Practice question

Kingdom Animalia recognized as monophyletic because all metazoan phyla trace to single common ancestor, a colonial choanoflagellate-like protoctist, confirmed through phylogenomic concatenation of hundreds of nuclear genes, 18S rRNA, homeobox Hox clusters, Wnt signaling and mitochondrial genome arrangement. Monophyly supported by exclusive shared derived characters: multicellular heterotrophy with ingestion, collagen type IV basal lamina, cadherin mediated adhesion, tight junctions, blastula stage and regulated apoptosis. Polyphyletic hypothesis requiring independent origins refuted by robust molecular trees and embryonic homology, thus all animals share exclusive common ancestry not convergent similarity.