Fungi Introduction & the Chytridiomycota

Outline

Kingdom Fungi

4 or 5 phyla:

• Chytridiomycota -- chytrids
• Zygomycota -- zygomycetes
• Ascomycota -- ascomycetes
• Basidiomycota -- basidiomycetes

and sometimes

• Deuteromycota -- fungi imperfecti or imperfect fungi

Kingdom characteristics (except chytrids):

heterotrophic

extracellular digestion

chitin cell walls

lack of motility

closed mitosis -- no centrioles: spindle pole bodies

unicellular or filamentous -- coenocytic or septate hyphae

Chytridiomycota

Fungi or protists?

Why not to include them in the Fungi:

most have a motile stage

mitosis is open

many have non-chitinous cell walls

primarily aquatic

different life cycles than most fungi

Why to include them in the Fungi:

most do use chitin in cell wall

saprobic and parasitic lifestyles

unicellular and filamentous morphologies

molecular evidence suggests close relationship to other Fungi

Seen as a link between aquatic, unicellular, motile protists and terrestrial, filamentous, non-motile fungi

Morphology

unicellular and flagellated

filamentous with flagellated stages (e.g., Allomyces)

Ecology

Aquatic or in soils

most are saprobes

important decomposers in aquatic ecosystems

many are parasites

on algae, animals, plants, other fungi

some live in guts of ruminant herbivores (e.g., cows)

help digest cellulose, etc.

 

Vocabulary

click here to go to Fungus vocabulary