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Author | Topic: The Human Genome and Evolution | |||||||||||||||||||
Tranquility Base Inactive Member |
But what is this invisible boundary that delimits the human 'kind'. Read my post to sfs. For the purposes of this discussion I'm happy to concede that I can't prove a 'kind' difference here.
For example, to persue your argument from an evolutionary perspective, we might use chimps as an outgroup and test sequence homology between humans chimps and Neanderthals and find the latter closer to humans than the former. So we have: Humans __________________________(common ancestor)Neanderthals_______/..................../ Chimps______________________/ Agreed.
Presumably, you deny common ancestry between humans and ANY other animal, so the human lineage has to be essentially unbranched beyond the level of human 'kind'. Yes, but it's just a postulate.
And yet the existence of Neanderthals shows that it HAS branched *below* the level of kind. Hold on. I include Neandethal (and Erectus) as part of the human kind.
So I ask, yet again, what is it that somehow prevents branching *above* the level of 'kind' ? Can you clarify your use of above and below before I contine.
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Tranquility Base Inactive Member |
Mick
The links work presently. Maybe ICR was down? They just reveamped their site a month ago and I know they are still reorganizing stuff. But the links work now.
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Tranquility Base Inactive Member |
EZ
Well I just assumed that at some point the 3 must have shared as common ancestor. Starting with the lineage that ultimately led to humans, I am simply assuming that Neanderthals diverged from this lineage later than chimps did, given they are obviously closer to humans. I am not an expert on hominid phylogeny either, I was just trying to make the point that once you accept branching lineages, you may as well accept that more and more branches occur all the way back. There is no known mechanism that could ensure the eternal integrity of a 'kind', however defined, because this would imply no branching had ever occurred above this level. I'm still trying to understand what you're saying. I'll try and paraphrase what you're saying: because trees include kind members AND kinds themsleves therefore kinds are invalidated as a concept. Is that what you're saying?
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Tranquility Base Inactive Member |
WK
Well unless you have secretly sequenced the genomes of all 'fly' species you are making this statement based upon a very small sample, pretty much just Drosophila really. The point is that every bioinformatician - mainstream or not - would expect to find them in other flies! It's of no interest to find it in other flies (at least as far as our discussion is concerned).
So your fly/mosquito specific genes are really only A. gambiae/D. melanogaster specific, to the best of our knowledge so far. Sure.
This doesn't neccessarily follow. The 1000 'specific' genes need not be directly related to the gross morphological/ anatomical characteristics preserved in Amber. Maybe not, but in principle time will tell. I'm sure you're aware that so-called ancient ambaer-bound insects look perfectly modern.
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Tranquility Base Inactive Member |
Then there is no point in arguing for retention of the term or discussing the matter further. You realise I was referring purely to the primate issue? It has a lot of utility outside of that realm.
So what happened to your precious human ‘kind’ created in God’s image ? My statmeents on the improtance of regulatory regions and uhnman-specific genes aside I'm simply prepared to concede that humans are not a good example at the genomic level.
But there is plenty of evidence for information *gain* in genomes, like for example in the article I cited back in message 56 of this thread. I have no problem with horizontal transfer! I'm talking about gai nto the enitre genomoshpere (not simply swappings)!
Plenty of other examples too. If divergence occurs primarily due to loss of information (genes), then why is it that we see organisms becoming more complex over time in the fossil record, rather than less? I'm sure you're aware that creationist view the fossil record as a Flood and recolonization event.
There is simply no evidence that some hypothetical initial ‘set’ of genomes were created. How, in your slippery view of the world, would we distinguish a ‘created’ genome from one that evolved ? If the data is consistent with the concept it does not matter if we cannot distinguish it from your scenario. It is unfrotunate, but not a problem per se.
When I asked if you deny branching of the human lineage, you said: TB writes:Yes, but it's just a postulate. You could construe my comment in that way. I would prefer to say it was a postulate that humans were not related to other primates.
Sorry, that’s not good enough. Without some sort of testability, postulates are just pipe dreams. Like I said, I prepared to concede - for the purposes of this discussion - your point on the human kind. But I'm going to point to the obvious realtive gains of genomic informaiton throuhgout the genomosphere.
Fine. But the basic morphological differences between Neanderthals and modern humans (and other lines of evidence, I suspect) strongly suggest they would have been genetically incompatible. I can handle that too - although I doubt you could prove it.
But I guess this distinction doesn’t matter to your definition of ‘kind’. Speciation is of no real consequence to your view Agreed.
of evolution because your imaginary immutable 'kinds' continue their evolution in parallel and can never be traced back to a common ancestor. . . excpet to the original kinds potentailly.
So I ask you, yet again, once you have separate gene pools what can possibly limit the degree of divergence of one organism from another ? Time and the alck of demonstration of the reality of the appearance of genuine genomic novelty. Of course, evolutionists have not proven that new gene types really arise. You assume they arose and then make statements of the consequences that has given the evidence. I'm a structural biologist and bioinformatician. I know precisely what has and what hasn't been demonstrated about the evolution of new gene types. I'm happy to discuss it at that level if you want.
I meant that if the human lineage branched into Neanderthals 'below' the point where it became recognizably 'human' (which it did, despite your insistence in considering them the same ‘kind’), then what prevents the human lineage from being one branch diverging from another lineage (above the level of human ‘kind’)? The first point is I see nothing about Neandertal that is not human. Secondly, we're kind of on the same sid on this. I'm prepared to say I beleive in macroeovlution and that maybe you could end up with genuinely 'new kinds' from a functional definition. That does not mean that our viewpoint is without use becasue, in principle, we still claim to be able to trace back mammals to, say a 100, original genomes and not further.
