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Member (Idle past 2963 days) Posts: 706 From: Joliet, il, USA Joined: |
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Author | Topic: Does the Darwinian theory require modification or replacement? | |||||||||||||||||||||||||||
shadow71 Member (Idle past 2963 days) Posts: 706 From: Joliet, il, USA Joined: |
molbiogirl writes:
Now. Since Wright contends that 99.5% of all mutations are random and undirected, let's see you cite a paper that supports directed mutation in something other than a microorganism I think we are on different wave lengths. I understand Shapiro as stating macro and micro evolution are 2 differenct entities and that maco is driven by directed mutations. Shapiro "Mobile DNA and evolution in the 21st century" writes: Although there remain many gaps in our knowledge, we are now in a position to outline a distinctively 21st century scenario for evolutionary change. The scenario includes the following elements: (1) hereditary variation arises from the non-random action of built-in biochemical systems that mobilize DNA and carry out natural genetic engineering; (2) major disruptions of an organism's ecology trigger cell and genome restructuring. The ecological disruptions can act directly, through stress on individuals, or indirectly, through changes in the biota that favour unusual interactions between individuals (cell fusions, interspecific hybridizations). Triggering events continue until a new ecology has emerged that is filled with organisms capable of utilizing the available resources; (3) ecologically-triggered cell and genome restructurings produce organisms which, at some frequency, will possess novel adaptive features that suit the altered environment. Novel adaptive features can be complex from the beginning because they result from processes that operate on pre-existing functional systems, whose components can be amplified and rearranged in new combinations. Competition for resources (purifying selection) serves to eliminate those novel system architectures that are not functional in the new ecology; (4) once ecological stability has been achieved, natural genetic engineering functions are silenced, the tempo of innovation abates, and microevolution can occur to fine-tune recent evolutionary inventions through successions of minor changes. Another paper is a: How Development Directs Evolution Epigenetics & Generative Ddynamics" Dr. Mae-Wan Hohttp://www.energysustainability.nl/mae-wan.pdf Here are some exerpts. Dr.Mae -Wan Ho writes: Abstract and IntroductionIn a paper published 30 years ago, Ho and Saunders (1979) proposed the then outrageous non-Darwinian idea that the intrinsic dynamics of developmental processes is the source of non-random variations that directs evolutionary change in the face of new environmental challenges; and the resulting evolutionary novelties are reinforced in successive generations through epigenetic mechanisms, independently of natural selection. Our proposal has held up well against subsequent research findings, and is all the more relevant in view of the numerous molecular mechanisms discovered in epigenetic inheritance (Ho, 2009a,b) that could transmit developmental novelties to subsequent generations. and later in the paper: Ho writes: Macroevolution therefore involves epigenetic and epigenetically directed genetic changes, and is decoupled from the random microevolutionary accumulation of base sequence changes. and part of conclusion: Ho writes: What implications are there for evolution? Just as interaction and selection cannot be separated, nor are variation (or mutation) and selection, for the selective‟ regime may itself cause specific epigenetic variations or directed‟ mutations. The organism experiences its environment in one continuous nested process, adjusting and changing, leaving imprints in its epigenetic system, its genome as well as on the environment, all of which are passed on to subsequent generations. Thus, there is no separation between development and evolution. In that way, the organism actively participates in shaping its own development as well as the evolution of its ecological and social community. We do hold the future in our hands; it is precious, be careful. Thus do Shapiro and HO see the future of evolution and both scientists do state a need for: The OP in this thread "Does the Darwinian theory require modification or replacement?" the answer that "micro evolution" may not direct mutations, but rather keeps organisms as they are and "macro evolution" directs the changes per Shapiro and Ho's theories.
molbiogirl writes:
Shadow.It's simple. Either cite Ho's published research or find another paper published in the research literature that supports your claim of directed mutation/directed evolution. Shadow. It's simple. Either cite Ho's published research or find another paper published in the research literature that supports your claim of directed mutation/directed evolution. You seem to lose perspective of the big picture, I am saying that evolution is directed in someway. It need not be mutational direction. Clearly the above cilted writings of experts in the field are saying that there is more to evolution than random mutation and natural selection. When you look at the research in these discplines: EvolvabilityEpigenesis Phenotypic plasticity evolutionary development (evo-devo) reticulat evolution endosymbiiosis and symbiogenesis horizoontal gene tansfer You have to at least acknowledge that the current theory of evolution is not complete, and may need change. So direction is most probably above the micro level and in the macro level as many papers are now stating. Please remember the OP is DOES THE DARWINIAN THEORY REQUIRE MODIFICATION OR REPLACEMENT. You cannot ignore all of the papers out there that say yes, and just say Shadow, show me mutation at the eukaroytic level that is directed.It is way above that level as the papers state. There are clearly papers that favor the positon that evolution to some extent is directed. Edited by shadow71, : No reason given.
