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Consider the phylogenetic tree below to answer the following questions: Lizards and snakes

Crocodilians
Pterosaurs
Ornithischian dinosaurs
Saurischian dinosaurs
Birds
Which number point on the tree represents the most recent common ancestor of crocodiles, dinosaurs, and birds?

User FGiorlando
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1 Answer

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Final answer:

The most recent common ancestor of crocodiles, dinosaurs, and birds in the provided phylogenetic tree would be the point where the lineages for archosaurs converge.

Step-by-step explanation:

In the provided phylogenetic context, if the tree was visible, the most recent common ancestor of crocodiles, dinosaurs, and birds would be found at the point where the evolutionary lineages of these groups converge. Given the information, this point represents the origin of the archosaurs during the Mesozoic period. The archosaurs include the modern crocodiles, as well as all dinosaurs and birds following the divergence of the Archosauromorpha. It's interesting to note that although birds possess a phylogenetic lineage stemming from the theropods within the Saurischian dinosaurs, rather than from the Ornithischian 'bird-hipped' dinosaurs, they are still closely related to crocodiles and other dinosaurs through this common ancestral group.

The phylogenetic relationships amongst these organisms are highlighted through the various evolutionary adaptations they have undergone. For instance, reptiles, which include crocodiles, have developed scaly skin containing keratin to prevent water loss, while birds have evolved feathers from their maniraptoran dinosaur ancestors which were adapted for flight.

User Pierre Chavaroche
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