KINGDOM FUNGI
Websites
http://tolweb.org/tree?group=Fungi&contgroup=Eukaryotes
http://www.ansci.cornell.edu/plants/toxicagents/amanita/amanita.html
http://www.lichen.com/
http://helios.bto.ed.ac.uk/bto/microbes/fungalwe.htm#crest
Introduction:
More than 100 000 species of fungi exist. Fungi are usually classified in
four divisions: the Chytridiomycota (chytrids), Zygomycota (bread moulds),
Ascomycota (yeasts and sac fungi), and the Basidiomycota (club fungi).
Placement into a division is determined by the way in which the fungus sexually
reproduces. The most useful characteristic for identifying these major groups is
the shape and internal structure of the sporangia. Endings used for levels of taxa
in kingdom Fungi are as follows: phylum (-mycota), class (-mycetes), order
(-ales), and family (-aceae).
When people think of mushrooms, they are probably thinking of the fruit of
club fungi (Basidiomycota). All the 25 000 species in this phylum produce spores
on a club-like structure called the basidium. The basidium may grow free or be
attached to a surface called the hymenium. Among the more famous in this
phylum are Agaricus (the common supermarket button mushrooms); Amanita
(species that are deadly, delicious, or hallucinogenic); Boletus (called porcini in
Italy and cèpe in France); and Cantherellus (the delicious and beautiful
chanterelle). Toadstools, shelf fungi, puffballs, rust, and smuts are other
examples.
Ascomycota, or sac fungi, produce their spores in special pods or sac-like
structures called asci. The prized morel and truffle are included among the 25
000 species of this phylum, as is Saccharomyces cerevisiae (brewer’s, baker’s,
and nutritional yeast), which is used to produce beer and bread.
1. Characteristics of fungi:
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Eukaryotes (cells contain many nuclei)
No chlorophyll – not plants
Cell wall made of CHITIN
Heterotrophs – must eat by absorbing nutrients
No roots or storage molecules
Saprophytes (decomposers like bacteria)
- release enzymes and digest outside body (extracellular)
- digested nutrients are ABSORBED by MYCELIUM
Comparing plants and fungi
See chart in book, page 136
2. Structure of fungi
The structure is adapted for two main functions:
i) absorption of nutrients
ii) reproduction
a) MYCELIUM:
main vegetative part of all fungi, not involved in
reproduction
def’n: a mesh of microscopic branching filaments called HYPHAE
that are usually on or below the surface (SUBSTRATE)
where the fungi grows or is attached
- the mycelium is usually not visible
b) REPRODUCTIVE PART:
- visible
- comes in a variety of shapes and sizes
- main job: to produce spores
3. Life Cycle of Fungi
A life cycle describes the development of an organism from a single cell to
its reproductive stage. The cycle is complete when the organism produces the
next generation. There is a wide variety of fungal life cycles. Fungi reproduce
both asexually and sexually but always produce spores as reproductive cells.
Sporangia:
structures that produce HAPLOID spores which spread by AIR (wind)
- spores GERMINATE (to grow / sprout ) and develop into new fungi
see Life Cycle of a Field Mushroom , Fig. 5 , page 138 in book
Fungi and Human Diseases
a) Ringworm: Microsporum – skin infection, easily spread if not treated
b) Athlete’s Foot: Epidermophyton floccosum – contracted from dirty shower floors
and running shoes
c) Amanita genus: cause many types of problems if eaten
ex. Amanita phalloides : death cap mushroom , worlds most
dangerous mushroom, FATAL
Importance of Fungi
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Decomposers:
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Food:
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Antibiotics:
Yeast:
Bioremediation:
along with bacteria, fungi recycle dead matter and
return nutrients to the soil
mushrooms(ex. porcini, white) , truffles, morels
Aspergillus, (used to flavour soft drinks)
many made from Penicillium, a bread mould
bread, wine making
some may be used to remove pollutants in toxic
dumpsites and wastewater treatment plants
Symbiotic Relationships
Organisms exist with other organisms. They share many different types of
relationships. These relationships are called symbiotic relationships, or symbiosis.
Fungi can exist in a symbiotic relationship.
ex. Mycorrhizae:
- a fungus that lives on or near plant roots
- symbiotic relationship: called MUTUALISM (both benefit)
- fungus receives nutrients from plant and helps plant’s
roots ABSORB nutrients like PHOSPHORUS
ex. Lichens:
an organism made up of a fungus and a cyanobacteria
(blue-green algae)
- both parts work together (mutualism)
- fungus releases enzymes to break down rock into nutrients
- cyanobacteria has chlorophyll for PS, and can provide food
 Lichens are ecologically important in plant SUCCESION because they are the first
organisms involved in making soil from rock.
- Lichens also are used by scientists as natural air-quality inspectors. The
presence or absence of certain lichens can be used to map
concentrations of pollutants.