1. Standard memberDavid C
    Flamenco Sketches
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    20 Dec '05 07:31
    Could the life cycle of a frog not be considered a microcosm of the evolutionary process? What about the metamorphosis of a butterfly?
  2. Standard memberscottishinnz
    Kichigai!
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    20 Dec '05 07:351 edit
    Originally posted by David C
    Could the life cycle of a frog not be considered a microcosm of the evolutionary process? What about the metamorphosis of a butterfly?
    Nope, no selection pressure. No selective death. It is a wonderful developmental process though and is indicative of the organisms that we evolved from. For example, during the embryonic phase all mammals exhibit a fish-like phase, with tail and everything...

    edit; actually, I should say all chordates, rather than all mammals, although the mammals are a subdivision of the chordata. They / we also have gills during development...
  3. Standard memberDavid C
    Flamenco Sketches
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    20 Dec '05 08:13
    Originally posted by scottishinnz
    Nope, no selection pressure. No selective death. It is a wonderful developmental process though and is indicative of the organisms that we evolved from. For example, during the embryonic phase all mammals exhibit a fish-like phase, with tail and everything...

    edit; actually, I should say all chordates, rather than all mammals, although the mammals are a subdivision of the chordata. They / we also have gills during development...
    Selection pressure or selective death aside, this is the process, right? Brain pan expands, lungs develop, leg bones form, etc.?
  4. Standard memberNemesio
    Ursulakantor
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    20 Dec '05 08:26
    Originally posted by scottishinnz
    For example, during the embryonic phase all mammals exhibit a fish-like phase, with tail and everything...
    I seem to recall that your conclusion -- that the embryonic phases like the fish-like
    one support evolution on some scale -- is spurious. I mean, doctors studying biology
    before the common era have been looking at miscarriages and surmising that we
    were higher on the hierarchy of animals because we can see fish-phase, lizard-phase
    or whatever.

    I don't know much about embryonic development and what these phases entail, I
    just remember that the 'we can see our evolutionary history in embryos' claim was
    not well respected.

    Or I could be totally inventing a memory!

    Nemesio
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