Systematic of Fungi PDF

tematic of Fun ys g S i  Course Code: BMD-322 Midterm exam: week 6 Assessment % Mid-term exam 10 Oral exam 10 Exercise-activities 20 Practical exam...

tematic of Fun ys g S i  Course Code: BMD-322 Midterm exam: week 6 Assessment % Mid-term exam 10 Oral exam 10 Exercise-activities 20 Practical exam 20 Final exam 40 100% Systematics in biology : is concerned with the classification systems and nomenclature of organisms. It is a branch of biological science that studies the distinctive characteristics of species and how they are related to other species through time. Classification Process of grouping things based on their similarities  The word fungus : refers to the Latin word (The word mycology comes from the Ancient Greek (mukēs), meaning "fungu) KINGDOM FUNGI To date, 100,000 species of People that study fungi are called fungi have been discovered. Mycologists. It is thought that there are over Fungi are not able to produce one million species still to be their own food as plants do. found. Fungi are said to be The fungi that most people are SAPROTROPHS, because they live familiar with are those that on dead organic matter such as form fruit bodies or leaves and wood. mushrooms. To obtain nutrients fungi secrete Fungi can live in many habitats special digestive enzymes which including the arctic, tropical degrade organic material outside rainforest, fresh and salt water. the mycelium. The degraded However, most fungi live in soil. compounds can then be ingested. Heterotrophic by Absorption Fungi get carbon from organic sources Hyphal tips release enzymes Enzymatic breakdown of substrate Products diffuse back into hyphae Enz ym cts atic breakdo u Prod En zymes Product diffuses back wn into hypha and is used  The Characteristics of Fungi Body form unicellular filamentous (tube-like strands called hypha ) mycelium = aggregate of hyphae. sclerotium = hardened mass of mycelium that generally serves as an overwintering stage. multicellular, such as mycelial cords, rhizomorphs, and fruit bodies (mushrooms) Yeasts Single celled fungi Candida Saccharomyces The Characteristics of Fungi Heterotrophy Saprophytes or saprobes - feed on dead tissues or organic waste (decomposers) Symbionts - mutually beneficial relationship between a fungus and another organism Parasites - feeding on living tissue of a host. Parasites that cause disease are called pathogens. The Characteristics of Fungi Cell wall present, composed of cellulose and/or chitin. Food storage - generally in the form of lipids and glycogen. Eukaryotes - true nucleus All fungi require water and oxygen (no obligate anaerobes). Fungi grow in almost every habitat imaginable, as long as there is some type of organic matter present and the environment is not too extreme.  Hyphae Tubular Hard wall of chitin Multinucleate Grow at tips Modifications of hyphae Fungi as Saprobes and Decomposers Fungi as Symbionts (Mutualism) Mycorrhizae “Fungus roots” Mutualism between: Fungus (nutrient & water uptake for plant) Plant (carbohydrate for fungus) Extremely important ecological role of fungi! “Ecto”mycorrhizae Mycorrhiza cross sections Fungal hyphae around root and between cells Lichens “Mutualism” between Fungus – structure Alga or cyanobacterium – provides food Lichen internal structure Lobaria Fungi as Parasites Fungi can infect plants and animals; including humans. Masses of spores cause discolouration of the leaves so infections of plants are called smuts, rusts, spots and other names describing the symptoms. Fungi can cause a variety of symptoms including leaf spots and blights, root rots, seedling blights, seed discoloration, wilts, and stem rots. Hyphae absorb both the water and nutrients needed for growth and reproduction of the fungi. They may also secrete enzymes, toxins, and other chemical substances that may be important factors in disease development and symptom expression. HUMAN-FUNGUS INTERACTIONS Beneficial Effects of Fungi Decomposition - nutrient and carbon recycling. Biosynthetic factories. Can be used to produce drugs, antibiotics, alcohol, acids, food (e.g., fermented products, mushrooms). Model organisms for biochemical and genetic studies. Harmful Effects of Fungi Destruction of food, lumber, paper, and cloth. Animal and human diseases, including allergies. Toxins produced by poisonous mushrooms and within food (e.g., grain, cheese, etc.). Plant diseases.  Hyphal growth from spore germinating spore mycelium Mycelia have a huge surface area Generalized Life Cycle of a Fungus Some fungi have more than one scientific name – Why? Teleomorph: the sexual reproductive stage (morph), typically a fruiting body (e.g., Morchella esculenta, Agaricus brunescens). Anamorph: an asexual reproductive stage (morph), often mold-like (e.g. Aspergillus flavus, Fusarium solani). Holomorph: the whole fungus, including all anamorphs and the teleomorph.