Audio Transcript Excerpt:
PROFESSOR: 'In evolutionary taxonomy, phylogeneticists organize groups of organisms based on their shared evolutionary histo

Question

Audio Transcript Excerpt:
PROFESSOR: 'In evolutionary taxonomy, phylogeneticists organize groups of organisms based on their shared evolutionary history. We categorize biological groupings into three distinct types: monophyletic, paraphyletic, and polyphyletic. A monophyletic group, or clade, comprises an ancestral species and all of its descendants—birds and crocodilians together with their archosaur ancestor form a valid clade. A paraphyletic group includes an ancestor and some, but not all, of its descendants—traditional 'reptiles' are paraphyletic because they deliberately exclude birds. Finally, a polyphyletic group comprises taxa derived from two or more distinct ancestral lines and excludes their common ancestor—such as grouping warm-blooded mammals and birds together as 'homeotherms' based on convergent physiology.'

Why is the traditional classification of 'reptiles' considered paraphyletic in modern cladistics?

Accepted Answer

Because it includes the common ancestor of all amniotes but arbitrarily excludes birds, which descended from that same lineage.

Answer

Because reptiles evolved from amphibian ancestors on multiple separate continents.

Answer

Because reptiles do not share any common skeletal features with one another.

Answer

Because cold-blooded animals cannot be analyzed using genetic sequencing.

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