Ch. 21 Fungi
What did Mr. Fungus say to Ms.
Algae, when he proposed?
I lichen you!
Ch. 21 Outline
• 21-1: The Kingdom Fungi
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What are Fungi?
Structure and Function of Fungi
Reproduction in Fungi
How Fungi Spread
• 21-2: Classification of Fungi
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The Common Mold
The Sac fungi
The Club Fungi
The Imperfect Fungi
Ch. 21 Outline
• 21-3: Ecology of Fungi
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All Fungi are Heterotrophs
Fungi as Decomposers
Fungi as Parasites
Symbiotic Relationships
What are Fungi
• Fungi used to be classified with plants, but they
are actually very different than plants
• Fungi are eukaryotic heterotrophs that have
cell walls
– Cell walls made up of chitin (Complex carbohydrate
found in the exoskeleton of insects)
• Fungi do not ingest their food, they break it
down outside their bodies by secreting
enzymes. Then, they absorb it.
Structure and Function of Fungi
• All fungi are multicellular except for
yeasts
• Hyphae: thin filaments that make up
fungi.
– Some hyphae have cross walls in them (cell
walls with openings in them)
– Hyphae have many nuclei in them
Hyphae
Nuclei
Cell wall
Cytoplasm
Cross wall
Cytoplasm
Hyphae With Cross Walls
Nuclei
Cell wall
Hyphae Without Cross Walls
Structure and Function of Fungi
• The bodies of multicellular fungi are composed
of many hyphae tangles together into a thick
mass called a mycelium.
– This gives fungi a very large surface area to absorb
nutrients.
• Fruiting body: reproductive structure growing
from the mycelium
– Ex. The Part of the mushroom you see!
Fruiting Body and Mycelium
Fruiting body
Hyphae
Mycelium
Reproduction in Fungi
• Most fungi reproduce both asexually and
sexually
• Asexual  happens when a hypha breaks off
and grows on its own or by the production of
spores
– Spores: reproductive cell that is capable of growing
into new organisms by mitosis alone
– Sprorangia: the structure that produce spores
• Sexual  two different fungi mate
How Fungi Spread
• Fungal spores are found in almost every
environment.
– Ex. Mold grows everywhere it seems!
• Many spores are light and dry  easily
scattered by wind.
• Others are dispersed by animals.
Classification of Fungi
• There are over 100,000 species of fungi.
They are classified based on their
structure and method of reproduction.
• Four main groups:
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Zygomycota (common molds)
Ascomycota (sac fungi)
Basidiomycota (club fungi)
Deuteromycota (Imperfect fungi)
Concept Map
Section 21-2
Fungi
are divided into the phyla
Zygomycota
Ascomycota
Basidiomycota
Deuteromycota
includes
includes
includes
includes
Common
molds
Sac fungi
Club
fungi
Imperfect
fungi
The Common Molds
• Zygomycetes are the molds you see on cheese,
breads, and meat. They are characterized by
the zygospore in their life cycle.
• Zygospore: resting spore that contains zygotes
formed during the sexual phase of the life cycle.
• Rhizoid: root-like structure that anchors the
fungi
Black Bread Mold
Zygospore
(2N)
FERTILIZATION
Sporangium
Gametangia
MEIOSIS
Sporangium
Spores
(N)
Zygospore (2N)
Spores (N)
Stolons
+ Mating type (N)
- Mating type (N)
Sporangiophore
Asexual
Reproduction
Rhizoids
Sexual Reproduction
Diploid
Haploid
The Sac Fungi
• The phylum Ascomycota is named for the
ascus, a reproductive structure that
contains spores.
• Ascospores: the spores produced in an
ascus.
• Yeasts are an example of Sac Fungi.
– Uses of yeast: baking breads and brewing
alcohol
Ascomycota
Fruiting body (N + N)
Hyphae
(N + N)
Ascus
(N + N)
Diploid
Zygote (2N)
Haploid
Hyphae (N)
Gametangia
Asci
FERTILIZATION
HYPHAE FUSE
MEIOSIS
+ Mating type (N)
Sexual Reproduction
- Mating type (N)
Ascus
Conidia (N)
Hypha (N)
Conidiophore
Hypha (N)
Asexual Reproduction
8 Ascospores
(N)
Ascomycota
The Club Fungi
• The Phylum Basidiomycota gets its name
from a specialized reproductive structure
that resembles a club.
– Basidium: the spore-bearing structure in
Basidiomycota
• Example of club fungi: Mushrooms
Basidiomycota
Fruiting body (N + N)
Gills lined
with basidia
Cap
Button
Gills
Stalk
Base
Basidia
(N + N)
Secondary
mycelium (N + N)
FERTILIZATION
HYPHAE FUSE
Primary mycelium (N)
Zygote (2N)
- Mating type (N)
Haploid
+ Mating type (N)
MEIOSIS
Diploid
Basidiospores (N)
The Imperfect Fungi
• Deuteromycota is an extremely varied
phylum. It is composed of those fungi
that are not placed in the other phyla
because researches have never been able
to observe a sexual phase in their life
cycle.
• Example: Penicillin notatum
– (The Source of Penicillin)
All Fungi are Heterotrophs
• Many Fungi are saprobes: obtain their
food from decaying organic matter.
• Others are parasites or symbiotes (live in
beneficial relationships with another
organism).
Fungi as Decomposer
• Fungi play an important role in
ecosystems because they break down and
recycle nutrients.
• They secrete enzymes outside of their
hyphae and then absorb nutrients.
Fungi as parasites
• Parasitic fungi cause serious plant and
animal diseases
• Ex. Athlete’s Foot
Symbiotic Relationships
• Some fungi form symbiotic relationships in which both
partners benefit. These are often essential to the
ecosystem.
• Lichens: association between a fungi and green algae or
cyanobacteria.
– The algae/cyanobacteria provide the fungus with food (since
they are photosynthetic)
– The fungus provides a large surface area to collect water and
minerals
– Lichens can exist in extreme environments (drought, cold) and
are many times the first to inhabit in an area.
Lichens
Symbiotic Relationships
• Mycorrhizae: The association of plant
roots and fungi
– Plants provide the food (photosynthesis)
– Fungi increases the surface area for
absorption
– About 80% of plants are in this type of
relationship
– This association is essential for many plants
to survive and reproduce
Mycorrhizae