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The Kingdom Fungi. Chapter 21. 21-1 The Kingdom Fungi. What are Fungi?. Fungi are eukaryotic heterotrophs that have cell walls made of chitin (a carbohydrate). Fungi DO NOT ingest their food, but rather they digest food OUTSIDE their bodies and the ABSORB it! (Fungi are decomposers)
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The Kingdom Fungi Chapter 21
What are Fungi? • Fungi are eukaryotic heterotrophs that have cell walls made of chitin (a carbohydrate). • Fungi DO NOT ingest their food, but rather they digest food OUTSIDE their bodies and the ABSORB it! (Fungi are decomposers) Reasons Fungi Not Plants! • No chlorophyll • Cell wall not Cellulose • NO vascular tissue • Do not photosynthesize (Not an autotroph)
Structure and Function of Fungi • Structure and Function • Multicellular (except yeasts) • Composed of hyphae—thin filaments one cell thick • Cross walls—cytoplasm and nuclei can move through openings • Without cross walls—contain many nuclei
Nuclei Cell wall Cytoplasm Cross wall Nuclei Cytoplasm Cell wall Hyphae Structure Close-Up Hyphae With Cross Walls Hyphae Without Cross Walls Section 21-1
Structure & Function of Fungi • Except for yeasts, ALL fungi are multi-cellular and composed of tiny filaments called hyphae. • The bodies of multicellular fungi are composed of many hyphae tangled together into a thick mass called a mycelium. • The mycelium is well suited to absorb food. • The fruiting body is a reproductive structure that develops from a mycelium that grows below the surface of the ground.
Fungi Structure Fruiting body Hyphae Mycelium Section 21-1
Reproduction in Fungi • Most fungi reproduce both asexually and sexually. • Asexual: • In some fungi, spores are produced in structures called sporangia. • Sporangia are found at the tips of specialized hyphae called sporangiophores. • Sexual: • Sexual reproduction involves a gametangium - a gamete-forming structure produced when the hyphae of opposing mating types of fungi meet.
How Fungi Spread • How Fungi Spread • Fungal spores • Scatter easily in the wind • Must land in favorable environment • Temperature • Moisture • Food • Some are specialized to lure animals, flies • Disperse spores over long distances
21-2 Classification of Fungi • Fungi are classified according to their structure and method of reproduction • The 4 main groups of fungi are: • Zygomycota (common molds) • Ascomycota (sac fungi) • Basidiomycota (club fungi) • Deuteromycota (imperfect fungi)
Zygomycota – The Common Molds • Zygomycetes are the familiar molds that grown on meat, cheese, and bread. • Ex: Rhizopus stolonifer (black bread mold). the rootlike hyphae that anchor the fungus to the bread are called rhizoids the stem-like hyphae that run along the surface of the bread are called stolons
Zygospore (2N) Sporangium Gametangia Spores (N) Sporangium Zygospore (2N) + Mating type (N) Stolons Spores (N) - Mating type (N) Sporangiophore Rhizoids Figure 21-5 The Life Cycle of Rhizopus Section 21-2 p. 531 FERTILIZATION MEIOSIS Sexual Reproduction Asexual Reproduction Diploid Haploid
Ascomycota – The Sac Fungi • The phylum Ascomycota is named for the ascus, a reproductive structure that contains spores. • Ascomycetes are the largest phyum in the kingdom Fungi. • Some are large and some are microscopic. • Examples: cup fungi (large) and yeasts (microscopic).
Fruiting body (N + N) Hyphae (N + N) Ascus (N + N) Zygote (2N) Hyphae (N) Asci Gametangia + Mating type (N) - Mating type (N) Ascus Conidia (N) 8 Ascospores (N) Hypha (N) Conidiophore Hypha (N) Figure 21-7 The Life Cycle of an Ascomycete Section 21-2 p. 533 Diploid Haploid FERTILIZATION HYPHAE FUSE MEIOSIS Sexual Reproduction Asexual Reproduction
Yeast is an Ascomycete Fungus • Yeasts • Unicellular fungi • Ascomycetes—baking and brewing • Budding—process of asexual reproduction—cell division • Alcoholic fermentation to obtain energy • Byproducts—carbon dioxide and alcohol
Yeast is an Ascomycete Fungus Candida sp.
