Kingdom Animalia

• Germ Layers:
  • Diploblastic: 2 layers (Ectoderm, Endoderm). e.g., Cnidaria.
  • Triploblastic: 3 layers (Ectoderm, Mesoderm, Endoderm). e.g., Platyhelminthes to Chordata.
• Coelom (Body Cavity):
  • Acoelomate: No cavity. e.g., Platyhelminthes.
  • Pseudocoelomate: False cavity (not lined by mesoderm). e.g., Nematoda.
  • Coelomate: True cavity (lined by mesoderm). e.g., Annelida to Chordata.
• Symmetry:
  • Radial: Division into equal halves by any plane. e.g., Cnidaria.
  • Bilateral: Division into right/left halves by one plane. e.g., Mammals.

• Phylum Porifera (Sponges): Pore-bearing (Ostia). Canal system for feeding. Spicules for support. e.g., Sycon.
• Phylum Cnidaria (Coelenterata): Have stinging cells (Cnidocytes). Two forms: Polyp (sessile) and Medusa (motile). e.g., Hydra, Jellyfish.
• Phylum Platyhelminthes (Flatworms): Dorso-ventrally flattened. Acoelomate. Excretion by Flame Cells. e.g., Tapeworm.
• Phylum Nematoda (Roundworms): Cylindrical body. Pseudocoelomate. e.g., Ascaris.

• Phylum Annelida (Segmented Worms): Metameric segmentation. Closed circulatory system. Excretion by Nephridia. e.g., Earthworm.
• Phylum Arthropoda: Largest phylum. Jointed appendages. Chitinous exoskeleton (molting). Open circulatory system. e.g., Insects, Crabs.
• Phylum Mollusca: Soft-bodied. Shell (usually). Radula for feeding. Mantle cavity. e.g., Snail, Octopus.
• Phylum Echinodermata: Spiny skin. Water Vascular System (Tube feet) for locomotion. Radial symmetry in adults. e.g., Starfish.

4 Key Characteristics: Notochord, Dorsal Hollow Nerve Cord, Pharyngeal Gill Slits, Post-anal Tail.

• Protochordata: Notochord persists or restricted to tail. e.g., Lancelet.
• Vertebrata: Notochord replaced by Vertebral Column.

1. Pisces (Fishes): Aquatic, gills, fins. Chondrichthyes (Cartilaginous, e.g., Shark) vs Osteichthyes (Bony, e.g., Rohu).
2. Amphibia: Dual life (Land/Water). Moist skin. 3-chambered heart. e.g., Frog.
3. Reptilia: Creeping mode. Dry scaly skin. Shelled eggs (Amniotes). e.g., Snake.
4. Aves (Birds): Feathers, wings, pneumatic bones. Warm-blooded. e.g., Sparrow.
5. Mammalia: Hair, Mammary glands. Warm-blooded.
   • Prototheria: Egg-laying (Platypus).
   • Metatheria: Pouched (Kangaroo).
   • Eutheria: Placental (Human).