Kingdom Fungi Revised Fall 2017 ** You will require your text book Biological Science during this lab ** Learning Objectives Building on the learning objectives from your lab syllabus, you will be expected to: 1. Recognize and identify (domain, kingdom, phylum, and genus/common name) the organisms covered in this lab. 2. Identify and describe the characteristics and reproductive structures of each organism. 3. Continue learning to make accurate sketches of biological structures. Introduction Organisms in Kingdom Fungi are eukaryotes that are filamentous and heterotrophic via absorption. Most have a multicellular body called a mycelium, which is composed of thin filaments called hyphae. Hyphae can vary in diameter & shape depending on function (ex.: absorption vs. spore production). They can also cluster together to form larger structures such as fruiting bodies (ex: mushrooms). While most fungi grow as hyphae, a singlecelled growth form called yeast is relatively common. Fungi mostly have a haploid sexual life cycle (= only the zygote is diploid), with asexual reproduction also being very common. Spores are most commonly dispersed by air and are produced by mitosis (asexual) or by meiosis immediately after sexual reproduction. While the meiospores are not strictly the product of sexual reproduction, they are often referred to as sexually-produced. The biological definition of sexual reproduction is fusion of gametes NOT meiosis & reduction of chromosome number. Fusion of gametes requires two processes fusion of the cytoplasm (= plasmogamy) which is followed by fusion of the nuclei (= karyogamy). Fungi are unusual in that karyogamy often takes place long after plasmogamy. Use Chapter 29 of your text for additional information, including Figure 29.7 on page 596 for a brief review of this kingdom. You will observe organisms from three of the most common fungal phyla. Activity1: Zygomycota A. Rhizopus, or black bread mold, is the representative organism for this phylum. Refer to Figure 29.16b on page 606 to review the life cycle of this group. Note that both sexual and asexual reproduction are common. Observe the prepared slide of Rhizopus, noting the hyphae as well as the zygosporangia. Sketch and label the field of view at either 100 or 400X. What processes occur within the zygosporangium? 1
Sketch and label the asexually produced sporangia. X Are the hyphae haploid or diploid? Are these spores genetically identical? Activity 2: Basidiomycota (Club Fungi) This phylum includes most of the large fungi, including many of the edible mushrooms sold in stores. Refer to Figure 29.16c on page 607 to review the life cycle of this group. Note that asexual production of spores is relatively uncommon. A. Observe the button mushrooms and shelf fungi on display. Despite their size, they are composed only of compacted hyphae they have very little anatomical diversity. What type of reproduction occurs in these specimens? After this event, what type of division produces spores? Observe the gills the increased surface area in these allows for increased spore production. B. Observe the prepared slide of Coprinus, making sketches at both 40X and 400X. Note the spore producing cells called basidia (singular basidium) that are along the gills and the thick-walled basidiospores attached to them. X X What is the ploidy level of these spores? 2
Are they all genetically identical? Why or why not? How much anatomical diversity is visible on this slide? Activity 3: Ascomycota (Sac Fungi) The sac fungi are a diverse phylum that includes most of the economically important yeasts, many types of molds, and a few large edibles, like morels. Refer to Figure 29.16d on page 607 to review the life cycle of this group. Some ascomycetes, such as many molds, rarely or never reproduce sexually. A. Make a wet mount slide using a drop of the prepared Saccharomyces culture. Observe and sketch the cells under the microscope. Yeast reproduce asexually via a process called budding (see Figure 29.4 the bulges on the cells are the start of buds). Look carefully and see if you note any budding cells. Are yeasts single-celled or multicellular? X How does their size compare to bacteria? (See the bacterial types slide in your box for comparison). B. Observe the demonstration slide of Penicillium mold. This slide shows the formation of asexual spores called conidia (see Figure 29.8, page 597). Sketch this at 400X. C. Observe the morels or other macroscopic specimens on display. How do these compare to the macroscopic examples of the Basidiomycota? 3
D. Observe the prepared slide of Peziza. Sketch the ascospores in the asci (singular ascus) at 400X. Are the ascospores genetically identical? Why or why not? How do these cells compare to the basidia and basidiospores in the Coprinus slide? E. Fungi have many types of symbiotic relationships with other organisms. One common example are the lichens. Lichens are a symbiotic relationship between a fungus, usually Ascomycota, and a photosynthetic green alga or cyanobacterium (or both!). See Figure 29.13 on page 602 for a view of their anatomical structure. What do the fungal cells receive from their symbiotic partner? Observe the lichens on display, noting their diversity of form. These include thin layers only on surfaces (crustose), leafy or ruffled foliose and upright branching fruticose growth forms. 4
Post-Lab Activity Revised Fall 2017 Complete the following summary tables: Summary Table for slides Kingdom Phylum Genus Common name Sexual structures? Asexual structures? Other features? Rhizopus Coprinus Saccharomyces Penicillium Peziza Summary Table for demonstration specimens Kingdom Phylum Common name Reproductive structures Other features Button mushroom Shelf fungi Morel Cup fungus Lichen 5