But now, from the above quotes, it seems you have conceded (1) you cannot provide a functional definition of how a ‘kind’ is delineated and held immutable and Not quite. I defined a functional definition at the genomic level. I make no statements about the phenotype. My personal intuition is that even on the mainstream tiemscale I wouldn't expect to see the arrival of eyes, immune systems and brains. But I can't argue that quantitatively.
you accept that you cannot disprove genetic evolution of humans from primates. So what earthly (scientific) use is your nebulous, biblically-derived concept of 'human kind'? I prepared to conceede that it has little scientific use for primates precisely becasue mammalian differnees are primarily in regulatory regions.
I think I can rest my entire case at this point. Fine. But don't build a straw man. Our claims and research concern the origin of all life forms. Not just mankind. This message has been edited by Tranquility Base, 07-11-2005 10:18 PM
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Tranquility Base Inactive Member |
Mick
here is gene number for a variety of species. Gene number appears to increase rather than decrease with time. That's we're the paridigm differnece is important. We beleive they all began essentially at the same time. Diversificaiton by gene loss is oemthing we propose for in-kind (de-)evolution. This is well documented in bacterial genomes and extremeophiles. You ca mfind just about any REDUNDANT sub-system absent in a family of related geneomes. You might view the others as gains but we would view them as losses in the other genomes. I fully agree that mammals have more genes than flies or bacteria. But we're not claiming common descent to that extent as you know.
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Tranquility Base Inactive Member |
WK
Yes, that's the poiint I just made too.
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Tranquility Base Inactive Member |
Mick
For this reason one cannot argue that genes are lost over time, while arguing for simultaneous origin. The hypothesis that gene number declines over time necessitates the belief that species arise from one another (otherwise, what does the decline mean?). But it's easy to lose genes even in a short amount of time. Losing genes is trivial compared to arriving at completely new genes!
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Tranquility Base Inactive Member |
WK
Maybe not, but not finding them in other flies or finding only some of them in other flies would be directly relevant to the discussion. Fine. We would interperet them as lost in the flies wihtout them and you would interperet them as gains in the flies that had them. The only reason to assume it either way is ideology.
Meh, phenotypes! These specimens preserved in amber are rarely more than 100 MY old and the lineages of Drosophila and anopheles are estimated to have diverged 250 MYA leaving at least a 100 MY for the mosquito to have evolved a morphological phenotype effectively indistinguishable from a modern mosquito. Fine.
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Tranquility Base Inactive Member |
EZ
True enough. Science does not address final origins. But it works very well to explain the 'how' without the need to invoke any metaphyscial intervention, so why postulate what isn't needed? Careful EZ. Science has never proven that significant novelties like eyes and immune systems could evolve. You simply assume such evoltuoin is possible becasue of your interpretation of the fossil record. All you have is whole swag of mechanisms for genomic plasticity. That's only a *prerequisite* for evolution of novelty.
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Tranquility Base Inactive Member |
deerbreh
I object to use of the term "macroevolution" on this thread. This term was invented by creationists. Evolutionary biologists do not differentiate between "macro" and "micro" evolution. It is just evolution. By using a term that is essentially a creationist construct there is a built in creationist bias to the discussion. If creationists wish to debate evolutionists they need to use the accepted terminology and not invent new terminology. Really? They are useful - if not perfect terms - in mainstream science. Here's even a mainstream abstract from Evol. Dev. I have posted before that demonstrates the difference between macroeovlution and microevolution. It's even in the paper's title:
Macroevolution is more than repeated rounds of microevolution. Erwin DH. Department of Paleobiology, National Museum of Natural History, Washington, DC 20560, USA. erwin.doug@nmnh.si.edu Arguments over macroevolution versus microevolution have waxed and waned through most of the twentieth century. Initially, paleontologists and other evolutionary biologists advanced a variety of non-Darwinian evolutionary processes as explanations for patterns found in the fossil record, emphasizing macroevolution as a source of morphologic novelty. Later, paleontologists, from Simpson to Gould, Stanley, and others, accepted the primacy of natural selection but argued that rapid speciation produced a discontinuity between micro- and macroevolution. This second phase emphasizes the sorting of innovations between species. Other discontinuities appear in the persistence of trends (differential success of species within clades), including species sorting, in the differential success between clades and in the origination and establishment of evolutionary novelties. These discontinuities impose a hierarchical structure to evolution and discredit any smooth extrapolation from allelic substitution to large-scale evolutionary patterns. Recent developments in comparative developmental biology suggest a need to reconsider the possibility that some macroevolutionary discontinuites may be associated with the origination of evolutionary innovation. The attractiveness of macroevolution reflects the exhaustive documentation of large-scale patterns which reveal a richness to evolution unexplained by microevolution. If the goal of evolutionary biology is to understand the history of life, rather than simply document experimental analysis of evolution, studies from paleontology, phylogenetics, developmental biology, and other fields demand the deeper view provided by macroevolution. Macroevolution is more than repeated rounds of microevolution - PubMed This message has been edited by Tranquility Base, 07-12-2005 11:05 PM
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Tranquility Base Inactive Member |
WK
Creation vs. evolution aside, the issues of precisely how eyes arose was always going to be more than beak reshapings. Creationists certainly did jump on it but it seems to me that researchers working at the big picture level use the terms.
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Tranquility Base Inactive Member |
My post was meant to be agreeing with you!
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Tranquility Base Inactive Member |
EZ
As you're aware these papers simply track either phenotype or where gene and protein-fold families re-appear. They do not address the geneuninely new molecular machinary required (quote from immune system paper):
A few molecules may have been created de novo. If you assume evolution of genuine novelty occurred it's all childishly simple, I agree.
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