Fungi & Molds
Fungi Are eukaryotic
heterotrophs.
Frequently decomposers,
sometimes parasites.
Usual structure is a mass of
entangled filaments called
Hyphae
Hyphae can have cross walls
(Septum) separating
individual cells. Or have no
separations.
Overall mass is called
mycelium
Reproduction
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Fungi differ from many organisms in that they:
Reproduce sexually & asexually
Longest stage of life cycle is in the haploid (N) stage
NOT the diploid (2N) stage.
Asexual reproduction is accomplished through the
creation and spreading of asexual spores.
Sexual reproduction is accomplished through creation
and spreading of sexual spores by opposite mating
types ((+) & (-)).
There are 3 major divisions of fungi
Division Zygomycota:
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Example: Black Bread mold
Hyphae produce Sporangium which form spores
asexually which are released to form new mycelia.
Reproduce sexually also.
Hyphae of (+) and (-) mating types called
Gametangia fuse to form a diploid (2N) Zygospore
Zygospore undergoes meiosis to produce spores
which are then released
Life Cycle of the Bread Mold
Sexual reproduction
Hyphae called Stolons of
opposite mating types (+ & -)
will fuse to form a structure
called Gametangia.
Diploid (2N) Zygospore is
formed.
Zygospore produces
sporandia which undergoes
meiosis to release haploid (N)
spores.
Division Ascomycetes (Sac Fungi)
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Named because sexual
spores are produced in
small sacs called asci
(ascus).
Asexual spores are
produced on conidia by
special hyphae called
conidiophores.
Division Basidomycota:
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Include mushrooms, shelf fungi & puffballs
Name derives from formation of a transient diploid
(2N) stage of the life cycle called the Basidium.
Life cycle of basidiomycota
NOTE: NEVER eat a wild mushroom. Many are
extremely toxic and can cause serious injury or death
if eaten.
Ecological Significance:
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Are valuable
decomposers which
function to return
organic material back to
the ecosystem.
Fungi can form valuable
symbiotic relationships
Example are lichens
which is a symbiotic
relationship with algae.
Fungi Significance
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Have great economic value
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Yeast is a unicellular fungus used for baking and brewing.
Many mushrooms are edible
Diseases caused by fungi.
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Plants are most vulnerable to molds & fungi.
It is a serious threat to agriculture some common crop diseases caused
by molds & fungi are:
Potato blight
Wheat rust
Corn smut
Can cause disease in humans.
"Athlete's foot"
Ring worm
Thrush and other yeast infections