KINGDOM: FUNGI Once classified as non-photosynthetic plants because of the way some grow, fungi aren't plants at all. Fungi are eukaryotic (membrane bound organelles in cells) heterotrophs (need to eat food) that have cell walls. The cell walls of fungi are made-up of chitin, a type of carbohydrate that is also found in the exoskeletons of insects. Fungi eat by digesting their food outside their bodies and then absorb it.  (decaying matter, parasites) Humans use a type of fungus (YEAST) to make bread rise during baking. The yeast commonly used is called Saccharomyces (which means sugar-fungi). This yeast metabolizes the nutrient in the (anaerobic - without oxygen) bread dough into alcohol and carbon dioxide. The alcohol evaporates during baking and the CO2 inflates the bread.  When making wine, the alcohol remains. Common molds (like the one that makes penicillin), mushrooms, morels, truffles, yeast, & athlete's food are fungi... Fungus that normally grow on our bodies are usually kept in check by bacteria.  Sometimes, over use of antibiotics or a weak immune system can disrupt this balance causing disease.. STRUCTURE Except for yeast, all fungi are multicellular.  Multicellular fungi are made of thin filaments called hyphae.  Each hyphae is only one cell thick. The bodies of multicellular fungi are composed of many hyphae tangled together into a thick mass called a mycelium. What we call a mushroom is actually the fruiting body of a fungus. (reproductive structure) Clusters of mushrooms are usually part of the same mycelium - which means that they are part of the same organism. Some mycelium can live for many years.  As time goes by, soil nutrients near the center of the mycelium become depleted. As a result, new mushrooms sprout only at the edges of the mycelium. (fairy rings / 10-30 meters in diameter) There are over 100,000 species of fungi!!! 30,000 are sac fungi (ascomycetes) ~ largest phylum... Bread mold: Sporangium are spheres atop filaments called sporangiophores where spores (2n) are stored.  Stolons connect sporangium clusters. Zygosporangium are where zygospores (2n) are formed. Zygospores germinates and the sporangium emerges. Mushrooms; Mushrooms belong to the phylum basidiomycota, or club fungi.  The spore bearing structure is called the basidium. Basidium are found on the gills that grow on the underside of mushroom caps. The club fungi - named after its reproductive structure the basidium, has several parts. 1. base   2. Stalk   3. Gills   4. Cap   5. basidia Fruiting bodies expand with astonishing speed, sometimes producing fully developed mushrooms overnight.  This remarkable growth rate is caused by cell enlargement, not cell division.  The cells of the hyphae enlarge by rapidly taking in water... REPRODUCTION IN FUNGI Most fungi reproduce both sexually and asexually.  Asexual reproduction takes place when cells or hyphae break-off and continue to grow on their own.  Some fungi make spores that grow into new organisms. Spores are made in a structure called a sporangium.  Sporangia are found in the ends of special hyphae called sporangiophores. Sexual reproduction involves two different mating types.  Since the gametes of the two types are the same size, they are not termed male and female, instead they are termed as (+ or -) when a + and a - hyphae meet, they form a diploid zygote.  This diploid zygote then makes more haploid spores similar to the ones made during asexuall reproduction. HOW FUNGI SPREAD Fungal spores are found nearly everywhere.  If the conditions are right (moisture, temperature, & food) mold spring up anywhere - like bathrooms or in the air. On any given day, a few liters of fresh air may contain hundreds of spores.  But only about 1 in a billion find the proper combination of food temperature and moisture to grow. Certain fungi like the stinkhorn attract animals by smelling like rotten meat.  When flies land on the fungus and eat the sticky smelly fluid on the fungus, spores are ingested - and pass through the flies digestive system unharmed - ready to be spread elsewhere. CLASSIFICATION OF FUNGI (by phylum) 1. Zygomycetes - zygospore (common molds) a. black bread mold - Rhizopus stolonifer 2. Ascomycetes - ascus, reproductive structure that contains spores (sac fungi) ~ largest phylum a. cup fungi / visible above ground b. yeast / microscopic c. morels d. truffles ($600 a pound) 3. Basidiomycetes - basidium, club like structure (club fungi) ~ perhaps the largest organisms in the world? a. mushrooms b. stinkhorns c. shelf fungi d. pigskin poison puffball (poisonous) e. fly algaric (poisonous) f. plant rust (parasitic) 4. Deuteromycetes - no sexual reproductive cycle observed (imperfect fungi) a. Penicillium notatum ~ penicillin