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Topic: Evolution in action? (Read 37704 times)
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meep-eep
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Good reply. A direct response to the questions asked for once.
1) Where do these chance mutaions take place in the body, specific location(s) please.For argument's sake let's say you may have a sixth finger or a 20% larger brain than the average person. If these mutations do not take place in a meaningful place in the body where you can pass it on to your offspring, what good are they? Mutations happen everywhere, in every cell (actually, I think the mutations usually happen during copying, so they only affect new cells). But usually, these mutations are harmless. A change in the code of a kidney cell that regulates the shape of the finger is not going to have any effect.
But the DNA in the sex cells will be copied all throughout the body of the child (including his own sex cells, having the consequence that the change will be passed on).
You do need the "right amount" of mutations. But this itself is regulated by evolution. If a system becomes "perfect", so no more mutations would occur, the species can no longer adapt to changing conditions, and will inevitably die out. If too many mutations occur, there will not be enough individuals fit to maintain the species. So natural selection itself ensures that those individuals with the best "mutation rate" will succeed.
(Note: It's also possible that mutations are more likely in sex cells (since there is a merger of two different strains of DNA involved), but I don't know enough about that. It is not a necessary part of my argument though. Just the fact that mutations that happen elsewhere are usually harmless is enough.)
2) Natural selection can only select for good mutaions by way of weeding out bad (detrimental) mutations. Thats it. So why do we not see (as Darwin asked) many neutral and flivorous body changes both living and in the fossil record? And especially internal systems such as the inner ear, the lungs, the liver, the heart, the brain etc. We do actually. I don't know what "flivorous" means, but there are many variations. Externally, you can see this in skin tones, eye color, freckles, shape of the face, etc. Internally, it's harder to see this, but just look how people react differently to some medicines. And I bet there are all sorts of little differences in organ size and form, and cell composition, etc.
As for the fossil record, I don't know what Darwin asked (quote and source please), but you can't tell a lot about the details of internal systems when only bones and petrified matter is left.
Can natural selection really fine tune organs to thier present state? And why do we not see half made organs, not quite evolved yet but on their way to becoming? We do actually. Look at your feet. It's not very useful to have separate toes when you're not using them for grabbing them, and the fossil record will show the form of them slowly changing to be better suited for upright walking, even though they're not all the way there. Same for the shape of the pelvis. Child birth has become more difficult for humans as they adapted to walk upright. The shape of the pelvis is changing, but as most women who had children will tell, it needs improvement. And if you want more examples look at the tail bone or the appendix (Evolution doesn't always mean adding things. Sometimes removing things is a benefit).
Natural Selection is fact an can account for much in the arena of survival of the fittest. Specifically the mechanical systems of the animal. Longer legs, sharper teeth, wider habitat etc. But what about the features that don't seem to offer a direct survival advantage? For example, is the individual really more "fit" if it has say a 5% better hearing than it's contemporaries? So maybe it can hear slightly better,see slightly better, taste better etc. but these are not nessicarily a distinct survival advantage and one would think they'd be just as competitive with their close family members. If a change doesn't have a large disadvantage, it will remain in the gene pool, and after a lot of generations, with sufficient interbreeding, there will be many individuals with that change. There are many such changes, some with a negligable benefit, some with a negligable disadvantage. But as there are many such changes, those changes will add up. And the ones that inherited many small good changes (like +1 hearing, +1 smell, +1 vision, +1 speed) will have a greater likelyhood of surviving. Which means there will be more species with good changes around.
Repeat this process for many generations, and you'll end up with a species with very significant improvements.
The complexity argument isn't this simple. We find that life and it's biological systems are "specifically" complex. For example I read that the human ear can detect sound wave vibrations half the distance of a molecule. Not only that but has safety features that damp down sounds that are too loud. (That's why one rock concert, or sonic boom won't destroy our ears). Our inner ear also has an organ so that our brains can process balance and allow us to walk upright, I don't know what you mean by "specifically".
