Phylum Annelida are truly coelomate animals with metameric segmentation. Capacious coelom and its divisions by septa into separate water tight compartments gives much greater control in the use of the hydrostatic skeleton so that changes in shape, shortening, lengthening or bending can be achieved in one segment without unduly influencing the adjacent segments. Phylum annelida includes primitive Archiannelids, Polychaetes and Oligochaetes. Primitive annelids are marine forms which might have given rise to polychaetes and oligochaetes separately. Polychaetes are polyphylectic. Polychaetes represent one line of evolution while Oligochaetes and their related forms second line of evolution. Echiuroids, sipunculids, priapulids and myzostomaria listed as classes of annelids are considered as independent phyla. However the fundamental pattern evolved in Annelids (coelom and segmentation) continue up to man.
DIAGNOSTIC CHARACTERS OF PHYLUM ANNELIDA
- Segmented and coelomate animals.
- Segmentation metameric.
- Closed circulation.
- Excretory organs metanephridia.
- Exoskeleton absent.
- Fresh-water, marine, terrestrial, burrowing or tubicolours.
CLASSIFICATION OF PHYLUM ANNELIDA
CLASS I POLYCHAETA
- Many setae or hair in each segment.
- Clitellum absent.
- Larva trochophore.
Order 1 Errantia
Order 2 Tubicola
Order 3 Sedentaria
CLASS III HIRUDINEA
- It includes leeches.
- Anterior and posterior suckers present. Parapodia absent.
- Only external segmentation.
Order 1 Acanthobdellida
- Primitive leeches.
- Coelom with compartments.
- Anterior sucker absent.
Example :- Acanthobdella.
Order 2 Rhynchobdellida or Agnathobdellida
Order 3 Arhynchobdellida or Gnathobellida
- CHIMAERA : RAT FISHCHIMAERA : RAT FISH CLASSIFICATION OF CHIMAERA : RAT FISH Phylum :- CHORDATA ( Notochord and dorsal tubular nerve cord present and gill-slits present). Group :- CRANIATA ( Cranium with brain present ...READ MORE
- PHYLUM PORIFERAPHYLUM – PORIFERA HISTORY The initial advantage of becoming multicellular is the opportunity for increase in size. Larger organisms are less subject to attack; they have greater reserves within ...READ MORE
- ALLIGATORALLIGATOR CLASSIFICATION OF ALLIGATOR PHYLUM :- CHORDATA (Notochord, dorsal tubular nerve cord present and gill slits present ) Group :- CRANIATA ( Definite head. Cranium with brain present ) ...READ MORE
- Comparative Study of Respiratory System of VertebrateComparative Study of Respiratory System of Vertebrate Respiratory Organs Exchange of 02 and C02 in an organism takes place in two locations. During internal respiration, also termed cellular or ...READ MORE
- GIRAFFEGIRAFFE CLASSIFICATION OF GIRAFFE : GIRAFFA CAMELOPARADALIS PHYLUM :- CHORDATA (Notochord, dorsal tubular nerve cord present and gill slits present ) Group :- CRANIATA ( Definite head. Cranium with ...READ MORE
- 8 MOST DANGEROUS ANIMALS IN THE OCEAN8 MOST DANGEROUS ANIMALS IN THE OCEAN The aquatic world is characterized by being an immense and mysterious ecosystem, in which the living beings that inhabit it merge and provide a simply wonderful ...READ MORE
- EUGLENAEUGLENA CLASSIFICATION OF EUGLENA PHYLUM :- PROTOZOA (Unicellular) SUB-PHYLUM :- PLASMODROMA (Cilia absent, locomotion by pseudopodia) CLASS :- MASTIGOPHORA (One or more flagella) SUB-CLASS :- ...READ MORE
- TORPEDO : ELECTRIC RAYTORPEDO : ELECTRIC RAY CLASSIFICATION of torpedo Phylum :- CHORDATA ( Notochord and dorsal tubular nerve cord present and gill-slits present). Group :- CRANIATA ( Cranium with brain present ). ...READ MORE
- COLUMBA LIVIA : PIGEONCOLUMBA LIVIA : PIGEON CLASSIFICATION OF PAVO COLUMBA LIVIA : PIGEON PHYLUM :- CHORDATA (Notochord, dorsal tubular nerve cord present and gill slits present ) Group :- CRANIATA ( Definite head. ...READ MORE
- ERYX : SAND BOA (DHAMAN)ERYX : SAND BOA (DHAMAN) CLASSIFICATION OF ERYX : SAND BOA (DHAMAN) PHYLUM :- CHORDATA (Notochord, dorsal tubular nerve cord present and gill slits present ) Group :- CRANIATA ( Definite head. ...READ MORE