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Thread: Can any one post a list of Classes in Chordata (AP Bio Proj)

  1. #1 Can any one post a list of Classes in Chordata (AP Bio Proj) 
    zLr
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    I'm presenting the Phylum Chordata and want to order my presentation by class, after defining the phylum

    I'm just having a -hell- of a hard time finding a definite lisit of the classes. The diagram of chordata in my AP book shows these 'groups':

    Urochordata (tunicates)
    Cephalachordata (lancelets)
    Myxini (hagfishes)
    Cephalaspidomorphi (lampreys)
    Chondrichthyes (sharks, rays, chimaeras)
    Actinopterygii (ray-finned fishes)
    Acinistia (coelacanthus)
    Dipnoi (lungfishes)
    Amphibia (frogs, salamanders)
    Reptilia (turtles, snakes, crocodiles, birds)
    Mammalia (mammals)

    The subtitle of this diagram tells you that it "shows the major clades of chordates."

    I know that mammalia, reptilia and amphibia are definite classes, but i also know that aves (birds) is also a class; but in the diagram they are grouped with the reptiles. So I know that this cannot be a complete or even accurate list of classes.

    I think this may demonstrate the phylogeny instead of the taxonomy. Please clarify


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    Forum Cosmic Wizard spuriousmonkey's Avatar
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    http://animaldiversity.ummz.umich.ed....html#Chordata


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    WYSIWYG Moderator marnixR's Avatar
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    is that the current orthodoxy, tetrapods just being 1 class of fish ? makes it a bit crowded at the level below
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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  5. #4 Re: Can any one post a list of Classes in Chordata (AP Bio P 
    Forum Professor sunshinewarrior's Avatar
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    Quote Originally Posted by zLr
    I'm presenting the Phylum Chordata and want to order my presentation by class, after defining the phylum

    I'm just having a -hell- of a hard time finding a definite lisit of the classes. The diagram of chordata in my AP book shows these 'groups':

    Urochordata (tunicates)
    Cephalachordata (lancelets)
    Myxini (hagfishes)
    Cephalaspidomorphi (lampreys)
    Chondrichthyes (sharks, rays, chimaeras)
    Actinopterygii (ray-finned fishes)
    Acinistia (coelacanthus)
    Dipnoi (lungfishes)
    Amphibia (frogs, salamanders)
    Reptilia (turtles, snakes, crocodiles, birds)
    Mammalia (mammals)

    The subtitle of this diagram tells you that it "shows the major clades of chordates."

    I know that mammalia, reptilia and amphibia are definite classes, but i also know that aves (birds) is also a class; but in the diagram they are grouped with the reptiles. So I know that this cannot be a complete or even accurate list of classes.

    I think this may demonstrate the phylogeny instead of the taxonomy. Please clarify
    Dear zLr

    You have a diagram of clades. Converting them into 'classes' will be difficult, even impossible, because Classes are old Linnean categories and do not work with modern cladistic systematics. Classes are, effectively, simply 'privileged' groups (in the Post-modern sense in which 'privilege' is seen as being put in a particular place, or accorded a particular status without substantial, evidential etc, backing) that accord with biologists' prejudices of what groups are 'important'.

    Cladistically, for instance, the Chondrichthyes are the counterparts of the entire set of groups listed below them: the actinopterygii, the mammalia, aves, amphibia etc (and reptilia is not actually a clade, in any case). So cladistics, while the most rigorous of methods for classification, is not the friend of those who want to produce rankings, like 'Class'. It's why you'll find fewer and fewer academic works that still talk about classes.

    Perhaps consider clades themselves, and choose those cladistic 'split' points as examples of the counter-intuitive nature of true classification?

    Best of luck anyway.

    cheer

    shanks
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