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Unformatted text preview: 1 Evolution of Fungi Fossil fungus ~460 mya about 1.5 bya: split of fungi and animal/choanoflagellate lineages (unicellular ancestors with flagellum) 2 Fungal characteristics • Heterotrophs by absorption – Decomposers, symbionts (e.g. mutualists, parasites) • Cell walls contain chitin • Fungal body consists of mycelia (branched network of hyphae) • Sexual life cycle • Asexual reproduction 3 • Chytrids • Zygomycetes • Glomeromycetes • Ascomycetes • Basidiomycetes Major Groups 4 Chytrids • chytridiomycosis of amphibians discovered in 1998 • may have contributed to extinction of several frog species • considered most primitive (basal) fungi • lack true hyphae • many aquatic (fresh water) • chemoheterotrophs • degrade chitin and keratin • few pathogens 4 5 – Strawberries, black bread mold, dung – Hyphae absorb nutrients – Zygosporangium (sexual dispersal and survival stage) 5 Zygomycetes Pilobolus sporangia on cow dung: sensing light (to aim spores) 6 Ascomycetes (sac fungi) • Unicellular: yeasts • Multicellular – Sexual reproduction in asci (sacs) – Asexual reproduction in conidia...
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