Fungi
(…and fungirl – that joke never gets old…)
Characteristics
• Fungi are eukaryotic,
nonphotosynthetic
organisms that can be
unicellular or
multicellular in form.
• Fungi are divided into
four groups depending on
their characteristics
• Deuteromycota
• Zygomycota
• Ascomycota
• Basidiomycota
Obtaining Nutrients
• Fungi are among the
most important
decomposers of organic
matter.
• Fungi are saprobes,
they obtain nutrients by
secreting enzymes and
absorbing simple
organic molecules from
their environment.
Structure of Fungi
• Fungi are made up of short filaments called hyphae.
– Mats of hyphae are called mycelium.
– Some species have partitions called septa in their hyphae,
making individual cells.
• Fungal cell walls contain chitin rather than cellulose, which is
found in plant cell walls.
From The Fungi Name Trail by Liz Holden & Kath Hamper
Decomposers! Yay!
• They grow on organic
matter then secrete
enzymes outside of their
bodies that digest this
organic matter.
• Without saprobes and
heterotrophic bacteria,
communities would be
buried in their own
garbage.
• Next they absorb the
digested organic matter.
• Without nutrient
recycling life could not go
on.
• This decomposition
releases nutrients back
into the ecosystem.
Reproduction
• Most fungi reproduce both asexually and sexually.
• Spores are the reproductive cells
Asexual Reproduction
• Asexually, fungi produce
thousands of genetically
identical haploid spores,
usually on modified cells
of the hyphae.
• When these spores are
placed in favorable
environmental conditions,
they germinate and grow
new hyphae, each of
which can form a
mycelium and produce
thousands of new asexual
spores.
Sexual Reproduction
• Fungi occur in mating types
that are sometimes called
minus and plus.
• When two different mating
types of the same species
encounter one another, the
hyphae of one mating type
fuse with the hyphae of the
opposite mating type.
• These fused hyphae give
rise to a specialized
structure, which produces
and scatters genetically
diverse spores.
Types of Fungi
The four major groups of fungi
are:
1. Common molds
(Zygomycota)
2. Sac fungi (Ascomycota)
3. Club Fungi (Basidiomycota)
4. Imperfect fungi
(Deuteromycota)
The classification is made
according to their
structures and method of
reproduction.
Common Molds (Zygomycota)
• Phylum includes the familiar
molds that grow on meat,
cheese, fruit, and bread.
• They produce spores in
round spore cases called
sporangia. When the
sporangia split open
hundreds of spores are
released into the air. Each
spore will develop into a new
mold if there is enough
moisture, food, and warmth.
Mold on
an orange
Sac Fungi (Ascomycota)
• Examples of these fungi
are yeast, molds,
morels, and truffles
(yum).
Truffles
(about $1000 worth)
• The phylum
Ascomycota is named
for the ascus, a tough
sac that contains
spores.
Club Fungi (Basidiomycota)
• The phylum
Basidiomycota gets its
name from a specialized
reproductive structure
that resembles a club.
• The spore-bearing
structure is called
basidudium
Club Fungi Examples
Mushrooms
Shelf fungi
Coral fungi
Puffballs
Imperfect Fungi (Deuteromycota)
• Fungi that do not have a
sexual stage are classified in
a group called fungi
imperfecti, or
deuteromycota. They can’t
reproduce sexually.
• Deuteromycota examples
are Penicillium, ringworm,
athlete's foot fungus,
tomato blight fungus, and
cucumber scab fungus.
Some “Fun”gi Facts
World's Largest Organism
•Armillaria ostoyae – honey mushroom
•Ascomycete
•3.5 miles across and takes up 1,665
football fields.
•Located in Malheur National Forest in
Eastern Oregon
•2400-7200 years old
Fairy Rings
• Clusters of mushrooms are
often part of the same
mycelium.
• Some mycelium live for many
years. As time goes by the
soil nutrients at the center of
the mycelium become
depleted.
• New mushrooms sprout on
the edges producing a ring.
Salem Witch Trials
The Salem Witch Trials of 1692
saw the arrest of some 250
persons suspected of
witchcraft.
Ergot is a fungus of rye grass. It
grows best in wet conditions.
Ingestion of infected rye can
cause feelings of numbness, or
suffocation – symptoms which
in the past might have been
interpreted as bewitchment or
possession by the devil.
Could ergotism have contributed to
the Salem Witch Trials?
• Rye was grown in Essex county in the late seventeenth
century.
• 1692 was a high moisture year, necessary for the
growth of ergot.
• 24 of the 30 victims experienced fits and hallucinations
along with the sensation of being pricked or bitten
• Others reported feeling a burning sensation in their
fingers, lameness or temporary blindness.
• All of these could be symptoms of ergotism.