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Kingdom Fungi Fungi Trivia.. • The largest living organism known is a fungus lying beneath >100 hectares of land in Michigan with an approximate mass of 500 tons. • Typically, members are hidden underground or a food source and we usually only see the reproductive structures above the surface. • Fungi are mostly found in damp, dark places like forest floors, between your toes and many more…. Kingdom Characteristics • Eukaryotic cells • Multicellular • Cell wall made of chitin • Heterotrophs NUTRITION Are heterotrophs, so they don’t make their own food (No photosynthesis). Can’t “eat” or ingest food like us animals. Therefore, Fungi are either… Saprophytes: Absorb food from dead, organic material Or Symbionts: Obtain food through a relationship with other living organisms Parasites: harm host organisms Mutualists: both fungi & other organims benefit Fungi Structure • Have rigid cell walls containing chitin • Produce spores – tiny haploid cell that disperses fungi through the air and germinates if it lands on a food source • Made of many thread-like hyphae, which rapidly branch into a mycelium (mass of hyphae) Basic Fungus Structures • Parasitic fungi absorb nutrients from a hosts body fluids and may produce haustoria – specialized hyphae that penetrate the cell wall with enzymes & absorb materials Fungi and their role in the world Beneficial Effects of Fungus: 1. DECOMPOSERS – break down dead plant and animal material - leave surrounding area enriched with unabsorbed nutrients 2. USED FOR FOOD - Edible mushrooms - Yeast (beer, bread) - Flavour to cheese - Wine, soy sauce - Truffles ($720/lb in 1990) 3. COMMERCIAL USE - Source of vitamins, enzymes, amino acids, antibiotics Ex. Penicillium Harmful effects of fungus 1. CROP DISEASE - 100’s of millions $$ spent trying to protect crops with fungicides - Most effective are methods that prevent spores from germinating ex. French wine industry - Also, breeding strains of plants resistant to fungus or using viruses to control fungus 2. DISEASE OF ANIMALS (HUMANS) Fungal diseases are referred to as mycoses and they can effect us at many different levels from cutaneous mycoses (skin, hair, nails) to systemic mycoses (internal organs). ex. Ring worm Athlete’s foot Symbiotic Relationships May be… PARASITIC ex. Potato blight ex. Wheat Rust MUTUALISTIC ex. Lichen ex. Mycorrhizae Potato Blight Struck first in 1845 and was at its worst in 1847, destroyed the crop and left millions starving. As many as 2 million died from starvation and disease as crops failed again and again. LICHEN Mutualistic relationship between FUNGUS and ALGAE. Algae: photosynthesis – provides fungus with source of organic nutrients Fungus: provides algae with water and minerals Can survive in harsh conditions Extremely resistant to drought and cold Micorrhizae (means: fungus foot) Mutualistic relationship between FUNGUS and PLANTS Fungus: Hyphae help plants absorb water, minerals and nutrients Plants: provide products of photosynthesis Kingdom Fungi Four phyla: Zygomycota Ascomycota Basidiomycota Deuteromycota NOTE: Mycota = Greek for mushroom Classification is based on the basic structure of the fungus and how it reproduces Zygomycota ~ Common molds Ex. Black bread mold Rhizopus stolonifer Ascomycota ~ Sac fungi Ex. Truffles Morels Yeast Basidiomycota ~ Club Fungi Ex. Mushrooms, bracket fungi, puffballs Deuteromycota ~ Imperfect Fungi Ex. Athletes foot, Ringworm, Penicillium The crazy fungus among us… Cordyceps fungus video clip Complete the handout “Fungi Introduction” Fungal Reproduction Fungi can undergo both asexual and sexual reproduction Each phyla has it’s own unique reproductive structures The reproductive structures of a fungus are generally what we see above ground. Asexual Reproduction Fragmentation: pieces of hyphae break off and form a new individual fungus Spore formation: A reproductive cell usually produced in the sporangia Sexual Reproduction Most fungi have 2 mating types (+ and -) Fungi spend the majority of their life cycle as haploid cells When hyphae of each mating type meet, they fuse together (joining their nuclei) to form a diploid structure This structure then undergoes meiosis to produce haploid spores Black Bread Mold (Rhizopus) Spore Dispersal Most species produce billions of weightless spores Use many different means of dispersal… 1. Wind 2. Rain drops 3. Animals Basidiomycota reproduction Fairy Ring: Forms when nutrients at centre of mycelium becomes depleted so mushrooms only sprout around the outside Some fairy rings can be 10 to 20 meters in diameter.