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The theory is evolution?

  1. Oct 21, 2011 #1
    The theory is evolution is well established and maybe considered by some the cornerstone of biology but where are the experiments which prove it . We have never seen bacteria that turn into something else also where is the evidence for the theory in the fossil record ? Also I can't understand how can a biological system with multiple complicated interconnected systems with very highy complicated biochemistry can evolve into something else radically different ? I want clarification of these points because I'm not a biologist and I do not know much in biology
     
    Last edited: Oct 21, 2011
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  3. Oct 21, 2011 #2

    bobze

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    2 hours of your time. Follow along with it. Its there to learn.

    Evolution 101
     
  4. Oct 21, 2011 #3

    Evo

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  5. Oct 21, 2011 #4
    Well , Thanks . the links you provided seem to try to explain evolution to school kids . I just want specific answers to the above questions . For example have we ever found bacteria that turned into something else more complicated? Also I need information about the fossil fuel findings that confirm the theory (e.g research papers and other resources)
     
  6. Oct 21, 2011 #5

    PAllen

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    All of your question are answered in the first link provided for you (I checked to make sure). Come back and ask more specific questions after you have read the material. No one else can think and learn for you.
     
  7. Oct 21, 2011 #6

    Fredrik

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    What makes you think good theories can be proved? They can't. Bad theories can however be disproved. And there are no experiments or observations that disprove the theory of evolution. There are lots of experiments and observations that are consistent with evolution, but none that's known to be inconsistent with evolution.

    Like what? If they turn into something very different in just one generation, or even in the time it takes to perform the longest experiment performed so far, this would indicate that something other than evolution is involved.

    It's kind of funny that when creationists are pressed to answer what they would consider evidence of evolution, they always say something like "a monkey giving birth to a human". It's funny because this is precisely the sort of thing that would disprove the theory, not prove it.

    Uh...everywhere. What you need to understand is that "gaps" in the fossil records are to be expected, for several reasons. One of them is that a vast majority of animals that die don't turn into fossils. But more importantly, you need to understand that creationists who complain about the "gaps" are extremely dishonest. Every time a fossil is found that is intermediate between two known species, they'll just say that now there are two gaps where there used to be one.

    I'm also not a biologist, and I don't know these things well enough to explain it, so I can only suggest that you check out some youtube videos, the talkorigins.org website, and perhaps read a book. I like "The blind watchmaker" (Dawkins).
     
  8. Oct 21, 2011 #7

    atyy

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    Much of the evidence is indirect. Evolution, unlike many sciences, is more like history or cosmology where we reconstruct what has happened on the assumption that the laws of physics are the same throughout space and time. The assumption can be falsified, but has not yet been, and it continues to make good predictions, so we accept it tentatively. An example of such indirect evidence is that the mitochondria in your body are similar to bacteria http://en.wikipedia.org/wiki/Endosymbiotic_theory. Also there are organisms that are on the "border" of unicellularity and multicellularity http://en.wikipedia.org/wiki/Dictyostelium.

    P.S.: Wikipedia references this amazing video
     
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  9. Oct 21, 2011 #8

    atyy

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    The site you linked to says "The central idea of biological evolution is that all life on Earth shares a common ancestor, just as you and your cousins share a common grandmother."

    Hurd cites Woese http://ncse.com/rncse/27/3-4/review-origins-life "It is in fact an area of considerable research and discussion whether there were multiple origins of life, and whether this can ever be untangled. Work by Carl Woese (especially 1998, 2002) argues strongly that multiple origins will never be disentangled. It is with a respect bordering on awe that I contemplate how Charles Darwin allowed for this in the last page of his Origin of Species, writing that life was originally breathed "... into a few forms or into one.""

    Which is more accurate?
     
  10. Oct 21, 2011 #9

    bobze

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    Most science is done via indirect evidence. You ever see a proton being accelerated in a accelerator and crashing into another one? If not, then you are using indirect evidence its is there and of the process that is taking place. In fact, I would go so far as to argue that indirect evidence in science--Is often more powerful than direct evidence in science. Indirect evidence allows us to observe the outcome of phenomena or the behavior of system in ways which can be very powerful for understanding that process in and of itself, often times in ways that direct observation of said phenomena would not be possible.

    I would have agreed with you that evolution is more like a "history" if this were 1950, however its time for you to catch up methinks. The modern study of evolution is done through EvoDevo, proteomics, molecular biology, etc. Not only is this stuff extremely "cutting edge" in melding both technology and scientific theory--it produces many testable applications of evolutionary theory and its underlying tenets everyday.

    There is much stronger evidence for evolutionary theory than endosymbiotic theory. No offense, but you should learn what you're talking about before offering advice on a topic.

