Survey of the Kingdom Fungi

1. Survey of the Kingdom Fungi Molds, Sac Fungi, Mushrooms, and Lichens p. 271-282

2. Background of a fungus�p.271 Common and important �Basic filamentous strands of cells that secrete enzymes and feed on the organic material on which they are growing� Some cause disease Important as decomposers Responsible for recycling nutrient from dead organisms

3. Structure of a fungus�p.271 Hypha (plural hyphae) - slender filament of cytoplasm and nuclei enclosed by a cell wall Mycelium � a mass of hyphae that makes up an individual organism Extracellular digestion � result of the hyphae secreting enzymes to digest the organic substrate Absorptive heterotrophs � fungi are classified as these because they absorb the digested nutrients and obtain energy from the organic molecules once made by the other organism

4. Fungi food�p.271 Saprophytes � fungi that feed on dead organic matter Parasites � fungi that feed on living organisms The parasitic fungi have modified hyphae called haustoria, which are thin extensions of the hyphae that can penetrate into cells of living organisms to absorb nutrients.

5. Fungal cell�p.271 Septa � the crosswalls that separate the cytoplasm and nuclei into cells Coenocytic � refers to fungi that do not have septa separating their nuclei; multinucleate Chitin � the material that fungal cell walls are made of; the same material that comprises insect and crustacean exoskeletons (the shells that are shed by insects and crustaceans)

6. Reproduction in fungi�p.272 All fungi can do asexual or sexual reproduction. Asexual reproduction includes: Mitosis Budding Fragmentation Sexual reproduction involves the same process in all fungi, but with differences in structures both physically and reproductively.

7. Asexual reproduction of fungi: Mitosis�p.272 Involves the mitotic production of haploid vegetative cells called spores, which are well protected for dispersing in the environment. Spores are produced in structures such as sporangia and conidiophores. Some fungi orient their spores toward the light of the sun which is called phototaxis. A fungus that performs phototaxis is Pilobilus.

8. Asexual reproduction in fungi: Budding & Fragmentation�p.272 Budding is mitosis with an uneven distribution of cytoplasm to the new cells (yeasts). After budding, the cell with the lesser amount of cytoplasm detaches and matures into a new organism. Fragmentation is the breaking of an organism into more pieces, each of which can develop into a new individual.

9. Sexual reproduction in fungi�p.272 Occurs with the familiar events of: Vegetative growth Genetic recombination Meiosis Fertilization Fungi reproduce sexually when hyphae of two genetically different individuals of the same species encounter one another. Examine the generalized sexual life cycle of a fungus in Figure 26.2 on p.272.

10. Classification of fungi�p.272 Diversity in the fungi results from modifications of fungal hyphae into specialized structures that are unique to a certain phylum, genus, or species. 3 Major Phyla: Zygomycota (Bread Molds) Ascomycota (Sac Fungi) Basidiomycota (Club Fungi) A fourth group includes the Fungi Imperfecti, not a real phylogenetic group but one that includes species with no known sexual phase of reproduction. Members of this group, also called Deuteromycota, are most related to the members of the Ascomycota. They have lost genes during their evolutionary path, but because of DNA sequencing, we are able to see that they are very similar to the ascomycetes.

11. Phylum ZYGOMYCOTA�p.273-275 750 species Includes the common bread molds Derive their name from resting sexual spores called zygospores. Most zygomycetes are saprophytic (obtain food from dead organic matter) and their vegetative hyphae lack septa (they are aseptate). We will be looking at Rhizopus, a common bread mold.

12. Procedure 26.3: Rhizopus�p.273 Its hyphae are modified into rhizoids (holdfasts), stolons (connecting hyphae), and sporangiophores (asexual reproductive structures). Observe Figure 26.3 on p.274 for the physical appearance of Rhizopus. Observe the petri plate containing the culture of Rhizopus, a black bread mold. Observe prepared slides of Rhizopus and locate sporangia and zygospores.

13. Rhizopus life cycle�p.275 Observe the zygotic meiosis life cycle of Rhizopus on p.275. Notice that Rhizopus is a fungus that has + and � strains instead of male and female because they are isogamous. When the hyphae of two individuals touch, they form a swelling called a gametangia. The walls separating the gametangia break down and the nuclei fuse to form a zygote. This fusion is sometimes called conjugation. The zygote forms a zygospore which undergoes meiosis to form haploid germinating cells that break out of the zygospore to produce a sporangiophore that produces spores asexually.

14. Phylum ASCOMYCOTA�p.275 Includes 30,000 species Includes yeasts, some molds, morels, and truffles Name derived from a microscopic sac-shaped reproductive structure called an ascus. Ascomycetes reproduce asexually by forming spores called conidia in modified hyphae called conidiophores. The conidiophores partition nuclei in longitudinal chains of beadlike conidia. See Figure 26.8 on p.276. Conidia form on the surface of conidiophores instead of within. Aspergillus and Penicillium are examples we will look at today along with Peziza and Morchella.

15. Procedure 26.4: Aspergillus & Penicillium�p.276 Look at the culture plates of Aspergillus and Penicillium to locate conidia. Examine prepared slides of Aspergillus, Penicillium, and Peziza. Examine the preserved specimens of Peziza and Morchella. Answer questions on p.276.

16. Sexual reproduction in Ascomycota�p.277 Observe the sexual reproduction process of an ascomycete on p. 277. Monokaryotic refers to cells with one nucleus from one parent. Dikaryotic refers to cells with one nucleus from each parent and the nuclei are NOT FUSED yet. Answer question 4 on p.276 when we finish with the life cycle.

17. Other Ascomycetes�

18. Phylum BASIDIOMYCOTA�p.278 Includes 25,000 species Derives its name from the characteristic basidia it has and is often called the �club fungi�. Includes mushrooms, puffballs, shelf fungi, and important plant pathogens such as rusts and smuts. The mushroom, a common basidiomycete has a cap. The stalk, also called the pileus, supports the cap of the mushroom. A mushroom also has gills on the underside of the cap. The gills are lined with microscopic club-shaped cells called basidia, where sexual reproduction takes place.

19. Sexual reproduction in Basidiomycota�p.279 Observe Figure 26.14 on p.282 for the sexual life cycle of basidiomycetes. Follow along on p.279 as we go over the life cycle.

20. Procedure 26.7�p.278 Examine the prepared slides of the common mushroom Coprinus. Locate the basidiospores in the gill cross sections. Examine the preserved specimens of earthstars, mushrooms, puffballs, shelf (bracket) fungi, wheat rust, and corn smut (if available).

21. Examples of Basidiomycetes�

22. Lichens�p.279 Includes 25,000 species Common, brightly colored Usually found when an ascomycete lives symbiotically with a photosynthetic algae or cyanobacterium. Symbiosis refers to two organisms living in a close or sometimes dependent situation. The cyanobacterium Nostoc is found in 90% of lichen species.

23. Types of lichens�p.280-281 Lichens have 3 basic growth forms: Crustose Foliose Fruticose Crustose lichens are flat, and two-dimensional because the thallus grows close to the surface of a hard substrate such as a rock or bark. Foliose lichens have small sheet-like parts of their thallus folded away from the substrate they are adhered to. Fruticose lichens are three-dimensional and often grow away from the substrate with erect stalks Lichens are extremely susceptible to air pollution.

24. Some lichens� 

25. Lichens�p.280-281 Observe the preserved specimens of lichens. Identify the crustose, foliose, and fruticose types. Answer questions on p.280.