📚 Quick Revision: Animal Kingdom (Protozoa to Chordata)

🔹 Protozoa: Unicellular, eukaryotic, heterotrophic. Examples: Amoeba (pseudopodia), Paramecium (cilia), Plasmodium (malaria). Reproduction: binary fission, conjugation. Contractile vacuole for osmoregulation.

🔹 Porifera (Sponges): Pore-bearing, asymmetrical, cellular level. Examples: Sycon, Spongilla. Canal system for water circulation. Skeleton of spicules/spongin.

🔹 Coelenterata (Cnidaria): Radial symmetry, diploblastic, cnidoblasts (stinging cells). Examples: Hydra, Jellyfish. Two body forms: polyp and medusa. Corals form reefs.

🔹 Platyhelminthes (Flatworms): Dorsoventrally flattened, triploblastic, acoelomate. Examples: Taenia (tapeworm), Fasciola (liver fluke). Flame cells for excretion. Parasitic with hooks and suckers.

🔹 Aschelminthes (Nematoda): Roundworms, pseudocoelomate, complete digestive system. Examples: Ascaris, Enterobius. Dioecious (separate sexes). Cause ascariasis, filariasis.

🔹 Annelida (Segmented worms): Metameric segmentation, closed circulation. Examples: Earthworm (Pheretima), Leech. Nephridia for excretion. Earthworm is hermaphrodite, cocoon formation.

🔹 Arthropoda: Largest phylum, jointed appendages, chitinous exoskeleton. Open circulation. Examples: Insects (Periplaneta), Arachnids (Aranea), Crustaceans (Palaemon). Metamorphosis in insects.

🔹 Mollusca: Soft-bodied, often with shell, muscular foot. Examples: Pila, Helix, Unio, Octopus. Respiration by gills (ctenidia). Radula for feeding.

🔹 Echinodermata: Spiny-skinned, pentamerous radial symmetry, water vascular system. Examples: Starfish (Asterias), Sea urchin. Tube feet for locomotion. High regeneration capacity.

🔹 Chordata: Notochord, dorsal hollow nerve cord, pharyngeal gill slits, post-anal tail. Classes: Pisces (fish), Amphibia (frog), Reptilia (lizard), Aves (birds), Mammalia (human). Key features: Pisces - scales, gills; Amphibia - moist skin, 3-chambered heart; Reptilia - dry scaly skin, 3-chambered heart; Aves - feathers, hollow bones, 4-chambered heart; Mammalia - mammary glands, hair, 4-chambered heart.

💡 Exam Tips: Focus on scientific names (Pheretima posthuma, Rana tigrina), characteristic features of each phylum, and examples. In CEE/NEB, 12-14 questions from Zoology are common.