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Junior Member (Idle past 5052 days) Posts: 1 From: Austin, TX, US Joined: |
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Author | Topic: Problems with evolution? Submit your questions. | |||||||||||||||||||||||
shadow71 Member (Idle past 2956 days) Posts: 706 From: Joliet, il, USA Joined: |
this is in reply to granny magda 483 & 488, bluejay 491 and nwr 486
Yes and I think that it's fair to say that it was a very unusual event. I'm not sure why you seem to think that NS could not have acted upon the earliest eukaryotes though. Remember, NS is what selects from amongst varieties that already exist. It does not create variety itself, it only acts as a filter. Just because the normal process of random mutation would have had a reduced role in the change to endosymbiosis does not mean that NS would not have taken place. I do not believe that Lane intended to imply this. I am not saying that NS was not involved after the jump from prokaryote to eukaroyte, or that NS & mutation were not involved in prokaryote prior to the jump.But the jump per Lane & Martin was a "unique event", that did not rely on NS. Not sure if I am clear, but I interpret this to mean that the jump from ProK to EuroK was a moment of Macro evolution. Some papers I have been reading are leaning toward the hypothesis that Macro evolution, or the transition to complex entities, does not rely on NS and mutation, but on genetic information engineering processes and are almost instant in nature compared to the gradualness of micro evolution. This seems to be in concert with Lane & Martin.Remember I am not a biologist, and you all should know that I am a practicing Roman Catholic who believes as the church does that evolution is a continuing process, but was not initiated by a Natural act. In other words, nature is performing it's, shall we say programmed, work.
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Dr Adequate Member (Idle past 306 days) Posts: 16113 Joined: |
I am not saying that NS was not involved after the jump from prokaryote to eukaroyte, or that NS & mutation were not involved in prokaryote prior to the jump. Then how does this "jump" differ from the evolution of any other form of symbiosis? And in what sense is it a "jump"? What exactly are you visualizing as happening here?
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shadow71 Member (Idle past 2956 days) Posts: 706 From: Joliet, il, USA Joined: |
Then how does this "jump" differ from the evolution of any other form of symbiosis? And in what sense is it a "jump"? What exactly are you visualizing as happening here? Lane and Martin state "The transition to complex life on Earth was a unique event..." I interpret that to mean a jump from simple prokaroyte to a complex eukaroyte. This is not a gradual mutation, natural selection process as in microevolution. It is a jump from one species to another, a macroevolution event. Edited by shadow71, : No reason given.
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Dr Adequate Member (Idle past 306 days) Posts: 16113 Joined: |
Lane and Martin state "The transition to complex life on Earth was a unique event..." I interpret that to mean a jump from simple prokaroyte to a complex eukaroyte. Saying that it was unique doesn't mean that it was a saltation. And I don't see how a saltation would have worked. Surely they can't have "jumped" in a single step from no symbiosis to obligate endosymbiosis. How do you envisage that happening?
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shadow71 Member (Idle past 2956 days) Posts: 706 From: Joliet, il, USA Joined: |
Saying that it was unique doesn't mean that it was a saltation. And I don't see how a saltation would have worked. Surely they can't have "jumped" in a single step from no symbiosis to obligate endosymbiosis. How do you envisage that happening? I am not a biologists, but can only rely on the papers I read by the experts in the field. Carl Woese's work indicates that there may have been a saltation whereas the proK's, EuroK's and Archaea arose from a change in cell organizations early on that gradually led to the evolution theory now accepted by Darwinians & neo-Darwinains.This seems in line w/ Lane & Martin's paper. If true this slatation or saltations may have been the precusor of micro evolution.
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Dr Adequate Member (Idle past 306 days) Posts: 16113 Joined: |
I am not a biologists, but can only rely on the papers I read by the experts in the field. Carl Woese's work indicates that there may have been a saltation whereas the proK's, EuroK's and Archaea arose ... How does Woese's work imply a saltation? If you're thinking of HGT, then obviously there has to be diversity before that can have any substantial effect. It can't create the three domains, it can only blur the boundaries between them. Edited by Dr Adequate, : No reason given.