"Detecting sound wave vibrations half the distance of a molecule" is absurd. The maximum frequency humans can hear is about 22Khz. Dividing the speed of sound in air by this number gives the wave length of the sound wave: λ = 343 [m/s] / 22000 [1/s] = 0.015 [m]. So about 1.5 cm. That's a long way off from half the "distance of a molecule" (whatever that means).
Now to the actual point you were making with this example:
This doesn't seem like a chance assembelage of parts to me. Take a look for yourself and tell me if this looks like a series of accidents to you. http://en.wikipedia.org/wiki/Ear
So let me just get back on track by pointing out that the ability of natural selection to produce large improvements over a long time period by culling out bad mutations, is the point which I am arguing here. Pointing out that there are large improvements does not argue your case.
So how does random mutation build this system or even a more simple version? And it has to be built BEFORE natural selection can "decide" if it's bad or good? I can't even begin to quantify how unlikely this is, let alone every biological system of every creature on earth being built in the same manner. No, no, no. Large improvements aren't built before natural selection. Natural selection produces large improvements through many small changes that have an incremental benefit, over a long period of time. I'm not sure why you are saying this. I thought you at least understood this part of how evolution is supposed to work. People have explained it often enough in this thread. Small mutations, culling, repeat. No foresight.
(Are you claiming that the ear is built to withstand rock concerts and sonic booms? I'd expect the ability is a side-effect of the ability to withstand large shocks, like a blow to the head, or something like that.)
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RTyp06
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Ok let's try this again.
1) Mutations. Mutations are usually neutral or bad. The vast majority are bad because the DNA code sequence is so exacting. So exacting in fact that the cell will splice out and repair mutaions on the fly. The entire science of gene splicing was born from this splice/repiair phenomena. As you can see, the cell doesn't "like" these changes and fights to retain the original DNA sequences. But genetic mutations do occasionally get through. Thus we see a whole host of genetic diseases. Fortunately (or deliberately) these genetic diseases are realitively rare. And we have yet to witness a true, "benefical" mutation. (Please no antibiotic resistant bacteria which I've covered in detail several times now)
2) The Genome: What scientists are finding is that the genome of all species has large quantities of Transposon or jumping Genes.
http://en.wikipedia.org/wiki/Jumping_genes
The more we study these mobile genetic sequences the more we are finding that they gently scramble the genetic code in safe places. This is why we all have a different wired brain, hair/eye color, different immune system etc. But they don't jump into "unsafe" areas such as the heart, liver, lungs etc. I liken this to changing the background,screen resolution or font of a windows application. Safe variables. The rest are hard coded constants.
This can be seen in dog or cattle breeding. You can achieve a vast variety of different looking animals but only within limits. Only so big, so small etc.
3) Natural selection. Natural Selection Is basicly a yes or no question. The point I'm trying to make with the ear example is how can a yes /no question , even over millions of years, add up to this finely integrated system? Natural selection supposidly has taken a bone in the skull of an acient fish and transformmed it into the ear canal and it's integrated bones and nerves. To me there must have been many neutral changes in the process. How did they add up to the ear we have today? Can a series of accidental mutaions to existing DNA code that the cell figths to retain, really add up to somthing better?
But as there are many such changes, those changes will add up. And the ones that inherited many small good changes (like +1 hearing, +1 smell, +1 vision, +1 speed) will have a greater likelyhood of surviving.
But isn't there an equal and perhaps even more likelyhood that individuals would end up with -1 hearing -1 smell -1 speed -1 intelligence, due to mutations usually causing harm?
Also what constitutes a +1 hearing? Is a little tighter ear drum, a little longer adutory canal, a slightly elongated cochlea a +1? And if it is, how can Natural Selection select for this since small incremental changes are most likely neutral? One would think these neutral changes could be a whole host of -1 or +1 with no real direction. There must have been many setbacks along the evolutionary route as well?
