Yeast
Brewer’s Yeast
Nutritional Yeast
Yeast Infection
Reproductive Structures of Some
Club Fungi Are Edible
Club Fungi: phylum Basidiomycota
Mushrooms, smuts, jelly fungi, puffballs, and
stinkhorns
Mushroom: the sexual reproductive, sporeproducing structure of club fungi; composed of
tightly packed hyphae.
– Under cap are gills radiating outward from center.
– Between gills are tiny clubs, or basidia, which
produce spores.
Club Fungi
Some = edible; many =
poisonous.
– Toadstool = poisonous
mushroom
– Amanita “death cap” =
very poisonous
– Some poisonous mushrooms have
hallucinogenic effects.
Some club fungi = plant parasites, e.g.
wheat rust, corn smut.
Imperfect Fungi Have No Known Sexual
Reproductive Structures
Unclassifiable based on reproductive
structures because they seldom, if ever,
manifest one.
Some, however, do resemble spp. whose
sexual reproductive structures are known
and these are classified accordingly
– Classification is based on similarity of
sporangia to those of spp. whose
classification is known.
Imperfect Fungi
Imperfect fungi: those with no known
sexual reproductive structure.
– Penicillium roquefortii: gives Roquefort
cheese its flavor and appearance.
Imperfect Fungi
– Penicillium camembertii:
used to manufacture
Camembert cheese.
Imperfect Fungi
– Penicillium notatum: used to produce
penicillin
Imperfect Fungi
– Others = parasites of crop plants and animals.
Imperfect Fungi
Athlete’s foot: formerly classified as imperfect,
but sexual spores have recently been
discovered and showed it to be a sac fungus.
Fungi Support Many Food Chains
Food supply for a soil community comes
from the outside.
– Plant roots serve as food for
some consumers.
– Remains of other dead
organisms = food for most.
Fungi Support Many Food Chains
– Decomposers (fungi and bacteria) = very important
members of soil communities.
– Beetles and other small animals use dead roots,
animals as source of starch, fats and protein.
– Some microorganisms can break down cellulose
(from plant cells) and chitin (from dead arthropods)
into waste products.
– Other fungi and bacteria can use these waste
materials as food.
– The inorganic wastes of these organisms, in turn,
feed still others.
Fungi Support Many Food Chains
– The soil community food chain is rather like
an assembly line in reverse.
Complex compounds are broken down one step at
a time into end products like carbon dioxide,
nitrates, ammonia and water.
– Plants then assemble these inorganic
molecules into organic compounds once
again.
Fungi Support Many Food Chains
– Some soil organisms produce compounds
that are harmful to others (as a means of
reducing competition for resources).
– We use some of these as antibiotics.
Aureomycin: from a bacterium
Penicillin: from a fungus
Fungi Support Many Food Chains
– Fungi as predators:
Catch nematodes (roundworms) in loops of
hyphae, while other hyphae invade bodies of
captive worms and digest them.
Fungi Support Many Food Chains
Assg.:
– Identify each organism in Fig. 12.20, p. 320,
and explain the role each plays in the process
of decomposition.
Mycorrhizal Fungi Help Many Plants
Grow
Some fungal hyphae establish a relationship
with plant roots Æ slight modifications in the
roots called mycorrhizae.
– p. 598
Mycorrhizal Fungi Help Many Plants
Grow
Mycorrhizae:
– Symbiotic relationships, the
fungi either wrap a sheath
around the root or penetrate
the root.
– Some plants grow much better
because of such associations.
– Increase the absorptive surface area of roots.
– Mycorrhizal fungi secrete acids which make
nutrients more readily usable by the plant.
– Absorb water.
– Protect plant from certain soil pathogens.
Mycorrhizal Fungi Help Many Plants
Grow
Mycorrhizae:
– In turn, fungus received
benefit of photosynthetic
products from the plant.
– Occur in all plant families
and are evident even in
some fossil plants.
– May have allowed plants
to adapt to terrestrial
existence by retaining
water and preventing
desiccation.
Lichens Are Symbiotic Pairs of
Organisms
Lichen: a symbiotic organism composed of a
fungus and either an algae, or a cyanobacterium
–
–
–
–
–
25,000 spp. have been identified.
Grow on rocks, tree trunks, and branches
Named according to the fungal participant.
p. 598
Fungus:
Provides the structural framework with
its hyphae
– Algae:
Provides photosynthetic food.
– Freddie Fungus and Alice Algae
Lichens Are Symbiotic Pairs of
Organisms
Freddie Fungus and Alice Algae
Lichens Are Symbiotic Pairs of
Organisms
Wolf lichen
Lichens Are Symbiotic Pairs of
Organisms
The algae (or cyanobacteria) can live
alone, but the fungus does not do well
without its producing partner.
Lichens Are Symbiotic Pairs of
Organisms
Lichens secrete acids which break down rocks,
beginning the process of soil formation.
– Are among the first organisms to colonize bare rocks,
soil, or ice.
– Can survive extremely dry conditions and extreme
temperatures.
– Do not grow except in moist environment
– Average growth rate: 0.1 mm/yr (very slow!)
– Can be used to age rocks’ existence in certain
locations.
Lichens Are Symbiotic Pairs of
Organisms
Reindeer moss:
– Consumed by reindeer and caribou.
– The moss (actually, a lichen) absorbs nutrients from
the soil and water, then concentrates them in its cells.
– Toxins are also concentrated and, if the atmosphere
is polluted, these can kill the lichen.
– Thus, reindeer lichen = an indicator species.
Lichens Are Symbiotic Pairs of
Organisms
– Some reindeer moss have been found with
heavy concentrations of radioactivity from
atomic bomb testing in the Arctic.
– When reindeer eat the lichen, they take up the
radioactivity.
– Inuits who eat the reindeer also absorb these
harmful materials.
Chapter 19 Outline
Protists (Kingdom Protista)
A. Algae (plant-like protists)
1. Green algae: phylum Chlorophyta
2. Diatoms (Golden algae): phylum Bacillariophyta
3. Brown algae: phylum Phaeophyta
4. Red algae: phylum Rhodophyta
B. Protozoa (animal-like protists)
1. Flagellates
a. Euglenoids
b. Dinoflagellates
c. Symbiotic Flagellates
2. Sarcodines
a. Amoeba
b. Radiolarians (silica shell)
c. Foraminifera (calcium carbonate shell)
3. Sporozoans (phylum Apicomplexa)
4. Ciliates (phylum Ciliophora)
C. Slime molds (fungus-like protists)
Chapter 19 Outline
Fungi (Kingdom Fungi)
A. Conjugating fungi (phylum Zygomycota)
B. Sac fungi (phylum Ascomycota)
C. Club fungi (phylum Basidiomycota)
D. Imperfect fungi
E. Lichen (taxonomy debated)
Symbiotic relationship of fungus and algae