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Fungi Chapter 31. Fungi More closely related to animals than plants Unicellular Most are multi-cellular Tropics to tundra Aquatics to terrestrial.

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Presentation on theme: "Fungi Chapter 31. Fungi More closely related to animals than plants Unicellular Most are multi-cellular Tropics to tundra Aquatics to terrestrial."— Presentation transcript:

1 Fungi Chapter 31

2 Fungi

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5 More closely related to animals than plants Unicellular Most are multi-cellular Tropics to tundra Aquatics to terrestrial Airborne spores Yeast in breads & beer

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7 Fungi Decomposers Recycle nutrients Help roots of plants absorb nutrients Disease causing (plants and animals) Treatment difficult

8 Body structure Hyphae Tiny filaments Composed of cytoplasm Surrounded by plasma membrane & cell wall Cell wall made of chitin Septa Cross-walls that separate cells of hyphae

9 Hyphae

10 Fig (b) Coenocytic hypha Septum (a) Septate hypha Pore Nuclei Cell wall

11 Body structure Mycelium: Mass of connected hyphae Surrounds & infiltrates material Maximizes contact with material Grows rapidly Grows underground so not visible

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14 Reproduction Each cell can have one or more nuclei Monokaryotic: One nuclei Dikaryotic: Two haploid nuclei that function independently

15 Reproduction Dikaryotic hyphae Heterokaryotic: Nuclei that are from two genetically distinct individuals Homokaryotic: Nuclei are genetically similar

16 Reproduction Sexually Asexually Spores are produced either way Spread by wind or on insects Suitable environment give rise to new fungal mycelium

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18 Reproduction Sexual reproduction 2 compatible mating types fuse Usually 2 haploid fuse to form diploid Some fungi remain 1n + 1n and not 2n +/- length of time

19 Reproduction Plasmogamy: Fusion of cytoplasm of mycelia Karyogamy: Fusion of nuclei Zygotes Meiosis Spore formation

20 Reproduction Asexually Molds Produce haploid spores by mitosis Yeasts Mitosis Buds

21 Fig Spores Spore-producing structures GERMINATION ASEXUAL REPRODUCTION Mycelium Key Heterokaryotic (unfused nuclei from different parents) Haploid (n) Diploid (2n) SEXUAL REPRODUCTION KARYOGAMY (fusion of nuclei) PLASMOGAMY (fusion of cytoplasm) Heterokaryotic stage Zygote Spores GERMINATION MEIOSIS

22 Fungi Heterotrophs Secrete hydrolytic enzymes (exoenzymes) Absorb nutrients(organic molecules)

23 Nutrients Digest wood (cellulose) Absorb the glucose Lignin (found in wood) Decomposer of living or dead organisms Yield carbon, nitrogen and phosphorus

24 Nutrients Obtain nutrients from tiny roundworms called nematodes Paralyze Penetrate Absorb nutrients from body Nitrogen source

25 Metabolic pathways Anaerobic fermentation Wines & cheeses Soy sauce Antibiotics & steroids Yeasts (single cell fungi) Bioremediation Using organisms to break up a toxin

26 Symbiosis Lichens Fungus & photosynthetic partner (algae) Mutualism some are parasitic Hyphae penetrate cell walls of algae Obtain nutrients from the algae Protects the algae from too much sun

27 Symbiosis Lichens first to invade a harsh environment Colored - pigments -protect the algae from the sun Pigments are used as natural dyes

28 Lichen

29 A fruticose (shrublike) lichen A foliose (leaflike) lichen Crustose (encrusting) lichens

30 Mycorrhizae Tree (plant) roots with fungi Fungi function as an extension of roots Plants absorb more nutrients, such as Zn, P, Cu Fungi gets organic materials from the plant

31 Mycorrhizae 1. Arbuscular: Fungal hyphae penetrate the trees roots Form coils around roots More common 2. Ectomycorrhizae: Hyphae do not penetrate the roots Helps trees grow in infertile areas

