Animal Kingdom

ANIMAL KINGDOM

Basis of Classification:

 

animal kingdom

 

Salient features of different phyla in the Animal Kingdom:

PhylumDigestive systemRespiratory systemCirculatory systemMonoecious/

dioecious

FertilizationDevelopment
PoriferaAbsentAbsentAbsentMonoeciousInternalIndirect
CoelenterataIncompleteAbsentAbsentMonoeciousInternalIndirect
CtenophoraIncompleteAbsentAbsentMonoeciousExternalIndirect
PlatyhelminthesIncompleteAbsentAbsentMonoeciousInternalIndirect
NematodaCompleteAbsentAbsentDioeciousInternalDirect/indirect
AnnelidaCompletePresentAbsentMonoecious/DioeciousExternalDirect
ArthropodaCompletePresentPresentDioeciousInternalDirect/indirect
MolluscaCompletePresentPresentDioeciousExternalDirect/Indirect
EchinodermataCompletePresentPresentDioeciousExternalIndirect
HemichordataCompletePresentPresentDioeciousExternalIndirect
ChordataCompletePresentPresentDioeciousInternalDirect

 

Distinctive features of different phyla in the Animal Kingdom:

Phylum Porifera:

  • Body cavity called Spongocoel present.
  • Water canal system present that helps in nutrition, respiration, excretion & reproduction.
  • The body has pores – mouth called Ostia & an outlet called Osculum.
  • Flagellated cells called Choanocytes present.
  • Skeleton made of Spicules & Spongin fibers.
  • Digestion is intracellular.

Phylum Coelenterata (Cnidaria):

  • Stinging cells called Cnidoblast / Nematocyst present for defense & offense.
  • Digestion is incomplete as mouth also acts as an anus.
  • Exhibit two basic body forms: Polyp & Medusa.
  • Metagenesis or alternation of sexual & asexual phases is seen. Both phases are diploid. E.g., Obelia.

Phylum Ctenophora:

  • Comb-like ciliary plates for swimming are seen.
  • Bioluminescence is seen.
  • Digestion is both extracellular & intracellular.

Phylum Platyhelminthes:

  • Flat body present.
  • Flame cells called as Solenocytes are meant for excretion & osmoregulation.
  • Self-fertilization occurs in Tapeworms.
  • Hook & suckers present in parasitic forms.
  • Planaria possess high regeneration capacity.

Phylum Aschelminthes (Nematode):

  • Syncytial epidermis.
  • Muscular pharynx present in the digestive system.

Phylum Annelida:

  • Metameric segmentation. The body is divided externally into rings.
  • Unjointed chitinous Setae present for locomotion, Nereis has Parapodia.
  • Haemoglobin in plasma.
  • Nephridia helps in excretion & osmoregulation.
  • Double ventral nerve cord consists of paired ganglia connected by lateral nerves.

Phylum Arthropoda:

  • Largest group with 900,000 species.
  • The thick exoskeleton is made of cuticle.
  • Jointed appendages.
  • Segmentation present.
  • Compound eyes present.
  • Excretory organs are Malphigian tubules.
  • The body cavity is Haemocoel (filled with blood).
  • Pheromones are secreted, that act as sex attractants.
  • Respiratory organs are book gills & trachea (book lungs).

Phylum Mollusca:

  • External skeleton of shell usually present.
  • The body has a distinct head, muscular foot & visceral hump.
  • Mantle covers the body.
  • The mouth has radula, a file-like rasping organ in the mouth.
  • Feather like gills is present in the mantle cavity that is respiratory & excretory.

Phylum Echinodermata:

  • Spines are present.
  • Water vascular system (ambulacral system), helps in locomotion, capture & transport of food and respiration.
  • Mesodermal endoskeleton of calcareous plates.
  • Shows bilateral symmetry in larvae & radial symmetry in the adult.

Phylum Hemichordata:

  • Worm-like animals.
  • Body divided into proboscis, collar & trunk.
  • Open circulatory system.
  • Respiration through gills.
  • The Excretory organ is proboscis gland.

Phylum Chordata:

  • Notochord present.
  • Dorsal hollow nerve cord.
  • Gill slits with limbs or fins present.
  • Closed circulatory system.
  • Ventral heart.
  • Post-anal tail present.

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