the below article. You may want to check it out.

 

http://www.as.utexas.edu/astronomy/education/spring07/scalo/secure/BergBiochemEvo.pdf

[foodchain]

By real cell I mean a cell that can evolve into a human being(and everything else).

 

Evolution will allow organisms to exist on the basis of what can survive. Evolution itself is a word used in general for such a process or processes, it does not however guarantee humans and or survival because life does not always make it and species go extinct.

 

As I said I've read stuff which said the probability for the first cell assembling was basically 0 and I had some ideas(non-creationist) to still "explain" the emerging of life against all odds. But if the probability is in fact nonzero than my ideas are irrelevant.

 

Well the probability I would say obviously was non zero. That point aside what’s the probability of say Iron existing, creationists don’t seem to have a beef with that, which I would only highlight as a bit of a paradox really in there whole though process is all. I like to point this out but obviously we have all the required chemistry and energy desired here on earth along with in regards to time a geologically stable planet with environments that don’t seem to change every other day. Just try to imagine the passing of a million years worth of time, or say ten million years worth of time. On a graph the time that would represent the lifespan of say even a person would seriously need some zooming to be able to be observed. No, science has not figured out the exact mechanisms that brought life along, science does however currently hold some pretty good evidence to how it might have come about. Then again the simple reality of life emerging which cannot be ruled out is the exact mechanisms or process that brought it about might need to be perfectly recreated, and if that’s not the case the entire process itself could take who knows in regards to time to complete. Lastly evolution in itself as a process is entirely natural, and in this you find from nano scale bacteria with in comparison very simple structure compared to say that of a placental mammal. Its just a matter of time before it is figured out I would say, unless the process again that spawned life would need basically a few hundred thousand years to complete, at that point I don’t think any human experiment would even be able to undertake such a task.