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Evolution/Cladistic definitions


Please tell me if I'm wrong how a cladist defines a trait or a taxon as a direct ancestor of another trait or taxon. If the taxon or trait is defined in terms of the most recent common ancestor of something and all its descendants then a cladist says this is directly descended from that, or this is that. If for example a cladist puts all (nonflying) dinosaurs and birds and their traits horizontally on his cladogram then birds are not from dinosaurs and neither are their traits from one another and birds are not dinosaurs. I read though that a cladist defines a dinosaur as "the most recent common ancestor of Passer (the sparrow) and Triceratops, together with all its descendants." Unless I'm wrong put that way a dinosaur is defined as vertically and horizontally present and so the cladist is now able to say that birds are from dinosaurs and bird traits from dinosaur traits and say that birds are really dinosaurs.

First, I have never encountered the word, "clandist, nor clandistic".  Neither are in any dictionary, and so I'm confused as to what you are reading, and by whom.  Find another word, straighten out this little problem, and I'll likely be able to figure out what exactly you are asking.  Vertically and Horizontally don't have  much to do with evolution, since the arrow of time goes only in one direction.  

Thus far, then, I really don't know what you're asking.


As for birds being dinosaurs, they are their descendents.  We have only recently seen feathered dinosaur fossils from China, that showed these animals as feathered.  And as well we know that many dinosaurs had a four chambered heart, and thus were warm blooded.

Sooooo if you can try again, with words that I have seen before, I'd be delighted to answer your question..........when I know exactly what it is asking.


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Elisabeth DeWald


I've been a public school teacher for 26 years. My major was history, but along the way, picked up minors in math, biology, zoology, and other life sciences. My whole life has been on one side of the desk or the other. Husband and Dad were both MDs so science and medicine was a natural for me. My dad once told me that I knew more medicine than most doctors. I can easily answer almost any life science question, most history questions, and lots of medical questions.


Taught math,history, science, geology, chemistry, biology in a public school setting

None at the present time


Majored in history in college, minored in all those subject mentioned. Masters degree in education. Grad courses, but no degree in religious studies, U of Chicago, Divinity School.

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Award at my one of my colleges of Best Student, in History as a year end award.

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I tutored for two years in math. Math however, if not used daily fades. My area of competency is in honors first year algebra, at this point.

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