21. CLASSIFICATION: Fungi

GeneralBiology_cool_Button1 Button_cool_Turq_LearnTools

MAIN TOPICS OUTLINE

21.1 GENERAL CHARACTERISTICS

21.2 CLASSIFICATION
LECTURE OBJECTIVES
1. Discuss the characteristics of the kingdom Fungi, and some criteria used in classifying fungi.
2. List the major phyla of the fungi and give some examples of each.
3. List the way fungi differ from bacteria, and protista.
4. Define selected key terms.
Key Terms:

def. Asci: Sac-formed, reproductive structure producing haploid spores.
def. Ascospores: Spores formed by sac fungi (Ascomycota).
def. Basidium: Club-formed, reproductive structure producing haploid spores.
def. Basidiocarp: The complete spore bearing structure, the mushroom, equivalent to a fruit, of a club fungus.
def. Basidiospores: Spores formed by club fungi (Basidiomycota).
def. Cap: Spore bearing structure of a club fungus.
def. Climax community: Last stage of succession, a relatively stable long-lasting community of organisms.
def. Climax ecosystem: An ecosystem with a climax community, the last stage in ecological succession. (An ecosystem in which populations of all organisms are in balance with each other and with existing abiotic factors. The biomes are climax ecosystems for their particular areas.)
def. Decomposer: Organism that uses dead organic matter as source of energy.
def. Ecological succession (ecology): The predictable process of changing one type of ecological community to another. (Gradual changes in the structure of a community, due to some abiotic change, ultimately leading to a climax community.)
def. Fungi: A eukaryotic, heterotrophic, saprotrophic organism.
def. Hypha: Each filament (slender "root") in a mycelium.
def. Lichen: A symbiotic relationship between a fungus and a photoautotroph, such as a green algae or a cyanobacteria.
def. Mold: A fungus (or protist if slime mold or water mold) that grows as a downy coating on animal or plant matter.
def. Mushroom: A (usually) club or umbrella shaped fleshy fungi in the Basidiomycota.
def. Mycelium: A mass of fine, branching filaments (hyphae) that is the food-absorbing part of most fungi.
def. Mycorrhize: "Fungus-root", symbiotic relationship (a form of mutualism) between a fungus and the roots of a plant.
def. Pioneer species (ecology): The first organisms in the succession process.
def. Saprotrophic (Saprophytic): "Rotten food eater", organism that secretes digestive enzymes and absorbs the resulting nutrients back across the plasma membrane
def. Spore: 1. Single celled reproductive structure, usually an asexual haploid cell that divides by mitosis to produce new haploid individuals (could also be a sexual haploid cell that first must unite with another sexual spore to produce a new life stage); 2. A resistant, resting body adapted to survive adverse environmental conditions.
def. Sporangium (pl. sporangia): In fungi (and plants), a structure within which cells undergoes meiosis to produce haploid spores.
def. Stalk: The structure between the cap and the mycelium of a club fungus.
def. Succession (ecology): See ecological succession.
def. Symbiosis (ecology): Relationship that occurs when two different species live together in a unique way.
21.1. General Characteristics

1. multi-cellular or single-celled (yeasts)
2. eukaryotic
3. heterotrophic (no chlorophyll) -- saprotrophic or parasitic
4. have cell wall
5. aerobic
6. large (compared to bacteria)

def. Asci: Sac-formed, reproductive structure producing haploid spores.
def. Ascospores: Spores formed by sac fungi (Ascomycota).
def. Fungi: A eukaryotic, heterotrophic, saprotrophic organism
def. Mold: A fungus (or protist if slime mold or water mold) that grows as a downy coating on animal or plant matter.
def. Saprotrophic (Saprophytic): "Rotten food eater", organism that secretes digestive enzymes and absorbs the resulting nutrients back across the plasma membrane
def. Decomposer: Organism that uses dead organic matter as source of energy
def. Spore: 1. Single celled reproductive structure, usually an asexual haploid cell that divides by mitosis to produce new haploid individuals (could also be a sexual haploid cell that first must unite with another sexual spore to produce a new life stage); 2. A resistant, resting body adapted to survive adverse environmental conditions.
def. Sporangium (pl. sporangia): In fungi (and plants), a structure within which cells undergoes meiosis to produce haploid spores.
def. Zygosporangium: Capsule-formed, reproductive structure producing haploid spores.
def. Zygospores: Spores formed by bread molds (Zygomycota).


-- Fungi invaded land about 430 million years ago (430 - 410 mya).
-- Reproduce by spores (most have both sexual and asexual reproduction stages.)
 (see def. of spore above)
-- Heterotrophic, decomposers (get their nutrients from nonliving matter -- sometimes dead organisms, in all levels of the food chain, and cause its decay).

