Why is the traditionally defined taxon Reptilia paraphyletic? What will be an ideal ...

Answer to q. 1

Birds share a common ancestor with reptiles, but birds are placed in a separate taxon. Bird innovations,
in a traditional sense represent such extreme divergence from ancestral morphology that they merit
recognition as a separate class.

Answer to q. 2

Anagenesis is the pattern of gradual phyletic change. Speciation as a result of anagenesis does not
result in an increase in biodiversity. When an ancestral species undergo speciation via divergence, two
descendant species are produced, both of which are distinct from the common ancestor. Cladogenesis
does increase biodiversity.

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