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Here is a question I am trying to find the answer to

Reptiles are a paraphyletic group because... ?

A) They include worm lizards, which have no limbs

B) The group doesn’t include birds

C) The group doesn’t include mammals

D) Not all of them have three- chambered hearts

I’m a bit confused about the reasoning. I know a paraphyletic group does not have all of its descendants so if birds were to be included it would become monophyletic. So is B the answer? Could anyone help explain it better?

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Tatiana
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    I think the question's phrasing is a little wobbly, which make it a little hard to understand. But I think you understood what your teacher was expecting. I agree with you, answer is B. – Remi.b Jul 16 '19 at 06:21

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I think the question's phrasing is arguably a little wobbly, typically as to the nature of what someone would mean by the term "reptile". But I think you understood what your teacher was expecting. I agree with you, answer is B.

Reptilia is a clade (clade = monophyletic group) that encompasses all species that we traditionally classify as reptiles + all birds. Hence, our traditional definition of reptile makes up for a paraphyletic group as birds aren't included.

Related post: If dinosaurs could have feathers, would they still be reptiles?

Remi.b
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    To me it seems "Reptiles are a paraphyletic group because the group doesn’t include birds" is fine and not the least "wobbly", assuming Reptiles != Reptilia. – mgkrebbs Jul 16 '19 at 17:16