Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Biology Chapter 11 The Kingdom Fungi How do fungi differ from plants? 1. Lack true tissues 2. Lack chlorophyll How do fungi differ from algae? 1. Lack chlorophyll 2. Completely heterotrophic (saprophytic or parasitic or both) How are fungi harmful? 1. Some can cause disease (example: page 297, ergot of rye, "St. Anthony's fire") or even death 2. Crop damage fungicide- a chemical substance used to kill or inhabit the growth of fungi How are fungi beneficial? 1. Provide leavening for breads [leavening- a substance which provides bubbles of gas in doughs or batters ("rise")] 2. Decompose organisms in the soil and damp areas (most important and most common) 3. Source of food (mushrooms and cheeses) 4. Medicines (penicillin) Alexander Fleming, 1929, First antibiotic Classification of Kingdom Fungi: Phylum Eumycophyta- true fungi; 47,000 species; (mushroom, mold, rust, yeast, smut); larger and more important Phylum Myxomycophyta- slime molds; 450 species Phylum Eumycophyta The True Fungi Most fungi are multicellular and have a distinct threadlike structure or filaments, which form the body of a fungus (called hyphae). Yeasts are unicellular. types of hyphae: Septate - hyphae that has a wall separating the individual cells the wall is called the septum (septa plural) Nonseptate - hyphae that lack septa see page 300 10th Biology Chapter 11 / The Kingdom Fungi 2 Hyphae serve different functions and are named accordingly: 1. Rhizoids - embedded in the material on which the fungus is growing; support the fungus and digests food 2. Aerial hyphae - not embedded in the material; absorb oxygen, produce spores, and spread the fungus 3. Stolons - aerial hyphae that produce new filaments 4. Sporophores - hyphae branches which produce spores 5. Haustoria - hyphae of parasitic fungi which enter the host's cells to obtain nutrition directly from the cytoplasm 6. Mycelia - masses of intertwined hyphae; forms the main body of a fungus mycologists - scientists who study fungi True fungi have cell walls composed of chitin (KY tin) - a hard substance also found in the exoskeletons of insects and crabs. Most are colonial They lack specialized structures for digestion - external digestion Most common type of reproduction: Asexual Asexual reproduction: spores - most common asexual method fragmentation by stolons spores form: either within an enclosure (Sporangium - where spores are made); the whole structure is called a sporangiophore (see page 301) or not within an enclosure (Conidia - where spores are made); the whole structure is called a conidiophore (ko NID ee uh for) Sexual reproduction: see page 302 Hyphae (haploid) of two different mycelia come in contact, resulting in a diploid zygote. This forms a zygospore or forms a new mycelium which grows and becomes highly specialized fruiting body which produces and dispenses spores. Classification in Phylum Eumycophyta perfect fungi - those which reproduce sexually imperfect fungi - those which do not reproduce sexually (1) Class Phycomycetes (a perfect fungus) contains many of the common molds Rhizopus nigricans - most common type of bread mold Its sporangium disperses tiny black spores 10th Biology Chapter 11 / The Kingdom Fungi 3 Not all molds which grow on foods spoil the food; some actually make them more tasty. For example, restaurants sometimes keep choice beefsteaks in a cooler where it is too cold for bacteria to grow but not too cold for a certain type of green mold to grow. The rhizoids of this mold grow slowly through the meat. The mold actually digests the meat for its own use. Later, when the green mold is scraped off and the meat is cooked, the steak is very tender and flavorful. Cheese molds: Cheese is formed by bacteria and molds. The bacteria help separate the solid, white curd from the watery whey of milk. After this separation is complete, mold spores are introduced into the curd and the molds are allowed to grow. The type of cheese that is formed depends on the kind of mold spores used, the rapidity with which the mold is allowed to grow, and the kind of milk curd used. Roquefort cheese is made from sheep's milk and a dark green type of mold; this famous French cheese was originally produced in cool caves where the mold grew very slowly. The pungent cheese known as Limburger is allowed to mold rapidly under warm and very humid conditions. Parasitic molds: cause serious problems for man because they feed on important foods. Examples: late blight fungus of potatoes - the potato blight of 1845 caused the starvation of approx. 250,000 people in Ireland; also affects tomatoes - in 1946 the tomato crop in the eastern U.S. was cut by half (est. loss of 50 million dollars) downy mildews - damages cabbage lettuce, cucumbers, spinach, beans, peas, and grapes Aquatic molds: often produce motile gametes cause a cottony growth on dead fish (2) Class Ascomycetes (a perfect fungus) "sac fungi" sexually produce spores called ascospores inside a sac called an ascus asexually - conidia Examples: molds of the genus Penicillium antibiotic flavors of Roquefort (Penicillium roqueforti) and Camembert cheese red bread mold (Aspergillus & Neurospora) cause plant diseases (ergot of rye, chestnut blight, & the Dutch elm disease) powdery mildews (cobwebby mycelia on leaves & stems of lilacs, grapes, roses, apples, and squash) morel - delicately flavored; the cup fungi (see 10th Biology Chapter 11 / The Kingdom Fungi 4 page 304); form a saucer or bowl-shaped fruiting body yeasts - small, colorless, unicellular, saprophytic mostly (some parasites); feeds on foods containing sugar, converting the sugar into alcohol and C02 in the process. yeasts reproduce asexually by budding (3) Class Basidiomycetes (a perfect fungus) "club fungi" produce spores in the club-shaped basidium; spores are called basidiospores most are saprophytes Examples: Mushroom see page 306; know its structure (gills, cap, stipe = fruiting body) Shelf fungi no gills - spores fall from holes on undersurface of fruiting body Rusts named for the rusty-colored spores that they leave on their hosts (such as wheat, oats, raspberries, melons, apple trees and evergreen trees); they are alternate parasites: means they must have two hosts in order to complete their life cycle (one is harmed and the other is not) Smuts produce masses of black spores on their hosts; attack grains (corn, oats, wheat, rye, barley); hyphae penetrate tissues of hosts and rob them of nourishment (can't grow); often destroy flowers so no grains are produced (4) Class Deuteromycetes (imperfect fungi) no sexual reproduction saprophytes plant parasites early blight of potatoes & tomatoes; apple pink rot; peach scab, and onion white rot human parasites ringworm, athlete's foot, thrush: a parasite of the mucous membranes of the mouth, nose and throat Phylum Myxomycophyta slime molds (plasmodium) see page 308 10th Biology Chapter 11 / The Kingdom Fungi 5 fan-shaped network of veinlike branches small group of unusual organisms - includes some yeasts normally found in moist habitats - sometimes on rotting logs, damp soil, and decaying organic material The Lichens lichens - a group of dual organisms (composed of both fungi and algae). The algae is surrounded by mycelium of the fungus, which provides the algae with a secure environment. Fungus provides the water and minerals; supports and protects the algae. The algae contains chlorophyll and is its food maker. Example of symbiosis: mutualism: two different kinds of organisms living together when both benefit and neither is harmed. (see page 309) 3 general categories of lichen (based on their appearance) 1) Crustose (KRUS TOCE)- crust-like; appear as flat or nearly flat smears of dried paint. 2) Foliose (FO lee oce)- leaf-like; small, crinkly leaves. 3) Fruticose (FR00 tih KOCE)- shrubby; have stalks or branches.