Lecture 16 – The Origin and Evolution of FungiTwo Main Themes:- Life Styleo Pure decomposero symbiotic- Sexo Methods of achieving diploidyo Spore formationLife Style – the pure decomposers- No mouth? No gut? No problem - Extracellular digestiono Enzymes secreted, soluble molecules absorbed- Ex. Lignino Wood-rotting fungi secrete lignin peroxidaseo Enzyme uses hydrogen peroxide to extract an electron from an aromatic ringo Resulting radical causes chain to break- Symbionts as friends: the mutualistso Mycorrhizae – fungal associates of plant rootso Lichen – green alga or cynaobacterium + ascmycete funguso Gut flora – chytrid fungi in cow rumenso Ectomycorrhizae – form sheaths around roots and penetrate between root cellso Arbuscular mycorrhizae – contact the plasma membrane of root cells- Symbionts as foes – the parasiteso microsporidia : unicellular parasites of insects and fisho amphibian killers : aquatic chytridfungi cause rapid frog die-offso Valley Fever (Coccidioidomycosis ):caused by a soil ascomycete,opportunistically attacks the lungs inthe desert SouthwestSex (Overview – a “typical” fungal life cycle)- Most of a fungus is haploid most of thetime- Diploidy is often achieved by fusion bymycelia- Spores from in a variety of waysSex (Chytridiomycota)Sex (Zygomycota)Sex (Basidiomycota)Sex
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