Finally, Natural Selection is reactionary. A change has to be made first before natural selection can act. No matter how minute, the change must be made first before NS can weigh in. There is no way around this. Even if a preceeding NS retained some valuable DNA code, that DNA code had to have mutated first.. So on and so forth until you reach back through evolution to the first dividing cell. The cell had to come first then natural selection.
Darwin Quote you asked for:
Darwin, On the Origin of Species,Chapter 9: On the Imperfection of the Geological Record
: "But just in proportion as this process of extermination has acted on an enormous scale, so must the number of intermediate varieties, which have formerly existed on the earth, be truly enormous. Why then is not every geological formation and every stratum full of such intermediate links? Geology assuredly does not reveal any such finely graduated organic chain; and this, perhaps, is the most obvious and gravest objection which can be urged against my theory. The explanation lies, as I believe, in the extreme imperfection of the geological record.
(emphasis added)
If random mutation is able to create the fantastic diversity of life and fine tune organs to the degree we see, it should be easy to reproduce in the lab. If random mutations are truely the driving force behind such amazing complexity then why does it reamin so elusive? Shouldn't we have been able to achieve somthing by artificial, random mutaion by now? We should be able to empirically demonstrate evolution in every eighth grade science course world wide. Evolution should be as easy as a grade school field trip to the nearest fossil dig.
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« Last Edit: February 21, 2007, 03:35:11 am by RTyp06 »
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Novus
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Mutations happen everywhere, in every cell (actually, I think the mutations usually happen during copying, so they only affect new cells). But usually, these mutations are harmless. A change in the code of a kidney cell that regulates the shape of the finger is not going to have any effect.
But the DNA in the sex cells will be copied all throughout the body of the child (including his own sex cells, having the consequence that the change will be passed on). Yes but cells in the human body deal with the DNA codes related to the cell itself and ignore the irrealivant DNA codes. So I'd argue that it's unlikely that a single cell will mutate then copy itself everywhere in the body. Thus it is unlikely to be passed to the sex cells.
And if you want more examples look at the tail bone or the appendix (Evolution doesn't always mean adding things. Sometimes removing things is a benefit).
Except that A) There is no proof whatsoever that we are losing our tailbone or appendix and B) Both are important . The tailbone is an anchor point for muscles and any doctor removing a healthy appendix today would probably lose his/her medical liscense for malpractice. Sure we can live without it but as is so without tonsils or perhaps a kidney. |
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Novus
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And we have yet to witness a true, "benefical" mutation. (Please no antibiotic resistant bacteria which I've covered in detail several times now)
How about Lactose tolerance?
The more we study these mobile genetic sequences the more we are finding that they gently scramble the genetic code in safe places. This is why we all have a different wired brain, hair/eye color, different immune system etc. But they don't jump into "unsafe" areas such as the heart, liver, lungs etc. I liken this to changing the background,screen resolution or font of a windows application. Safe variables. The rest are hard coded constants.
The harmless changes to "safe" areas are, of course, going to be much more common in living specimens than changes that affect critical aspects of the organism (dramatic negative changes will probably kill the baby before birth; less dramatic changes may leave it an invalid).
3) Natural selection. Natural Selection Is basicly a yes or no question.
No, it isn't. I assume you mean the question is "reproduce or not?". However, you must also take into account how many children an organism gets, what sort of environment it can provide for them and so on.
The point I'm trying to make with the ear example is how can a yes /no question , even over millions of years, add up to this finely integrated system?
Never underestimate the power of simple operations in large quantities. Consider what genetic algorithms can achieve even in a vastly simplified context.
But as there are many such changes, those changes will add up. And the ones that inherited many small good changes (like +1 hearing, +1 smell, +1 vision, +1 speed) will have a greater likelyhood of surviving. But isn't there an equal and perhaps even more likelyhood that individuals would end up with -1 hearing -1 smell -1 speed -1 intelligence, due to mutations usually causing harm?
There must have been many setbacks along the evolutionary route as well?
Lots. Happens all the time.
