Fungi General Characteristics Classification Symbiotic Relationships in Lichens.
-
Upload
brittney-gaines -
Category
Documents
-
view
238 -
download
0
Transcript of Fungi General Characteristics Classification Symbiotic Relationships in Lichens.
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