Kingdom+Fungi

Fungi 1) Characteristics of Fungi a) The basic structural units of multicellular fungi are their threadlike filaments called **hyphae**. i) Cross walls called **septa** divide hyphae into individual cells that contain one or more nuclei. (1) Septa are porous, allowing cytoplasm and organelles to move from one part of the fungus to another. ii) Some hyphae have no septa and nuclei flow freely through the cytoplasm. b) Hyphae elongate at their tips and branch extansively to form a network of filaments called a **mycelium**. c) The cell walls of most fungi contain a complex carbohydrate called **chitin**. 2) Adaptations a) They are decomposers i) Extracellular digestion – Food is digested outside of the cells, and the digested products are absorbed. ii) Different food sources and relationships (1) Saprophyts are decomposers and feed on waste or dead organic material. (2) Mutualist live in sybiotic relationship with another organish. (3) Parasites absorb nutriets from living cells. (a) Parasitic fungi may produce hyphae called **haustoria**, which penetrate and grow into host cells and directly absorb the host cells’ nutrients. 3) Reproduction- Fungi reproduce sexually and asexually. a) Fragmentation- an asexuall form of reproduction, in which pieces of hypae break off and grow into new mycelia. b) Budding- the process by which unicellular fungi reproduce asexually, mitosis occurs and new individuals pinch off and mature. c) Spores ar produced by most fungi. They grow when they land in favorable condtions i) **Sporangium** are sacs or cases in which spores are produced.  ii) The advantage of spores is that they are lightweight, protected by the sporangia, and they are produced in large numbers. 4) Zygomycotes- A phylum of fungi that reproduce asexually by producing spores. a) **Stolons** are hyphae that grow horizontally on food, rapidly producing a mycelium. b) **Rhizoids** are hyphae that penetrate the food and anchor the mycelium. c) Zygomycotes can reproduce asexually and sexually. i) Some hyphae grow sporangium at their tips, which produced asexual spores. The spores that are released spread, and those that land on a moist food supply form new hyphae.  ii) When conditions are unfavorable, zygomycotes reroduce sexually. They produce zygospores