Supergroup Opisthokonta – Fungi – Lab Exercises

Please choose one live specimen or prepared slide to image. Take a picture under the microscope and submit via Canvas. Make sure that your picture is appropriately centered, cropped, and focused. Add a scale bar.

Exercise 1: Examine moldy bread

Many fungi are commonly called molds. Mold is an informal term and does not correspond to a taxonomic group. Molds are generally zygomycetes or ascomycetes. Examine the demonstration of moldy bread.

How many kinds of mold do you see?

Examine the bread under the stereo microscope. Do NOT take the bread out of the bag. You should be able to see the mycelium (mass of hyphae) of one or more of the molds. You will also observe spherical structures. These are sporangia. Within them, spores form asexually, by mitosis. Draw a mycelium and sporangium.

Exercise 2.1: Examine wild molds collected on your own

Last week, you collected a wild mold from your home, work, or other location. Examine your mold under the stereo microscope. Sketch what you see. (If your mold did not grow, or the plate dried out, or you forgot your mold, use a classmate’s mold for this exercise).

Exercise 2.2: Make a wet mount of your mold

Place a drop of water on a slide. Using a toothpick, take a tiny sample from the margin of your mold growth. Cover it with a coverslip and examine under the compound microscope. Draw what you see.

Exercise 3: Examine endophyte growth on plates prepared last week

Examine your group’s plates from last week. Observe under a stereo microscope.

Do you observe fungal growth on your surface-sterilized leaf plate? If so, sketch it below.

Do you observe fungal growth on your negative control?

                  If so, does it look similar to the experimental plate?

If there is growth, make a wet mount using the procedure described in Exercise 1.1 and sketch what you see below.

Exercise 4: Examine a chytrid.

Allomyces is a filamentous chytrid. Its life cycle includes a multicellular diploid (sporophyte) generation and a multicellular (haploid) generation. Examine a prepared slide of the sporophyte generation. Draw what you see, labeling a hypha and a sporangium.

Exercise 5.1: Examine demonstration plate of Rhizopus stolonifera (zygomycete)

Rhizopus stolonifer is commonly known as black bread mold. It is a common mold that grows on food items. Observe and draw a part of the mycelium and a sporangium.

Exercise 5.2: Examine prepared slide of Rhizopus sporangia and zygotes (Rhizopus combination)

The spherical sporangia produce spores asexually (by mitosis). Draw and label a hypha and sporangium.

Examine zygospores on the same slide. The zygospores appear dark. They result from the fusion of two haploid hyphae. Draw and label a zygospore.

Exercise 5.3: Examine demonstration plate of Phycomyces zygospore formation

Examine the demonstration plate under the stereo microscope. Draw a zygospore.

Exercise 6.1: Examine demonstration plate of Aspergillus niger (ascomycete)

Aspergillus niger is an ascomycete that causes black mold on plants, including onions and fruit. It is also the source of commercially produced enzymes. These include glucoamylase, which is used to produce high-fructose corn syrup, and alpha-galactosidase, which is used in Beano and other anti-flatulence pills.

Examine Aspergillus niger under the stereo microscope and sketch what you see.

Exercise 6.2: Examine Penicillium (ascomycete)

Penicillium is an ascomycete. Some species produce penicillin, which is used as an antibiotic drug. Look at the demonstration plate of Penicillium under the stero microscope and draw what you see.

Penicillium produces spores asexually in structures called conidia. Examine the prepared slide of Penicillium. Identify and sketch the conidia.

Exercise 6.3: Examine prepared slide of Saccharomyces (ascomycete)

Saccharomyces cerevisiae is a yeast that belongs to Phylum Ascomycota. It is used for baking, brewing, and winemaking. Examine the slide under the 63x objective. Do you observe any budding cells?

Exercise 7.1: Examine prepared slide of Coprinus (basidiomycete)

Coprinus is a genus of basidiomycetes that produce mushrooms. Examine the prepared slide of the gills in cross section. Note the basidiospores projecting from the interior margin of the gills. Draw and label part of the gill, including a basidiospore.

Exercise 7.2: Examine specimens of mushrooms (basidiomycetes)

We have procured several mushrooms for you to examine. If time permits, dissect a gill and make a wet mount. Examine under the microscope and draw what you see.

Exercise 8.1: Examine prepared slide of a lichen

Examine the cross section through the thallus of a foliose lichen. Distinguish the upper cortical, medullary, and lower cortical layers of the thallus.  Are unicellular photobionts visible?  Which layer are they found in?  Make a drawing of the thallus, labeling its various features.

Exercise 8.2: Examine the available lichen specimens.  

Observe the differences between foliose, fruticose, and crustose lichens (if available).  Sketch one of each.

Preparation for animal labs: the protostomes

Exercise 9: Observe and desiccate tardigrades

Tardigrades belong to Clade Ecdysozoa. They are also known as water bears, and are known for their ability to survive extreme conditions, including heat, cold, radiation, dehydration, and the vacuum of space.

Obtain tardigrades from the live culture. Make a wet mount using a depression slide and observe under the compound microscope.

How many appendages do the tardigrades have?

Can you see the tardigrade’s claws? How many claws per appendage?

Place your tardigrades in a small petri plate. Draw off as much water as possible without removing the tardigrades. Label the plate with your group name or initials and the date. Place the plate in the hood. We will allow the culture to dry completely, and rehydrate them next week.

Exercise 10: Observe and cut planarians

Planarians are flatworms of Phylum Platyhelminthes. They are lophotrochozoans. Observe how the planarian(s) move. 

Planarians are known for their ability to regenerate. As a group, choose how to cut your planarians and record below. Draw a simple sketch with your plane(s) of section. You may cut anywhere and as many times as you wish. You may cut completely through the animals, or try to make a two-headed or two-tailed planarian.

Label the petri plate with your group name or initials and the date and place in the hood. Fill the petri plate more than halfway with dH2O so that the culture will not desiccate (they’re not tardigrades!). 

Do you predict that the planarians will completely regenerate by lab next week?