The cell had to come first then natural selection.
Anything that replicates itself with a possibility of change is subject to both mutation and natural selection. See e.g. the Spiegelman Monster.
Geology assuredly does not reveal any such finely graduated organic chain; and this, perhaps, is the most obvious and gravest objection which can be urged against my theory. The explanation lies, as I believe, in the extreme imperfection of the geological record.
What's wrong with the suggestion in the sentence following the underlined one?
If random mutation is able to create the fantastic diversity of life and fine tune organs to the degree we see, it should be easy to reproduce in the lab. If random mutations are truely the driving force behind such amazing complexity then why does it reamin so elusive? Shouldn't we have been able to achieve somthing by artificial, random mutaion by now? We should be able to empirically demonstrate evolution in every eighth grade science course world wide.
Expecting laboratory reconstruction of a process that has taken millions of years and an entire planet to complete is ridiculous, especially since the whole point is that process can not be explicitly guided to make it faster.
Evolution should be as easy as a grade school field trip to the nearest fossil dig.
Why should there be that many and varied fossils? You're requiring a standard of evidence that is essentially impossible to provide with the available historical data and experimentation time, assuming the theory is true. I can't think of a way to convince you that doesn't involve time travel or very large amounts of well-preserved fossils suddenly being found. Methodologically speaking, that's insane.
Let's turn this around: if intelligent design and/or creationism is true, why doesn't the creator/designer create/design something completely different in front of our noses? In most creationist models (any one that assumes an omnipotent ever-lasting creator), at least, this is entirely possible; intelligent design models that rely entirely on a finely-tuned starting point and no further designer interaction naturally don't allow this. If intelligent design is true, why is evolution (or microevolution, if you want to make the distinction) even permitted, considering that it interferes with the design? And why is the designer exempt from having to be designed?
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RTyp06
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Uhh, this is evidence of a beneficial mutation how? I do remember an article where they knocked out the gene that allows Lactose digestion and low and behold, through mutation, lactose digestion was restored. Come to find out there is a "spare tire" gene that is one mutation away from taking over the role. When both genes were knocked out, lactose digestion never "evolved" again. Seems anything beyond a one point mutation is next to impossible.. I'll see if I can find the article again.
3) Natural selection. Natural Selection Is basicly a yes or no question.
No, it isn't. I assume you mean the question is "reproduce or not?". However, you must also take into account how many children an organism gets, what sort of environment it can provide for them and so on.
Yes there are many variables involved but if you think about it, Natural Selection breaks down to Live or Die. Period. How prolific a species is, is irrelevant, although it may dictate (or play a role in) how long the species tenure here on earth is, it will either die out or survive. Again, a Yes, No.
Never underestimate the power of simple operations in large quantities. Consider what genetic algorithms can achieve even in a vastly simplified context.
I'm not familiar with genetic algorithms but I think I get the jist. A simple operation can add up to somthing complex as long as there is a large quantity of them? I need more...
Much greater, especially if you take a complex system like the human ear. Where do you think all these deaf people come from, for example? Now note that the chances of a deaf person reproducing are much worse than those of a hearing person (at least in the wild; modern civilisation mitigates the chance of being eaten a lot).
Hunh? You lost me there...
There must have been many setbacks along the evolutionary route as well?
Lots. Happens all the time.
Ok, so is evolution pushing biologicals in a decidedly "better" direction or not then?
The cell had to come first then natural selection.
Anything that replicates itself with a possibility of change is subject to both mutation and natural selection. See e.g. the Spiegelman Monster.
I find these two sentences from that Wiki link particularly interesting:
"It was created by Sol Spiegelman" and "Such a short RNA had been able to replicate very fast in these unnatural circumstances."
Created by a human brain, with human intervention and in an unnatural enviornment... Anyway, Im not seeing where mutation and natural selection are any part of this expiriment.
Geology assuredly does not reveal any such finely graduated organic chain; and this, perhaps, is the most obvious and gravest objection which can be urged against my theory. The explanation lies, as I believe, in the extreme imperfection of the geological record.
