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Kingdom: Fungi. Fungi are absorptive heterotrophs Most are multicellular. Ecological Importance Fungi bind soil, absorb water & breakdown detritus to recycle nutrients (decomposers). Figure 29.2. Choanoflagellates. Green algae. Land plants. Red algae. Myxozoa. Animals. Fungi.
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Kingdom: Fungi Fungi are absorptive heterotrophs Most are multicellular
Ecological Importance Fungi bind soil, absorb water & breakdown detritus to recycle nutrients (decomposers)
Figure 29.2 Choanoflagellates Green algae Land plants Red algae Myxozoa Animals Fungi
Fungi & animals are derived from a protistan lineage Similarities between fungi & animals Heterotrophs Presence of Chitin (in some animals) Glycogen as storage molecule rRNA sequence data similarities
Fungi • Cell = Hypha • Mass of hyphae = Mycelium • Reproductive structure (fruiting body) that makes spores Mycelium Fungal Hyphae Mycelium grows outward in a ring
Features of Fungi Cell walls of chitin Hyphae Septate- with crosswalls Coenocytic- multinucleate Spores for dispersal & dormancy Fruiting body produces spores (in some) Most produce no gametes (derived trait) Flagellated gametes (ancestral trait) Sex:Nuclear exchange & fusion
Pore (a) 926 nm Cell wall Septa Fruiting body (b) Reproductive structure Hyphae Mycelium
Multicellular fungi are composed of hyphae Unicellular fungi are called yeasts 138 µm 3.73 µm Hyphae: an adaptation for absorption Fungal hypha maximizes surface area to volume ratio.
Lifestyles of Fungi Saprobes- decomposers breakdown organic molecules in soil or water Parasites- pathogens of plants & animals Mutualists- with autotrophs
Mycorrhizaemyco = fungus / rhiza = root Symbiotic mutualism + Plant gets water & minerals + Fungus gets sugar (food) Fungus absent Fungus present Western Red Cedar
Ectomycorrhizae Mycorrhizal fungi Enhances plant nutrient uptake (phosphorous) by increasing absorptive surface area of roots Endomycorrhizae (VA) Fungus wraps around plant roots & grows between or within root cells
Lichens: symbiotic mutualisms between fungi & cyanobacteria or green algae
Types of Lichens • Crustose • Foliose • Fruiticose
phylum: Chytridomycota“Chytrids” Ancestral clade Flagellated gametes (male & female) Unicellular or multicellular mycelia Aquatic: most live in freshwater
phylum: Zygomycota“Bread molds” • Coenocytic hyphae • No fleshy fruiting body Asexual Reproduction: Conidia Sexual Reproduction Zygospore in zygosporangium
phylum: Ascomycota“Sac Fungi” • Coenocytic w/ perforated septae • Ascospores produced in sacs called asci • Asci located in fruiting bodies
Ascus (sac) produces 8 ascospores (4 by meiosis & 4 by mitosis)
Euascomycetes Peziza sp. = cup fungus Asci inside of cup
Ascomycete pathogen of plants reproducing asexually by conidia
Hemiascomycetes Yeasts are unicellular fungi that conduct fermentation Glucose is broken down anaerobically to produce ATP: CO2 & ethanol are by-products Asexual reproduction Budding or fission • Sexual reproduction • 2 haploid cells fuse • zygote undergoes meiosis • (entire cell becomes an ascus) • 4 or 8 haploid cells are produced
Lichen Ascocarp
phylum: Basidiomycota“Club Fungi” • Coenocytic w/ perforated septae • Spores produced from basidium
Basidiocarp = mushroom “cap” Mycelia in the soil
1 basidium makes 4 basidiospores by meiosis
Figure 29.4c Sexual reproduction Basidiomycota Basidium 2n MEIOSIS Mature fruiting body (n + n) Spores (n) Hyphae of different mating types attract Heterokaryotic mycelium begins to grow FUSION Spores (n) germinate to form hyphae 1. Hyphae fuse (monokaryotic hyphae) 2. Exchange nuclei (heterokarytic hyphae) 3. Fruiting body forms - Nuclei fuse (in basidium) 4. Meiosis makes spores