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Rrhain Member Posts: 6351 From: San Diego, CA, USA Joined: |
mike the wiz writes:
quote: Yes. Methinks you are confusing equality with implication. That is: (X = Z) -> (Z = X) However: (X -> Z) ~-> (Z -> X) That is, equality is when two things are the same. All squares are equal. Implication, though, is when one thing leads to another: That is a logical pathway that may or may not be reversible: All squares are rectangles ("Being a square" implies "being a rectangle") but not all rectangles are squares ("Being a rectangle" does not imply "being a square.")
quote: If you think they have something to do with equality rather than implication, yes. Rrhain Thank you for your submission to Science. Your paper was reviewed by a jury of seventh graders so that they could look for balance and to allow them to make up their own minds. We are sorry to say that they found your paper "bogus," specifically describing the section on the laboratory work "boring." We regret that we will be unable to publish your work at this time. Minds are like parachutes. Just because you've lost yours doesn't mean you can use mine.
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Rrhain Member Posts: 6351 From: San Diego, CA, USA Joined: |
mike the wiz responds to me:
quote:quote: Huh? What on earth does that have to do with anything? I asked you to specifically indicate what the problem is and you wander off on a tangent. If 1 exists, 2 exists, addition exists and works, and equality exists and works, how can that not force a concluion that 1 + 1 = 2? If you agree that all of the mechanisms of evolution exist and work, how is that not proof positive that evolution is a reality? What, specifically, is the problem?
quote: So if the facts of evolution exist and work, how is that not proof positive that evolution is a reality? What, specifically, is the problem?
quote: But you just said that they do. If mutations exist and change morphology and if selection weeds out morphologies that do not match the adaptive landscape, how is that not proof positive of a "change" of "design"? What, specifically, is the problem?
quote: Huh? How can they "already be there" if they are mutations? Just what do you think mutation is? You just said you agree with the conclusions of science and here you are denying one of them. This would be where you justify your denial. Be specific. Rrhain Thank you for your submission to Science. Your paper was reviewed by a jury of seventh graders so that they could look for balance and to allow them to make up their own minds. We are sorry to say that they found your paper "bogus," specifically describing the section on the laboratory work "boring." We regret that we will be unable to publish your work at this time. Minds are like parachutes. Just because you've lost yours doesn't mean you can use mine.
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Blue Jay Member (Idle past 2720 days) Posts: 2843 From: You couldn't pronounce it with your mouthparts Joined: |
Hi, Shadow.
shadow71 writes: I am not saying that NS was not involved after the jump from prokaryote to eukaroyte, or that NS & mutation were not involved in prokaryote prior to the jump.But the jump per Lane & Martin was a "unique event", that did not rely on NS. I see what you're getting at. The trouble is that mutations also create a kind of "jump" that doesn't involve NS; and NS only gets involved after those little mutational "jumps" too. This goes back to Granny's original explanation: Lane & Martin's comment suggests that, what happened in the "jump" from prokaryote to eukaryote is "symbiosis + natural selection" rather than "mutation + natural selection." This is what makes them call it a "unique event": symbiosis is less common than mutation as a mechanism of evolution. Because it allows the ecological and/or physiological networking of entire independent genomes into a single, collaborative unit, symbiosis can be thought of as adding several useful, new traits or alleles at the same time. This makes it "bigger" than more typical mutations. And, the endosymbiotic origin of organelles almost certainly didn't happen in a single, giant "jump": for example, there are many kinds of eukaryotic cells alive today that absorb prokaryotes by phagocytosis, then, for whatever reason, fail to digest them, and simply let the prokaryotes live, grow and reproduce inside them, creating a co-habitation relationship that is midway between separate organisms and fully-symbiotic organisms. -----
shadow71 writes: Some papers I have been reading are leaning toward the hypothesis that Macro evolution, or the transition to complex entities, does not rely on NS and mutation, but on genetic information engineering processes and are almost instant in nature compared to the gradualness of micro evolution. There are so many usages of the term "macro-evolution" that I groan every time I hear someone use the word. "Transition to complex entities" is not a description I've ever heard for it before, though. There does seem to be a fad of finding new mechanisms for evolution these days. I'm not sure what drives people to think evolution needs new mechanisms, but I figure I'll just let them have their fun and assume that it must be contributing something of value to science (otherwise why would they be doing it?). At any rate, don't get hung up on "macro-evolution": none of the definitions that people give it are really that meaningful in the long run. -Bluejay (a.k.a. Mantis, Thylacosmilus) Darwin loves you.
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Dr Adequate Member (Idle past 306 days) Posts: 16113 Joined: |
And, the endosymbiotic origin of organelles almost certainly didn't happen in a single, giant "jump": for example, there are many kinds of eukaryotic cells alive today that absorb prokaryotes by phagocytosis, then, for whatever reason, fail to digest them, and simply let the prokaryotes live, grow and reproduce inside them, creating a co-habitation relationship that is midway between separate organisms and fully-symbiotic organisms. Can we hear more about this please? Thanks.
