Transcript Slide 1

Kingdom:
Fungi
A Mushroom walks into a
bar and the bartender
says, “We don't serve your
kind here!” and the
mushroom says, “Why? I'm
a Fungi!”
Mycology
Myco- = fungus
-ology= study of
General Characteristics of Fungi:
 Eukaryotic
 Decomposers – the best recyclers around
 No chlorophyll – non photosynthetic
 Most multicellular (hyphae) – some unicellular
(yeast)
 Non-motile
 Cell walls made of chitin (kite-in) instead of
cellulose like that of a plant
 Are more related to animals than plant
kingdom
 Lack true roots, leaves and stems
 Absorptive heterotrophs -Digest food externally and
then absorb it
Lack of chlorophyll affects the
lifestyle of fungi…
Not dependant on light
Can occupy dark habitats
Can grow in any direction
Can invade the interior of
a substrate with
absorptive filaments
Structures
Bread mold
Hyphae
 Body of fungus made of tiny filaments or tubes
called hyphae .
 Contain cytoplasm and nuclei (more than 1)
 Each hyphae is one continuous cell
 Cell wall made of chitin
 A tangled mess of hyphae is called mycelium
 Rhizoids are root-like parts of fungi that anchor
them to the substrate (whatever they are
bonding to)
 Mycelium increase the surface area of the
fungi to absorb more nutrients.
Hypha
Mycelium
Figure 17.15B, C
CLASSIFICATION OF FUNGI:
Fungi can be classified into 5 groups
Figure 17.17A
Basidiomycetes
(club fungi)
Ascomycetes
(sac fungi)
Glomeromycetes
(arbuscular mycorrhizal fungi)
Zygomycetes
(zygote fungi)
Chytrids
 Fungi evolved from an aquatic, flagellated
ancestor
Chytrids
Glomeromycetes (Mycorrhizae fungi)
 Mycorrhizae are mutually beneficial
associations of plant roots and fungi
 Common and may have enabled plants to colonize
land
 Help create an extending network for the plant to
absorb more nutrients and water
A mycorrhizal fungus enveloping roots of a red pine tree
Ascomycetes (Sac fungi)
Truffles and yeast
Figure 17.17D
Basidiomycetes (club fungi)
 Puff ball mushroom
Figure 17.17E
Zygomycetes (zygote fungi)
Bread
Mold
Figure 17.17B, C
Fungus Reproduction:
Fungi produce spores in both asexual and sexual
life cycles
 Mushrooms let out spores from their pores that
are carried by the wind to meet other spores and
become a new fungi
 Yeast are unicellular and divide into new fungal
cells (mitosis)
In some fungi, fusion of haploid hypha produces a
heterokaryotic stage containing nuclei from two
parents (fusion of cytoplasm)
After the nuclei fuse, meiosis produces haploid spores
(can grow in fungi and are the asexual part of the life
cycle)
General Fungi Reproduction Cycles:
 Video clip of reproduction
Key
Heterokaryotic
stage
Haploid (n)
Heterokaryotic (n + n)
(unfused nuclei)
Diploid (2n)
Fusion of nuclei
Fusion of cytoplasm
Spore-producing
structures
Spores
(n)
Asexual
reproduction
Sexual
reproduction
Meiosis
Mycelium
Spore-producing
structures
Germination
Germination
Figure 17.16
Zygote
(2n)
Spores (n)
But fungal groups do differ in their life
cycles and reproductive structures
Key
Zygosporangium (n + n)
Haploid (n)
Heterokaryotic (n + n)
Diploid (2n)
Mycelia of
different
mating types
Cells fuse
2
3
Fusion of
nuclei
1
Meiosis
4
Young
zygosporangium
(heterokaryotic)
Sporangium
Figure 17.18A
Spores
(n)
Reproduction in Basidiomycetes:
Key
3
Haploid (n)
Diploid nuclei
Fusion of
nuclei
Heterokaryotic (n + n)
Meiosis
Diploid (2n)
4
Basidia
Spores
released
Spores (n)
Mushroom
5
2
Figure 17.18B
Growth of
heterokaryotic mycelium
1
Fusion of two hyphae
of different mating types
Germination of spores
and growth of mycelia
Basidiomycota (typical mushroom)
ASCOMYCOTA
FUNGI NUTRITION:
Fungi absorb food after digesting it outside
their bodies
Fungi are heterotrophic eukaryotes
That digest their food externally and absorb the
nutrients
Figure 17.15A
FUNGI NUTRITION:
 Fungi use digestive enzymes to break down
their food then absorb the liquid. (acquire
nutrients such as nitrogen)
Examples:
 trap nematodes (little worms who feed on
fungi) and paralyze them with special juices
then absorbs and digests the nitrogen out of
them.
