Biological Principles II
Fungal Diversity
Name ____________________________________
INTRODUCTION
Fungi are multicellular organisms which obtain their nutrients through absorption. Most break
down dead organic matter and release inorganic nutrients for plants.
e body of a fungus is referred to as a mycelium and is composed of strands called hyphae. Fungi
reproduce by forming spores which are spread through the wind. Often times spores are produce
by a fruiting body, a stalk-like structure formed during the sexual union between two individual
fungi of the same species. Fungi are classified based on the characteristics of this fruiting body.
PHYLUM CHYTRIDIOMYCOTA
Perhaps the oldest and simplest fungi are the chytrids. e majority of these microscopic fungi
are unicellular and can be found living in freshwater environments, moist environments, leaf
litter, and on insects and amphibians.
We will examine is the chytrid Allomyces arbusculus. It lives
in fresh water or moist soil and its mycelium is visible
with the naked eye. e base of the mycelium is attached
to a plant by rhizoids. During its life cycle, the trunk will
branch and the tips of branches differentiate into a double
sporangium. e bottom sporangium is often reddish and
small (male) while the top one is clear and larger (female).
Each will produce flagellated gametes that will eventually
fuse together, producing a diploid zygote. e zygote is biflagellated for a short period of time. A
system of rhizoids is sent out from the basal end while aerial hyphae are sent out from the
anterior end.
Procedure
1. Create a wet mount of Allomyces arbusculus. Look at it
first with the 4x objective to find a specimen, and
then study it through your 40x objective. Observe the
mycelium and find four types of sporangia described
in the life cycle. Draw examples in the spaces on the
next page.
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Mycelium
Gametosporangium
Gametes
Resistant Sporangium
Zoosporangium
Zoospores
PHYLUM ZYGOMYCOTA:
e zygomycetes, commonly called bread molds, are all multicellular, terrestrial, and live on dead
material. eir hyphae can be very branched and extend deep into the bread. Members of this
division produce spores from sporangia. Some sporangia resemble a fuzzy black globe at the end
of a long stalk. In contrast, the sporangia formed when two individuals join in sexual union
resemble a fuzz black globe joined to each individual by hyphae. is structure is called a
zygosporangium and gives the group its name.
Procedure
1. Examine the samples of Rhizopus. In the petri dish, note how the two strains have joined
together to form zygosporangia. Begin with the 4x objective to find a specimen, and then
study it through your 40x objective. Observe the mycelium and find an example of a
sporangium.
2. Next, obtain a prepared slide of Rhizopus zygosporangium. Look at it first with the 4x
objective to find a specimen, and then study it through your 40x objective. Observe the
mycelium and find an example of a zygosporangium. Draw an example in the space below.
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Mycelium
Sporangium
Zygosporangium
PHYLUM ASCOMYCOTA:
e ascomycetes are the largest group of fungi. ey include yeasts, molds, morels, and truffles. Its
name is derived from a microscopic sac-like structure called an ascus, which is what forms spores
sexually. Most of the members of this division absorb nutrients from decaying matter, but some
are parasitic and can cause disease.
Many ascomycetes are of economic importance. Yeast is used for baking and for brewing beer.
Others grow on grapes and are extremely important for wine production. Other types form a
symbiotic relationship with algae to form lichen.
Procedure
1. Examine the culture of the ascomycete Penicillium. One species, Penicillium notatum, is the
type from which penicillin is derived. Two other species, Penicillium roqueforti and P.
camemberti, are used in cheese production. Obtain a prepared slide of Penicillium. Look at it
first with the 4x objective to find a specimen, and then study it through your 40x objective.
Observe the mycelium and find an example of a conidiophore. Draw examples in the spaces
below.
Mycelium
Conidiophore
2. Examine the culture of Saccharomyces, or common yeast. Yeast is a fungus that is a unicellular
fungus usually. ey do form large colonies like the streak that you see growing on this tube.
Obtain a prepared slide of Saccharomyces. Look at it first with the 4x objective to find a
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specimen, and then study it through your 40x objective. Observe the oval shaped cells. You
may see cells reproducing by budding or splitting in two. Draw a few of the budding cells that
you see in the space below.
3. Examine the rehydrated morel Morcella. Morcella is a cup fungus which is often used in
gourmet cooking. Obtain a prepared slide of Peziza. is is also a small cup-shaped fungus.
e inside of the “cup” should be lined with asci. Look at it first with the 4x objective to find
a specimen, and then study it through your 40x objective. Observe these long sacs filled with
red-stained ascospores. You may see hyphae extending towards the base of the cup. Draw a
few of the asci and ascospores that you see in the space below.
Budding Yeast Cells
Peziza Ascus
PHYLUM BASIDIOMYCOTA:
e basidiomycetes, or club fungi, are the most familiar types of fungi. ese produce spores with
a large fruiting body called a basidiocarp or mushroom. e mushroom has a stalk with a cap. On
the underside of the cap are gills where the spores are made. Basidiomycetes include all types of
puffballs, bracket fungi, and the familiar mushroom. Some species are edible, while others are
poisonous. Some, such as the rusts and smuts, can cause disease in grain crops, which can have
serious economic effects.
Procedure
1. Obtain a portabella cap and identify the following structures:
Stalk: e upright portion which supports the cap.
Cap: e umbrella shaped portion of the mushroom.
Gills: On the underside of the cap, radiating folds of tissue on which spores are formed
2. Sketch a typical mushroom in the space below and label the stalk, cap, and gills.
3. Examine the slide of Coprinus using the compound microscope. Note the gills, basidia, and
basidiospores. In the space below, draw a section of the gills, indicating a basidium, and
basidiospores.
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Mushroom
Section of Coprinus gill
LICHEN:
ese composite organisms consist of a fungus
growing symbiotically with a photosynthetic
green algae. e fungus contributes to this
mutualistic association by absorbing minerals
and moisture from the environment. e algae
are nestled among the fungal hyphae, where they
benefit from the absorptive processes, and, in
turn, produce carbohydrates and other organic
molecules, which are absorbed by the fungus.
Lichen are found from the arctic to the tropics,
growing on rocks, trees, and soils. About 25,000
kinds of lichens have been described, ranging in
color from black to white to delicate shades of green, yellow, brown, and red.
Procedure
1. Examine the lichen available in the lab. ere are three general forms: (1) crustose lichen
which grow like a crust on surfaces; (2) foliose lichen which are branched and leafy in
appearance; and (3) fruticose lichen which are shrub-like with branching and intertwining
fibrous parts.
a. Which type or types of lichen is growing on the rock?
b. Which type or types of lichen is growing on the tree bark?
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