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Author Topic:   mutation and evolution
Spofforth
Inactive Member


Message 2 of 20 (33184)
02-25-2003 7:32 PM
Reply to: Message 1 by John
02-25-2003 4:10 PM


quote:

I think you misunderstand. How did you calculate the odds? Did you consider that there are astronomical numbers of experiments running simultaneously and that this has been occurring for a couple of billion years?

quote
Attempting to cut the numbers by appealing to populations isn't relevant to the issue. Consider: Ten species with 100,000 individuals each. For simplicity, lets say they reproduce at the same rate and produce one offspring per generation. Each generation can be considered as 1 million genetic experiments-- ie, each generation produces 1 million individuals, each with a mutation or two. That these mutations do not cross species does not cut the total number of mutations. It does mean that the mutation is limited to the offspring of originating population. Perhaps nine of the ten species die out, but the tenth survives as it had the lucky mutation.
The problem I see with that line of reasoning is that if you take into account that a new species can only arise from a previous species, according to evolutionary theory, then you can only take into account the mutations that occur within the parent species. That would lower the mutation rate significantly.
If species A has a mutation, however it has no way to pass the mutation to species B that survives in the immediate area, the mutation would have no significance in population B. Therefore the populations that are affected and have the ability for mutation decrease significantly.
quote:
Funny, you want student to understand biological systems but do not wish to expose them to a key component of biology.
The key component I would want them to know before knowing any theory is the scientific method. I am not opposed to exposure of students to evolutionary theory, but I am opposed to teaching it as fact especially since so much depends on mutation rates in various populations.
quote:
But what is with the "coding for amino acid which is coding for a protein" part? Amino acids don't code for anything. They are components, like Lego.
I'm sorry I mispoke, I meant to say build. I just meant that if the right amino acid was not in place then the protein would most likely be an irrelevant part of the organism.
quote:
The reason creationists opt for this restricted definition is that mutation can and does modify existing protein and this happens quite a lot. So really, you've cut the rope from under yourself.
My contention would be that the existing protein is not modified all that frequently because the point mutations that would be most likely to survive often do not even change the protein. If you are looking at the codes for amino acids there can be several variations of bases that code for each one thus lowering the frequency of mutations that cause protein changes. I would certainly not argue against natural selection, I would however argue that it is acting on variation that is already present in the population. The gene frequency of a population may change. However, it is difficult to argue that an organism has changed without seeing the actual physical change in comparison to a genetic change. I would especially argue this point in complex organisms where one change might affect many systems.

This message is a reply to:
 Message 1 by John, posted 02-25-2003 4:10 PM John has replied

Replies to this message:
 Message 3 by John, posted 02-25-2003 11:45 PM Spofforth has replied
 Message 4 by Peter, posted 02-26-2003 4:32 AM Spofforth has not replied

  
Spofforth
Inactive Member


Message 7 of 20 (33319)
02-26-2003 11:29 PM
Reply to: Message 6 by John
02-26-2003 11:05 AM



quote:
--------------------------------------------------------------------------------
The problem I see with that line of reasoning is that if you take into account that a new species can only arise from a previous species, according to evolutionary theory, then you can only take into account the mutations that occur within the parent species.
--------------------------------------------------------------------------------
This is a repetition of the first objection you made, and I responded to it.
You are right, I was viewing your statements as something completely out of context. I was viewing populations A,B,...F as completely separate populations and not as parts of the original. I apologize for the redundancy.

This message is a reply to:
 Message 6 by John, posted 02-26-2003 11:05 AM John has not replied

  
Spofforth
Inactive Member


Message 8 of 20 (33321)
02-27-2003 12:00 AM
Reply to: Message 3 by John
02-25-2003 11:45 PM




Spofforth: The key component I would want them to know before knowing any theory is the scientific method.
--------------------------------------------------------------------------------
John: Why do you hold this up as so important, but dismiss the results it produces? Very few things have as much evidence behind them as does the ToE.

Yes there is evidence that tends to lead in the direction of evolution. I just find it hard to promote a theory as fact if the lineage of DNA cannot fully be traced from generation 1 to generation x. If the possible path is discussed and alternative theories are thrown in the student can draw his/her own conclusions based on the method or have an understanding of how to research it further if they choose.

Have you bothered to look it up? I've found quite a few examples and posted a couple of them for you. Have you decided to look the other way?

