Hyphae spores of most species are haploid except for

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Unformatted text preview: gal hyphae & spores of most species are haploid except for transient diploid stages that form during sexual life cycle haploid = one gene; diploid = two genes Some mycelia have become genetically heterogeneous through the fusion of 2 hyphae with genetically different nuclei heterokaryon In many fungi with sexual life cycles union occurs in two distinct stages called (1) (2) plasmogamy = fusion of 2 parents cytoplasm only one gene karyogamy = fusion of haploid nuclei undergo process of meiosis; go from diploid state back to haploid May be separated by hours to centuries Meiosis restores haploid condition before spores are produced. During interim hybrid mycelium exists as heterokaryon diploid to haploid Origin of Fungi Fungi evolved from a flagellated ancestor as did animals. DNA sequence data indicate that fungi, animals and their protistan relatives form a clade – opisthokonts. More closely related to nuclearids than to the choanoflagellates. Multicellularity must have evolved in animals and fungi independently. REMEMBER MAKE FLASHCARDS Zygote fungi Arbuscular mycorrhizal fungi Sac fungi Club fungi Glomeromycota Ascomycota Basidiomycota > 100,000 species of fungi are known (1.5x106 possible) Chytrids Chytridiomycota Diversity of Fungi Zygomycota Fungi classified into five major phyla Phylum Chytridomycota: Chytrids may provide clues about fungal origins idea of what early Chytrids fungi looked like - mainly aquatic -some saprobes - other parasites (protists, plants & animals) Form uniflagellated spores called zoospores Chytrids are the most primitive fungi Fungi evolved from protists that had flagella now only found in chytrids Phylum Zygomycota - Zygote fungi - form resistant structures during sexual reproduction ~600 species, mostly terrestrial One group forms mycorrhizae - mutualistic association with roots of plants Common zygomycete is black bread mold Rhizopus stolonifer - horizontal hyphae spread out over food penetrate & absorb nutrients Asexual phase - bulbous black sporangia develop at tips of upright hyphae Can reproduce sexually if food supply used up cannot freeze or dry up Pl...
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This document was uploaded on 03/02/2014 for the course BIO 109 at University of Missouri-Kansas City .

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