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33 Endophytes Fungus lives inside the plant Intercellular spaces Help defend plant against herbivores Symbiotic relationship between fungi & ruminant animals Fungi helps digest the cellulose

34 Parasitic Mycosis Fungal infection Ringworm Athlete’s foot Candida albicans

35 Parasitic Aspergillus Produces toxin harmful to humans. Pneumocystis Causes a rare pneumonia in AIDS patients Chytridomycosis Fungal infection that harms amphibians Other fungal infections harm plants Chestnut trees, corn

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37 Figure 31.UN07 Fungal PhylumDistinguishing Features Chytridiomycota (chytrids) Zygomycota (zygomycetes) Glomeromycota (arbuscular mycorrhizal fungi) Ascomycota (ascomycetes) Basidiomycota (basidiomycetes) Flagellated spores Resistant zygosporangium as sexual stage Arbuscular mycorrhizae formed with plants Sexual spores (ascospores) borne internally in sacs called asci; vast numbers of asexual spores (conidia) produced Elaborate fruiting body (basidiocarp) containing many basidia that produce sexual spores (basidiospores)

38 Fungi Mycologists: scientists that study fungus Five groups 1. Chytrids 2. Zygomycetes 3. Glomeromycetes 4. Ascomycetes 5. Basidiomycetes

39 1. Chytridiomycota (chytrids) Aquatic fungi Flagellated spores called zoospores Diverged earliest Chitin in the cell walls

40 2. Zygomycota Bread molds Fruit molds Zygosporangium: Contains one or more diploid nuclei Forms a hard covering Good growth conditions Undergoes meiosis then mitosis Releases spores

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42 Zygomycota Rhizopus growing on bread SEXUAL REPRODUCTION Young zygosporangium (heterokaryotic) Gametangia with haploid nuclei Mating type (–) Mating type (+) Diploid (2n) Haploid (n) Heterokaryotic (n + n) PLASMOGAMY Key Diploid nuclei Zygosporangium 100 µm KARYOGAMY MEIOSIS Sporangium Spores Dispersal and germination ASEXUAL REPRODUCTION Dispersal and germination Sporangia Mycelium 50 µm

43 BREAD MOLD

44 Fig µm

45 3. Glomeromycetes Arbuscular mycorrhizae Hyphae with plant roots Very few species

46 4. Ascomycetes Sac fungi Marine, freshwater & terrestrial Yeast Asci: sac like structure containing sexual spores Ascocarps: contain asci Fruiting bodies Microscopic or macroscopic

47 Ascomycota Key Haploid (n) Diploid (2n) Dikaryotic (n + n) Conidiophore Mycelium ASEXUAL REPRODUCTION Germination Hypha PLASMOGAMY Haploid spores (conidia) Conidia; mating type (–) Mating type (+) SEXUAL REPRODUCTION Dikaryotic hyphae Ascus (dikaryotic) Mycelia KARYOGAMY Diploid nucleus (zygote) Germination Asci Dispersal Ascocarp Eight ascospores Four haploid nuclei MEIOSIS

48 YEAST

49 Figure Morchella esculenta Tuber melanosporum

50 5. Blasidiomycetes Mushrooms, shelf fungi, puff balls Blasidium (Latin means “little pedestal”) Long-lived dikaryotic mycelium Leads to more genetic re-combinations Blasidiocarps (mushroom) Produced sexually Fruiting bodies Wood decomposers

51 Basidium Blasidiomycetes SEXUAL REPRODUCTION Diploid (2n) Haploid (n) Dikaryotic (n +n) Key PLASMOGAMY Mating type (+) Haploid mycelia Dikaryotic mycelium Mating type (–) Basidia (n+n) Gills lined with basidia Basidiocarp (n+n) KARYOGAMY Diploid nuclei MEIOSIS Basidium containing four haploid nuclei Dispersal and germination Basidiospores (n) Basidium with four basidiospores Basidiospore 1 µm Haploid mycelia

52 Figure 31.17c Maiden veil fungus


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