Armillaria ostoyae, honey mushroom, 3.5 miles across and more than 2000 years old. The small mushrooms visible above ground are only the tip of the iceberg. Photo used for educational purposes by Dr. Jan A. Nilsson, Biology Department, South Texas Community College, Texas, USA. To make the information reliable available to students in the course the photo was downloaded from URL: http://www.factmonster.com/spot/fungus1.html. Photo credit given on that web page: (AP Photo/Oregon State University)

21.2. Classification
-- the scientific name of most fungus groups ends with -mycota


21.21 Phylum Zygomycota ("molds", bread-molds)


def. Zygosporangium: Capsule-formed, reproductive structure producing haploid spores.
def. Zygospores: Spores formed by bread molds (Zygomycota).

-- spores formed in spore sacs called zygospores (+ mating type, - mating type).
-- Economic importance: molds (destructive growth).


• Rhizopus, black bread mold


21.22 Phylum Ascomycota (sac fungi)


def. Asci: Sac-formed, reproductive structure producing haploid spores.
def. Ascospores: Spores formed by sac fungi (Ascomycota).

-- spores formed in spore sacs called ascospores (sac-shaped cells called asci.)
-- Economic importance: e.g., yeast (rise dough, and form alcohol), penicillium.

• Saccharomyces, yeast
used for bread, beer, and wine production
• Candida, yeast
infections of the vagina
• Penicillium
used as antibiotic
• Cup fungus
• Morels


21.23 Phylum Basidiomycota (club fungi)


def. Mushroom: A (usually) club or umbrella shaped fleshy fungi in the Basidiomycota.
def. Mycelium: A mass of fine, branching filaments (hyphae) that is the food-absorbing part of most fungi.
def. Mycorrhize: "Fungus-root", symbiotic relationship (a form of mutualism) between a fungus and the roots of a plant.
def. Hypha: Each filament (slender "root") in a mycelium.
def. Stalk: The structure between the cap and the mycelium of a club fungus.
def. Cap: Spore bearing structure of a club fungus.
def. Basidium: Club-formed, reproductive structure producing haploid spores.
def. Basidiocarp: The complete spore bearing structure, the mushroom, equivalent to a fruit, of a club fungus.
def. Basidiospores: Spores formed by club fungi (Basidiomycota).

• mushroom
• toadstool
• shelf fungus
• coral fungus
• puffball
• smut.

-- Most have a club-shaped structure with a stalk and a cap.
-- Spores formed in club-shaped spore sacs called basidiospores.
-- Economic importance: edible mushrooms, many live in symbiosis with tree roots mycelium connected with roots by structures called mycorrhiza -- cover huge areas and are very old.

Hypha -- Hyphae -- Mycelium -- Mycelia


21.24 Phylum Mycophycophyta (lichens)


def. Lichen: A symbiotic relationship between a fungus and a photoautotroph, such as a green algae or a cyanobacteria.
def. Pioneer species (ecology): The first organisms in the succession process.
def. Ecological succession (ecology): The predictable process of changing one type of ecological community to another. (Gradual changes in the structure of a community, due to some abiotic change, ultimately leading to a climax community.)

-- Symbiotic relationship (mutualistic) between a

green algae / cyanobacteria and a fungus:

 - the fungus protects the algae
- the algae / cyanobacteria photosynthesize (gain energy)

-- Live in inhospitable places such as bare rocks and tree trunks (important pioneer species in ecological succession).

• Reindeer moss



21.25 Phylum Deuteromycota (Imperfect fungi)


-- All other fungal groups reproduce both sexually and asexually. The imperfect fungi have no known sexual reproduction stage.

• Predatory fungus
• Athletes foot
• Aspergillus


not on-line Dr. Thinkwell ../Thinkwell_f/21_Fungi_5498_5521.mov


Copyright 2002, 2003, 2004, Jan A. Nilsson. Web page layout and design © and intellectual property Jan A. Nilsson. All rights reserved. Reproduction of the whole or any part of the contents without written permission is prohibited. Page created 10.XII.2002, last updated 16.II.2004, most likely during the wee hours of the morning on a G3 PowerBook owned by Jan A. Nilsson.

-- Disclaimer: "Dr. Nilsson's CyberOffice", at the time of writing located as a file under the South Texas Community College's (STCC) web server with the general URL http://stcc.cc.tx.us/, is the intellectual property of Dr. Jan A. Nilsson, member of STCC biology faculty. The content of Dr. Nilsson's CyberOffice does not necessarily reflect the opinions and beliefs of the STCC faculty, staff, administration, and Board of Trustees.