KINGDOM ANIMALIA: HIGH-YIELD QUICK NOTES
Core Classification Matrix & Diagnostic Phylum Hallmarks
1. BASIS OF CLASSIFICATION
Phylum Organization Symmetry Germ Layer Coelom Segmentation
Porifera Cellular Asymmetrical None / Diploblastic-like Acoelomate Absent
Cnidaria Tissue Radial Diploblastic Acoelomate Absent
Ctenophora Tissue Biradial / Radial Diploblastic Acoelomate Absent
Platyhelminthes Organ / Organ-system Bilateral Triploblastic Acoelomate Absent
Aschelminthes Organ-system Bilateral Triploblastic Pseudocoelomate Absent
Annelida Organ-system Bilateral Triploblastic Coelomate Present (Metamerism)
Arthropoda Organ-system Bilateral Triploblastic Coelomate (Hemocoel) Present
Mollusca Organ-system Bilateral Triploblastic Coelomate Absent
Echinodermata Organ-system Larva: Bilateral | Adult: Radial Triploblastic Coelomate Absent
Hemichordata Organ-system Bilateral Triploblastic Coelomate Absent
Chordata Organ-system Bilateral Triploblastic Coelomate Present
2. DIAGNOSTIC SPECIAL FEATURES
Porifera: Water canal system (ostia → spongocoel → osculum), choanocytes (collar cells), spicule/spongin skeleton.
Cnidaria: Cnidoblasts (nematocysts for defense/offense), polyp & medusa forms, metagenesis (*Obelia*).
Ctenophora: 8 ciliated comb plates (locomotion), colloblasts (lasso cells), bioluminescence, strictly marine.
Platyhelminthes: Dorso-ventrally flat, flame cells (protonephridia) for osmoregulation/excretion, hooks/suckers, high regeneration (*Planaria*).
Aschelminthes: Cylindrical (round), syncytial epidermis, muscular pharynx, distinct sexual dimorphism (females longer).
Annelida: True metamerism, longitudinal/circular muscles with chitinous setae or parapodia, paired nephridia.
Arthropoda: Chitinous exoskeleton shed via ecdysis (molting), jointed appendages, Malpighian tubules, open circulation.
Mollusca: Unsegmented soft body with muscular foot, visceral hump, mantle with ctenidia (gills), and rasping radula.
Echinodermata: Water vascular system with tube feet (podia), calcareous spiny endoskeleton, adult pentaradial symmetry.
Hemichordata: Worm-like body (proboscis, collar, trunk), stomochord, proboscis gland for excretion.
Chordata: Dorsal notochord, dorsal hollow nerve cord, pharyngeal gill slits, post-anal tail.
Core Classification Matrix & Diagnostic Phylum Hallmarks
1. BASIS OF CLASSIFICATION
Phylum Organization Symmetry Germ Layer Coelom Segmentation
Porifera Cellular Asymmetrical None / Diploblastic-like Acoelomate Absent
Cnidaria Tissue Radial Diploblastic Acoelomate Absent
Ctenophora Tissue Biradial / Radial Diploblastic Acoelomate Absent
Platyhelminthes Organ / Organ-system Bilateral Triploblastic Acoelomate Absent
Aschelminthes Organ-system Bilateral Triploblastic Pseudocoelomate Absent
Annelida Organ-system Bilateral Triploblastic Coelomate Present (Metamerism)
Arthropoda Organ-system Bilateral Triploblastic Coelomate (Hemocoel) Present
Mollusca Organ-system Bilateral Triploblastic Coelomate Absent
Echinodermata Organ-system Larva: Bilateral | Adult: Radial Triploblastic Coelomate Absent
Hemichordata Organ-system Bilateral Triploblastic Coelomate Absent
Chordata Organ-system Bilateral Triploblastic Coelomate Present
2. DIAGNOSTIC SPECIAL FEATURES
Porifera: Water canal system (ostia → spongocoel → osculum), choanocytes (collar cells), spicule/spongin skeleton.
Cnidaria: Cnidoblasts (nematocysts for defense/offense), polyp & medusa forms, metagenesis (*Obelia*).
Ctenophora: 8 ciliated comb plates (locomotion), colloblasts (lasso cells), bioluminescence, strictly marine.
Platyhelminthes: Dorso-ventrally flat, flame cells (protonephridia) for osmoregulation/excretion, hooks/suckers, high regeneration (*Planaria*).
Aschelminthes: Cylindrical (round), syncytial epidermis, muscular pharynx, distinct sexual dimorphism (females longer).
Annelida: True metamerism, longitudinal/circular muscles with chitinous setae or parapodia, paired nephridia.
Arthropoda: Chitinous exoskeleton shed via ecdysis (molting), jointed appendages, Malpighian tubules, open circulation.
Mollusca: Unsegmented soft body with muscular foot, visceral hump, mantle with ctenidia (gills), and rasping radula.
Echinodermata: Water vascular system with tube feet (podia), calcareous spiny endoskeleton, adult pentaradial symmetry.
Hemichordata: Worm-like body (proboscis, collar, trunk), stomochord, proboscis gland for excretion.
Chordata: Dorsal notochord, dorsal hollow nerve cord, pharyngeal gill slits, post-anal tail.
