1. Fungi General Characteristics Classification Symbiotic Relationships in Lichens

2. General Characteristics  Eukaryotic  Nonphotosynthetic  Most are multicellular heterotrophs  Most are microscopic molds or yeasts  Have filaments called hyphae Cell walls contain chitin (also found in insects); distinguishes them from plants (cell walls of cellulose) Cell walls contain chitin (also found in insects); distinguishes them from plants (cell walls of cellulose)  Microscopic to 861,000 ft 2  Study of fungi = mycology  Feeding: secrete enzymes then absorb digested nutrients through cell wall  Store energy as glycogen  Most are saprophytic (recyclers!)

3. Most fungi are…  Molds Tangled masses of filaments of cells Tangled masses of filaments of cells Ex. Fungus that grows on bread and oranges Ex. Fungus that grows on bread and oranges  Yeasts Unicellular organisms Colonies resemble those of bacteria Best known as microorganisms that make bread rise

4. Structure of Fungi Mycelia Rhizoids

5. Structure (cont.)  Hyphae form mat called mycelium (see next slide)  Divided hyphae called septate hyphae  Non-septate hyphae are called coenocytic hyphae  Hyphae grow by cell division at the tip, increasing mycelium  Some can change form due to changes in environment (see Histoplasma capsulatum, page 544 – changes from mycelium to unicellular yeast due to temperature/nutrient availability in human)

6. Mat of hyphae = mycelium

7. Histoplasma 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

8. Reproduction  Asexual  Fragmentation Septate hypha dries and shatters; releases individual cells that act as spores Septate hypha dries and shatters; releases individual cells that act as spores  Budding “pinches off” to produce a small offspring cell “pinches off” to produce a small offspring cell  Sporangiophores Hyphae look like stalks Hyphae look like stalks Top has enclosing sac filled with sporangiospores Top has enclosing sac filled with sporangiospores  Conidiophores No enclosing sac around conidia No enclosing sac around conidia -most reproduce both sexually and asexually

9. Reproduction (cont.) SSSSexual NNNNeither male nor female, but “+” or “-” WWWWhen “+” and “-” of same species encounter, hyphae fuse then give rise to structure that produces and scatters genetically diverse spores MMMMost are haploid throughout most of their life cycle

10. Phylum 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

11. Phylum 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

12. 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 Ascomycota

13. Fungi imperfecti  Fungi that do not have a sexual stage  “deuteromycota”  Most of the species of fungi that were formerly classified in this group, are now classified in the phylum Ascomycota

14. Mycorrhizae and Lichens Compare and contrast (using page 549) - Make sure to identify the 3 types of lichens - Make sure to identify the 3 types of lichens - Make sure to know which phyla form mycorrhizae and to which lichens belong - Make sure to know which phyla form mycorrhizae and to which lichens belong