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Diversity of Fungi 10 Mar KB – Plant Function Chapters 38, 40, and 39 (Pp

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Diversity of Fungi 10 Mar KB – Plant Function Chapters 38, 40, and 39 (Pp Upcoming Syllabus (middle third) 24 Feb KB – Fungi Chapter 31 26 Feb KB – Prokaryotes, Protists, Photoautotrophy, Endosymbioses Chapters 28, 29 3 Mar KB – Plant Diversity Chapter 30 5 Mar KB – Plant Form and Function Chapters 36, 37 Diversity of Fungi 10 Mar KB – Plant Function Chapters 38, 40, and 39 (pp. 857-866, 873-882, 887-888) (Freeman Ch31) 12 Mar WS - Population Growth and Regulation Chapter 52 17&19 Mar Spring Recess 24 Mar KB – Plant Community Ecology, Disturbance, Succession Chapters 30, 53 26 Mar KB – Galapagos Case Study Wikelski 2000 and www.darwinfoundation.org/en/galapagos/marine www.darwinfoundation.org/en/galapagos/land 24 February 2009 31 Mar Part 2. Discussion and Review. ECOL 182R UofA 1 2 Thanks to Joanna Masel 02 Apr EXAM 2 K. E. Bonine VIDEOS Kevin Bonine Tree of Life 182 Office Hours 3.8 bya 10-noon Tuesdays BSE 113 2+ bya -also M 1-2 and W 11-noon- -206 and 437 students have priority- Orange 3 4 Opisthokonts (Fungi and Animals are closely related) 5 6 1 Chitin How fungi live (tough but flexible nitrogen-containing polysaccharide) • All use absorptive nutrition, secreting •Production of chitin is a shared derived digestive enzymes and absorbing the trait for breakdown products –fungi •Most are saprobes (feed on dead matter) – choanoflagellates – Earth’s main decomposers (with bacteria) –animals – principal decomposers of cellulose & lignin • Evidence that fungi are closer to – nutrient (re)cyclers animals than plants •Some are parasites •A few are mutualists 7 8 Cell structure of multicellular fungi Incomplete division into cells Cell-like Vegetative body compartments = mycelium separated by (plural mycelia) septa (singular septum) Composed of Free threadlike movement of hyphae organelles, (singular hypha) sometimes even nuclei, and other 10 coenocytic hypha septate hypha materials 11 Fungus structure Fungal hyphae attack a leaf •Hyphaemay – disperse to look for nutrients – clump together to exploit a food source •Mushroomsare a fruiting (reproductive) structure •Most Unicellular fungi are called Yeast Hyphae give a large surface:volume ratio, 12 which helps with absorptive nutrition 13 2 Symbiotic fungi Symbiotic fungi Lichens are symbiotic associations of a fungus with a - unicellular photosynthetic eukaryote • Mycorrhizae are – cyanobacterium mutualistic associations -or both of fungi and plant roots a! •The fungus obtains re e a ac organic compounds, rf su of ts Lichens are while the plant is Lo important provided with water pioneer species and soil nutrients • Some plants can’t grow 14 without them 15 Symbiotic fungi Fungi increase surface area for nutrient and water absorption by plant EMF AMF Mycorrhizae = mutualistic associations of fungi and plant roots 16 17 Predatory fungus! Fungi are very important cyclers of nutrients. Especially Carbon, Nitrogen, Phosporus. 18 Fungus capturing a nematode worm 19 3 Fungal reproduction Alternation of Generations can be complex Haploid (N) (~gametes) •Sexual OR asexual •Life cycles distinguish 4/5 phyla Fertilization •When sex has not been observed, Diploid (2N) provisionally classified as imperfect fungi (aka deuteromycetes): ~ 25,000 species Meiosis Haploid (N) Sexual Reproduction Depicted Here 20 (Meiosis & Fertilization) Etc. 21 Alternation of Haplontic life cycle Generations • Haploid is dominant, multicellular structure Both the haploid and the diploid •Often diploid only very briefly as a zygote have multicellular forms. •Meiosisproduces haploid nuclei again • Haploid spores divide mitotically to form Compare to haploid hyphae Haplontic and Diplontic. 