Station 1:
Bracket Fungi
Found in woodlands where they are a major wood rotting group. Once
a tree is infected, the fungus cannot be killed. They cause millions of
dollars in damage through lost wood production and lumber decay.
The only treatment may be to harvest younger trees before the rot
spreads too far. Bracket fungi are usually hard and leathery or woodlike and have no stems. Woody shelves are a micro (small) habitat.
They provide a unique place for animals to live. Spiders, mites, and
insects live in large shelves.
Some of the bracket or shelf fungi is used for herbal medicine.
1. What is the primary function of the
bracket fungi?
2. What kinds of organisms use these
fungi as a habitat?
3. What is the bracket fungi also
called? Why do you think it has this
name?
Station 2:
Do you like to eat yeast?
There are about 160 species of single-celled fungi called yeasts.
Some yeasts are used in baking, brewing and fermentation. Yeast
does its work primarily by interacting with sugar and starches in
either the dough of bread or liquid brewing and fermentation.
Brewers’ yeast has long been considered nutritionally useful to
humans because it contains a high quantity of B vitamins. Some
yeasts can cause decay in fruits and vegetables.
1. How do we use yeast in our everyday lives?
2. Look at the microscope slide. It shows you how budding in yeast
occurs. Draw what you see. What is budding an example of?
3. Use the hand lens to look at the yeast in the petri dish. How does it
make the bread rise? Describe what you think happens.
Budding yeast
Station 3:
Penicillin
One of the most beneficial uses of a fungus came with the virtually accidental
discovery of the antibiotic penicillin by Sir Alexander Fleming in 1928.
Antibiotics, many of them derived from fungi, have helped revolutionize the
practice of medicine in the 20th century.
Alexander Fleming was studying deadly bacteria in 1928 when he made this
dramatic discovery. For examination purposes, Fleming had removed the cover
of the bacteria culture plate with which he was working. A mold formed on the
exposed culture. Fleming noticed that in the area surrounding the mold, the
bacteria had disappeared.
He kept the strain of mold alive and began testing it on laboratory animals. In
1929 he published his first medical paper proving that a lowly mold from soil was
a powerful microbe killer that did not injure human tissue.
The mold was Penicillium notatum.
1. What did Alexander Fleming study?
2. How did Fleming discover the ‘miracle drug’?
3. Look at the microscope slide provided. It is of Penicillium. Can you
see the hyphae and the spores? Draw what you see.
Station 4:
Molds:
One chief difference between molds and other fungi is that molds, in their life
cycles, alternate between animal and plant behavior. The fact that they are able
to, at certain states of their lives, move about, gives them a similarity to protozoa,
or tiny one-celled animals. Yet most of their functions and by their appearance,
they resemble fungi. Most of them are saprophytic, obtaining their nutrition from
dead organic matter such as meat, cheese, bread, fruits and vegetables. Some
molds also produce mycotoxins that can pose serious health risks to humans
and animals. Inhaling or touching mold or mold spores may cause allergic
reactions or asthma attacks in sensitive people. Mold in the home can usually be
found in damp, dark or steamy areas e.g. bathroom or kitchen, cluttered storage
areas, recently flooded areas, basement areas, plumbing spaces, areas with poor
ventilation and outdoors in humid environments. Symptoms caused by mold
allergy are watery, itchy eyes, a chronic cough, headaches or migraines, difficulty
breathing, rashes, tiredness, sinus problems, nasal blockage and frequent
sneezing.
1. Look at the moldy bread with the hand lens. Can you see the hyphae (small
filaments)? Can you see any spores? They look like tiny dots.
2. What is the meaning of saprophytic?
3. Why do some molds pose health risks to humans and animals?
Station 5:
Lichens:
These are found on places like tree trunks, rocks and old boards. Each lichen
consists of a fungus and an alga or cyanobacteria that live together so intimately
that they resemble one organism. This is an example of a mutualistic relationship
where both organisms benefit. The fungus makes up the bulk of the body. The
algal and/or cyanobacterial partner(s) possess the green pigment chlorophyll,
enabling them to use sunlight’s energy to make their own food from water and
carbon dioxide through photosynthesis. They also provide vitamins to the
fungus. Cyanobacteria can make amino acids directly from the nitrogen gas in
the atmosphere, something neither fungi nor algae can do. The fungus, in turn,
protects its partners from drying out and shades them from strong sunlight by
enclosing the photosynthesizing partners within the body of the lichen.
