MD writes:
The insistence that the "lack of true novelty across the biological spectrum is a powerful indication of common descent" is based on the assumptions that life could only arise as we see it today because of the conditions on the earth were the way they were.
crashfrog writes:
Er, no, it's based on observation.
Yes. I know it's based on observations. But, if some conditions has been different in the past, the process of natural selection could have produced a totally different product.
PaulK notes something very similar to your thoughts when he says:
PaulK writes:
So evolution propsoes "unlimited plasticity" in the sense of proposing quite definite limits on plasticity. For instance the basic tetrapod body plan has been altered in various ways but remains recognisable in everything from frogs to bird to humans. And need I point out other famous examples like the panda's "thumb"?
crashfrog and PaulK, I have no doubt that the basic tetrapod body plan has been altered in various ways but remains recognisable in everything from frogs to bird to humans. The point I'm trying to make is that, as a generally random process, it didn't
have to happen this way. Had conditions been different for any reason in
the earliest periods of the speciation of life, evolutionary processes could have produced something totally different from the basic tetrapod body plan -- and still have lead to the development of frogs, birds, and humans that
didn't have the basic tetrapod body plan.
Do you understand what I'm trying to explain?
I'm not saying that the evidence of common descent indicates unlimited plasticity. I'm saying that the common ancestry of life
could have diverged sharply in the past to result in a nearly unlimited range of possibilities of species that we could only imagine today. Just because life evolved the way it did, doesn't mean it had to evolve exactly that way. If some initial conditions had been different, totally different species could have been formed -- which is what I mean by unlimited plasticity.
I'll put a qualifier as "potential" unlimited plasticity just to be clear as I review the starting points of this topic within this discourse.
MD writes:
Yes, but if one simply changes the parameters of the process of natural selection, one could end up with many different starting points.
The insistence that the "lack of true novelty across the biological spectrum is a powerful indication of common descent" is based on the assumptions that life could only arise as we see it today because of the conditions on the earth were the way they were.
Change the initial conditions, and one could end up with totally different "lack of true novelties" on an alien planet for example -- and these unique features might even be "totally novel" to our life-forms here on earth.
In other words, what you've just said sounds very similar to the Anthropic Principle that creationists often use to counter (unsuccessfully I might add) evolutionary claims.
crashfrog writes:
That's hardly "unlimited plasticity." In fact the great similarity and lack of true novelty across the biological spectrum is a powerful indication of common descent.
MD writes:
In other words, what you've just said sounds very similar to the Anthropic Principle that creationists often use to counter (unsuccessfully I might add) evolutionary claims.
crashfrog writes:
In what way? What I've just said is an observation - there's very little biological novelty. There's almost no feature of any organism you can point to for which you can't find some precursor in another related organism.
I don't see the least similarity to an argument from the Anthropic Principle.
Maybe I'm wrong, but this is how I see it.
The anthropic principle basically states that if some of the finely-balanced quantities were not finely-tuned then our universe could have grossly different properties. Some have claimed that this is evidence for an intelligent designer. I don't think it is though. It seems to me that if we were for example intelligent cats with blue
blood, we'd be looking back and concluding that everything had to be intelligently made so that we could be intelligent cats with blue blood.
Similarly,
The theory of evolution basically states that if some of the finely-balanced species were not finely-tuned then the speciation of life on earth could have grossly different properties. Some have claimed that this is evidence for a lack of true novelty. I don't think it is though. It seems to me that if we were for example evolved
from the basic tetrapod body plan, we'd be looking back and concluding that everything had to evolve so that we could have the the basic tetrapod body plan.
MD writes:
I already explained what it would display on a philosphical level.
crashfrog writes:
No, you didn't. If you had, or had explained to sufficient clarity, I wouldn't have had to ask
.
I thought I did already.
For example in post 101 I posted:
MD writes:
On the one hand, athiestic scientists would probably love the chance to prove certain fundamentalist groups wrong when they say it can't be done. On the other hand, theistic evolutionists could then enjoy partaking in the creation of life as their Lord did ages ago.
Then again, perhaps people would simply find that it actually cannot be done after all. For that matter, if the experiment were succesful over a period of 200 to 400 years say (or longer), this would greatly reduce the potential time theorized necessary for evolution to transpire if indeed a "Divine Intelligent Agent" was guiding its
course.
MD writes:
On a scientific level, it would essentially prove that the greater claims of the theory of evoltion are a fact.
crashfrog writes:
No, it really wouldn't.
While the usage of the word "fact" might be an error on my part, I still think that it would certainly lean the body of evidence in the favor of evolutionary theories.
Wouldn't this simply be an example of forced evolution?
MD writes:
In other words, humanity could say with 100% certainty that evolutionary mechanisms CAN produce what we're claiming they can produce -- and they would have perfectly documented evidence of it.
crashfrog writes:
But since they didn't employ evolutionary mechanisms to achive the outcome, how could they be said to have done that? They'd have evidence of no such thing.
Yes, but doesn't this statement discount the forced evolution that's being conducted in the labs?
I mean, it's a simulated experiment to further test the claims of evolutionary theories.
Aren't there any laboratory experiments which are claimed as evidence of evolution?
