What is a Fungus? · Kingdom Fungi • eukaryotic heterotrophs • Most are multicellular • Have...

What is a Fungus?

Kingdom Fungi

• eukaryotic heterotrophs

• Most are multicellular

• Have cell walls made of chitin

• Some are saprophytes (decomposers), others

parasites (harm other organisms) while others

still are symbiants (live on but do nor harm other

organisms).

• All use extracellular digestion. They produce

powerful digestive enzymes that they secrete

into their food, then absorb the nutrients into

their cells.

• All Reproduce through some form of

Sporulation (although some Fungi species can

also reproduce by budding and fragmentation)

• the body a typical fungus is made up of tangled

filaments called a mycelium. Each individual

filament is called a hyphae.

• Yeast are an exception (they are unicellular)

Hyphae

mycelium

• Fungi can be parasitic:

– Cordyceps fungus

– Ringworm

– Athlete’s foot

– Tomato blight fungus

Athlete’s footRingworm

Tomato

blight

fungus

Mycorrhizae

• Fungi form symbiotic realtionships with the

roots of some plants

Fungus Asexual Reproduction

• Spores produced in sporangia (sporulation)

• fragmentation

Orange peel mold

More spores

Spores and budding

Fungus Sexual Reproduction

• Hyphae of two different mating types

(‘+’ and ‘-’) can fuse to form a gamete forming

structure (gametangium).

• Two fused gametes form a diploid zygote

nucleus which then divides by meiosis.

Phylum Oomycota: Protistlike

FungiThe Water Moulds and Mildews

• Aquatic

• Parasitic on land plants and fish.

• Cell walls contain cellulose not chitin.

• Spores swim using a flagellum (only fungus with motile spores)

Plasmopara viticola,

the downy mildew of

grapes. Almost wiped

out the European wine

industry.

Phylum Zygomycota

Common Molds

Most species are Terrestrial Organisms found primarily in Soil

• Black Bread Mold, Rhizopus stolonifera, not only grows on Bread, but anywhere there is water and nutrients.

• Common Molds life cycles includes both Asexual and Sexual Stages.

Phylum Ascomycota: Sac Fungi

• Largest phylum

• Include yeasts, morels and truffles

• Saprobes that feed off of dead organisms

• Sexual and asexual reproduction

morels

Budding

yeast

Type of

cup

fungus

Ergot

• LSD itself has origins in a naturally occurring fungal disease of rye

grains, ergot. Although this fungus is the source of drugs useful in

treating migraine and hemorrhaging, it is also the notorious cause of

hallucinations & temporary insanity in people who inadvertently eat

affected grain. In medieval times, French peasants suffering from

ergot poisoning were thought to be consumed by holy fire- St.

Anthony's Fire- because they frequently complained of excruciating

sensations of burning, not to mention infections of gangrene caused by

the interruption of circulation in the limbs. Though the control of

ergot, by burning infected crops, is relatively simple, incidents of ergot

poisoning have been reported as late as 1951.

Phylum BasidiomycotaClub Fungi

• “mushrooms”

• Saprobes that live off of dead organisms

• Mushrooms, toadstools, bracket fungi, puffballs

annulus

Stalk

(stipe)

Gills (arrow

shows spores)

Cap

(pileus)

mycelium

Poisonous Mushrooms of Nova Scotia

Squirrels & other rodents often

feed on Fly Agaric, but this does

not mean the fungus is edible by

humans. While ingestion of a

single mushroom may cause no

lasting effects, consumption of

ten or more can be FATAL.

Magic MushroomsMAGIC" MUSHROOMS

REALLY AREN'T MAGIC AT

ALL.

In fact, their alarming effects are the

harsh and sometimes not so short

result of disruptive chemical

interference with the body's nervous

system.

It is a criminal offence to gather,

possess or sell any of them.

Phylum Deuteromycota –

Imperfect Fungi

• Cannot be placed in any other phyla because

their sexual reproduction has never been

observed

• Resemble many of the other phyla

Athlete’s foot

Ringworm

Tomato

blight

fungus

Penicillium

Fungi in Nature

Ecological Significance

• The principal role of fungi is to decompose and

recycle living material

Symbiotic Relationships

• Lichens are symbiotic partnerships between a

fungus and a photosynthetic organism. There are

many other examples

Lichens • Made up of 2 organisms: sac fungi and algae

• Live on rocks, trees and soil

• Food for some animals

• Help in the formation of soil by breaking down rock.

Mr. Fungi meet Mr. Algae

Lichen Examples

Crustose lichens:

finely textured,

coloured patches

on rocks and trees.

Fruticose lichen:

Lacy and branched.

The copper brown

lichen blows around

the Arctic tundra.

Reindeer moss.

Foliose lichen:

Lobed or leaf-

like lichen. The

are attached to

rocks and trees

by hyphae.

Fungi and Human Life

• Bread and alcohol industries rely on yeast.

• Many mushrooms are a delicacy however some

are poisonous.

• Potato Blight & Wheat Rust are notable diseases

of plants.

• Human diseases include ringworm, athletes foot,

mouth, urinary tract and vaginal infections.

• Some fungi kill other organisms

Dutch Elm Disease:

• Spores are spread to healthy elms by a

burrowing beetle. The new spores germinate

under the bark.