What's wrong with the suggestion in the sentence following the underlined one?
That's a good question and does depend partially on our own view of the fossil record. In Darwinian evolutionary terms, the fossil record is remarkably incomplete meaning there must be trillions upon trillions of species that lived and we are unaware of them. I disagree with this, somewhat. Yes there probably are many species we are unaware of but, in the 180 years since Darwin we have found many, many more fossils. What we are finding is completely new animals (even different phyla!) that don't seem to fit into the tree of life and species that are closely related. The so called "missing links" that connect animal phyla (right at the trunk of the tree ) are suspiciously sparse and questionable at best.
Expecting laboratory reconstruction of a process that has taken millions of years and an entire planet to complete is ridiculous, especially since the whole point is that process can not be explicitly guided to make it faster.
Ahh but why can't we speed up the process? Bacteria have a high reproduction rate and by artifically introducing mutegens, we should be able to evolve Bacteria easily. That is unless random mutation is really not the driving force behind evolution?
I read an article a while back that fruit flys are a popular subject because of their short life and high reproduction. They also have rather large DNA strands. Interestingly we've been able to make them grow extra wings, eyes legs etc. by mutating their DNA. But evolution has never occured because the new limbs and eyes were useless and made the animal a hopeless cripple.
Why should there be that many and varied fossils?
Becuase if evolution proceeds in small incremental steps, we should see this preserved in the fossil record and living today. We should see scales turning into feathers. Fins turing into feet etc.
You're requiring a standard of evidence that is essentially impossible to provide with the available historical data and experimentation time, assuming the theory is true. I can't think of a way to convince you that doesn't involve time travel or very large amounts of well-preserved fossils suddenly being found. Methodologically speaking, that's insane.
Well you probably won't convince me without empirical scientific evidence. Evidence that has never been found. At this point it's looking like it never will be found. Also keep in mind that we have found many well preserved fossils. Fossils that show soft tissues and organs. The Bergess Shale formation in Canada is one of them and dates to the mid and late Cambrian. These animals seem just as "evolved" as anything alive today.
Let's turn this around: if intelligent design and/or creationism is true, why doesn't the creator/designer create/design something completely different in front of our noses?
I cannot speak from a creationist point of view and not all intelligent design theorists believe in a god or diety. How new design plans come about remains a mystery. Instead ,I look at biology from the other direction. I think that anything designed by an intelligence has certain empiricaly detectable properties.
Specified and Irreducible complexity are perhaps two of these properties and can't, as of yet, be produced by any blind, naturalistic force.
If intelligent design is true, why is evolution (or microevolution, if you want to make the distinction) even permitted, considering that it interferes with the design?
Perhaps the designer wanted diversity and programmed it into the DNA? btw how does micro evolution interfere with the design?
And why is the designer exempt from having to be designed?
That's a philosophical question. I think the scientifc method has limits. Let's say for arguments sake that a god does exist and created the universe and life. Is there any way we could empircaly detect god? The closest we could come would be to expect order and purpose in the universe with an intelligence similar to ours..
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« Last Edit: February 23, 2007, 03:06:26 am by RTyp06 »
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RTyp06
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Sure, most mutations just affect a limited part of a single organism, and if they have a noticeable effect it's usually harmful (e.g. cancer). However, you need to note that mutagenic factors (e.g. radiation) often affect large parts of the body, not just a few cells (especially penetrating forms like gamma radiation).
What kind of odds would you put on gamma radiation (or any other massive mutegen) changing existing DNA sequences into anything positive? To me, randomly mutating DNA sequences would no more likely produce any sort of positive result than randomly modifying,moving,adding or deleting the parts inside your television would improve the picture. It's just not going to happen.
Not removing a healthy appendix is just an application of the "if it ain't broke, don't fix it" principle. As long as it isn't hurting the organism, taking the risk of complications in surgery is unnecessary. That certainly doesn't mean it's important (no significant problems have been noted in people lacking one by birth or surgery to my knowledge, and it doesn't seem to do anything).
