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KINGDOM FUNGI. Oldest Fungi fossils – 450 to 500 mya Can be colorful or plain They exist as Parasites, Mutualists (live symbiotically with another organism), & Decomposers. Characteristics of Fungi.
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Oldest Fungi fossils – 450 to 500 mya • Can be colorful or plain • They exist as Parasites, Mutualists (live symbiotically with another organism), & Decomposers
Characteristics of Fungi • Fungi can be found in various places: air, water, damp walls, gardens, foods, toes… everywhere! • Can be unicellular (yeasts) OR multicellular • Have a cell wall composed of chitin for strength and flexibility • All fungi are heterotrophs • Most are decomposers (break down their food then absorb food through cell walls)
Uses of Fungi • There are several food uses for fungi • Produce CO2 and ethyl alcohol • Soy sauce and blue-veined cheese • Citric acid: soft drinks, jam, candies • Fungi are also used in medicine • The first antibiotic to be discovered was penicillin • Discovered by Fleming in 1928
Feeding Relationships • Use extracellular digestion to get foodfood is digested outside the fungal cells by enzymes & is absorbed through the mycelium • Parasitic Fungi • Mutualistic Fungi • Decomposers
Parasitic Fungi: Absorb nutrients from living hosts through haustoria (specialized hyphae that penetrate & grow into host cells without killing them) • Mutualistic Fungi: live in symbiotic relationship w/plant roots; absorb nutrients from hosts but give benefits (retain water & minerals) {larger surface area} • Decomposers: breakdown dead organic material
Mutualism in Fungi 2 types: • Mycorrhizae- fungus lives in close contact with plant roots {mostly Basidiomycotes, some Zygomycotes} • Lichen- fungus and photosynthetic green algae or cyanobacteria live together {make spongy structure that looks like a single organism – 200,000sp}
Fungi and Diseases • Some fungi can cause disease or health conditions in humans, such as Athlete’s foot and Ringworm • Other fungi can cause disease to plants
Reproduction in Fungi • Asexually • Fragmentation: pieces of hyphae broken off of a mycelium grow into new mycelium • Budding: used by unicellular fungi (yeast). Mitosis takes place, new indiv. pinches off & matures
This is a cross-section of hyphae. It shows septa, pore and cytoplasm.
Sexual Reproduction in Fungi • Spore production: spore = reproductive cell. Most fungi produce spores. Sporangium (part seen) produces spores by mitosis or meiosis. Spore transported to place of favorable conditions--hyphae emerges and grows new mycelium
Fungal Adaptations • Spore production • Number of spores • Broadcast release • Spore dispersal by water, wind, & animals
Classification of Fungi • Phylum Zygomycota (zygospore-forming) • decomposers • Reproduce asexually by producing spores • Reproduce sexually by forming thick-walled spores (zygospores)
Phylum Ascomycota (sac fungi) • Largest group; named for ascus (sac-like structures that form sexual spores) • Cause plant & animal diseases • Economically important – Yeasts & Truffles • Asexual reproduction = mycelium elongate conidiophores produce conidia (haploid spores) carried by wind, water, & animals
Phylum Basidiomycota • Unicellular & multicellular; Terrestrial & Aquatic • Sexual (cap & gills) or Asexual - Mushrooms • Phylum Deuteromycota • Imperfect Fungi – incomplete knowledge of life cycle • Sexual & asexual reproduction with or w/out conidia inside same cycle • Beneficial – Penicillin; Tart taste to foods (soy sauce, jams, jellies, soft drinks, etc)