Topic3-1 - BIOL 1030 TOPIC 3 LECTURE NOTES Topic 3 Fungi(Kingdom Fungi Ch 31 I Kingdom Fungi A general characteristics 1 monophyletic group 2

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BIOL 1030 – TOPIC 3 LECTURE NOTES Topic 3: Fungi (Kingdom Fungi – Ch. 31) I. Kingdom Fungi A. general characteristics 1. monophyletic group 2. ~100,000 known species (probably a million or more unknown) 3. heterotrophs with cell walls made of chitin 4. most multicellular, with slender filamentous units called hyphae 5. filaments can be packed tightly together (ex: mushroom) 6. most have nuclear mitosis (nuclear membrane remains intact during mitosis) 7. digest food with secreted enzymes (external digestion) 8. no motile stages for most (no swimming cells – lack cilia and flagella) B. fungal morphology 1. hyphae may be divided into cells by crosswalls called septa ; typically, cytoplasm flows through septa hyphae can form specialized structures for things such as feeding, and even for food capture haustoria are specialized hyphae that penetrate cells (for feeding or other purposes) 2. mass of hyphae is called a mycelium 3. much of fungal tissue is below ground or inside other organisms 4. visible parts usually reproductive structures – mushrooms, morels, etc. C. fungal reproduction 1. reproduce by spores sexual spores are meiospores (formed by meiosis) asexual spores are mitospores (formed by mitosis) 2. sexual reproduction for most by zygotic meiosis, but sometimes in a weird way haploid phase predominates BUT, syngamy (fertilization) has 2 steps plasmogamy : union of gamete cells karyogamy : union of gamete nuclei some fungi do plasmogamy but delay karyogamy, forming cells that each have two separate haploid nuclei; these hyphae are called dikaryotic example of fungal life cycle with dikaryotic hyphae: mushroom dikaryotic mycelium is major phase only when mushroom is formed does karyogamy occur, followed by meiosis D. five phyla plus "imperfect fungi" 1. phyla separated mainly by how meiospores are formed (how sexual reproduction done) 2. Phylum Chytridiomycota – chytrids 3. Phylum Zygomycota – zygomycetes 4. Phylum Glomeromycota – glomeromycetes 5. Phylum Ascomycota – ascomycetes; sac fungi 6. Phylum Basidiomycota – basidiomycetes; club fungi 7. imperfect fungi (also known as deuteromycetes) E. fungal phylogeny 1. Kingdom Fungi forms a clade with Kingdom Animalia, choanoflagellates, and perhaps others 2. last common ancestor between Fungi and Animalia apparently about 670 million years ago (MYA) 3. basal fungal group for Fungi appears to be Chytridiomycota, which is likely paraphyletic
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This note was uploaded on 04/17/2008 for the course BIOL 1030 taught by Professor Folkerts during the Spring '07 term at Auburn University.

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Topic3-1 - BIOL 1030 TOPIC 3 LECTURE NOTES Topic 3 Fungi(Kingdom Fungi Ch 31 I Kingdom Fungi A general characteristics 1 monophyletic group 2

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