Lecture 17 Key Concepts/Terms

How do fungi fit onto the eukaryotic tree?

have traits that make it seem plant like (unique haploid stages and non motile)
fungi are its own monophyletic clade and actually more closely related to animals than plants

Opisthokonts

organisms from an ancestor with posterior flagellum (includes fungi, animals, and some protists)

what is the sister taxa of opisthokonts

choanoflagellates

what are the "unifying" fungal traits

can have multiple different cell types OR be unicellular
are heterotrophs and absorb nutrients
have cell walls with chitin
some have dikaryon stages (no other organisms do)
many have both sexual and asexual reproduction
three styles of nutrient acquisition

fungal cell types

unicellular (free-living)
multicellular

hyphae

The branching, threadlike tubes that make up the bodies of multicellular fungi

septate fungi

have hyphae divided into cells by septa, with pores allowing cell-to-cell movement of organelles

coenocytic fungi

a fungus that lacks septa and hence whose body is made up of a continuous cytoplasmic mass that may contain hundreds or thousands of nuclei

what does coenocytic fungi mean for evolution?

indicates that cell separation isn't actually that important for fungi

septa

the cells that make up hyphae are divided by these cross sections

Mycelium

densely branched network of the hyphae of a fungus

what is the form of digestion of fungi?

external digestion (absorptive heterotrophy)

absorptive heterotrophs

digest food outside their body and then absorb it

how does the fungal body plan reflect nutrient intake in fungus?

digestive reproductive structures with clusters of hyphae (mycelium)

chitin

Polysaccharide found in arthropod exoskeletons and fungal cell walls.

fungal nuclei

normally haploid, with the exception of transient diploid stages formed during the sexual life cycles

dikaryons

cell containing two haploid nuclei n+n

dikaryon formation

formed from the fusion of two haploid mating strains

can fungi reproduce both sexually and asexually in one life cycle?

yes

Most fungi spend most of their lives in a ______ _______, reproducing ________

haploid state; asexually

spores are reproductive structures

by wind they turn into new individuals; produce new spores by mitosis

plasmogamy

the union of the cytoplasms of two parent mycelia

karyogamy

Fusion of two haploid nuclei to form a diploid nucleus. Occurs in many fungi, and in animals and plants during fertilization of gametes

importance of sexual stages for identification

critical for defining species andphylogenetic placement of fungi

microsporidia

microscopic unicellular parasitic fungi
obligate, intracellular parasites
replicated by host cell
lack mitochondria

mitosome

an organelle found within certain unicellular eukaryotes which lack mitochondria

chytrids

aquatic
unicellular life stages
flagella present
coenocytic

chytrids having flagella means what evolutionarily

the first fungi were probably aquatic

what group of fungi is believed to be killing off amphibians?

chyrids

zygomycetes

saprobic or parasitic
coenocytic
sexual reproduction is rare
karyogamy and plasmogamy in life cycle

gametangia

in primitive plants, a protective jacket of cells in which gametes and zygotes develop and which prevents drying out.

zygosporangium

In zygomycete fungi, a sturdy multinucleate structure in which karyogamy and meiosis occur.

zygospore

resting spore that contains zygotes formed during the sexual phase of a mold's life cycle

Glomeromycetes

mycorrhizal
coenocytic
do not form mycelia
this group probably made the invasion of plans on land possible

Mycorrhizae

Ecological relationship between the mycelium of a fungus and the roots of certain plants

ascomycetes

septate
dikaryon forming (short dikaryon stages)
bear spores in cups or sacs

types of ascomycetes

cup fungi
baker's yeast
common molds
cheese molds
plant pathogens

basidiomycota

basidiomata bear spores
septate
dikaryon forming (long dikaryon stages)

basidioma

the multicellular fruiting bodies of the Basidiomycetes often with a protective layer and lined with basidium

basidiocarps

Fruiting bodies where the basidiomycetes produce sexually

mutualist fungi

both organisms benefit; both organisms depend on each other; lichens; mycorrhizal

saprobe fungi

eat dead material; decomposers: clean our world

parasitic fungi

​​eat living material; i.e.: athlete's foot or ringworm

why are fungal diseases hard to treat?

because unlike bacteria, fungi are eukaryotes. Antibiotics only target prokaryotic cells.

Batrachochytrium dendrobatidis

chytrid been associated with declining harlequin frog populations

cup fungus

In the picture above is a fungus in which the spore-producing layer forms the lining of a shallow cup.

baker's yeast

ascomycete; Fungi used for bread and brewing

penicillin

common mold; ascomycete

truffles and morels

two types of ascomycetes that are commonly used in cooking

chestnut blight

a fungal infection that has nearly eliminated the American chestnut (ascomycete)

dutch elm disease

a fungal disease of elm trees that is spread by elm bark beetles (ascomycete)

cooking mushrooms

basidiomycete

athlete's foot

fungal infection of the foot (parasitic fungi)

ringworm

A highly contagious, fungal infection of the skin or scalp.

Which of the following statements is FALSE about fungi?

A) fungi can be either heterotrophic or autotrophic
B) septa are divisions between fungal cells with small pores that allow cytoplasm to flow between the cells
C) fungal cell walls contain chitin, which is the same material found in insect exoskeletons
D) the fungi and the choanoflagellates are part of a group called the Opisthokonts
E) all fungi are part of a single monophyletic group

A) fungi can be either heterotrophic or autotrophic

E) either A or C would be accurate

What trait can accurately label the tick mark with the question mark on the tree below?

A) septate
B) coenocytic
C) dikaryotic
D) reproductive parts are basidiomata
E) either A or C would be accurate