Practice question

Bryophytes occupy moist sheltered microhabitats partially because sexual reproduction remains ecologically constrained by ancestral requirement for external liquid water during fertilization. Antheridia release numerous biflagellated spermatozoids in mosses and liverworts requiring continuous water film to swim chemo-tactically toward archegonial neck to fertilize sessile egg. Eggs are immobile within venter, spores wind dispersed but not motile, swimming zoospores absent in embryophytes. Flagellated sperm dependency explains bryophyte restriction to damp shaded rock walls and seasonal reproductive activity synchronized after rain, analogous to pteridophyte fertilization requiring water.