CLASSIFICATION OF PROTOZOA

By -
Phylum Protozoa is classified into 4 distinct sub-phyla on the basis of type of locomotory organelles found in them. The 4 sub-phyla of phylum Protozoa are as follows:
  1. Sarcomastigophora
  2. Sporozoa
  3. Cnidospora
  4. Ciliophora

1.  SARCOMASTIGOPHORA

  • Locomotory organelles may be Pseudopodia or Flagella.
  • Nucleus is monomorphic.
  • Asexual reproduction is by binary or multiple fission.
  • Sexual reproduction occurs by fusion of gametes.
​Sub-phylum Sarcomastigophora is further divided into 3 Super classes i.e.,Mastigophora, Opalinata, Sarcodina

(a) MASTIGOPHORA (SUPER CLASS)

  • Flagella are present as locomotory organelles, so they are also called Flagellata. Flagella also acts as food capturing organ.
  • Body is covered by a layer of very thin cuticle or pellicle.
  • Nutrition is holozoic, holophytic or saprozoic.
  • Asexual reproduction by longitudinal fission.
​Super class Mastigophora has further 2 classes                                      i.e.,Phytomastigophora and Zoomastigophora.
(i)  PHYTOMASTIGOPHORA (CLASS)
  • They possesses chromatophores.
  • Only 1 or 2 flagella are found.
  • Nutrition is holophytic.
  • Ex- Euglena
(ii)  ZOOMASTIGOPHORA (CLASS)
  • Chlorophyll bearing chromatophores are absent.
  • In addition to pseudopodia, more than 2 flagella are present as locomotory organelles.
  • Undulating membrane may be present.
  • Nutrition is holozoic.
  • Ex- Trypanosoma

(b)  OPALINATA (SUPER CLASS)

  • All are parasites of frogs and toads.
  • Body is covered by flagella and arranged  in oblique rows over the entire body surface.
  • Nuclei are monomorphic.
  • Reproduction by simple binary fission or by gamete formation.
  • Ex- Opalina

(c)  SARCODINA (SUPER CLASS)

  • Locomotory organelle is Pseudopodia.
  • Body is not usually covered by pellicle.
  • Gamete formation is more common.
Super class Sarcodina is further divided into 3 classes i.e., Rhizopoda, Actinopoda, and Piroplasmea.
(i)  RHIZOPODA (CLASS)
  • Locomotory organelles are lobopodia or filopodia. Axopodia are absent.
  • All are creeping forms.
  • Ex- Amoeba, Entamoeba
(ii)  ACTINOPODA (CLASS)
  • Axopodia is found as locomotory organelle.
  • Test may or may not be present.
  • Reproduction is by both sexual and asexual method.
  • Gametes are usually flagellated.
  • Ex- Actinophrys
(iii)  PIROPLASMEA (CLASS)
  • They are small, round, rod shaped or amoeboid forms.
  • Parasites of R.B.Cs of vertebrates.
  • Ex- Babesa

2.  SPOROZOA

  • All of them are parasites.
  • Locomotory organelles are absent. But gametes may have cilia or flagella.
  • Body is covered by thick cuticle or pellicle.
  • Asexual reproduction by multiple fission.
Sub-phylum Sporozoa is further classified into 3 classes, such as: Telosporea, Haplosporea, Toxoplasmea.

(a)  TELOSPOREA (CLASS)

  • Pseudopodia are generally absent. Locomotion is by gliding body movement.
  • Reproduction is both sexual and asexual.
  • Ex- Plasmodium

(b)  TOXOPLASMEA (CLASS)

  • Locomotory organelles are absent in all the stages.
  • Reproduction is by binary fission.
  • Ex- Toxoplasma

(c)  HAPLOSPOREA (CLASS)

  • Pseudopodia may be present, but flagella is absent.
  • Spore cases are present.
  • Reproduction is only asexual.
  • Ex- Icthyosporidium

3.  CNIDOSPORA

  • All are parasites.
  • Zygotes gives to one or more trophozoites.
  • Trophozoites are multinucleated.
Cnidospora has 2 distinct classes, such as: Myxosporidea and Microsporidea.

(a)  MYXOSPORIDEA (CLASS)

  • Parasites of fishes.
  • Spores are of multicellular origin.
  • Spores possesses a bivalved membrane.
  • Ex- Myxobolus.

(b)  MICROSPORIDEA (CLASS)

  • Endoparasites of Arthropods and Vertebrates.
  • Spores are of unicellular origin.
  • Small spores with univalved membrane.
  • Ex- Nosema

4.  CILIOPHORA

  • Cilia are the locomotory organelles.
  • Posses 2 nuclei i.e., one meganucleus (vegetative nucleus) and another micronucleus (reproductive nucleus).
  • Nutrition is heterotrophic.
  • Asexual reproduction is by binary fission or budding.
  • Sexual reproduction is by conjugation, autogamy or by cytogamy.
    Sub-phylum Ciliophora has only one class i.e., Ciliata.

(a)  CILIATA (CLASS)

  • Cilia are present throughout the life.
  • Nuclear dimorphism is marked.
  • Anal aperature (cytopyge) is permanent.
  • Ex- Paramecium

Comments

Post a Comment

comment