FUNGi POWER POINT

FUNGI http://blog.stayfreemagazine.org/images/fries25.jpg CLICK SOME FRIES TO FIND OUT MORE!

C H A R A C T E R I S T I C S S T R U C T U R E bigger than a blue whale? really??? REPRODUCTION & EVOLUTION NOT FOR THE… squeamish!!! TOUR FUNGI HALL TO LEARN MORE! (don’t be afraid to click  ) ECOLOGY

CHARACTERISTICS OF FUNGI
eukaryotic
heterotrophic – secrete enzymes into food and absorb digested materials through cell walls
most are saprophytic – absorb organic materials from dead organisms, “nature’s recycler”
many are microscopic
BACK TO FUNGI HALL

STRUCTURE OF FUNGI
made up of hyphae (filaments), collectively called mycelium
mycelium 
cell walls contain chitin (also found in insect and crustacean exoskeletons)
plant cell walls contain ???
eubacteria cell walls contain ???
CONTINUED

CELLULOSE!

PEPTIDOGLYCAN!

STRUCTURE OF FUNGI
cells can be coenocytic – have many nuclei or have separated by septa – “walls”
range in size from microscopic (yeast) to the largest organism in the world (Armillaria – 3.1 mi 2 )
some are dimorphic – can change form based on environmental conditions, can grow as mycelium in soil or as unicellular organisms in humans (Histoplasma)
BACK TO FUNGI HALL

REPRODUCTION IN FUNGI
reproduce both asexually (genetically identical offspring) and sexually
most fungi are haploid throughout their life cycle
sexual reproduction occurs when hyphae of different mating types
(+ and -) meet and fuse together
BACK TO FUNGI HALL

FUNGAL EVOLUTION
evolved at about the same time as early plants – 460 million years ago
BACK TO FUNGI HALL

THE FUNGAL PHYLA

Rhizopus stolonifer (black bread mold)
600 species
coenocytic
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Rhizopus mycelium (moldy strawberries)
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Spinellus fusiger - mushroom parasite
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Pandora neoaphidis - parasitic fungus that kills green peach aphids
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Zygomycota Life Cycle
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mature zygospore
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Rhinocerebral Zygomycosis – causes lesions of the palate, face and brain Conidiobolus coronatis - causes polyps in the nose or masses under the skin, found in tropical areas
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25,000 species
form a basidiocarp , a reproductive
structure also known as a mushroom!
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DEADLY MUSHROOMS Some Amanita species associated with oak trees contain alpha-amanitin which works by slowly attacking RNA polymerase, an enzyme in the liver. It ultimately affects the central nervous system and kidneys. Death often results if a liver transplant or other heroic measures are not performed.
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Chlorophyllum molubdites - most common cause of mushroom poisoning in the US
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Omphallotis olearius dine on rotting tree stumps, yum!!!
CONTINUED
BACK TO FUNGI CHARACTERISTICS

Sexual Reproduction in Basidiomycota
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basidium and basidiospores
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bracket fungus - hemlock varnish shelf fungus
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coral fungus
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30,000 species
believed to have evolved most recently
live in salt, freshwater and terrestrial habitats
phyla includes morels, powdery mildews, yeasts and cup fungi
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sac fungi
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Sexual Reproduction in Ascomycota
hyphae of 2 mating strains form gametangia
female - ascogonium male - antheridium
gametangia fuse and move into ascogonium, nuclei pair but do not fuse
cells divide mitotically, each heterokaryotic hyphae grows and intertwines to form an ascocarp (reproductive body)
asci form on the surface of the ascocarp, near the tips of some hyphae
each ascus has 2 nuclei that fuse
each diploid nucleus undergoes meiosis to produce 4 haploid nuclei
haploid nuclei divide once by mitosis so that each ascus ends up with 8 haploid ascospores
ascus ruptures to release ascospores that germinate
CONTINUED – yes, there is a diagram!

CONTINUED
Sexual Reproduction in Ascomycota

asci with 8 spores in each
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Xylaria polymorpha - aka Dead Man’s Fingers, often found at the base of beech trees
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Xylaria polymorpha cut in half (note the asci - the small black dots!)
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10,000 species
no sexual reproductive phase has been discovered
many are similar to ascomycetes
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Athlete’s foot - caused by Tricophytom ruburm
lives within and eats outer skin layers (parasite)
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Ringworm - can be caused by the same organism that causes Athlete’s Foot or other organisms, eats skin (parasite)
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Penicillium roqueforti …DE-licious
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Aspergillus can be a parasite (eye infection caused by Aspergillus )
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some organisms in this phyla can be used to make soy sauce (soy bean fermentation) BACK TO FUNGI HALL

ECOLOGICAL IMPORTANCE and IMPACT of FUNGI

may have helped early plants obtain nutrients through a symbiotic relationship
played an important role in plant evolution 460 million years ago
many fungi are plant parasites responsible for 15-20% of crop loss yearly
CONTINUED

play an essential role in maintaining equilibrium in every ecosystem (even the human body) by recycling nutrients ,
breaking down wastes and keeping other populations in check
replace essential nutrients that plants remove from the soil
BACK TO FUNGI HALL

wheat rust - produces spores in barberry plants that then migrate to wheat fields
CONTINUED

corn smut…not for popping  CONTINUED

SYMBIOSIS
lichens and mycorrhizea
fungus is usually an ascomycete (can be a basidiomycete)
photosynthetic organism is green algae or cyanobacteria
CONTINUED

what does each organism get from the relationship ?
what is the ecological importance of these organisms ?
lichens BACK TO ECOLOGY

fungi provide moist shelter for the algae, while the algae provide a constant food supply (through photosynthesis) to their fungal host
CONTINUED

lichens are often the first organisms to inhabit barren areas (succession), creating soil by breaking down rock and adding organic nutrients (from their decay) lichen growing on gneiss
CONTINUED

mycorhizzae are symbiotic relationships between the roots of most plants and fungi
the fungi fix nitrogen so that it can be used by plants, while they use the plants as a shelter and food source

FUNGi POWER POINT

by kim angerson on Aug 29, 2009

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