Transcript fungi - Mr. Wells` wikispace

FUNGI
Mycology - the study of fungi
fungi - singular
fungus - plural
4 Main Characteristics of Fungi
1) fungi are eukaryotic
•they have a nuclei & mitochondria
2) they are heterotrophs
•they depend on other organisms for food
3) they are multicellular
4) they cannot move on their own
4 Reasons Fungi Are Different From Plants
1) fungi lack chlorophyll
2) fungi are not photosynthetic
•cannot produce their own food
•most are saprophytes
•some are parasites
3) they never reproduce by seeds
Saprophytefeeds on
dead/decaying
organisms
4) most fungi have cell walls made
of “chitin”… Except molds
•Plant cell walls are made of what?
cellulose
•molds have cell walls made of cellulose…like plants
• Smallest = Yeast cells
• Largest = 3.5mile wide HUMUNGOUS
FUNGUS!!!!!
– The famous “honey mushroom” (Armillaria
ostoyae) covering some 2,200 acres in Oregon’s
Malheur National Forest
• If it’s so big, why
can’t we see it?
• Almost all of it is
underground…
Fungi Are Decomposers…
Parts of a Fungus
Hyphae - network of thin thread-like structures
that form the “body” of a fungus
hypha - singular
hyphae - plural
•
Hyphae contain cytoplasm & 1 or more nuclei
• Hyphae branch out until they cover & digest their food
• Hyphae may either be “sepate” (with cell walls) or
“aseptate” (no cell walls, with many nuclei!)
Septate and
Non-septate Hyphae
Parts of a Fungus
Mycelium - a mass of hyphae
mycelia - plural
•The mycelium is usually hidden in the soil, in
wood, or another food source
•A mycelium may fill
a single ant, or cover
many acres
Mushrooms are for sexual reproduction
(~flowers)
Mycelium = body of the fungus
Hyphae = the “bricks” from which the mushroom is built
Fungi usually
reproduce via
“spores”
Germ tube
(Growing Spore)
(initial hypha)
single hypha
Mass of hyphae
(mycelium)
FUNGI
• FRUITING BODY
– The visible part
– Contains spore-producing structures
– Larger ones we call “mushrooms” or “toadstools”
Fungal Mycelia
Examples of Fungal Mycelia
FUNGI
• FEEDING TYPES
(NUTRITION)
– Saprophytic – feed on
dead matter
– Parasitic – feed on
living organisms
FUNGI
• HABITATS
– Need organic material, moisture
– Live almost everywhere, from polar icecaps to
deserts to oceans
– Reach new areas through spores carried by
wind
– Spores are necessary to find new food
sources
FUNGI
• FOUR GROUPS OF FUNGI -- 81,500
species of fungi divided by structure and
reproduction
– ZYGOMYCETES – bread molds
– ASCOMYCETES – sac fungi (morels,
truffles, and yeasts
– BASIDIOMYCETES – mushrooms, puff
balls
– DEUTEROMYCETES – imperfect fungi
(penicillium)
Phylogeny of Fungi
FUNGI
• Common molds – Zygomycetes
– Frequently found in soil or on dead animals or plants
– Reproduce asexually AND sexually
• Sexually if an opposite mating type makes contact…
– Hyphae lack septa
– Specialized hyphae
• Rhizoids that absorb nutrients and hold molds to their food
source
• Stolons that connect groups of rhizoids together
• Sporangia produces spores during reproduction
FUNGI
• ZYGOMYCOTA gets its name from the tough
spores produced during sexual reproduction
Asexual Reproduction in
Rhizopus stolonifer
zygospore (2n)
nuclear fusion
Diploid Stage
Haploid Stage
meiosis
germinating
zygospore
50 µm
spores
(n)
young zygospore
spores
(n)
gametangia
fusing
Zygospore
Spore sac
mycelium
develops from
germinated
spore
stolon
ASEXUAL rhizoids
REPRODUCTION
(mitosis)
contact between hyphae of
two mating strains
FUNGI
• Sac fungi – Ascomycetes
• Powdery mildews, yeasts, fungi in lichens, and
morels
• Characteristic that links these are production of
saclike structures called asci during sexual
reproduction
• Asexuall reproduction is rare
Reproduction in
Ascomycetes
Ascomycetes: Scarlet Cup,
Truffles and Morel
Carbon Balls Fungus
FUNGI
• Club Fungi – Basidiomycetes
• “Mushrooms” are club fungi
• Reproduce sexually (asexual reproduction is rare)
• Three visible structures of mushrooms
– Stipe
– Cap
– Gills made from tightly packed mycelia
• Fruiting bodies are called basidia
Structure of a Mushroom
Remember: most of a mushroom is the underground mycelium…
Structure of a Mushroom
ANNULUS
STIPE
Gills
Basidiomycetes (club fungi):
Greville's bolete (top left), turkey
tail (bottom left), stinkhorn (right)
Shaggy Mane
Witch’s Butter
Stinkhorn
Amanita
A Fairy Ring…
• Why is it a circle?
• Soil nutrients in the center have been depleted!
FUNGI
• Imperfect fungi – Deuteromycetes
• Reproduce asexually and NOT sexually
• Examples are athlete’s foot & ringworm
• Example that is helpful is Penicillium because it
make the antibiotic
• Spores called conidia come from hyphae called
conidiophores
IMPERFECT FUNGI
IMPERFECT FUNGI
Aspergillus
A Moldy Orange &
Penicillium
Budding Yeast
FUNGI
• ECOLOGICAL ROLES
– Decompose dead organisms; clear out dead
plants and animals
– Recycle nutrients
FUNGI
• ECOLOGICAL ROLES
–
Symbiotic Relationships
A) LICHEN --a symbiotic association between a
fungus and a photosynthetic partner, usually a
cyanobacterium or green alga.The fungal hyphae
provide protection and hold moisture while food
is provided by the photosynthetic partner.
Lichens
Anatomy of a Lichen
FUNGI
• ECOLOGICAL ROLES Cont.
B) Mycorrhizae: a symbiotic association between
a fungus and plant roots.
– 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 receives sugars synthesized by the plant
during photosynthesis.
Mycorrhizae
Test of Benefits of
Mycorrhizae
FUNGI
• ECOLOGICAL ROLES
– Some parasitic fungi are actually
human pathogens causing athlete's
foot and ringworm
– Some parasitic fungi are plant
pathogens that destroy crops
– Produce medicine (antibiotics)
Common Mold, Rhizopus,
Decomposing Strawberries
Fungal Diseases of Plants
FUNGI
• ECONOMIC ROLES
– Used directly as food, or to make food
• Yeasts are useful in the making of bread
and fermented drinks.
Fungal Production of
Antibiotic