3 Modes of Nutrition
in Fungi:
Saprophytes
Parasites
Mutualists (symbionts)
Saprophytes
Use non-living organic material
Important scavengers in ecosystems
Important in recycling carbon, nitrogen and
essential mineral nutrients
Parasites
Use organic material from living
organisms, harming them in some way
Range of hosts from single-celled diatoms
to fungi, to plants to animals to humans
Mutualists (symbionts)
 Fungi that have a mutually beneficial
relationship with other living organisms
 Mycorrhizae – beneficial relationship with fungi
with plant root
More than 90% of plants in nature have a mycorrhizal in
roots (example: Truffles- expensive delicacy!)
 Lichens – associations of fungi with algae or
cyanobacteria
Food source for animals, breaking down rocks into soil
Parasitic fungi harm plants and
animals
Parasitic fungi cause 80% of plant diseases
Can kill plants and affect crops
Figure 17.19A–C
Many fungi are harmful to humans
Can cause human diseases – allergies,
athletes foot, ringworm, yeast infection
Ringworm
A contagious fungal infection having
characteristic red ring that can appear on
an infected person’s skin
Can affect the scalp, the body (particularly
the groin), the feet, and the nails
Also called Tinea
Benefits of Fungi
Fungi also form mutualistic relationships with
animals
Some animals benefit from the digestive
abilities of lichens
Figure 17.21
Benefits of Fungi:
Lichens consist of fungi living mutually
with photosynthetic organisms
Fungal
hyphae
Algal
cell
Figure 17.20A, B
Colorized SEM 1,000 
 Lichens consist of algae or cyanobacteria
(protists or bacteria) within a fungal network
Lichens
Benefits of Fungi
Fungi have enormous ecological,
economic and practical uses
 Ecological= fungi are essential decomposers;
mycorrhizae increase plant growth
 Economic/Practical= antibiotics and food
(making bleu cheese/ truffles and truffle hunting)
Staphylococcus
aureus
Figure 17.22A, B
P enicillium
Zone of
inhibited
growth
More Useful Fungi:
Yeasts – baking and brewing beer
Antibiotics – penicillin & cephalosporin
Production of organic acids – citric acid in
Coke
Steroids and medicines – birth control pills
MAJOR PARTS OF A MUSHROOM:
 Cap (Pileus) - The top part of the mushroom.
 Cup (Volva) - A cup-shaped structure at the base of the mushroom. The
basal cup is the remnant of the button (the rounded, undeveloped
mushroom before the fruiting body appears). Not all mushrooms have a
cup.
 Gills (Lamellae) - A series of radially arranged (from the center) flat
surfaces located on the underside of the cap. Spores are made in the
gills.
 Mycelial threads - Root-like filaments that anchor the mushroom in the
soil.
 Ring (Annulus) - A skirt-like ring of tissue circling the stem of mature
mushrooms. Not all mushrooms have a ring.
 Scales - Rough patches of tissue on the surface of the cap
 Stem (Stape) - The main support of the mushroom; it is topped by the cap.
Not all mushrooms have a stem.
Structure of a Basidiomycetes