Well the appendix is a mystery. We don't know if it has function or not and only a few species of animals have them. Interestingly, humans have the largest, most pronounced appendix of any species, is supplied by a rich blood supply and the tissue texture/color sets it apart from any other organ. it almost seems that the human appendix is evolving into somthing rather than a reminant of an evolutionary ancestor.
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Valaggar
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it almost seems that the human appendix is evolving into somthing rather than a reminant of an evolutionary ancestor.
It can't be evolving, since it has no function. As such, it doesn't constitute an advantage, so the bearer of a larger appendix isn't better adapted.
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Death 999
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We did. You did. Yes we can. No.
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Ever heard of exaptation? Lack of purpose now does not imply future lack of purpose.
There must have been many setbacks along the evolutionary route as well? Lots. Happens all the time. Ok, so is evolution pushing biologicals in a decidedly "better" direction or not then?
Yes. Many individuals suffer setbacks. MANY individuals suffer setbacks. Evolution makes that matter much much less than the few who get an advantage.
Anything that replicates itself with a possibility of change is subject to both mutation and natural selection. See e.g. the Spiegelman Monster. I find these two sentences from that Wiki link particularly interesting: "It was created by Sol Spiegelman" and "Such a short RNA had been able to replicate very fast in these unnatural circumstances."Created by a human brain, with human intervention and in an unnatural enviornment... Anyway, Im not seeing where mutation and natural selection are any part of this expiriment.
There it is. Mutation, selection... and what the guy devised himself was about one third as good as the stuff that then evolved.
The so called "missing links" that connect animal phyla (right at the trunk of the tree ) are suspiciously sparse and questionable at best.
At the root of the phyla was a looong time ago, back when critters were just beginning to fossilize well. Or do you forget the last time we were over this?
Bacteria have a high reproduction rate and by artifically introducing mutegens, we should be able to evolve Bacteria easily. That is unless random mutation is really not the driving force behind evolution?
Artificially induced mutation is very different from naturally occurring mutation. See the difference between induced rat tumors and natural tumors that develop on their own. That's evolution in miniature.
These animals seem just as "evolved" as anything alive today.
O RLY? Cellularly, yes, we haven't changed much in a long time.. Soft tissues, as well, were well-developed before fossilization was able to come along. And then they could grow hard bits. So they could fossilize.
Your problem with this is what? That it wasn't hard bits THEN soft tissue development? Sorry history doesn't suit your tastes, man.
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« Last Edit: February 23, 2007, 07:01:05 pm by Death 999 »
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Novus
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Uhh, this is evidence of a beneficial mutation how? I do remember an article where they knocked out the gene that allows Lactose digestion and low and behold, through mutation, lactose digestion was restored. Come to find out there is a "spare tire" gene that is one mutation away from taking over the role. When both genes were knocked out, lactose digestion never "evolved" again. Seems anything beyond a one point mutation is next to impossible..
Recently (in evolutionary terms) gaining the ability to digest a new food source isn't beneficial?
In any case, your counterargument is silly. If you remove everything that's close to the desired functionality, it will of course take longer for it to redevelop (you're selecting against it).
Yes there are many variables involved but if you think about it, Natural Selection breaks down to Live or Die. Period. How prolific a species is, is irrelevant, although it may dictate (or play a role in) how long the species tenure here on earth is, it will either die out or survive. Again, a Yes, No.
I understand why you find evolution so implausible; you're oversimplifying most of what makes it work out of it. The longer a species survives (and the greater the numbers), the more chances it has of changing into something that can survive in a changed environment.
I'm not familiar with genetic algorithms but I think I get the jist. A simple operation can add up to somthing complex as long as there is a large quantity of them? I need more...
Wikipedia has a few good summaries on the subject of Evolutionary algorithms. Genetic algorithms are perhaps the best established subset of these and have been successfully applied to a large amount of tricky search problems.
