Animal Kingdom (Class 11 Biology)

• Basis of Classification

  • Levels of Organization
    • Cellular level
    • Tissue level
    • Organ level
    • Organ system level
  • Symmetry
    • Asymmetry (e.g., Sponge)
    • Radial symmetry (e.g., Hydra, Starfish)
    • Bilateral symmetry (e.g., Annelids, Arthropods)
  • Germ Layers
    • Diploblastic (Ectoderm & Endoderm)
    • Triploblastic (Ectoderm, Mesoderm & Endoderm)
  • Coelom (Body Cavity)
    • Acoelomates (No coelom)
    • Pseudocoelomates (False coelom)
    • Coelomates (True coelom)
  • Segmentation
    • Metamerism (e.g., Earthworm)
  • Notochord
    • Non-chordates (Without notochord)
    • Chordates (With notochord)

• Classification of Phyla (Non-Chordates)

  • Phylum Porifera
    • Sponges, canal system, choanocytes
    • Example: Sycon, Euspongia
  • Phylum Coelenterata (Cnidaria)
    • Cnidoblasts, radial symmetry, polyp and medusa
    • Example: Hydra, Aurelia (Jellyfish)
  • Phylum Ctenophora
    • Comb jellies, bioluminescence
    • Example: Pleurobrachia
  • Phylum Platyhelminthes
    • Flatworms, dorsoventrally flattened, flame cells
    • Example: Taenia (Tapeworm), Fasciola
  • Phylum Aschelminthes
    • Roundworms, circular cross-section, pseudocoelomate
    • Example: Ascaris, Wuchereria
  • Phylum Annelida
    • Segmented worms, nephridia, longitudinal and circular muscles
    • Example: Pheretima (Earthworm), Hirudinaria
  • Phylum Arthropoda
    • Largest phylum, jointed appendages, chitinous exoskeleton, malpighian tubules
    • Example: Apis (Honeybee), Bombyx, vectors (Anopheles, Culex)
  • Phylum Mollusca
    • Soft-bodied, shell, mantle cavity, radula
    • Example: Pila (Apple snail), Octopus
  • Phylum Echinodermata
    • Spiny-skinned, water vascular system, radial symmetry in adults
    • Example: Asterias (Starfish), Echinus
  • Phylum Hemichordata
    • Worm-like, stomochord, proboscis gland
    • Example: Balanoglossus, Saccoglossus

• Classification of Phylum Chordata

  • Fundamental Characteristics
    • Presence of notochord
    • Dorsal hollow nerve cord
    • Paired pharyngeal gill slits
  • Subphylum Urochordata
    • Notochord in larval tail (e.g., Ascidia)
  • Subphylum Cephalochordata
    • Notochord from head to tail region (e.g., Amphioxus)
  • Subphylum Vertebrata
    • Notochord replaced by vertebral column
    • Superclass Agnatha (Jawless)
      • Class Cyclostomata (e.g., Petromyzon)
    • Superclass Gnathostomata (Jawed)
      • Class Chondrichthyes
        • Cartilaginous fish, placoid scales, gill slits without operculum (e.g., Scoliodon / Shark)
      • Class Osteichthyes
        • Bony fish, cycloid scales, operculum present (e.g., Rohu, Hippocampus)
      • Class Amphibia
        • Dual life (land and water), moist skin, tympanum (e.g., Rana / Frog)
      • Class Reptilia
        • Creeping/crawling, dry cornified skin, amniotes (e.g., Snake, Turtle)
      • Class Aves
        • Birds, feathers, pneumatic bones, forelimbs modified into wings (e.g., Columba / Pigeon)
      • Class Mammalia
        • Mammary glands, hair on skin, viviparous (mostly), external ears / pinna (e.g., Homo sapiens, Rat)