Doesn't this count for something?.
crashing writes:
Reaching in and modifying DNA to achieve a desired outcome isn't an evolutionary process; it isn't even close to an evolutionary process. In fact it's the exact opposite of random mutation and natural selection; it's more like specified mutation and random selection.
Yet Darwin himself saw a close parallel between the artificial selection of breeders and the natural selection of nature.
As Darwin's original hypothesis has undergone extensive modification and expansion, but the central concepts stand firm. Studies in genetics and molecular biology -- fields unknown in Darwin's time -- have explained the occurrence of the hereditary variations that are essential to natural selection. Genetic variations result from
changes, or mutations, in the nucleotide sequence of DNA, the molecule that genes are made from. Such changes in DNA now can be detected and described with great precision.
Why would this not be considered a simulation of evolution if we are exprimenting with chimp DNA, inserting, modifying, and deleting certain sequences?
On a different note:
MD writes:
Because this isn't proving that the greater claims of evolution are 100% certain -- unless, or course, one thinks that a human being was born immediately from a lesser primate without any intermedite stages.
crashfrog writes:
Well, of course no one thinks that. But what you're describing isn't close to the evolutionary model, either. It's as cartoonish an oversimplifcation of the historical reality as the idea of a chimp giving birth to humanity in one signle saltational event.
But I'm not talking about a chimp giving birth to humanity in
one signle saltational event. That was actually your suggestion if I recall correctly -- and it was in response to my note about animal rights activists being concerned about the violation of these creatures inherent "chimpanzeeness" too.
MD writes:
While certain animals rights groups might object to the genetic violation of these creatures inherent "chimpanzeeness", it seems to me that a project of this magnitude would certainly attract a large base of researchers.
crashfrog writes:
Furthermore why do it the hard way when we could simply take a chimp zygote, knock out its nucleus, and insert human DNA?
I may be wrong, but I think you've now answered your own question with your statement below (which I've already quoted above).
crashfrog writes:
Well, of course no one thinks that. But what you're describing isn't close to the evolutionary model, either. It's as cartoonish an oversimplifcation of the historical reality as the idea of a chimp giving birth to humanity in one signle saltational event.
Consequently, PaulK, you said the following:
PaulK writes:
The rest of the stuff is just speculation - humans and chimps have been seperated long enough that interbreeding is unlikely to be suvvessful even without the chromosomal difference.
I'm not talking about interbreeding. That was crashfrog's simple suggestion it appears.
I'm talking about genetically modifying the chimpanzees over
several generations by forced evolution in a control setting
Experimenting on the human-chimpanxee line is also fraught with ethical questions - which you seem to take no account of at all.
I didn't say it wasn't -- and I've already noted that animals rights groups would be concerned.
But that's beside the point. I have no plans on actually conducting an experiment like this. I'm just interested in how one would go about doing it.
Anyway, coming back to my point, the idea for this experiment was not to produce a human from a chimpanzee in one single saltational event. The idea was to, over a period of at least 200 years, simulate evolutionary processes via genetic manipulation thoughout a larger series of artificially selected saltational events. One can
quibble over the usage of artificial selection for this if they like. However, Darwin himself saw a close parallel between the artificial selection of breeders and the natural selection of nature.
If I recall correctly, this is what I had said earlier.
MD writes:
Or, going several steps further in the other direction, has anyone ever delved into what it would take to artificially manipulate the genes of some other living primate today (say a chimpanzee) and attempt to make it more human with each generation.
Admittedly, this would be a large on-going undertaking involving several research fields and financial contributions. However, it would be interesting is they could use genetic manipulation to simulate mutations and natural selection in order to accomplish the following very quickly over many generations what would normally
require millions of years:
1: Fuse two of the smaller chimpanzee chromosomes to genetically produce a new species that has 23 chromosomes like humans do (instead of 24 like chimpanzees).
2. Reduce the 23 kilobases of repeating DNA sequences on the chimpanzee telomere to 10 kilobases of repeating DNA like that of the human telomere.
3. Although 18 pairs of chromosomes are ‘virtually identical’ between humanity and chimpanzees, chromosomes 4, 9 and 12 show evidence of being ‘modified.’ in some way. It would be interesting if genetisists could manipulate the chimpanzee generations so that the markers on these chromosomes would go in the same order as in the human -- the Y chromosome in particular would have to made into a different size and have many markers line up where ordinarilly they do not do so.
4. Genetically re-engineer chromosome 21 in particular so as to remove the large, non-random regions of difference between the two different types of genomes.
5. Determine the regions that might correspond to insertions that are specific to the human lineage -- and attempt to reproduce them genetically as appropriate.
While certain animals rights groups might object to the genetic violation of these creatures inherent "chimpanzeeness", it seems to me that a project of this magnitude would certainly attract a large base of researchers.
Instead of trying to clone humans, perhaps the better experiment is to try to produce humans via generations of
genetically altered chimps.
To break down these steps more clearly, picture something like this outline going on for an extended period of 100 years at the
very least.
chimpanzee --> genetically engineered saltational event --> genetically engineered saltational event --> genetically engineered saltational event --> genetically engineered saltational event --> genetically engineered saltational event --> genetically engineered saltational event --> genetically engineered saltational event -->
genetically engineered saltational event --> genetically engineered saltational event --> human
Does this make my questions clearer?
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