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Copyright Pearson Prentice Hall 21-2 Classification of Fungi Photo Credit: ©D. Cavagnaro/DRK Photo Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Classification Fungi are classified according to their structure and method of reproduction. The four main groups of fungi are: Common molds (Phylum Zygomycota) Sac fungi (Phylum Ascomycota) Club fungi (Phylum Basidiomycota) Imperfect fungi (Phylum Deuteromycota) Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Common Molds The Common Molds p530 Familiar molds that grow on meat, cheese, and bread are called zygomycetes. Terrestrial organisms Zygomycetes have life cycles that include a zygospore. A zygospore is a resting spore that contains zygotes formed during the sexual phase of the mold's life cycle. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Common Molds Life Cycle of a Black Bread Mold p531 MEIOSIS FERTILIZATION Zygomycetes have life cycles that include a zygospore. During sexual reproduction in the bread mold Rhizopus stolonifer, hyphae from two different mating types form gametangia. The gametangia fuse, and zygotes form within a zygospore. The zygospore develops a thick wall and can remain dormant for long periods. The zygospore eventually germinates, and a sporangium emerges. The sporangium reproduces asexually by releasing haploid spores produced by meiosis. Sexual Reproduction Asexual Reproduction Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Common Molds Rootlike hyphae, called rhizoids, penetrate the body of its food source. Rhizoids Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Common Molds The hyphae that run along the surface of the food source are called stolons. Stolon Rhizoids Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Common Molds The hyphae that push up into the air are the sporangiophores, which form sporangia at their tips. sporangia greek: phoros = Holder sporangiophore: Sporangium holder sporangiophores Stolon Rhizoids Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Common Molds Hyphae from different mating types fuse and produce gamete-forming structures called gametangia. sporangia Gametangia + Mating type (N) - Mating type (N) sporangiophores Stolon Rhizoids Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Common Molds Haploid (N) gametes produced in the gametangia fuse with gametes of the opposite mating type to form diploid (2N) zygotes. Zygotes develop into thick-walled zygospores. The zygospore produces spores and the spores are eventually released and grow into new hyphae. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Sac Fungi The Sac Fungi p532 The phylum Ascomycota is named for the ascus, a reproductive structure that contains spores. The largest phylum – more than 30,000 species Includes morels, yeast, cup fungus, truffles Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Sac Fungi Fruiting bodies – the part of the fungus you see above ground. It contains the spore producing structures. The morel and the truffle are edible ascomycetes. Many wild mushrooms are poisonous and look identical to edible ones. The decision to eat a wild mushroom should only be made by an expert mycologist. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Sac Fungi Yeasts Yeasts are unicellular fungi. Reproduction is usually asexual but under the right conditions a yeast cell can reproduce sexually. Dry granules of yeast contain ascospores, which become active in a moist environment. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Sac Fungi Life Cycle of Sac Fungi p533 The life cycle of an ascomycete usually includes both asexual and sexual reproduction. Asexual reproduction: spores called conidia are formed at the tip of conidiophores Sexual reproduction: a tiny sac called ascus contains ascospores Copyright Pearson Prentice Hall

Sexual reproduction of the sac fungi

Copyright Pearson Prentice Hall The Club Fungi The Club Fungi p534 The phylum Basidiomycota, or club fungi Most of what we call mushrooms fit into this phylum. Also include the bracket fungi which are found growing on the surface of trees. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Club Fungi The Club Fungi p534 The visible part of the fungus is the reproductive part. The spore producing structure is called the basidium, which is found in the cap of the mushroom. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Club Fungi Life Cycle of Club Fungi Basidiomycetes undergo an elaborate the most complex life cycle of the fungi. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Club Fungi Life Cycle of Club Fungi p534 The club fungi are named after the club shape of their reproductive structure, the basidium. The cap of a basidiomycete such as a mushroom is composed of tightly packed hyphae. The lower side of the cap is composed of gills—thin blades of tissue lined with basidia that produce basidiospores. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Club Fungi When the right combination of moisture and nutrients occurs, spore-producing fruiting bodies push above the ground. Fruiting body (N + N) Gills lined with basidia Gills Cap Stalk Base Basidia (N +N) Copyright Pearson Prentice Hall

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Copyright Pearson Prentice Hall The Club Fungi Diversity of Club Fungi Basidiomycetes include shelf fungi, puffballs, toadstools, earthstars, jelly fungi, and plant parasites known as rusts. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Club Fungi Diversity of Club Fungi Mushrooms as Meat-Eaters Ten species of mushrooms prey upon animals for food. They attack nematodes (roundworms) in soil and rotting wood. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Imperfect Fungi The Imperfect Fungi p536 Imperfect fungi, or Deuteromycota, are fungi that cannot be placed in other phyla because researchers have never been able to observe a sexual phase in their life cycles. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Imperfect Fungi A well-known genera of the imperfect fungi is Penicillium. Penicillium notatum is a mold that grow on fruit and is the source of the antibiotic penicillin. Believed to be related to ascomycetes – similar asexual reproduction Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Imperfect Fungi Deuteromycota includes the fungus that cause : Athlete’s foot Ringworm other skin infections black spot of roses tomato blight Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 21-3 Ecology of Fungi Photo credits: ©D. Cavagnaro/DRK Photo Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 21-3 Ecology of Fungi The oldest known fungi fossils are about 230 million years old. Fungi may have helped early plants obtain nutrients and may have been essential to plants’ colonization of the land. Copyright Pearson Prentice Hall

All Fungi Are Heterotrophs Fungi rely on other organisms for energy. Many fungi are saprobes, which are organisms that obtain food from decaying organic matter. Other fungi are parasites, which harm other organisms while living directly on or within them. Other fungi are symbionts that live in close and mutually beneficial association with other species. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Fungi as Decomposers Fungi as Decomposers What is the main role of fungi in natural ecosystems? Fungi maintain equilibrium in nearly every ecosystem, where they recycle nutrients by breaking down the bodies and wastes of other organisms. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 21-2 Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 21-2 Fungi grow best in an environment that is cool. moist. dry. salty. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 21-2 Yeasts are ascomycetes. zygomycetes. basidiomycetes. deuteromycetes. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 21-2 Penicillium is a(an) ascomycete. basidiomycete. deuteromycete. zygomycete. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 21-2 Sac fungi have a characteristic reproductive structure called a(an) ascus. basidium. budding capsule. sporophyte. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 21-2 The basidiospores of club fungi are produced on thin structures called fruiting bodies. buttons. gills. stalks. Copyright Pearson Prentice Hall

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