I have looked at them and they are discussing what I would consider microevolutionary changes. I believe that microevolutionary changes do occur because there is variation within every population. I believe that environmental changes can assist in microevolutionary changes. The thing that I cannot conceive, even given the possibility of billions of years, is that microevolutionary changes could lead to the wide scale variation in organisms today. The changes that are seen cause organisms to fit into specific niches and occur in response to environmental changes, ie. presence of nylon and not carbohydrate or pesticide resistance, however the populations tend to rebound as the stimulus is removed and the fitness of the "mutant" decreases in the population. If I am mistaken and there is evidence of current macroevolution, divergence of species, please point me in that direction.

This message is a reply to:
 Message 3 by John, posted 02-25-2003 11:45 PM John has replied

Replies to this message:
 Message 9 by Peter, posted 02-27-2003 2:54 AM Spofforth has replied
 Message 10 by John, posted 02-27-2003 8:54 AM Spofforth has replied
 Message 15 by nator, posted 02-28-2003 7:55 AM Spofforth has not replied

  
Spofforth
Inactive Member


Message 11 of 20 (33391)
02-27-2003 9:34 PM
Reply to: Message 9 by Peter
02-27-2003 2:54 AM



quote: If the environmental pressures don't go away, or
some of the population are isolated so that the two sub-populations
are subjected to different environmental pressures it's surely
reasonable to surmise that they would diverge. We know that such
divergence is possible (otherwise there would be fewer breeds
of dogs, cattle, cats, etc.).
However if the environmental pressure were removed would the populations not tend to rebound toward their predivergent state? Which would tend to eradicate the mutation from the population or store it in a dormant state within the population. If this is the case is it not possible that genetic information has always had messages in dormant states waiting to be turned on when environmental conditions were right and off when they were not? Yes, selective breeding has led to a vast diversity of domesticated animals. If left to nature would they not reach a state of equilibrium in their genetic material?

quote: It's been brought up before (not sure where, sorry), but not
discussed in full (I think) ... but what about species which
can inter-breed, but produce infertile offspring?
Doesn't that suggest that the species (horses&donkeys, lions&tigers,
various zebras) are diverging to a point where, should the
trend continue, they would be unable to interbreed?
Is that still micro-evolution?
Or is it the first step on the rung to more profound diversity?


I would venture to guess that this would still be micro-evolution. However, would the interbreeding variants within the population again be able to reproduce freely and produce a population that reaches some state of equilibrium?

This message is a reply to:
 Message 9 by Peter, posted 02-27-2003 2:54 AM Peter has replied

Replies to this message:
 Message 14 by Peter, posted 02-28-2003 4:57 AM Spofforth has not replied

  
Spofforth
Inactive Member


Message 12 of 20 (33393)
02-27-2003 10:11 PM
Reply to: Message 10 by John
02-27-2003 8:54 AM



quote: That is a serious mistatement of fact. Since Darwin proposed his version of evolution 150 years ago, it has passed every test. Every bit of evidence that we've been able to scrape up has fallen into place in support of the ToE. Despite what creationists promulgate, there is no real challenge to the theory at the moment and there never really has been.
Puntuated equilibrium to explain gaps in the fossil record, modern synthesis to correct for Darwin's nonrandom mutation?

We only get to see a few seconds of the ball-game.
There is nothing anyone can do about this. Relationships of long duration we have to infer from the evidence we have at our disposal.


So from where would the evidence for the evolutionary process as an absolute come? This sounds a lot like my were you there argument. If you cannot see the entire game how do you know what occured in the first thirty seconds? Sure you can make inferences from the evidence, but that does not make a theory fact.

Quote: Yes, indeed. Evolution does occur because there is variation within a population. Your mistake is in assuming that, or insisting that, this variation is stable.
Quote: In other words, if you wish to describe all adaptation as variation within existing DNA, you have to explain why the bacteria would have the ability to eat nylon prior to nylon having been invented. Why would its genes code for the ability to eat something that was yet to exist for it to eat?
Gene turned off (dormant) inversion, Gene turned on (active)point mutation followed by deletion. Perhaps chromosomes were designed with the ability to alter genetic material in response to environmental change. Intelligent designer: synthetic material will arise someday as a result of human intelligence designed by me, there may someday be a need for natural means of disposal, Poof --> nylon eating bacteria?

This message is a reply to:
 Message 10 by John, posted 02-27-2003 8:54 AM John has replied

Replies to this message:
 Message 13 by Coragyps, posted 02-27-2003 10:49 PM Spofforth has not replied
 Message 16 by John, posted 02-28-2003 12:25 PM Spofforth has not replied

  
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