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Fungi. INTRODUCTION. EUKARYOTES NON-MOTILE HETEROTROPHS (ABSORPTIVE) MOST ARE MULTICELLULAR. Reproduction is both sexual and asexual Cell walls made of chitin. Characteristics. Decomposers (saprobes), parasites, mutualistic symbionts (lichens) Hyphae: body filaments
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INTRODUCTION • EUKARYOTES • NON-MOTILE • HETEROTROPHS (ABSORPTIVE) • MOST ARE MULTICELLULAR. • Reproduction is both sexual and asexual • Cell walls made of chitin
Characteristics • Decomposers (saprobes), parasites, mutualistic symbionts (lichens) • Hyphae: body filaments • Mycelium: network of hyphae
Fungus Life Cycle • Rhizopus Stolonifera is the common black bread mould • The small black dots or fuzz on the bread are reproductive structure of the bread mould. • The bread mould reproduces asexual but can also reproduce sexually when times are favorable by zygospores • These are diploid cells that contain two copies of every chromosome. • A thick wall develops around the zygospore for protection. The zygospore remains dormant until conditions are favorable for growth. Once this happens the zygospore will absorb water and the nuclei will undergo meiosis
Cont’d • Sexual Reproduction Phase; The zygospores develop after two haploid (monoploid) hyphae of opposite types (+ and – mating strains) combine and fuse together to form zygospores. The bread mould is made up of two forms of hyphae. The horizontal hyphae are the stolons and the downward growing hyphae are the rhiziods. • The stolens spread out over the surface of the bread while the rhiziods anchor the mycelium to the bread surface. The rhiziods secrete enzymes that digest the food and absorb the digested nutrients
Fungal Groups Phy: Chytridiomycota • aquatic fungi; chytrids • closest to protists (flagella) Phy: Zygomycota • Rhizopus (food mold) • mycorrhizae: mutualistic with plant roots •
Fungal Groups con’t • Phy.: Ascomycota •sac fungi • yeasts, truffles, morels •asci: spores • Phy.: Basidiomycota • club fungus •mushrooms, puffballs, shelf fungus, rusts •basidiocarps: produce spores
Molds •only the asexual stage (asexual spores) •Penicillium (antibiotic, cheese) Yeasts •unicellular, asexual budding •Saccharomyces (bread, alcohol)
Lichens • symbiotic association held in a hyphae mesh •alga provides food, fungus provides physical environment •pioneer organisms Mycorrhizae •root and fungi mutualism •found in 95% of vascular plants •exchange of organic minerals •increases absorptive surface of roots
ECOLOGICAL IMPACTS OF FUNGI Without Fungi and Bacteria, ecosystems would be deprived of essential recycling of nutrients. • Fungi are especially important decomposers of wood.
