Biology 1108

1
Lecture 11

• Biology 1108
• Chapter 31 Fungi

2
Learning Objectives

• Define
• Mycorrhizae
• Gametangia
• Zygosporangium
• Asci
• Ascocarps
• Give examples
• From each phylum
• Contrast
• Ascospores vs. conidia

3
Phylum Chytridiomycota

• Mostly aquatic
• Originally thought to be protists
• They have flagellated cells
• Now thought to be fungi
• Molecular evidence
• Absorptive nutrition
• Chitinous cell walls

4
Chytridiomycota

• Note branching hyphae
• Remember these are the only fungi w/flagellated
  cells (not shown here)

5
Phylum Zygomycota

• The zygote fungi
• Some form mycorrhizae in plant roots
• Black bread mold Rhizopus is example

6
Potential Test Question

• Label EVERYTHING
• Heterokaryotic, haploid, diploid stages
• Sporangia
• Spores
• Etc., etc.

7
Rhizopus Life Cycle

• Reproduces sexually if food limited
• Requires opposite mating types
• Haploid spores
• Genetically diverse (different from either
  parent)
• Sexually produced
• Asexually produced

8
Zygosporangia

• Can remain dormant for long periods
• Resist freezing drying

9
Sporangia

• Pilobolus can actually aim their sporangia
• Grows in dung
• Shoots up to 2 m!

10
Phylum Ascomycota

• The sac fungi
• Produce eight sexual ascospores in saclike asci
• Asexual spores (conidia) produced on
  conidiophores
• From Greek dust
• Sexual stages are fruiting bodies, or ascocarps

11
Some Ascomycetes

• Morels
• Some yeasts
• Truffles

12
Phylum Basidiomycota

• The club fungi
• Named for the club-shaped basidium, Latin for
  little pedestal

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Basidiomycete Life Cycle

• Asexual reproduction possible, but rare
• Note basidia

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Shelf Fungi

• Shelf fungi are basidiomycetes
• Good at dissolving lignin (hard material in wood)
• Some harmful to trees
• Help forest recycle nutrients

15
Stinkhorn Fungus

• Also a basidiomycete
• Attracts flies w/ decaying meat odor
• Flies spread spores on feet

16
Mushrooms

• The basic grocery store mushroom is a
  basidiomycete
• Fairy rings

17
Review of Fungi

• This table focuses on differences
• What are shared characteristics?
• Cell wall?
• Spores?

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Dueteromycetes

• Imperfect Fungi
• Cannot be easily classified, because no known
  sexual life stages
• When its discovered, its moved to the
  appropriate phylum
• Penicillium

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7th Inning Stretch
20
Non-Phylogenetic Groupings

• Molds
• Yeasts
• Lichens

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Mold

• Molds have no phylogenetic basis
• Simply a rapidly growing, asexually reproducing
  fungus (of any phylum)
• Rhizopus is an example, but only in asexual stage
• Penicillium also a mold

22
Yeasts

• Single-celled fungi of aquatic or moist habitats,
  called yeast when reproducing asexually
• Some have asci, are Ascomycota
• Ex Saccharomyces
• Some have basidia, are Basidiomycota
• Some are imperfect fungi

23
Lichens

• Often mistaken for mosses (which are plants)!
• Actually a symbiosis between fungi algae
• Can be basidiomycete or ascomycete
• Each unique combination a species (2500)

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Lichen Life Cycle

• Reproduce by small clusters of hyphae surrounding
  algae
• Called soredia
• Algae fungi can reproduce independently

25
Lichen Ecology

• A mutualism?
• Sometimes fungus kills algae
• Lichens grow where neither algae nor fungi could
• Some lichen algae can exist independently
• Lichen fungi totally dependent upon relationship

26
Lichens Are Tough

• Passively absorb nutrients, water from rain, fog
• Can exist in harsh environments
• Arctic tundra (reindeer moss is actually a
  lichen!)
• Dry environments
• The bark of a tree!
• A rock!
• Release of acids important in soil formation

27
Air Pollution

• Only real enemy of lichens
• Passive uptake of nutrients from rain fog makes
  them susceptible

28
Mycorrhizae

• Literally fungus roots
• Mutualism between plant fungus
• Can be of any fungal phylum