22 23 Chytrids Dikaryotic Lifestage (no dikaryote) Zygomycetes • Unique to fungi Dikaryotic • Two haploid (n) cells fuse, but not their nuclei stage Haplontic = n + n dikaryote Alternation of generations • Plasmogamy (cell fusion) followed later by Karyogomy to produce Ascomycetes Basidiomycetes Diploid (2n) Zygote Haplontic Haplontic 24 Basidiocarp25 Dikaryotic stage Dikaryotic stage 4 Chytrid Fungi A chytrid fungus (Batrachochytrium dendrobatidis; Bd) has been implicated in the worldwide decline of numerous amphibian species. Frogs infected with this fungus suffer chytridiomycosis, a disease affects amphibian skin and is often fatal. Chytrid zoospores can survive in damp conditions and may be transported between frog populations in muddy clothing and footwear. - water balance -respiration - immune system 26 African Clawed Frog? 27 Asexual reproduction via spores Yeast are fungi Production of • All five fungal phyla have unicellular species haploid spores • Those of all phyla except chytrids are called within sporangia yeasts •The yeast Saccharomyces cerevisiae makes CO2 and ethanol during fermentation • Used for bread and beer Production of naked spores at the tips of hyphae (not within sporangia) called 28 conidia 29 Fungal spores are everywhere Plants are not • Every breath we take is full of fungal spores so lucky (~10,000/m3 of air) Parasitic fungus Ustilago maydis (corn smut) • Most humans only succumb to fungal pathogens when immunocompromised Fungus (aka mold, mildew, etc.) causes lots of crop damage -Dutch Elm disease - Chestnut blight ring worm some pneumonias sporotrichosis 30 31 5 Neither was this ant Fungal asexual reproduction • Cell division by unicellular fungi – equal division (fission) Spores of this fungus don’t – production of a daughter cell (budding) germinate until ingested by an ant • Simple breakage of the mycelium 32 33 Basidiomycete life cycle Fungal Sexual reproduction BasidiosporesBasidiospores give rise to haploid hyphae. Haploid hyphae of + Mating type different mating types fuse, forming dikaryotic • Some fungi have more than 2 mating types hyphae. -MatingMycelial type • Mating types don’t look different hyphae The basidium Dikaryotic mycelium •Mating can only occur between different is the Young characteristic basidiocarp sexual reproductive mating types, preventing self-fertilization Gills lined structure of the with basidiaPileus basidiomycetes. Basidiospores • Sexual reproduction when hyphae (or Basidiospores form The basidiocarp outside the basidium. is topped by a cap, motile cells in chytrids) of different or pileus, which has gillsBasidiocarp on its underside. mating types meet and fuse (fruiting structure) Fused Nuclei ms Basidium nucleus roo Basidia develop on the sh surfaces of the gills. 34 Mu Nuclear fusion and meiosis 36 take place in the developing basidium. Basidiomycete life cycle Important points about sex and reproduction •Sex= 2 nuclei fusing and undergoing meiosis •Reproduction= one individual giving rise to multiple: can be sexual or asexual • Genetic recombination = any gene exchange: not just sex, also nonreproductive processes such as conjugation •Dikaryoticindividuals include 2 fused individuals, but not fused nuclei •“Spores”can be sexual or asexual, reproductive or not: normally a small, tough cell with potential to s oom become new organism. Often capable of latency. shr Mu 37 Can be plant, bacterial, protist or fungal. 39 6 Five Fungi Phyla ~Aquatic Only fungi group Chytrids with flagella 1+ bya Includes Batrachochytrium dendrobatidis (Bd) causing amphibian die-offs 40 41 Glomerocytes Ascomycetes Important mycorrhizae Includes brewer’s associations with and baker’s yeast. plants Lots of plant parasites. Molds and Mildew. Penicillin. Stinky cheese 42 production. 43 Basidiomycetes Named after basidiocarp, Which we know as a mushroom 44 7.
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