23.2 Diversity in Kingdom Fungi Notes

Diversity in Kingdom Fungi

Fungi are very diverse, and this diversity is evident in their various reproductive structures.
Fungi are classified into three phyla according to the structures produced during sexual reproduction:
- Zygomycota
- Ascomycota
- Basidiomycota

Zygomycetes are members of the phylum Zygomycota.
They have thick-walled sexual structures known as zygosporangia.
Black bread mold, known as Rhizopus stolonifer, is an example of this phylum.
Reproduction is mostly asexual rather than sexual.
They have specialized hyphae in which haploid spores are produced and carried to new locations by wind when mature.
These fungi often live in the soil and obtain nutrients by feeding on decaying animal and plant matter.
Stolons: mycelia that grow on the surface of bread.
Rhizoids: hyphae that anchor the fungus.

This group of fungi has a sac-like sexual reproduction structure known as an ascus.
This structure produces the haploid spores involved in asexual reproduction within interwoven hyphae.
Examples of ascomycetes include:
- Yeast:
  - Common name of unicellular ascomycetes.
  - Approximately 350 species.
  - Saccharomyces cerevisiae: used for making alcoholic beverages and bread.
  - Candida albicans: causes milk-white lesions on the lips, mouth, and throat, a disease known as thrush.
  - Yeasts reproduce asexually through binary fission or budding, where a large cell pinches itself off and forms a smaller cell.

The most commonly known type of fungi are Basidiomycetes; they are members of the phylum Basidiomycota.
Basidiomycetes derive their name from their club-shaped sexual reproductive structure called the basidium, in which spores are produced.
Examples of these fungal organisms include toadstools, mushrooms, jelly fungi, shelf fungi, and puffballs.
Basidiomycetes reproduce sexually, with the exception of rusts and smuts, which reproduce asexually.
Some Basidiomycetes are plant pathogens.
While most mushrooms are harmless, some can be deadly for humans.
Amanita muscaria (fly agaric) and other species of Amanita are nicknamed "death angel" and "destroying angel" because of their toxicity to humans.

Deuteromycetes refer to about 17,000 species of fungi that have no known sexual stage.
Often considered a separate phylum, these asexually reproducing organisms have often been classified in the phylum Ascomycota.
Examples of Deuteromycetes include:
- Penicillium
- Aspergillus: used to ferment soy sauce and make nitric acid
- Fungi that cause skin disorders such as athlete's foot and ringworm.