10 Question 10 Non-vertebrate chordates Invertebrata\" Fishes (vertebrates) Acti

Question

10 Question 10 Non-vertebrate chordates Invertebrata" Fishes (vertebrates) Actinistia Dipnoi Amphibia Vertebrate column tetrapods Pisces Testudinate digits Lepidosauria endothermia The diagram above shows the phylogenetic tree for all chordates. The term reptile is used to group turtles (Lepidosaura) and Crocodiles,alligators, etc (Crocodylia). Looking at the phylogeny, the group we call reptiles forms a . group (Testudinata), lizards O Polyphyletic, because turtles, lizards and crocodiles do not share the most recent common ancestor o Paraphyletic, because all reptiles share a recent common ancestor but birds also descend from that ancestor although birds are not considered reptile. OMonophyletic, because reptiles share a recent common ancestor and all the descendants from that ancestor are O Cannot be determined from the diagram

Explanation / Answer

The class Reptilia is traditionally defined as paraphylatic because it excludes birds and mammals. According to International Code of Zoological Nomenclature (ICZN) mammals, birds and reptiles are equal rank. However mammals came from the synapsids (which were once described as "mammal like reptiles") and birds descended from dinosaurs both of which were reptiles.

Therefore the option 2 "Paraphyletic, because all reptiles share a recent common ancestor but birds also descend from the ancestor although birds are not considered reptile" is the correct one

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.