    Again, most of the study of modern evolution is done through molecular biology. For instance just published in Nature this week; http://www.nature.com/nature/journal/v478/n7369/full/nature10532.html"



    I'm not sure what you are asking? Are you asking which is more accurate whether there is multiple origins of life (MOL) or a single one?

    If so, I'd suggest you are again confused. All extant life found on earth thus far, shares a common ancestor. Hence as the website Evolution 101 suggests; "The central idea of biological evolution is that all life on Earth shares a common ancestor, just as you and your cousins share a common grandmother", is accurate.

    Whether life emerged one time or many is unknown and something we may never know. If life had multiple origins, which is possible, but died out, we may never know. It certainly remains possible however, that hiding somewhere in the world exists a hopeful little monster that doesn't share a common ancestor with other life on earth. Regardless, that idea is only speculation as we have never found any evidence to suggest such an organism exists.

    Examining the molecular biology and genetics of life existing in the 3 extant domains however (Eubacteria, Archaebacteria, Eukaryota), reveals that we all stem from a common ancestor.
     
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  11. Oct 22, 2011 #10

    atyy

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    Woese conjectures in PNAS June 9, 1998 vol. 95 no. 12 6854-6859 "The ancestor cannot have been a particular organism, a single organismal lineage. It was communal (13, 22), a loosely knit, diverse conglomeration of primitive cells that evolved as a unit, and it eventually developed to a stage where it broke into several distinct communities, which in their turn become the three primary lines of descent. The primary lines, however, were not conventional lineages. Each represented a progressive consolidation of the corresponding community into a smaller number of more complex cell types, which ultimately developed into the ancestor(s) of that organismal domain. The universal ancestor is not an entity, not a thing. It is a process characteristic of a particular evolutionary stage."

    He further conjectures in PNAS June 25, 2002 vol. 99 no. 13 8742-8747 "primitive cells initially did not have stable genealogical records" and "Extant life on Earth is descended not from one, but from three distinctly different cell types."

    Woese's ideas seem dissimilar from the idea that the universal ancestor is analogous to cousins sharing a grandmother. Is that mistaken? Or have Woese's hypotheses been falsified?
     
    Last edited: Oct 22, 2011
  12. Oct 22, 2011 #11

    HallsofIvy

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    No, those are not different. Woese says that life descended from "three distinctly different cell types". But cells themselves were relative "late comers" in evolution. It may very well be that there were "three distinctly different cell types" but the similarity of DNA throughout those different cell types indicates they were themselves evolved from the same pre-cell ancestor.
     
  13. Oct 22, 2011 #12

    atyy

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    Why then does Theobald cite Woese's proposal as being different from monophyly?

    "Furthermore, several researchers have proposed that early life was characterized by rampant horizontal gene transfer, leading some to question the monophyly of life11,14,15" [Theobald's reference 15 is Woese, 2002; Theobald's paper is Nature doi:10.1038/nature09014]
     
  14. Oct 22, 2011 #13

    bobze

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    Early cells may certainly have, in the words of Dawkins, "swapped genes with reckless abandon" (lateral gene transfer), but this only further supports that "proto-cellular" or "pre-cell" life stems from a common ancestral replicator.

    Proponents that each domain of life has its own independent origin of life would then be suggesting, in a nutshell, that life arose at least 3 times--yet in a manner so similar to each other it allowed the sharing of ancestral genes. In other words, the same hereditary mechanism for these independent origins would have had to arise identically more than once.

    The best and most simplest answer to why early cells were capable of lateral gene transfer was because they shared a common ancestor. No different than observed today, where lateral gene transfer is more common among closely related bacterial taxa.

    Sounds like someone needs a heavy dose of Einstein's beard trimmers. Introducing degrees of freedom and excess baggage as an extraordinary claim, require extraordinary evidence.
     
  15. Oct 22, 2011 #14

    atyy

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    So you would not agree with Woese's proposal that "A modern type of genome replication mechanism did not exist at the root of the universal tree (14). Virtually no homology (orthology) exists between the bacterial genome replication mechanism and that basically common to the archaea and the eukaryotes (although a number of bacterial and archaeal DNA polymerases, some of which serve repair functions, do show sequence homology). Modern genome replication mechanisms seem to have evolved twice (14). .... Having to rationalize those features unique to each of the three major cell types (10, 39) on the assumption they evolved late in the game (in the period covered by the universal tree) is clearly problematic." PNAS June 25, 2002 vol. 99 no. 13 8742-8747 ?
     
    Last edited: Oct 22, 2011
  16. Oct 22, 2011 #15

    Evo

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    This article is better at addressing the issues in the preceeding posts.

    http://www.nature.com/scitable/topicpage/the-two-empires-and-three-domains-of-14432998
     
    Last edited: Oct 26, 2011
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