Transcript Foundations of Biology - Geoscience Research Institute

Luke 13:20, 21
20 And again he said, Whereunto
shall I liken the kingdom of
God?
21 It is like leaven, which a
woman took and hid in three
measures of meal, till the
whole was leavened.
©2000 Timothy G. Standish
Kingdom
Fungi
Timothy G. Standish, Ph. D.
©2000 Timothy G. Standish
Fungi In The Scheme Of Life
Plantae
Fungi
Animalia
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Protista
Monera
©2000 Timothy G. Standish
Why Fungi Are Important
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Important as decomposers
Spoil food
Produce antibiotics
Produce substances used as drugs (“magic” mushrooms,
ethanol etc.)
Cause disease in plants
Cause disease in animals (Athlete’s foot, yeast
infections etc.)
Poison humans and animals (afflotoxin, toadstools etc.)
Important food source
Produce important fuels and industrial chemicals (i.e.,
ethanol)
©2000 Timothy G. Standish
Fungal Characteristics
 Eukaryotic
 Multicellular
 Heterotrophic
 Absorb
nutrients - may be saprobes (absorb
from dead material), parasites, or mutualistic
symbionts (with algae make lichen).
 Secrete powerful hydrolytic enzymes
 Cell walls contain chitin, an amino sugar
polysaccharide also found in arthropod
exoskeletons
 Lack flagella
©2000 Timothy G. Standish
The Body Plan of Fungi
 Vegetative
body consists of mycelia
made up of networks of hyphae
 Hyphae - Long threads of cells
designed to maximize surface area and
also transport nutrients
 Fungus-like protists:
– Lack this body structure
– Lack cell walls of chitin
©2000 Timothy G. Standish
Hyphae
Hyphae are designed to increase the surface area
of fungi and thus facilitate absorption
 May grow fast, up to 1 km per day, as they spread
throughout a food source
 Haustoria - Specialized structures budding off
hyphae of parasitic fungi which penetrate host
cells to absorb nutrients
 May be coenocytic, having no septa between
cells, or septa may be present with pores through
which cytoplasm can flow moving nutrients
through out the fungus
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©2000 Timothy G. Standish
Hyphae
Pores
Septa
Coenocytic
©2000 Timothy G. Standish
Classification of Fungi
 Lichens
represent a mutualistic (?) relationship
between fungi and algae
 Classification of fungi is based on lifecycle,
specifically reproductive structures
 Three major phyla, all end with mycota:
 Zygomycota - Zyg = yolk - Zygote forming
fungi, the black bread molds
 Ascomycota - Asc = sack - Truffles, yeasts,
many plant pathogens
 Basidiomycota - Basidium = club - Mushrooms
©2000 Timothy G. Standish
Zygomycota
Zygomycota - Zyg = yolk - Zygote forming
fungi, the black bread molds etc.
 About 600 described species
 Mostly terrestrial
 Mycrorrhizae - Zygomycetes that form a
mutualistic relationship with tree roots increasing
root surface area and thus water and mineral
uptake while benefiting from sugar sent down
from leaves
 Hyphae are coenocytic, septa are only found in
reproductive cells
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©2000 Timothy G. Standish
Ascomycota
Ascomycota - Asc = sack - Truffles, yeasts, many
plant pathogens
 Over 60,000 described species
 Some associate with algae to form lichen
 Some, including truffles, form mycrorrhizae
 Some live on mesophyll cells producing toxins to
protect leaves from insects
 Hyphae have septa
 Important marine saprobes
 Important tool for studying genetic recombination
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©2000 Timothy G. Standish
Basidiomycota
Basidiomycota - Basidium = club - Mushrooms
 About 25,000 described species
 Important decomposers of wood because of their
ability to hydrolyze lignin
 Some form mycrorrhizae including half the
mushroom formers
 Few are strictly plant parasites, but of those that
are, the smuts and rusts are especially bad
 Form long-lived dikaryotic mycelia
 Asexual reproduction is uncommon
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©2000 Timothy G. Standish
Lichens
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Lichens - Mutualism (?) between fungi and algae
Over 25,000 species described
Ascomycetes are usually the fungal component, although
some basidiomycetes lichens are known
Filaments green algae usually make up the algal
component, although some use cyanobacteria
Scientific names are the names of the fungus
Hyphae account for most mass
Fungus provides moist environment protection and
minerals
Algae provide fixed carbon
Cyanobacteria may provide fixed nitrogen
©2000 Timothy G. Standish
Deuteromycota Imperfect
Fungi
Deuteromycota - Deuter = second - The
imperfect fungi
 These organisms exhibit all the characteristics
of fungi, but have not been observed
reproducing sexually
 As classification is based on sexual
reproduction, Deutoeromycetes cannot be
definitively placed in any phylum
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©2000 Timothy G. Standish
Chytridiomycota:
Protists or Fungi?
 Chytrids
have flagellated zoospores and
thus do not fit perfectly with the fungi
 Other characteristics are very fungus-like:
– Cell walls with chitin
– Unicellular or coenocytic hyphae
– Enzymes common to fungi which are lacked
by fungus-like protists
©2000 Timothy G. Standish
©2000 Timothy G. Standish