FUNGI
Jan 03, 2016
Mycology -
the study of fungifungi - singularfungus - plural
1) fungi are eukaryotic•they have a nuclei & mitochondria
2) they are heterotrophs
•they depend on other organisms for food3) they are multicellular
4) they cannot move on their own
4 Main Characteristics of Fungi
1) fungi lack chlorophyll
2) fungi are not photosynthetic•cannot produce their own food
3) they never reproduce by seeds4) most fungi have cell walls made of “chitin”… Except molds
4 Reasons Fungi Are Different From Plants
cellulose•Plant cell walls are made of what?
•molds have cell walls made of cellulose…like plants
•most are saprophytes•some are parasites
Saprophyte-feeds on dead/decaying organisms
• 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…
Hyphae - network of thin thread-like structures that form the “body” of a fungus
• 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!)
• Hyphae contain cytoplasm & 1 or more nuclei
hypha - singularhyphae - plural
Parts of a Fungus
Mycelium - a mass of hyphaemycelia - 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
Parts of a Fungus
Mushrooms are for sexual reproduction (~flowers)
Mycelium = body of the fungus
Hyphae = the “bricks” from which the mushroom is built
single hypha
Mass of hyphae (mycelium)
Germ tube (Growing Spore)
(initial hypha)
Fungi usually reproduce via
“spores”
FUNGI• FRUITING BODY
– The visible part– Contains spore-producing structures– Larger ones we call “mushrooms” or “toadstools”
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)
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
nuclear fusion meiosis
zygospore (2n)
spores (n) Zygospore Spore sac
mycelium develops from germinated spore
rhizoids
stolon
ASEXUAL REPRODUCTION
(mitosis)
contact between hyphae of two mating strains
germinating zygospore
Diploid Stage
Haploid Stage
young zygospore
gametangia fusing
50 µm
spores (n)
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
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
ANNULUS
STIPE
Basidiomycetes (club fungi): Greville's bolete (top left), turkey tail (bottom
left), stinkhorn (right)
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
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.
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.
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)
FUNGI
• ECONOMIC ROLES– Used directly as food, or to make food
• Yeasts are useful in the making of bread and fermented drinks.