Practice question

Chytridiomycota are only true fungi retaining flagellated zoospores with single posterior whiplash flagellum similar to opisthokont sperm architecture, representing ancestral character retained from opisthokont ancestor. Flagellum inserts posteriorly pushing cell forward with undulatory propulsion. Ascomycota and Basidiomycota completely lack motile cells, Zygomycota sensu lato produce non-motile sporangiospores. Zoospore ultrastructure with kinetosome, microtubular roots and rumposome marks chytrids distinct. This trait places them as basal fungal lineage diverging before loss of flagellum, crucial for phylogenetic placement and ecological role in aquatic decomposition and amphibian disease.