Lichens have a truly remarkable resistance to drought. A dry lichen can quickly
absorb from 3 to 35 times its weight in water! Lichens can also absorb moisture
from dew or fog, even from the air itself if the humidity is very high and the
temperature is low.
Lichens have many uses. Some are used to scent soaps and make perfumes.
Others were used in the past to dye woolen cloth. The Lapp people, who live
above the Arctic Circle in Scandinavia and Russia, harvest lichens as winter food
for their reindeer, just like farmers in temperate zones stockpile hay. Sheep in the
deserts of Libya survive, in part, by eating crustose lichens growing on rocks.
Lichens are also important in making soil. Soil is made up of organic matter, such
as decayed plants, and minerals. Species that grow on rocks infiltrate and wedge
apart pieces of the rock by both pressure and chemical action.
1. How do lichens adapt to harsh
conditions?
2. What does mutualistic mean?
3. Name the 2 parts a lichen consist
of.
4. Name 3 uses of lichens.
Station 6:
Fungi:
The Latin word for mushroom is ‘fungus’. The word stand for a whole group of
organisms that do not contain chlorophyll and lack complex structures such as
roots, stems, leaves and flowers. Included among the fungi are mushrooms,
molds, yeasts, mildews, rusts, smuts and truffles.
They get their food from other plants and animals. When they get it from living
organisms, they are parasites. When they get it from dead organic matter, they
are called saprophytes.
The record price paid for a single white truffle was set in December 2007, when a
casino owner paid 330,000 USD (£165,000) for a specimen weighing 1.5 kilograms
(3.3 lb).
Mildew
1. What is the difference between
a parasite and a saprophyte?
2. What do the organisms in these
pictures have in common?
Corn smuts
Truffle
Station 7:
Where can you find a fungus?
Fungi live both on land and in the water. Fungi usually grow best in environments
that are slightly acidic (a pH measurement of 5 or so; a pH of 7 is neutral). They
can grow on substances with very low moisture. Fungi live in the soil and on your
body, in your house and on plants and animals, in freshwater and seawater. A
single teaspoon of topsoil contains about 120,000 fungi. Only a small portion of
those that live on land is normally visible. Most of the fungus grows
underground and form the mycelium which is a tangled mass of hyphae. The
visible parts of the fungi vary greatly in size. Some are so tiny they cannot be
seen without the aid of magnification. Others are quite large.
In 1992 scientists announced the discovery of a giant underground fungus,
Armillaria ostoyae, that covered 1,500 acres in Washington State. It is believed by
most to be bigger than the 110-foot- (33.5-meter-) long, 200-ton blue whale. Based
on its current growth rate, the fungus is estimated to be 2,400 years old but could
be as ancient as 8,650 years, which would earn it a place among the oldest living
organisms as well. The only visible signs of its existence were above ground
mushrooms and a rot deadly to trees.
1. What is the mycelium?
2. Describe the habitat requirements for most fungi.
The only sign of the
Armillaria ostoyae above
ground are these golden
honey mushrooms.
Station 8:
Mycorrhizae:
It is a symbiotic association between a fungus and the roots of a
vascular plant. The plant provides carbohydrates made through
photosynthesis to the fungus and the fungus helps with the
absorptions of water and minerals out of the soil. The fungus also
acts as a moist cushion against heat and drought. Both organisms
benefit in this association.
Research since these discoveries show that 90 percent of all green
plants on land form these relationships. The fungal hairs are much
finer than root hairs, and so have a much larger surface area
compared to roots. They can grow into small places that plant roots
cannot.
1. Describe 3 ways how
the fungus help plants in
this relationship.
Plant on the left is without mycorrhizae. Plant on the
right with mycorrhizae.