Biology Today - May 2018

1. Which group of protista is photosynthetic in the presence of sunlight and behave like
   heterotrophs when deprived of sunlight?


2. How does archaebacteria differ from eubacteria?


3. Why phylogenetic system of classification is considered as highly dynamic?

KINGDOM FUNGI

• They are achlorophyllous, heterotrophic, spore-forming,
  non-vascular, eukaryotic organisms which often contain
  chitin or fungal cellulose in their cell walls and possess
  glycogen as food reserve.


• They have absorptive type of nutrition and are
  parasites or saprotrophs.


• The body of fungus is filamentous and is called
  mycelium. The filaments are known as hyphae.


• Hyphae are either multicellular or multinucleate.


• Reproduction is of three types : sexual, vegetative and
  asexual.


• Vegetative reproduction occurs by budding, fission,

fragmentation, sclerotia and rhizomorphs.

• Asexual reproduction occurs through the formation of different type of spores.


• Sexual reproduction occurs by planogametic copulation, gametangial contact, gametangial copulation, spermatogamy and
  somatogamy.


• Kingdom Fungi is classified as follows :

Mycelium aseptate

Phycomycota (lower or algal fungi)

Oomycetes

(Oogamous fungi)

Ascomycetes

(Sac fungi)

Zygomycetes

(Conjugation fungi)

Basidiomycetes

(Club fungi)

Mycelium septate

Eumycota (Higher fungi)

Sexual

reproduction

not known

Fungi Imperfecti

or Deuteromycota

Kingdom Fungi

Sexual reproduction known

• In oomycetes the mycelium is coenocytic (multinucleate and aseptate).


• Asexual reproduction involves the formation of spore containing sacs or sporangia which produce zoospores in aquatic
  environment. In terrestrial environment, the sporangia often behave as spores and equivalent to conidia.


• Zoospores are usually biflagellate.


• Gametes are usually nonflagellate.


• Sexual reproduction takes place by gametangial contact and the product of sexual reproduction is oospore.


• Some examples are Albugo candida, Phytophthora infestans, Pythium debaryanum.


• Zygomycetes is a class of terrestrial fungi which are mostly saprotrophic, rarely parasitic.


• The mycelium is coenocytic.


• Motile cells are absent. Sexual reproduction occurs through gametangial copulation or conjugation.