If you want more on how this applies to our evolution, you could try The Blind Watchmaker by Richard Dawkins.
Hunh? You lost me there...
I was just agreeing with you that harmful mutations are common, and arguing that they will be weeded out pretty effectively.
Ok, so is evolution pushing biologicals in a decidedly "better" direction or not then?
The "better" creatures are more likely to reproduce. Note also that "good" depends on the environment; it doesn't have to mean "more intelligent" or "more complex", just "more likely to appear in large quantities several generations later".
Created by a human brain, with human intervention and in an unnatural enviornment... Anyway, Im not seeing where mutation and natural selection are any part of this expiriment.
Actually, I was arguing that mutation and natural selection work even without a cell and that Spiegelman's original chain evolved into a more efficient one (without his encouragement; he was just trying to prove that RNA life was possible).
Ahh but why can't we speed up the process? Bacteria have a high reproduction rate and by artifically introducing mutegens, we should be able to evolve Bacteria easily. That is unless random mutation is really not the driving force behind evolution?
Sure, you can do interesting stuff with bacteria, but I thought you didn't want to talk about that. Still, even with some creative application of mutagens, you're still talking about a vastly smaller and shorter experiment than the evolution of life on Earth.
Becuase if evolution proceeds in small incremental steps, we should see this preserved in the fossil record and living today. We should see scales turning into feathers. Fins turing into feet etc.
Right, except that, as you point out, such "in-between" creatures don't survive too well, so they're rapidly replaced by either the old-style creature or something new; this is called Punctuated equilibrium. This goes a long way to explaining the gaps in the fossil record.
Well you probably won't convince me without empirical scientific evidence.
Well, as noted previously, we disagree on whether we have this.
Specified and Irreducible complexity are perhaps two of these properties and can't, as of yet, be produced by any blind, naturalistic force.
Nice try, except specified complexity is gibberish (as I've previously explained) and irreducible complexity, while a good argument, doesn't seem to have any evidence.
Perhaps the designer wanted diversity and programmed it into the DNA? btw how does micro evolution interfere with the design?
Actually, you have a point there. If the designer wants diversity, you could get microevolution, but it would still be jump-started by design.
And why is the designer exempt from having to be designed?
That's a philosophical question. I think the scientifc method has limits. Let's say for arguments sake that a god does exist and created the universe and life. Is there any way we could empircaly detect god? The closest we could come would be to expect order and purpose in the universe with an intelligence similar to ours.. |
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RTyp06
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Recently (in evolutionary terms) gaining the ability to digest a new food source isn't beneficial?
Yes it is, so I stand corrected. This is a beneficial mutation. But restoring a previously lost function doesn't explain how the function came about in the first place. And it's not really gaining a new ability but rather restoring itself.
In any case, your counterargument is silly. If you remove everything that's close to the desired functionality, it will of course take longer for it to redevelop (you're selecting against it).
It's not just a matter of taking longer, it never redevelopes.
Yes there are many variables involved but if you think about it, Natural Selection breaks down to Live or Die. Period. How prolific a species is, is irrelevant, although it may dictate (or play a role in) how long the species tenure here on earth is, it will either die out or survive. Again, a Yes, No.
I understand why you find evolution so implausible; you're oversimplifying most of what makes it work out of it. The longer a species survives (and the greater the numbers), the more chances it has of changing into something that can survive in a changed environment.
Where is your evidence that the longer a species survives the more chance it has of changing? Crocs and Alligators for example haven't changed in millions of years. And what exactly am I oversimplifying?
Wikipedia has a few good summaries on the subject of Evolutionary algorithms. Genetic algorithms are perhaps the best established subset of these and have been successfully applied to a large amount of tricky search problems.
Ok thanks.
The "better" creatures are more likely to reproduce. Note also that "good" depends on the environment; it doesn't have to mean "more intelligent" or "more complex", just "more likely to appear in large quantities several generations later".
