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Kingdom Fungi. What is the largest organism on Earth?. The blue whale! 75 to 85 ft long Heart = 200,000 lbs =. X 30. Man. It’s a fungus! Armillaria sp. Lives underground in the Malheur national forest in eastern Oregon 3.5 miles across (~18,500 ft) 200 X’s length of blue whale
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What is the largest organism on Earth? The blue whale! • 75 to 85 ft long • Heart = • 200,000 lbs = X 30 Man
It’s a fungus! • Armillaria sp. • Lives underground in the Malheur national forest in eastern Oregon • 3.5 miles across (~18,500 ft) • 200 X’s length of blue whale • Covers area of 1,600 football fields • 2,400 to 7,000 years old
Fungi: “Eukaryotic, spore-producing, achlorophyllous organism with absorptive nutrition that generally reproduces both sexually and asexually and whose usually filamentous, branched somatic structures, called hyphae, are typically surrounded by cell walls” –Alexopoulous, 1996 pg. 2
Today’s Lecture Outline • Importance of Mode of Nutrition as a Selective Force in Evolution • Essence of Fungi • Evolution within the Kingdom Fungi • Zygomycetes • Ascomycetes • Basidiomycetes
Today’s Lecture Outline I. Importance of Mode of Nutrition as a Selective Force in Evolution II. Essence of Fungi III. Evolution within the Kingdom Fungi IV. Zygomycetes V. Ascomycetes VI. Basidiomycetes
I. Nutrition How fungi obtain their food: “Absorptive heterotrophs” • secrete digestive enzymes into the external environment to break down a substrate into smaller molecules. • absorb these smaller molecules through their plasma membranes • Bacteria “feed” the same way
I. Nutrition Fungi exhibit symbiotic relationships: • “Saprophytes” • feed on dead organic matter (ex. old logs, dung) • “Parasites” • feed on healthy organism (ex. humans, insects, plants, animals) • “obligate parasites”- require a living host at all times
I. Nutrition Ecological Niches and Habitats: • Available substrates (food) are the selective forces in fungal diversity • Each type of fungi have specific digestive enzymes that determine what they can digest and where they are found. • Loaf of bread (starch)
Rhizopus on bread Spores (air dispersed)
I. Nutrition Ecological Niches and Habitats: • Available substrates (food) are the selective forces in fungal diversity • Each type of fungi have specific digestive enzymes that determine where they are found and what they live off of. • Loaf of bread (starch) • Wood (cellulose and lignin)
Shelf or wood-rotting fungi Ex. Basidiomycetes
I. Nutrition Ecological Niches and Habitats: • Available substrates (food) are the selective forces in fungal evolution • Each type of fungi have specific digestive enzymes that determine where they are found and what they live off of. • Loaf of bread (starch) • Wood (cellulose and lignin) • Mammals (keratin: protein component of skin, hair and nails)
Candida sp. Parasites Athlete’s Foot Trichophyton Thrush
I. Nutrition Ecological Niches and Habitats: • Available substrates (food) are the selective forces in fungal diversity • Each type of fungi have specific digestive enzymes that determine where they are found and what they live off of. • Loaf of bread (starch) • Wood (cellulose and lignin) • Mammals (keratin, protein component of skin, hair and nails) • Plant tissue (plant cells)
Strong pressure Plant Cells Blue Mold of Grape Botrytis sp. Wheat Rust Puccinia http://www.apsnet.org/education/LabExercises/Cytology/Top.html
I. Nutrition Ecological Niches and Habitats: • Available substrates (food) are the selective forces in fungal diversity • Each type of fungi have specific digestive enzymes that determine where they are found and what they live off of. • Loaf of bread (starch) • Wood (cellulose and lignin) • Mammals (keratin, protein component of skin, hair and nails) • Plants (plant cells) • Microscopic soil organisms (animal cells)
Microscopic soil organisms (animal cells) • Dactylaria candida Fungal ring Nematode
I. Nutrition Fungal life depends on many things: • Substrate (food) • Temperature • 10-40° C • pH • 4-7
I. Nutrition • Symbiotaphrina sp. and Candida sp. live in guts of beetles • Low pH • help detox the food for the beetle and get to eat as well. • Mutalistic relationship Cells
I. Nutrition Fungal life depends on many things: • Substrate (food) • Temperature • 10-40 C • pH • 4-7 • Oxygen • most are aerobic • Few are anaerobic (yeast used in baking and fermentation) • Light • Needed to trigger the production of some sexual & asexual structures • Molds in basement are fine in the dark!