Some Ascomycetes Scarlet Cup Fungus Morel
Sac Fungi - Ascomycota CUP FUNGI (visible to the eye) YEASTS (microscopic)
Basidiomycota – The Club Fungi • The phylum Basidiomycota gets its name from a specialized reproductive structure (called a basidium) that resembles a club. • Includes: • Mushrooms • Shelf fungi • Puffballs • Earthstars • Jelly fungi • Plant rusts • Bird’s nest fungi
Fruiting body (N + N) Gills lined with basidia Gills Cap Stalk Button Base Basidia (N + N) Secondary mycelium (N + N) Primary mycelium (N) Zygote (2N) - Mating type (N) + Mating type (N) Basidiospores (N) Figure 21-8 The Life Cycle of a Basidiomycete Section 21-2 p. 534 FERTILIZATION HYPHAE FUSE Haploid Diploid MEIOSIS
Some Basidiomycetes Shelf Fungi Giant Puffball
The Club Fungi • Diversity of Club Fungi • Mushrooms • Shelf fungi • Puffballs • Earthstars • Jelly fungi • Rusts • Edible and Inedible Mushrooms • Almost identical • Some inedible can cause severe illness or death
Diversity of Club Fungi PUFFBALL EARTH STAR MUSHROOM SHELF FUNGI BIRD’S NEST FUNGI JELLY FUNGI
Deuteromycota – The Imperfect Fungi • Deuteromycota is an extremely varied phylum composed of those fungi that are not placed in other phyla. • The term imperfect implies that these fungi do not appear to have sexual reproduction. • Ex: Penicillium notatum – the source of antibiotic penicillin.
Deuteromycota (Imperfect Fungi) -Regarded as imperfect because they exhibit no sexual stage has been observed in their life cycle -Members are not closely related and are not necessarily similar in structure or appearance; do not share a common ancestry, polyphyletic = coming from many ancestors – hmm weird
Truffles are round, warty, fungi that are irregular in shape. They vary from the size of a walnut to that of a man's fist. Since the times of the Greeks and Romans these fungi have been used in Europe as delicacies, as aphrodisiacs, and as medicines. They are among the most expensive of the world's natural foods, often commanding as much as $250 to $450 per pound. Truffles are harvested in Europe with the aid of female pigs or truffle dogs, which are able to detect the strong smell of mature truffles underneath the surface of the ground. The female pig becomes excited when she sniffs a chemical that is similar to the male swine sex attractant. The use of dogs to find truffles is also and option.
21-3 Ecology of Fungi • All Fungi Are Heterotrophs • Saprobes - Organisms that obtain food from decaying organic matter • Parasites - which harm other orgnisms • Symbionts - live in close and mutually beneficial association with other species • Capture live animals • Pleurotus ostreatus • Lives on the sides of trees and trap worms to digest them
21-3 Ecology of Fungi • Fungi as Decomposers • Maintain equilibrium in nearly every ecosystem by recycling nutrients • Release digestive enzymes that break down organic material into simple molecules which diffuse into the fungus
21-3 Ecology of Fungi • Fungi as Parasites • Cause serious plant and animal diseases and a few cause diseases in humans • Plant Diseases • Smuts, mildews, rusts Corn smut Plant mildew Spruce rust
21-3 Ecology of Fungi • Parasitic fungi cause serious plant and animal diseases: • wheat rust • mildew on fruit
Other Basidiomycetes Rusts and Smuts Rust infecting wheat leaves Rust infecting a Leaf Whitrot Smut digesting old wood
21-3 Ecology of Fungi • Human Diseases • Athlete’s foot, ringworm • Candida albicans (yeast)—oral thrush • Bacteria and yeast in the human body keep each other in check
21-3 Ecology of Fungi • Other Animal Diseases • Cordyceps—grasshoppers in rain forests in Costa Rica
21-3 Ecology of Fungi • Symbiotic Relationships • Mutualistic (both benefit) • Lichens • Fungus and an alga or a cyanobacterium or both • Live mostly on bare rock and in places that most other organisms cannot live • Break down rock into soil • Autotroph makes food, fungus absorbs water and nutrients and serves as an anchor
Lichens: Symbiotic Partnerships Algal Layer Fungal Hyphae AttachmentStructure