FungiFungi

General CharacteristicsGeneral Characteristics

ClassificationClassification

Symbiotic Relationships in LichensSymbiotic Relationships in Lichens

General CharacteristicsGeneral Characteristics EukaryoticEukaryotic NonphotosyntheticNonphotosynthetic Most are multicellular Most are multicellular

heterotrophsheterotrophs Most are microscopic Most are microscopic

moldsmolds or or yeastsyeasts Have filaments called Have filaments called

hyphaehyphae Cell walls contain Cell walls contain chitinchitin

(also found in insects); (also found in insects); distinguishes them from distinguishes them from plants (cell walls of plants (cell walls of cellulose)cellulose)

Microscopic to 861,000 ftMicroscopic to 861,000 ft22

Study of fungi = mycologyStudy of fungi = mycology Feeding: secrete Feeding: secrete

enzymes then absorb enzymes then absorb digested nutrients digested nutrients through cell wallthrough cell wall

Store energy as glycogenStore energy as glycogen Most are saprophytic Most are saprophytic

(recyclers!)(recyclers!)

Most fungi are…Most fungi are…

MoldsMolds Tangled masses of Tangled masses of

filaments of cellsfilaments of cells Ex. Fungus that Ex. Fungus that

grows on bread and grows on bread and orangesoranges

YeastsYeasts Unicellular organismsUnicellular organisms Colonies resemble Colonies resemble

those of bacteriathose of bacteria Best known as Best known as

microorganisms that microorganisms that make bread risemake bread rise

Structure of Structure of FungiFungi

Mycelia

Rhizoids

Structure (cont.)Structure (cont.) Hyphae form mat called mycelium (see next Hyphae form mat called mycelium (see next

slide)slide) Divided hyphae called septate hyphaeDivided hyphae called septate hyphae Non-septate hyphae are called coenocytic Non-septate hyphae are called coenocytic

hyphaehyphae Hyphae grow by cell division at the tip, Hyphae grow by cell division at the tip,

increasing myceliumincreasing mycelium Some can change form due to changes in Some can change form due to changes in

environment (see environment (see Histoplasma capsulatum, Histoplasma capsulatum, page 544 – changes from mycelium to page 544 – changes from mycelium to unicellular yeast due to temperature/nutrient unicellular yeast due to temperature/nutrient availability in human)availability in human)

Mat of hyphae = myceliumMat of hyphae = mycelium

Histoplasma capsulatumHistoplasma capsulatum

• Able to change form in response to changes in environment

• Grows as mycelium on ground

• Invades human: increase in temperature & available nutrients cause

it to grow unicellularly

ReproductionReproduction AsexualAsexual FragmentationFragmentation

Septate hypha dries and Septate hypha dries and shatters; releases individual shatters; releases individual cells that act as sporescells that act as spores

BuddingBudding ““pinches off” to produce a pinches off” to produce a

small offspring cell small offspring cell SporangiophoresSporangiophores

Hyphae look like stalksHyphae look like stalks Top has enclosing sac filled Top has enclosing sac filled

with sporangiosporeswith sporangiospores

ConidiophoresConidiophores No enclosing sac around No enclosing sac around

conidiaconidia

-most reproduce both sexually and asexually

Reproduction (cont.)Reproduction (cont.) SexualSexual Neither male nor female, Neither male nor female,

but “+” or “-”but “+” or “-” When “+” and “-” of same When “+” and “-” of same

species encounter, species encounter, hyphae fuse then give hyphae fuse then give rise to structure that rise to structure that produces and scatters produces and scatters genetically diverse sporesgenetically diverse spores

Most are haploid Most are haploid throughout most of their throughout most of their life cyclelife cycle

Phylum ZygomycotaPhylum Zygomycota•Most are terrestrial organisms•Hyphae are coenocytic•Rhizopus stolonifer

•Hyphae anchor mold to surface•Hyphae that penetrate surface are called Rhizoids•Hyphae that grow across the surface of bread are called Stolons

•Reproduction•Congugation – 2 compatible mating types meet hyphae via gametangium•Gametantium from both hyphae contain nucleus from mating type•Gametangia fuse•Nuclei mix and fuse in pairs•Now Zygosporangium•Becomes dormant•Good conditions= sproangiophore grows, producing sporangium; ruptures and releases haploid spores

Phylum BasidiomycotaPhylum Basidiomycota•“Club Fungi”•Form basidia=clublike reproductive structures during sexual reproduction (see ↓)•Basidiocarp

•Spore-bearing•Mushrooms = stalk + cap

•Underside of cap = gills lined with dikaryotic (2 nuclei) basidia.•Nuclei fuse to form zygote (2n); zygote undergoes meiosis=4 haploid•=4 basidiospores, released into air; good conditions=they germinate and form mycelia that grow underground; if compatible mating types meet, their haploid hyphae fuse and form a basidiocarp which appears above ground

•Have saclike compartments where sexually produced spores form •“Sac Fungi”•Live parasitically •Habitats include: salt water, fresh water, and land•Reproduction:

•Hyphae of 2 types form male and female haploid gametangia•Male=antheridium; female=ascogonium

•Gametangia unite via a tube; nuclei from male move to female; dikaryotic hyphae grow out of the female and intertwine with the original (parent) monokaryotic hyphae, forming ascocarp; cells are monokaryotic•Ascocarp= sacs called asci Saccharomyces cerevisiae (traditional brewer’s and baker’s yeast)

•Make bread rise, ferments grapes, makes beer

Phylum Phylum AscomycotaAscomycota

Fungi imperfectiFungi imperfecti Fungi that do not have a sexual stageFungi that do not have a sexual stage ““deuteromycota”deuteromycota” Most of the species of fungi that were formerly Most of the species of fungi that were formerly

classified in this group, are now classified in the classified in this group, are now classified in the phylum Ascomycotaphylum Ascomycota

Mycorrhizae and LichensMycorrhizae and Lichens

Compare and contrast Compare and contrast (using page 549) (using page 549)

- Make sure to identify - Make sure to identify the 3 types of lichensthe 3 types of lichens

- Make sure to know - Make sure to know which phyla form which phyla form mycorrhizae and to mycorrhizae and to which lichens belongwhich lichens belong