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Mammals evolving from birds rather than reptiles.

  1. Sep 12, 2015 #1
  2. jcsd
  3. Sep 12, 2015 #2

    blue_leaf77

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    Cynodonts, an ancestor of modern mammals had been living 110 million years before archaeopteryx did.
     
  4. Sep 12, 2015 #3

    SteamKing

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    Depends on how far back you go.

    This is a picture of everybody's great-great-great- ... -great-great-great grand daddy:

    Dimetrodon_grandis.jpg
    Dimetrodon was a creature which is grouped into what are known as synapsids, due to the construction of their skulls. Synapsids pre-date reptiles as we know them today, but the synapsid line split into two main groups, one group which evolved into sauropsids, which eventually became modern reptiles and birds, and the other group which led to early mammals and eventually present-day mammals.

    https://en.wikipedia.org/wiki/Mammal

    I'm not aware of any scientist who advocates credibly that mammals, including monotremes, evolved from birds or their early reptile-like ancestors. From the fossil record, any evolvin' of birds and monotremes appears to have occurred along separate lines in time. The duck bill and the egg-laying of the platypus appear to be an evolutionary coincidence.
     
  5. Sep 12, 2015 #4

    blue_leaf77

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    I think this is what evolutionists term as convergent evolution.
     
  6. Sep 12, 2015 #5

    SteamKing

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    Yeah, that's the ticket.
     
  7. Sep 12, 2015 #6
    That actually looks like my great aunt after she quit smoking about 15 years ago :confused:
     
  8. Sep 12, 2015 #7

    Ygggdrasil

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    DNA evidence refutes the possibility that mammals evolved from birds:
    (http://tolweb.org/Amniota/14990)

    In other words, if you look at shared gene sequences between birds, mammals, repltiles, and other amniota, it's clear that mammals and all of their relatives fall on one branch and reptiles and birds fall on the other branch:
    amniota61.png
    These relationships are supported by the synapsids fossils referenced by SteamKing above.

    Here's a link to the Hedges 1994 study referenced in the quote that refutes the mammal-bird connection: http://www.pnas.org/content/91/7/2621.long
     
    Last edited: Sep 12, 2015
  9. Sep 12, 2015 #8
    But seriously folks...

    Yeah, I'd have to agree with this. At least from the perspective of brain evolution, mammals and birds took two fundamentally different paths in their development of advanced brain structures over their more ancestral forms. The mammalian brain evolved a neocortex out of the dorsal pallium of the amphibian-reptile primordial structure, while the avians developed a hyperstriatum out of the more subcortical dorsal ventricular ridge. These are two distinct paths of evolution.
     
  10. Sep 12, 2015 #9
    Why would you think this was more convergent versus divergent evolution? The monotremes including the platypus and the echidna are the most primitive of egg laying mammals next to the egg-laying reptiles. Doesn't this make sense that these are species diverging in their evolution from their reptilian ancestors rather than converging from who and what knows where? Where is this converging egg laying behavior and duck-billed phenotypy coming from?
     
  11. Sep 12, 2015 #10

    blue_leaf77

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