Kingdom Fungi
The Study of Fungi is called Mycology
What is probably the largest living organism on earth has been
discovered in the Malheur National Forest in eastern Oregon. A fungus
living three feet underground is estimated to cover 2,200 acres. After
testing samples from various locations, scientists say it is all one
organism.
Officially known as Armillaria ostoyae, or the honey mushroom, the
fungus is 3.5 miles across and takes up 1,665 football fields. The small
mushrooms visible above ground are only the tip of the iceberg.
Experts estimate that the giant mushroom is at least 2,400 years old, but
could be 7,200 years old.
Characteristics of Kingdom Fungi
In order to belong to the Kingdom Fungi, organisms must:
•
•
•
•
Be Multicellular
Have Eukaryotic cells
Be Heterotrophs
Must have cell walls
• Most fungi are sedentary..(they don’t move
around, they live their lives anchored somewhere)
Cell Walls
• The cell walls of Fungi are
made of Chitin (Chitin is a
sugar… the same substance
which makes up the
exoskeleton of insects)
• Some fungi have cross walls,
or septa, which divide the
filaments into
compartments having a
single nucleus.
septum
Some cells lack septa and are
multi-nucleated, or coenocytic
(have many nuclei)
• Digestion takes place outside the body
(extra-cellular)
• Fungi are Absorptive Feeders
…they simply ingest (absorb) digested
foods thru their cell walls
Facts
• Fungi live and grow in their food
• only seen when the fruiting bodies
emerge…. By then it’s too late
Facts
• Cell Walls are either partial or
absent………. The cytosol is
circulated through simple cyclosis.
Ecological Role
• The major role of Fungi is as
Decomposers (they are the great
recyclers)…. They are Saprophytes
Fairy Ring
Fairy Ring
The Primary
Structures of a Fungi
•
Spores
(haploid reproductive cell)
Hypha
(a single filament)
Mycelium
(a mass of hyphae)
Fruiting Body
(reproductive and dispersion)
Spores: Haploid Reproductive Cells
Spore with Developing Hypha
**(some fungi have haustoria, hyphae that can penetrate their host)
Spore
Hypha
The Hypha begins to branch as it
digests its way through the food.
A Mass of Hyphae form the Mycelium
The Mycelium growth in a Petri Dish
Fungi spend most of their time as haploid (n)
organisms. However, most form a temporary
diploid structure for reproduction. The three
following stages occur during sexual
reproduction…. plasmogamy, karyogamy and
meiosis.
Plasmogamy is the fusion of two haploid
cells from two separate fungi strains. The
fusion forms a dikaryon (a cell with the two
haploid nuclei). A hypha containing a
dikaryon is called a dikaryotic hypha.
Karyogamy is the fusing of the two haploid
nuclei of a dikaryon to form a single
diploid nucleus.
Meiosis of the diploid nucleus restores the
haploid number.
n
2n
n
Fungi Reproduction
• Fungi reproduce both sexually and asexually.
• Asexual reproduction includes:
1. fragmentation: the breaking up of hypha
2. budding: the pinching off of a small hypha outgrowth
3. asexual spores: there’s two kinds of asexual spores
a. Sporangiospores are produced by sporangia which are
located on top of a filament called a sporangiophore.
b. Conidia are formed at the tips of specialized hyphae
called conidiophores.
Asexual Spores
Sporangium:
Produces the
sporangiospores
Sporangiophore:
Holds up the
sporangium
Asexual Spores
The Conidiophores look like tubes… the conidia look like
small black dots inside the tubes.
Classification of Fungi
mostly classified by the shape of the “Fruiting Bodies”
The “Fruiting Bodies” are the reproductive structures.
• Phylum Zygomycota (bread mold)
• Phylum Basidiomycota (mushrooms, puff balls,
bracket fungi)
• Phylum Ascomycota (cup fungi)
• Phylum Deuteromycota (Imperfect fungi)
Phylum Zygomycota
A common Zygomycota is Bread Mold
Hyphae lack septa
Sexual reproduction is by conjugation
(fusing) hyphae from two different
strains, followed by plasmogamy,
karyogamy and meiosis and the
production of Zygospores.
Zygomycota
Sporangium:
Produces the spores
Sporangiophore:
Holds up the
sporangium
A nice bowl of mold
Want an orange ?
Zygomycota does !!
Phylum Basidiomycota
• Mushrooms
• Puffballs
• Shelf (Bracket) Fungi
• Have Septa and reproduce sexually
• Underground hyphae intertwine and grow upward to
produce a reproductive structure called a basidiocarp.
This basidiocarp is what we call a mushroom.
• Basidiospores are produced on the basidia,
reproductive structures, which are found on the edges
of the gills.
Agaricus (gills)
Amanita phalloides “Death Cap”
Boletes: tubes instead of gills
Chanterelles: vase-shaped
Morels
Puff Balls
Shelf Fungi
Phylum Ascomycota
• Cup Fungi
• Yeast
• Mildews
• The largest group of fungi
• Named for the reproductive sacs or Asci that
form near the tips of the hyphae. Ascospores
are formed here and released into the air when
the ascus ruptures. These spores germinate to
form new hyphae.
Cup Fungi
Phylum Deuteromycota
• Athlete’s Foot
• Ringworm
• Penicillium
– Called “imperfect because a sexual
reproductive stage has not been observed.
Penicillium: source of penicillin
Athlete’s Foot
Athlete’s Foot
Athlete’s Foot
Ringworm
Ringworm
Ringworm
Lichens
• symbiotic association
held in a
hyphae mesh
alga provides food,
fungus provides
physical environment
•air pollution detection
Many Fungi are involved in Mycorhizzae relationships…Over
90% of plants have fungi associated with their roots. The fungus
absorbs and concentrates phosphates for delivery to the plant roots.
In return, the fungus receive sugars synthesized by the plant.
The End