Kingdom Fungi - Herscher CUSD #2
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Transcript Kingdom Fungi - Herscher CUSD #2
Chapter 21
Mrs. LaLone
Kingdom Fungi
Mycologists study fungus!
Eukaryotic Organisms
Ex: Mushrooms, yeasts, molds
70,000+ species of Fungus
Mostly Terrestrial
Form spores at some stage of lifecycle
Have a Cell Wall
Composed of chitin – Nitrogen based polysaccharide
Resistant to breakdown by microorganisms
More resistant than cellulose
Nutrition
All are Heterotrophic
Most are saprophytic – feed on the remains of dead
organisms “decomposers”
Fungi secrete enzymes that initiate digestion outside the
hypha
Then absorb nutrients through the plasma membranes of
their cells
Some are parasitic – obtain nutrients from living
organisms; ex: plant pests
Climate
Grow best in moist environments
Produce spores in dry environments (resting stage)
Optimum pH is slilghtly acidic ~5.6
Range from 2-9
Wide temperature range
Body Plans
Unicellular: Yeasts
Multicellullar: filamentous molds
Mildews
Wheat rust
Corn smut
Mushrooms
Other fungi
Body Plans
Filamentous molds
Mold – consists of long, branched threads (filaments)
“hyphae”
Form a tangled mass/tissue “mycellium”
Some coenocytic – large, multinucleated mass
Some have septa – cross-walls with pores
Dikaryotic – contain 2 genetically distinct nuclei
Monokaryotic – contain only one nucleus
See Figure 21-1
Fig. 21-1, p. 407
Fungus
Have 2 distinct stages
Vegetative stage
Often goes unnoticed
Conspicuous Reproductive stage
The familiar form that people notice
Mushrooms, puffballs, bracket fungi
Reproduction
Sexual
Fruiting bodies (the familiar forms of fungi)
Ex: mushroom top
Plasmogamy
2 different hyphae come together and cytoplasm fuses
2 haploid nuclei fuse (karyogamy)
Results in diploid zygote nucleus
Meiosis occurs; producing haploid spores
Reproduction
Asexual
Fission
Budding
Spore Formation
Spores – nonmotile reproductive cells (wind & animals)
Produce on aerial hyphae
Allows air currents to disperse cells
Classification
Based on:
Characteristics of sexual spores
Characteristics of fruiting bodies
DNA & RNA sequences
Kingdom Fungi
5 Phyla
Phylum Chytridiomycota (Chytrids)
Phylum Zygomycota (Sporangium Fungi)
Phylum Glomeromycota (Mycorrhizae)
Phylum Ascomycota (Sac Fungi)
Phylum Basidiomycota (Club Fungi)
Phylum Chitridiomycota: Chytrids
Fungus that produce flagellated cells at some stage in
its life
Inhabit ponds, damp soil, & some in saltwater
Most are decomposers, some cause diseases in plants
and animals
Most unicellular or few cells that compose a
thallus a simple body that lacks roots, stems, or leaves
&
rhizoids anchor/root-like
Phylum Zygomycota
Black Bread Mold
Produce zygospores
Coenocytic hyphae
See figure 21-6
Zygomycetes
Fig. 21-6, p. 410
Phylum Glomeromycota
Mycorrhizae – “Fungus Roots” a symbiotic association
between fungus and plant root
The roots supply the fungus with sugars, aminoacids,
and other organic substances
The mycorrhizal fungus benefits the plant by extending
the reach of its roots
helps plant take in more water and minerals
Coenocytic (no septa) hyphae
Asexual – blastospore (multinucleate spores)
Glomeromycetes
Fig. 21-8, p. 412
Fig. 21-15a, p. 419
Fig. 21-15b, p. 419
Phylum Ascomycota
Sac Fungi
Their spores are produced in little sacs called asci
Hyphae usually have perforated septa
Cytoplasm and nuclei can move from one cell to another
Examples:
Powdery mildews (cause food to spoil)
Cup fungi
Edible morels and truffles
Yeasts
Diseases caused: Dutch elm disease, chestnut blight, ergot disease
on rye, mildew on fruits
Nonmotile
Sexual – ascospores (ascocarp=fruiting body)
Asexual – spores called conidia
Ascomycetes
Fig. 21-11a, p. 415
Phylum Basidomycota
“Club Fungi”
Mushrooms, bracket fungi, puffballs
Parasites – wheat rust & corn smut
Develop basidium & basidiospores
Masses of hyphae form buttons
Each button forms a mushroom = stalk + cap
Called a “basidiocarp”
Have gills on lower surface of cap
Fig. 21-12, p. 416
Fig. 21-13, p. 417
Phylum Basidomycota
Ecological Importance
Decompose
Release CO2 to Plants
Without fungus, minerals would be locked up in dead
organic matter; life would cease
Ecological Importance
Symbiotic relationships
Animals (ex: cattle) cannot digest cellulose and lignin by
themselves
Fungi in gut do this
Mycorrhizae and plant roots
Lichens – symbiotic relationships between fungus +
photosynthetic organism
Ex: green alga or a cyanobacterium + ascomycete fungus
Lichens
Fig. 21-16, p. 420
Lichens
3 Growth Forms
Crustose – flat and grow tightly attached to rock
Foliose – Flat, leaflike lobes, not as tightly attached
Fruticose – Grow erect, branched/shrublike
Lichens
Tolerate extremes of temperature and moisture
Do not grow in heavily polluted cities
Fungi are used to produce
Beer – yeasts ferment grain (barley)
Bread – yeast produce carbondioxide, and alcohol (evaporates
during baking)
Cheeses
Wine – yeast ferments fruit sugars to become ethyl alcholol
Penicillin – produced by a mold
200 species of edible mushrooms
70 poisonous
No easy way to distinguish
Some have similar chemicals as LSD – trancelike state and
colorful visions
Used for insecticides
Prevent spreading of malaria
Fungal Diseases
Superfical infections (only infect skin, hair, or nails)
Ringworm
Athlete’s foot
Jock itch
Candidiasis – yeast infection of mouth, throat, and vagina
Opportunistic fungi (occur when immune system is
compromised)
Histoplasmosis – infection of lungs caused by inhaling the
spores of a fungus abundant in bird droppings
Liver damage and cancer
Caused by mycotoxins commonly grow on peanuts, pecans,
corn, and other grains