lu5 fungi

Question 1

What are fungi

Answer 1

• (singular fungus)
• kingdom of usually
  multicellular eukaryotic
  organism
  -important roles in nutrient
  cycling (decomposers) in an
  ecosystem (STF1023)
• reproduce both asexual
  and sexually
• have symbiotic associations with
  bacteria and plants
• also responsible for
  some disease in plants and
  animals.

Question 2

6 characteristics

Answer 2

1. cells contain nuclei with chromosomes (unlike bacteria, but
   like plants and animals)
2. cannot photosynthesize (heterotroph)
3. absorb their food (osmotrophic)
4. Forms very narrow, tubular, branching filaments called hyphae
5. Reproduce by spores
6. Cell wall made of chitin

• Fungi are found in all temperate and tropical regions of the world where there are suitable moisture to enable them to grow.
• There are either terrestrial or aquatic (freshwater/marine).

Question 2

basic structure

Answer 2

Multicellular bodies of fungi are
composed of many hyphae tangled together into
a thick mass called
a mycelium

• Hyphae can be septate,i.e., divided into hyphal compartments separated bya septum, each compartment containing one or more nuclei or can be coenocytic,i.e., lacking hyphal
  compartmentalization

a) septae (hypha disintegrated)
b) nonseptate hypa (integrated)

Question 2

Fungi may develop specialized structures for..

Answer 2

• nutrient uptake from living hosts; this include haustoria in plant- parasitic fungi of nearly all divisions, and arbuscules of several mycorrhizal fungi, which penetrate the host cells
  for nutrient uptake by the fungus.

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Question 3

The fungal mycelia may..

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Answer 3

become visible macroscopically, either as:
- concentric rings on various surfaces (commonly
called mold- do not confuse with slime-mold)
- colonies (fungal mycelia grown on solid agar media in laboratory
petri dishes)

Question 3

A mushroom, is..

Answer 3

reproductive structure growing from
the mycelium in the soil.

Question 3

Classification

Evolutionary tree of
the major groups of
fungi
(before 2008)

Answer 3

1. chytridiomycota - chytrids
2. zygomycota - zygote fungi
3. glomeromycota - arbuscular mycorrhizal fungi
4. ascomycota - sac fungi
5. basidiomycota - club fungi

Question 4

Classification (after 2008)

Answer 4

• Kingdom fungi is a monophyletic group which diverged from a common ancestor with the animals approximately 800-900 million years ago.
• The true fungi (Eumycota) which make up the kingdom Fungi consist of some of 7 phyla (Ainsworths & Bisby, 2008):

i. Chytridiomycota (706 spp. in 105 genera)
ii. Blastocladiomycota (179 spp. in 14 genera)
iii. Neocallimastigomycota (20 spp. in 6 genera)
iv. Microsporidia?? (1300+ spp. in 170 genera)
v. Glomeromycota (169 spp. in 12 genera)
vi. Ascomycota (64 163 spp. in 6355 genera)
vii. Basidiomycota (31 515 spp. in 1589 genera)

Note: The phylum Zygomycota is not accepted in the phylogenetic classification of fungi because of
remaining doubts about relationships between the groups that have traditionally been placed in this phylum. The consequences of this decision are the recognition of the phylum Glomeromycota.