Classification of Phycomycetes

Phycomycetes are further classified into 3 subclasses based on the method and result of sexual reproduction, and their somatic structures:

 Archimycetes

• The non-mycelial thallus will be round or lob-shaped because of the enlargement of zoospores.
• They sometimes possess rhizoids.
• Their higher forms may be developed into rudimentary mycelium.
• Includes 3 orders:
  • Chytridiales: They are often known as chytrids. They include both soil and aquatic inhabiting species. They are an order of water molds.
  • Ancylistales: They are an unusual member of aquatic Phycomycetes. Sporophores are generally unbranched or rarely branched, having one conidium per branch.
  • Protomycetales: They are spore sac compounds. They are a small group of plant-parasitic Archimycetes.

Oomycetes

• They have well-developed coenocytic mycelium.
• Oogamy is their mode of sexual reproduction.
• Mostly motile zoospores are the accessory spores formed in most of them.
• Includes 5 orders:
  • Blastocladiales: They have a thallus that consists of branched and single basal cells with sporangia at one end and rhizoids at the other. The genus of Blastocladiales are Blastocladia and the family is Blastocladiaceae.
  • Monoblepharidales: They have simple and unbranched filamentous thallus. They can reproduce through autospores and zoospores. Sometimes oogamous sexual reproduction can occur.
  • Leptomitales: They are an order of water molds. They contain the Apodachlya genus.
  • Saprolegniales: They are an order of freshwater mold. 
  • Peronosporales: many diseases of plants are sometimes classified under this order. They are an order of water molds.

Zygomycetes

• They have well-developed mycelium.
• Conjugation of two gametangia is their mode of sexual reproduction.
• Here accessory spores are non-motile aplanospores, and they are known as sporangiospores and formed within the sporangium.
• It Includes 2 orders-
  • Mucorales: They are typically fast-growing. Their hyphae don’t have septa. These are saprotrophic. A few of them cause animal and human diseases also.
  • Entomophthorales: Most species are the pathogens of insects. Production of ballistic asexual spores is observed in most species. When they don’t land on a suitable host, they make one for themselves.

Biological classification can be defined as the method used to categorize and group living organisms based on their features and functions, also known as taxonomy. The first biological classification is done by Aristotle, who classified living organisms based on morphological characteristics. According to the classification of Aristotle, organisms can be classified as Organisms that have red blood cells and Organisms that don’t have red blood cells. After that, Carolus introduced the system of kingdoms. According to him, there are two kingdoms, Animalia and Plantae. But still, there are some organisms that didn’t get any categorization from this classification. Then R.H. Whittaker classified organisms. R.H. Whittaker classified living organisms into 5 kingdoms based on their cell structure, complexity, reproduction, mode of nutrition, and phylogenetic relationships. The five kingdoms are Monera, Protista, Fungi, Animalia, and Plantae.