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Biology II

Biology II. Fungi. Introduction of Fungi. They are classified as eukaryotes (have a membrane bound nucleus) Fungi can be divided into two basic morphological forms: Yeasts Hyphae. Yeast. Unicellular fungi Reproduce asexually by blastoconidia formation (budding) or fission. Hyphae.

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Biology II

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  1. Biology II Fungi

  2. Introduction of Fungi • They are classified as eukaryotes (have a membrane bound nucleus) • Fungi can be divided into two basic morphological forms: • Yeasts • Hyphae

  3. Yeast • Unicellular fungi • Reproduce asexually by blastoconidia formation (budding) or fission

  4. Hyphae • Multicellular • Reproduce asexually and/or sexually

  5. Most Fungi occur in the hyphae form as branching, threadlike tubular filaments • Lack cross walls (coenocytic) • Have cross walls (septate) • Clamp connections at the septa which connect the hyphae elements

  6. Common Characteristics of Fungi • Heterotrophy-eat other organisms as food • Three major categories of heterotrophs • Saprophytes-Feed on dead tissue or organic waste • Symbionts- mutually beneficial relationship between a fungus and another organism • Parasites- feeding on living tissue of a host • Parasites that cause diseases are called pathogens • Some parasites are obligate parasites (require a living host) • Others are facultative or nonobligate(do not require a living host in order to survive)

  7. Common Characteristics • Body Form • Unicellular • Filamentous-tube-like strands called hypha or hyphae • Mycelium- total of hyphae • Sclerotium=Hardened mass of mycelium that generally serves as an overwintering stage • Multicellular-such as mycelial cords, rhizomorphs, and fruit bodies (mushrooms)

  8. Common Characteristics • Fungus is often hidden from view • It grows through its food source, excretes extracellular digestive enzymes, and absorbs dissolved food • Indeterminate growth

  9. Common Characteristics • Spores- asexual (product of mitosis) or sexual (product of meiosis) in origin • Purpose of Spores • Allows the fungus to move to new food source • Resistant stage- allows fungus to survive periods od adversity • Means of introducing new genetic combinations into a population

  10. Common Characteristics • Vegetative phase of fungus is generally sedentary • Cell wall present, composed of cellulose and/or chitin • Food Storage- generally in the form of lipids and glycogen • Eukaryotes-true nucleus and other organelles present

  11. Common Characteristics • All fungi require water and oxygen • Fungi grow in almost every habitat imaginable, as long as there is some type of organic mater present and the environment is not too extreme • Diverse group, number of describer species is about 69,000 (estimated 1.5 million species total)

  12. Phylums of Fungi • Phylum Zygomycota- common mold found on land • Reproduce by zygospores • Ex: Rhizopus- common bread mold • Contain root-like structures (rhizoids) to anchor in bread. Stolons on surface of bread.

  13. Phylum Basidiomycota • Basidiomycetes- the club fungi, about 22,300 species • Includes mushrooms, toadstools, puffballs, shelf fungi, rusts, bird’s nest fungi and smuts • Characterized by perforate septatehypahe and the production of basidium (club) following sexual reproduction.

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