Chapter 29

• Fungal Nutrition

  • Heterotrophs, must find their own food
  • Do not ingest their food, instead nutrients are absorbed from the environment
• Decomposers 


  break down and absorb nutrients from nonliving organic material.
• Parasites 


  Absorb food from cells of living hosts. Can potentially be pathogenic.
• Mutualists 


  absorb nutrients from a host, but reciprocate with actions that benefit the host
• Cell walls in fungi are composed of chitin
• The morphology of fungi allows for ease of

  • Spread
  • Nutrient Acquisition
• Hyphae

  • Network of tiny, connected filaments that collectively make the mycelium of the fungus
  • (Think of a singular thread in the mycelium)
• Mycelium

  • The mass network of hyphae in a fungus
  • Infiltrates the material where the fungus feeds
  • Maximizes the surface area: volume ratio
• Hyphae are divided into cells by septa (akin to a cross wall)
• Fungus prioritizes its energy and resources into adding hyphal length.
• Specialized hyphae

  • Arbuscules - branching hyphae that allows fungi to exchange nutrients with living plants.
  • Mycorrhizae - mutualistic association of a fungus and plant roots
• Spores

  • Designed for dormancy and dispersal
  • Can be carried long distances by wind or water
  • If they land in a viable place, they germinate and produce mycelium
• Cryptomycetes

  • Unicellular
  • Flagellated spores
  • Over 30 identified species
• Microsporidians

  • Unicellular
  • Parasites
• Chytrids

  • Ubiquitous in lakes and soil environments
  • Have flagellated spores
• Zoopagomycetes

  • Multicellular
  • Parasitic or symbiotic in animals
• Mucoromycetes

  • Fast growing molds (food rotting during storage)
  • Can withstand harsh environments (even resistant to freezing/drying)
• Ascomycetes

  • Produce ascospores in saclike structures called asci
  • 'Sac Fungi'
• Basidiomycetes

  • What you think of when you think of fungus
  • 50,000 species
  • Reproductive appendage called a basidium, which produces sexual spores
  • important decomposers of wood/plant material
• Black mold

  • Aspergillus niger
  • needs moisture to grow
• Lichens

  • Symbiotic association between a photosynthetic microorganism (usually an algae) and a fungus
  • The photosynthetic organism provides carbon compounds and fixes nitrogen
  • The fungus provides an environment supportive for growth