Phylum Aschelminthes

In phylum Aschelminthes, the organisms also called roundworms because the body is circular in cross-section. These organisms are endoparasites. They are cylindrical, unsegmented, and triploblastic animals.

Characteristics Features of Aschelminthes

The characteristics features of Aschelminthes are:

  • Habitat– These animals exist as free-living, aquatic, and terrestrial or may be found as a parasite in plants and animals.
  • Level of organization– An organ-system level of organization is found.
  • Symmetry– They are possessing a bilaterally symmetrical body. the distinct head is absent in Aschelminthes.
  • Germinal layer– Triploblastic animals
  • The body cavity or Coelom– These animals are pseudo coelomate.
  • The alimentary canal is complete.
    • A well-developed muscular pharynx is found with the alimentary canal.
    • A complete digestive system is present.
  • Excretion– Waste products are removed from the body cavity by an excretory tube through the excretory pore. In some forms protonephridia or rennet cells or giant cells as excretory organs.
  • Circulatory and respiratory system: absent.
  • The sense organs are in the form of pits, papillae, bristles, and eyespots.
  • The body is covered with a thick cuticle i.e. syncytial, it is flexible, non-living, and made up of protein (scleroprotein)
  • Reproduction– sexes are separate- dioecious
    • Dioecious- males and females are distinct. Females are longer than males.
    • Fertilization takes place internally.
    • The development may occur direct – as the young ones resemble the adult or indirectly.
Some examples of Aschelminthes: Ascaris (roundworm), Wuchereria (Filarial worm), Ancylostoma (Hookworm), Brachiomus, Colotheca, Urodasys, Macrodasys, Echinoderes, Centroderes, etc.
Example of Aschelminthes

Example of Aschelminthes

    Classification of Aschelminthes
    1. Nematoda
      • The members are endoparasites
      • The body is Bilaterally symmetrical and vermiform.
      • A complex cuticle covers the body.
      • Example: Ascaris (roundworm), Ancyclostomata (hookworm), Enterobius (pinworm)
    2. Rotifera
      • The organisms are microscopic aquatic.
      • sexes are separate
      • Excretion through protonephridia tubes.
      • Example: Brachiomus, Colotheca
    3. Gastroticha
      • They are free-living aquatic organisms.
      • Sexes separate or united
      • Example: Urodasys, Macrodasys
    4. Kinorhyncha
      • These are marine and microscopic organisms.
      • Internally segmented body
      • separate sexes
      • Development is indirect (with the larval form)
      • Example: Echinoderes, Centroderes
    5. Nematophora
      • The body of these organisms is slender and unsegmented.
      • Also called hairworm
      • Sexes are found separate.
      • example: Nectonema, Gordius

    You can also read:

    Spread Your Love

    7 Comments

  1. pcsclasses · January 29, 2021 at 9:10 pm

    On your demands….

  2. All Competitive Classes Characteristics and Classification of Phylum Chordata Science - · February 5, 2021 at 4:18 pm

    […] of animals, Major phyla Phylum -Porifera, Coelenterata (Cnidaria), Ctenophora, Platyhelminthes, Aschelminthes, Annelida, Arthropoda, Mollusca, Echinodermata, and Hemichordata. In this blog, we’ll continue with the phylum Chordata its characteristic features and […]

  3. PCSSTUDIES - Characteristics and Classification of Phylum Chordata % - · April 25, 2021 at 12:08 am

    […] of animals, Major phyla Phylum -Porifera, Coelenterata (Cnidaria), Ctenophora, Platyhelminthes, Aschelminthes, Annelida, Arthropoda, Mollusca, Echinodermata, and Hemichordata. In this blog, we’ll continue with the phylum Chordata its characteristic features, and […]

  4. Animal kingdom PCSSTUDIES - Biology - Animal kingdom · May 18, 2021 at 2:04 pm

    […] organ system level of Organisation is found in animals like Annelids, Arthropods, Molluscs, Echinoderms, and […]

  5. Classification of Animals- Phylum Porifera to Platyhelminthes % Biology % · May 28, 2021 at 11:12 am

    […] Aschelminthes, Annelida, Arthropoda, Mollusca, Echinodermata, and Hemichordata […]

  6. Amphioxus (Lancelet) - PCSSTUDIES - Science Amphioxus (Lancelet) · August 11, 2021 at 10:54 pm

    […]  Aschelminthes, […]

  7. Subphylum - Urochordata - PCSSTUDIES - Biology · November 19, 2021 at 11:05 pm

    […]  Aschelminthes, […]

  8. Leave a Reply