Zoology — Important Diagrams
All diagrams that appear in TGBIE 1st Year Zoology exams — listed unit-wise with key labels.
Unit III & IV: Animal Diversity
Earthworm (Pheretima) external view
Labels: Mouth, prostomium, clitellum, segments, dorsal pore, typhlosole (internal), setae
T.S. of earthworm
Labels: Cuticle, epidermis, circular muscle, longitudinal muscle, coelom, intestine with typhlosole, dorsal and ventral blood vessels, nerve cord
External features of a frog (Rana)
Labels: Head, trunk, forelimbs (4 fingers), hindlimbs (5 toes with webbing), tympanum, nostrils, eye, dorsal and ventral surfaces
Unit VII: Periplaneta americana
Digestive system of Periplaneta
Labels: Mouth, pharynx, oesophagus, crop, gizzard, stomach (mesenteron), ileum, colon, rectum, anus, gastric caeca, Malpighian tubules
Nervous system of Periplaneta
Labels: Supra-oesophageal ganglion (brain), sub-oesophageal ganglion, ventral nerve cord, 6 abdominal ganglia, connectives, nerve roots
Structure of Ommatidium
Labels: Corneal lens, crystalline cone, rhabdom, retinal cells, pigment cells, basement membrane, nerve fibre
Reproductive system (male Periplaneta)
Labels: Testes, vas deferens, seminal vesicle, mushroom gland, ejaculatory duct, phallomere
External morphology of Periplaneta
Labels: Head (antennae, compound eyes, mouthparts), thorax (pro-, meso-, meta-thorax with legs and wings), abdomen (10 segments, cerci, anal styles in male)
Unit VI: Parasitic Life Cycles
Life cycle of Plasmodium vivax
Labels: Sporozoite → liver cells (exo-erythrocytic schizogony) → merozoites → RBCs (erythrocytic schizogony) → trophozoite → schizont → gametocytes → mosquito (sporogony)
Life cycle of Ascaris lumbricoides
Labels: Egg in soil → infective egg (ingested) → larva hatches in intestine → migrates (heart → lungs → intestine) → adult worm → eggs passed in faeces
Unit VIII: Ecology
Carbon Cycle
Labels: CO₂ in atmosphere, photosynthesis (plants absorb), respiration (organisms release), decomposition, combustion, ocean absorption
Ecological Pyramids
Labels: Pyramid of numbers (producers → herbivores → carnivores), pyramid of biomass (inverted in aquatic), pyramid of energy (always upright)
Food chain — lake ecosystem
Labels: Phytoplankton → zooplankton → small fish → large fish → decomposers; label producer, primary consumer, secondary consumer, tertiary consumer
Exam Tip: Periplaneta Diagrams
Periplaneta LAQs are the most diagram-heavy in Zoology. Prepare all 5 system diagrams separately and label each one completely. The digestive system and nervous system diagrams are asked most frequently.