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New Cat's Eye Inactive Member |
Lane and Martin state that a prokaryote has evolved once in four billion years into a eukaryote. So I am still quite confused. From your later posts, its seems like you think that L&M are saying that the prokaryote evolved one time in one single organism. Yeah? This is the source of your confusion, me thinks.
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Blue Jay Member (Idle past 2720 days) Posts: 2843 From: You couldn't pronounce it with your mouthparts Joined: |
Hi, Dr A.
Dr Adequate writes: Can we hear more about this please? Way to put me on the spot, man!. I don't know anything else: I just have some lecture notes from an undergraduate plant diversity course that don't say anything more than what I already wrote, and memory of a couple slides the professor showed. I'll have to look it up later, when I have time. -Bluejay (a.k.a. Mantis, Thylacosmilus) Darwin loves you.
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Meddle Member (Idle past 1293 days) Posts: 179 From: Scotland Joined: |
Rickettsia, Chlamydia and some Mycobacteria such as M.leprae are all obligate intracellular pathogens of eukaryotes. Interestingly the genome of Rickettsia has been sequenced and has shown that it is related to mitochondria. You can read about it here. Obviously mutation and natural selection would be involved in the bacteria surviving within the eukaryote, then in the transition to parasite and finally organelle.
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Blue Jay Member (Idle past 2720 days) Posts: 2843 From: You couldn't pronounce it with your mouthparts Joined: |
Hi, Malcolm.
Now I understand what happened. I had heard this Rickettsia/mitochondria story before, and I got the details of it confused with the details of a Cyanobacteria/chloroplast example from my plant diversity course. In the Cyanobacteria/chloroplast example, the eukaryote (which did not lack mitochondria) engulfed the bacterium, but took a long time before getting around to digesting it within the vacuole. This gave the bacterium enough time to photosynthesize and reproduce inside the host cell. It became a mutualism, because, while the bacterium is protected from predators, the host cell is able to uptake excess photosynthate from the bacterium. I still don't have a taxon name for the organism, nor any more details than this, such as, how the bacterium gets minerals (which it can't photosynthesize). I suspect that, since the vacuole is used to eject waste products after the prey is consumed, it may double as a waste reservoir, and may thus have waste products from the host cell from which to extract minerals. Edited by Bluejay, : No reason given. -Bluejay (a.k.a. Mantis, Thylacosmilus) Darwin loves you.
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shadow71 Member (Idle past 2956 days) Posts: 706 From: Joliet, il, USA Joined: |
How does Woese's work imply a saltation? If you're thinking of HGT, then obviously there has to be diversity before that can have any substantial effect. It can't create the three domains, it can only blur the boundaries between them. In the paper "Molecular signatures of ribosomal evolution" Just a moment... one of the authors being Carl R. Woese they state; "Evidence today strongly suggests that a highly developed translation system was a necessary condition for the emergence of cells, as we know them. In the universal phylogenetic tree (UPT) format, this maturation of the translation system seems to be represented by the tree's basal branchings, where first the bacterial and then the archaeal and eukaryotic lineages appear individually to emerge. What lies beneath the "root" locus, the evolution leading up to it, cannot be captured in familiar tree representation. It would seem to be some distributed universal ancestral state from which the (three) primary organismal lineages materialized via one or a brief series of major evolutinary saltations in which the state of the evolving cellular organization and the accompanying evolutionary dynamic underwent dramatic change. The aboriginal evolutionary dynamic may have been "Lamarckian" in the sense that it seems likely to have involved massive pervasive horizontal transfer of genes (HGT), innovation sharing. The kind and frequency of the HGT envisioned would make evolution early on effectively communal. This communal evolutinary dynamic comes to an end relatively suddenly and transroms largely into the familar genealogical dynamic when the evolving organisms in the community reach a stage of 'critical complexity,' wherein their organizations change significantly and rapidly, becoming more refined and individualized, more 'self-composed'. These we call Darwinian transitions..." That seems to me to be in line with what Lane and Martin are saying. Sorry my cite does not work. You may google"molecular signatures of ribosomal evolution Elijah Roberts, ... Carl R. Worse Edited by shadow71, : correct site Edited by shadow71, : add autors at bottom Edited by shadow71, : No reason given. Edited by Admin, : Fix link.
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