Today’s Lecture Outline • Importance of Mode of Nutrition as a Selective Force in Evolution • Essence of Fungi • Evolution within the Kingdom Fungi • Zygomycetes • Ascomycetes • Basidiomycetes
II. Essence of Fungi Fungi are made up of “hypha (pl. hyphae)”: • It is the smallest unit of a fungus • However, some fungi exist as single celled yeasts
Fungal Hypha Tip • Hyphal Wall: • Made of Chitin • -Keeps shape of hyphae • -Also found in outer shell of insects • Septations: • -crosswall • -porous • (allow for movement of cellular materials from one section to the next) Hyphal Wall Septation
II. Essence of Fungi • Characteristics of hyphae: • Long, filamentous • Branched in some cases • Grow apically (at the tips) • New hyphaal areas arise when septal pores or “crosswalls” form after elongation • Evolutionary advanced fungi exist in the “dikaryotic state” (N + N) • 2N= diploid and N= haploid • N + N= two haploid nuclei • Some hyphae exist this way for long periods of time • Eventually the two nuclei will fuse and the fungus will become dipolid (2N) • Unique to fungi
II. Essence of Fungi Evolution of Fungi: • Hyhpae have very large surface areas • Important for obtaining food • greater the surface area = greater contact with substrate to digest and absorb Substrate or Bacterium Which has more surface area? • Hyphal shape has been selected for during evolution • by a fungus’ mode of nutrition
II. Essence of Fungi “Mycelium” (pl. mycelia): • a mass of hyphae that makes up a fungal body http://www.anselm.edu/homepage/jpitocch/genbios/31-01-FungalMycelia-L.jpg
II. Essence of Fungi Characteristics of reproductive structures: • Asexual spores (conidia) • Product of mitosis • The way a fungus increases in number • Sexual spores (names vary) • Products of meiosis • The way a fungus obtains genetic diversity
II. Essence of Fungi Complex fruiting bodies: • Evolved to aid the fungus in dispersing spores • Shapes • Aid in water splash or wind dispersal • Water pressure • Trajectory • Smells • Insect attractants
Mass of spores • Pilobolus sp. • Grow on dung • Use “turgor pressure” (internal pressure created by osmosis) to disperse spores • Why would Pilobolus need to travel so far? http://herbarium.usu.edu/fungi/funfacts/Dispersal.htm
“Stink horns” • The fungus undergoes “self- digestion” • The spore are released as it disintegrates • Attracts insects and animals by its smell • They pick up spores and disperse them
Shape aids in dispersal (water splash) Spores (asexual)
Shape aids in dispersal (falling spores are picked up by wind and carried to new locations) http://www.nccpg.com/Default.Aspx?Page.Aspx?Page=119
Today’s Lecture Outline • Importance of Mode of Nutrition as a Selective Force in Evolution • Essence of Fungi • Evolution within the Kingdom Fungi • Zygomycetes • Ascomycetes • Basidiomycetes
III. Evolution within in Kingdom Fungi ~450 million years ago
Today’s Lecture Outline • Importance of Mode of Nutrition as a Selective Force in Evolution • Essence of Fungi • Evolution within the Kingdom Fungi • Zygomycetes • Ascomycetes • Basidiomycetes
IV. Zygomycetes Unique characteristic of Zygomycetes: • “zygospore” a thick-walled resting spore • Sexual spore • No flagella http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookDiversity_4.html
Zygospore (sexual) Sporangia -gives rise to spores (asexual) IV. Zygomycetes
IV. Zygomycetes Examples & Impact: • Parasitic: Entomophthora muscae
IV. Zygomycetes Examples & Impact: 2. Sabropic on soil, litter and dung -important in forest ecosystems 3. Secondary metabolites (by-products of fungal metabolism) are collected for industry use • amylases, organic acids and formic acid used in cortisone
Today’s Lecture Outline • Importance of Mode of Nutrition as a Selective Force in Evolution • Essence of Fungi • Evolution within the Kingdom Fungi • Zygomycetes • Ascomycetes • Basidiomycetes
V. Ascomycetes Unique characteristics of Ascomycetes: • “ascus” (pl. asci) fungal sac where ascospores are formed and held until dispersal. • 8 ascoscpores (sexual spores that are a product of meiosis) in an ascus • “ ascocarp” fungal structure that holds multiple asci
V. Ascomycetes Asci with 8 ascospores http://biodidac.bio.uottawa.ca/thumbnails/filedet.htm?File_name=ASCO005B&File_type=GIF
V. Ascomycetes Types of Ascocarps: Ascus Ascus Ascus Cleistothecium -enclosed Perithecium -flask-shaped Apothecium -cup-shaped Some ascomycetes do not produce an ascocarp; They have “naked” asci • http://fai.unne.edu.ar/biologia/fungi/fungiclas.htm
V. Ascomycetes Examples and Impact: • Plant pathogens • Cryphonectria parasitica • Pathogen on American chestnut trees • Accidentally introduced to the New York Botanical Garden from an Asian tree. • Killed a majority of American chestnuts in the U.S. • Other chestnuts are still around but not as large and majestic as the American version
V. Ascomycetes Examples and Impact: 1. Plant pathogens • Claviceps purpurea • Causes “Ergot of rye”
Harmful if consumed: • Holy fire/ St. Anthony’s fire • 17th century France and Germany, rye bread was a popular food • Fungus would get into the flour and people would ingest it • LSD-like symptoms • Burning skin • Hallucinations • Loss of appendages • Thought it was an act of God (not bread) • Infection in cattle feed • loss of tails • aborted fetuses • Salem witches in 1689 • Why women were crazy
V. Ascomycetes Examples and Impact: • Fermentation (brewing beer and alcohol) • Anaerobic yeast (Saccharomyces pastorianus) • “zymase” a mixture of enzymes that convert glucose to ethyl alcohol and carbon dioxide