mader: biology 8 th ed. the fungi chapter 23. mader: biology 8 th ed. outline characteristics...
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Mader: Biology 8th Ed.
Outline• Characteristics• Structure• Reproduction• Evolution• Sac Fungi• Yeasts• Club Fungi• Smuts and Rusts• Imperfect Fungi• Symbiotic Relationships
Mader: Biology 8th Ed.
Characteristics of the Fungi
• Kingdom Fungi contains the fungi.– Mostly multicellular eukaryotes that share
a common mode of nutrition.HeterotrophicCells release digestive enzymes and
then absorb resultant nutrient molecules.
Some are parasitic.Several have mutualistic relationship.
Mader: Biology 8th Ed.
Structure of Fungi
• Yeasts are best known example of unicellular fungi.– Body (thallus) of most fungi is multicellular
mycelium.Network of hyphae give the mycelium a
large surface area per unit volume.
Mader: Biology 8th Ed.
Structure of Fungi
• Fungal cells are quite different from plant cells.– Lack chloroplasts and have a cell wall
containing chitin and not cellulose.– Energy reserve is glycogen, not starch.
• Nonmotile– Septate fungi have cross walls in their
hyphae.– Nonseptate fungi are multinucleated.
Mader: Biology 8th Ed.
Reproduction of Fungi
• Both sexual and asexual reproduction occur.
• Fungal sexual reproduction involves three stages:– Haploid Hyphae– Dikaryotic Stage– Diploid Zygote
Mader: Biology 8th Ed.
Reproduction of Fungi
• During sexual reproduction, hyphae from two different mating types fuse.– Hyphae that contains paired haploid
nuclei is said to be dikaryotic.– Fungal spores germinate directly into
haploid hyphae without embryological development.
• Asexual reproduction usually involves the production of spores.– Unicellular yeasts reproduce by budding.
Mader: Biology 8th Ed.
Evolution of Fungi
• Has been suggested fungi evolved from red algae because both fungi and red algae lack flagella in all stages of the life cycle.– Zygospore Fungi
(phylum Zygomycota) are mainly saprotrophs living off animal and plant remains.
Produce spores with sporangia. Name refers to the zygospore seen
during sexual reproduction.
Mader: Biology 8th Ed.
Sac Fungi• Most sac fungi (phylum Ascomycota) are
saprotrophs that digest resistant materials containing cellulose, lignin, or collagen.– Most are composed of septate hyphae.– Ascus refers to the fingerlike sac that
develops during sexual reproduction.Asci usually surrounded and protected
by sterile hyphae within an asocarp.– Asexual reproduction involves production
of conidiospores.
Mader: Biology 8th Ed.
Yeasts
• Term yeasts is generally applied to unicellular fungi.– Many are ascomycetes.– Budding is common form of asexual
reproduction.– Sexual reproduction results in the
formation of asci and ascospores.– When some yeast ferment, they produce
ethanol and carbon dioxide.
Mader: Biology 8th Ed.
Club Fungi
• Club fungi (phylum Basidomycota) include mushrooms and bracket fungi.– These are fruiting bodies called
basidiocarps.Contain basidia, club-shaped structures
that produce basidiospores.– Usually reproduce sexually.
Mader: Biology 8th Ed.
Smuts and Rusts
• Smuts and rusts are club fungi that parasitize cereal crops.– Great economic importance because of
annual crop losses.Do not form basidiocarps.Life cycle often requires two different
plant hosts to complete the cycle.
Mader: Biology 8th Ed.
Imperfect Fungi
• Imperfect fungi (phylum Deuteromycota) always reproduce asexually by forming conidiospores.– Produced at tips of modified aerial
hyphae.– Known as imperfect in the sense that a
sexual stage has not yet been observed.Penicillium - PenicillinAspergillus - Soy sauceCandida albicans- Yeast infections
Mader: Biology 8th Ed.
Symbiotic Relationships
• Lichens– Association between a fungus and a
cyanobacterium or green alga.Specialized fungal hyphae penetrate
photosynthetic cells and transfer nutrients directly to the fungus.
Can live in areas of extreme conditions and contribute to soil formation.
Mader: Biology 8th Ed.
Mycorrhizas
• Mycorrhizas are mutualistic relationships between soil fungi and the roots of most plants.– Help plants acquire mineral nutrients.
Give plant greater absorptive surface.
Mader: Biology 8th Ed.
Review• Characteristics• Structure• Reproduction• Evolution• Sac Fungi• Yeasts• Club Fungi• Smuts and Rusts• Imperfect Fungi• Symbiotic Relationships