Basis of Classification:
Salient features of different phyla in the Animal Kingdom:
|Phylum||Digestive system||Respiratory system||Circulatory system||Monoecious/|
Distinctive features of different phyla in the Animal Kingdom:
- 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.
- Comb-like ciliary plates for swimming are seen.
- Bioluminescence is seen.
- Digestion is both extracellular & intracellular.
- 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.
- 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.
- 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).
- 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.
- 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.
- Worm-like animals.
- Body divided into proboscis, collar & trunk.
- Open circulatory system.
- Respiration through gills.
- The Excretory organ is proboscis gland.
- Notochord present.
- Dorsal hollow nerve cord.
- Gill slits with limbs or fins present.
- Closed circulatory system.
- Ventral heart.
- Post-anal tail present.