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shadow71 Member (Idle past 2963 days) Posts: 706 From: Joliet, il, USA Joined: |
NoNukes writes:
Wouldn't Shapiro have defined "purifying selection" if he was not using the term in its ordinary sense? I don't know. --------------------------------------------------------------------------------
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Dr Adequate Member (Idle past 313 days) Posts: 16113 Joined: |
I think we are on different wave lengths. I understand Shapiro as stating macro and micro evolution are 2 differenct entities and that maco is driven by directed mutations. And if he ever finds a scrap of a shred of a scintilla of evidence for this, his opinion will suddenly become interesting.
Clearly the above cilted writings of experts in the field are saying that there is more to evolution than random mutation and natural selection. Which, by a complete non-coincidence, is exactly what the theory of evolution says.
When you look at the research in these discplines: EvolvabilityEpigenesis Phenotypic plasticity evolutionary development (evo-devo) reticulat evolution endosymbiiosis and symbiogenesis horizoontal gene tansfer You have to at least acknowledge that the current theory of evolution is not complete ... Why? Things that we know about are part of the current theory. Are you seriously trying to pretend that horizontal gene transfer isn't part of the theory of evolution? Or endosymbiosis? You might as well pretend that recombination isn't either. To know that the current theory was incomplete we would have to know that there is an evolutionary mechanism that we don't yet know about. Well, of course we can't know that; but there may be. And when it is discovered and shown to exist it will de facto be part of the theory.
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jar Member (Idle past 423 days) Posts: 34026 From: Texas!! Joined: |
Dr Adequate writes: And when it is discovered and shown to exist it will de facto be part of the theory. As pointed out to him in Message 3 of this very thread. Anyone so limited that they can only spell a word one way is severely handicapped!
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shadow71 Member (Idle past 2963 days) Posts: 706 From: Joliet, il, USA Joined: |
molbiogirl writes:
And where does Badyaev discuss directed mutation? Directed evolution? --------------------------------------------------------------------------------
badyaev writes:
Second, such reduced integration and subsequent accommodation of stress-induced variation by developmental systems enables organismal ‘memory’ of a stressful event as well as phenotypic and genetic assimilation of the response to a stressor.Third, in complex functional systems, a stress-induced increase in phenotypic and genetic variance is often DIRECTIONALchannelled by existing ontogenetic pathways. This accounts for similarity among individuals in stress-induced changes and thus significantly Edited by shadow71, : No reason given.
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Theodoric Member Posts: 9201 From: Northwest, WI, USA Joined: Member Rating: 3.2 |
You never discuss any of this in your own words. I am quite sure you have no idea what any of what you post even means.
Please explain what Badyaev is saying so that a layman like I can understand. Also, please explain how this supports your claim that this is supportive of directed mutation or evolution. Facts don't lie or have an agenda. Facts are just facts
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molbiogirl Member (Idle past 2671 days) Posts: 1909 From: MO Joined: |
That's not directed mutation nor is it directed evolution.
That's genetic assimilation. See? There in the quote?
Second, such reduced integration and subsequent accommodation of stress-induced variation by developmental systems enables organismal ‘memory’ of a stressful event as well as phenotypic and genetic assimilation of the response to a stressor. I addressed genetic assimilation in Message 421. Allow me to remind you.
There is nothing exotic about the concepts of genetic accommodation and assimilation. Badyaev writes: Third, in complex functional systems, a stress-induced increase in phenotypic and genetic variance is often DIRECTIONAL channelled by existing ontogenetic pathways. Directional is not directed.Directed has a very specific meaning. Provide a cite that supports your claim of directed mutation or directed evolution.
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molbiogirl Member (Idle past 2671 days) Posts: 1909 From: MO Joined: |
Shapiro "Mobile DNA and evolution in the 21st century" writes: Please cite Shapiro supporting directed mutation or directed evolution in higher organisms.
Dr.Mae -Wan Ho writes: For the sixth time, CITE A PAPER IN THE RESEARCH LITERATURE.
Evolvability Epigenesis Phenotypic plasticity evolutionary development (evo-devo) reticulat evolution endosymbiiosis and symbiogenesis horizoontal gene tansfer None of these are directed mutation/directed evolution.Provide support for your claim of directed mutation/directed evolution or withdraw your claim. ABE
You cannot ignore all of the papers out there that say yes, and just say Shadow, show me mutation at the eukaroytic level that is directed. I have provided the definition of directed evolution twice.I will try a third time. A definition of adaptive mutation is that only useful, not deleterious or neutral, mutations occur during selection (7, 12, 29). Are you seriously claiming that phenotypic plasticity meets this criteria?Or evolutionary development? Or HGT? Or any of the above? Fantastic. Please provide a cite that supports your claim that "that only useful, not deleterious or neutral, mutations occur during selection" re: ANY of the above listed processes. Edited by molbiogirl, : No reason given.