Which is the fittest? The most prolific. Which is the most prolific? The fittest. Seems like circular reasoning to me.
Actually, I was arguing that mutation and natural selection work even without a cell and that Spiegelman's original chain evolved into a more efficient one (without his encouragement; he was just trying to prove that RNA life was possible).
He used an artifical solution containing RNA replicase http://en.wikipedia.org/wiki/RNA_replicase .Most likely from a virus. The test RNA which became shorter and shorter was placed in fresh solution each time. The test RNA would never have replicated without help from the RNA replicase. So how exactly does this prove that RNA life is possible?
Sure, you can do interesting stuff with bacteria, but I thought you didn't want to talk about that. Still, even with some creative application of mutagens, you're still talking about a vastly smaller and shorter experiment than the evolution of life on Earth.
The problem is that thus far, evolution of life can't be demonstrated in ANY capacity.
Right, except that, as you point out, such "in-between" creatures don't survive too well, so they're rapidly replaced by either the old-style creature or something new; this is called Punctuated equilibrium. This goes a long way to explaining the gaps in the fossil record.
Punctuated Equilibrium is an interesting theory and probably the most plausible evolutionary varient. It recognizes the sudden apperance of species in the fossil record. Especially the cambrian explosion. What remains a mystery is how large macroscopic changes can happen so quickly. One would think that large changes would require alot of DNA re programming.
Nice try, except specified complexity is gibberish (as I've previously explained) and irreducible complexity, while a good argument, doesn't seem to have any evidence.
Then you should see the work of this guy: http://www.ag.uidaho.edu/mmbb/p_minnich_s.htm
He has devoted much time studying the bacterial flagellum. Specificly knocking out genes that build the flagellum.
We will simply disagree wether specified complexity is gibberish or not.
I suppose much of this comes down to that I feel that explaining intelligent life by assuming an intelligent designer is just begging the question. Even if true, it still doesn't explain where the intelligence came from.
Thus we may have found the limits of the scientific method.
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« Last Edit: February 24, 2007, 04:53:50 pm by RTyp06 »
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Death 999
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We did. You did. Yes we can. No.
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It's not just a matter of taking longer, it never redevelopes.
Yeah, because you had how many knockouts reproducing for how many generations? What? Of order a hundred knockouts reproducing of order five generations? Evolution would not in any estimate produce any noticeable effects that quickly (except those of people who believe that the ark contained the roots of all modern species).
You're complaining that our pot of water didn't boil the moment we turned the stove on.
Where is your evidence that the longer a species survives the more chance it has of changing? Crocs and Alligators for example haven't changed in millions of years.
Also answered, many times... a species which is well adapted to its present situation is under very little evolutionary pressure and tends to stay largely the same for very long periods, in no small part because it turns down its mutation rate. This has been directly observed in bacteria; and sexual selection is a great stabilizer when it does not run amok (peacocks).
The "better" creatures are more likely to reproduce. Note also that "good" depends on the environment; it doesn't have to mean "more intelligent" or "more complex", just "more likely to appear in large quantities several generations later". Which is the fittest? The most prolific. Which is the most prolific? The fittest. Seems like circular reasoning to me.
It's not circular reasoning. We're talking about definitions of terms. What makes a creature fit is its ability to reproduce in the long run. That means several generations down the road -- as far as the influence of this individual extends.
Now, one good way to achieve that is to have a lot of kids. That's where being prolific fits in. If you have no kids, they're not likely to have kids either (as the saying goes), so being at least a little bit prolific is fairly important.
This is no more 'circular reasoning' than to say that the thing that goes on top of the table is higher than the table. Because it's not reasoning yet. It's just definitions; and each of these terms can be defined in terms of the other if desired, or other terms. That you chose to define each in terms of the other is not a weakness of the system.
Thus we may have found the limits of the scientific method.
Depending on what you're referring to, it seems more like we've found the limits of the 'make random stuff up and believe it to be true' method.
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