Lecture22_Fungi - How does absorption occur What limits the...

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Fungi I. What are fungi? A. Morphological diversity 1. Growth forms a. Yeasts = b. Mycelia = multicellular bodies made up of tube-like hyphae • in many species the cells are • at other stages they are 2. Reproductive structures a. Chytridiomycota: b. Zygomycota: haploid, multinucleate hyphae that merge to form c. Basidiomycota: dikaryotic fruiting bodies like mushrooms, brackets, puffballs--see haploid spores (products of meiosis) produced in d. Ascomycota: dikaryotic fruiting bodies in cup fungi, morels, most lichens see haploid spores (products of meiosis) produced in B. Phylogeny Basidiomycetes, ascomycetes, and Glomeromycota (a zygomycete) form monophyletic lineages
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II. How do fungi make a living? Absorptive lifestyle: almost all fungi absorb nutrients • saprophytes: • parasites: • mutualists: A. The importance of shape Observation: All fungi are unicellular or consist of thin, highly branched tubes. Question: Are these shapes an adaptation to an absorptive lifestyle?
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Unformatted text preview: How does absorption occur? What limits the rate of absorption if nutrients are abundant? Problem: With increasing size, volume increases faster than surface area. For a sphere: volume = area = Radius (mm) Volume (mm 3 ) Area (mm 2 ) S.A:Vol ratio 1 2 3 4 5 Conclusion: Single cells and thin, highly branched tubes have a Where is absorption occurring in your body? What other types of shapes increase area and decrease volume in structures responsible for absorption? B. Extracellular digestion Question: How do fungi get nutrients in the first place—before absorbing them? cellulose: lignin: III. What is the ecological impact of fungi? A. They B. They Mycorrhizae = fungi that live in association with plant roots 1. Ectomycorrhizal fungi • Extremely common in • Transfer 2. Arbuscular mycorrhizal fungi (AMF) • 80% of • especially • transfer...
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This note was uploaded on 04/10/2008 for the course BIOL 180 taught by Professor Freeman during the Fall '07 term at University of Washington.

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Lecture22_Fungi - How does absorption occur What limits the...

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