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NoNukes Inactive Member |
Shadow71, I hope you will molbiogirl's questions. But I did want to summarize my understanding.
My own understanding is that the only thing presented so far that purports to explain evolution without natural selection is Ho's talk. Shapiro and Wright discuss non-random mutations acted on by natural selection. Cairns' Origin of mutants has been self refuted, and Zheng's paper was actually damaging to s71s cause. Non-random mutations plus natural selection, in my opinion, don't get us away from evolution as Darwin understood it. There are some other papers, but their relevance is still under discussion. (Ho, and Badyaev) What concerns me is that you do not seem to know what natural selection is, and cannot seem to recognize selection when scientist mention it in their papers. Yet, that's pretty much the portion of modern theory that Darwin did have a handle on in Origin of Species. How can a discussion of modifications to the current theory be meaningful without knowing what the current theory is? Also, it is helpful when you sprinkle some of your own commentary in between quotes from the papers when you present them. You do this sometimes, but not often enough.
and "macro evolution" directs the changes per Shapiro and Ho's theories. I have no idea what this sentence means. At some point, we need to agree on what definition of directed you are insisting on, so that we can meaningfully discuss it. In some sense, natural selection directs evolution.
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jar Member (Idle past 423 days) Posts: 34026 From: Texas!! Joined: |
I think it might be worthwhile to point out that micro and macro are really just human labels. All change is micro as it happens, but humans, looking back over the evidence can point to two or more examples and say "There's enough difference between sample A and sample Z to say that there has been a BIG change and we will call that Macro."
If we had all of the samples that actually were the lineage between sample A and sample Z what we would see would be a spectrum and succession of small changes, we would say "Wow, look at all the small (Micro) changes and how sample Z is so different from sample A yet almost identical to sample Y." Anyone so limited that they can only spell a word one way is severely handicapped!
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NoNukes Inactive Member |
jar writes: I think it might be worthwhile to point out that micro and macro are really just human labels. All change is micro as it happens Of course all terms are mere labels. Shapiro uses the term macro-evolution to refer to evolution by a different mechanism than that used for micro-evolution. On the other hand, in discussions here, we have typically used the term macroevolution to refer to an accumulated microevolution. Creationists have sometimes insisted that such accumulation is somehow limited from producing new kinds. I'm not sure which definition of macroevolution is the "correct" one, but I believe at least a couple authors cited in this discussion have used definitions similar to Shapiro's.
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jar Member (Idle past 423 days) Posts: 34026 From: Texas!! Joined: |
I'm still not sure what would make one mechanism "macro" as opposed to "micro" though, and so far I cannot find anything at least in this thread, that explains just what is so different.
Anyone so limited that they can only spell a word one way is severely handicapped!
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NoNukes Inactive Member |
jar writes: I'm still not sure what would make one mechanism "macro" as opposed to "micro" though, and so far I cannot find anything at least in this thread, that explains just what is so different. Shapiro speculates that macroevolution is ecological stress driven mutation mechanisms that generate complex structures. Microevolution is a slower mechanism that uses random mutations. Shadow71 has quoted sections of Shapiro's work using these definitions.
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jar Member (Idle past 423 days) Posts: 34026 From: Texas!! Joined: |
NoNukes writes: jar writes: I'm still not sure what would make one mechanism "macro" as opposed to "micro" though, and so far I cannot find anything at least in this thread, that explains just what is so different. Shapiro speculates that macroevolution is ecological stress driven mutation mechanisms that generate complex structures. Microevolution is a slower mechanism that uses random mutations. Shadow71 has quoted sections of Shapiro's work using these definitions. Yes, but that is still pretty much just word salad. What keeps micro evolution from creating complex structures. What complex structure has Shapiro identified as being produced by his definition of "macro evolution"? So far I haven't seen any evidence of that presented at all. Anyone so limited that they can only spell a word one way is severely handicapped!
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NoNukes Inactive Member |
jar writes: What keeps micro evolution from creating complex structures. Perhaps I have overstated a bit. Shapiro's idea is that stress invokes mechanisms that are targeted at locations that will produce novel complex structures, while random mutation have a much lower likelihood of doing so. Shapiro discusses such might be the case. In any event, Shapiro describes that under stress there is a higher mutation rate, and higher likelihood of a mutation affecting a relevant biological function. When the stress is relieve, strictly random mutations at a lower rate occur. You'll have to read the paper to see if you believe that Shapiro is convincing. Wright describes some similar effects and some evidence. I don't recall if she uses the terms micro/macroevolution I'm not defending either paper, but I don't call it word salad. If nothing else, macroevolution differs by using mutations that are responsive to stress (in frequency and/or location) and working faster than microevolution through strictly random mutation. And yes some evidence is cited. Shapiro's paper has a combination of speculation and some evidence. You'll have to judge credibility for yourself. I'm not a biologist, but I don't think the "word salad" criticism is justified.
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