Structural Organisation in Animals
Class 11 · Biology
4 ideas in Class 11 Biology, explained in plain words, with games and quizzes to practise.
Cells to Organ Systems
Part of: Tissues and Frog Body
Similar cells with matrix form tissues; four basic types weave organs like hearts; organs team into systems. Outer form is morphology; inner organs are anatomy. Epithelia line with one free face and junctions.
Why it matters. Division of labour scales from Hydra to humans. Tissue mix explains organ jobs.
Key words
- Tissue
- : Similar cells plus matrix working at one job.
- Epithelial tissue
- : Sheets of cells lining surfaces with one free face.
- Morphology
- : The study of an animals outer form and shape.
- Anatomy
- : The study of an animals inner organs and structure.
- Organ
- : A part like the heart built from several tissues.
- Organ system
- : Organs teamed by physical or chemical links for shared work.
Try it in two minutes
- Order cells to systems.
- Name four tissue types.
- Split morphology from anatomy.
Try at home. Name the systems behind one meal.
Frog Morphology
Part of: Tissues and Frog Body
Rana tigrina bridges water and land with cool tracking bodies, camouflage shifts, burrow sleeps, mucus skin, head-trunk build, webbed leaps, blinking lids, ear drums, and marked males with voice sacs and grip pads.
Why it matters. Each outer trait meets a habitat need. Male marks reveal mating roles.
Key words
- Poikilotherm
- : Body temperature follows the surroundings.
- Aestivation
- : Summer sleep to escape heat and dryness.
- Hibernation
- : Winter sleep to escape cold and food shortage.
- Camouflage
- : Colour shifts that hide the frog from enemies.
- Rana tigrina
- : The common Indian frog studied as a vertebrate model.
- Copulatory pad
- : Male grip pads used to hold the female during mating.
Try it in two minutes
- Count digits on each limb.
- Spot ear drums and lids.
- Separate male from female.
Try at home. Sketch a frog and label ten parts.
Frog Digestion, Respiration and Circulation
Part of: Frog Organ Systems
Short carnivore guts run mouth to cloaca with bile and pancreatic juices feeding villi. Skin breathes underwater; lungs join on land. Triple hearts with sinus venosus and conus arteriosus drive portal-linked circuits of nucleated red cells; lymph runs lean.
Why it matters. Diet shortens guts; habitat doubles breathing; three chambers split flows. Special veins preview mammalian portals.
Key words
- Villi
- : Folds of the gut wall that absorb digested food.
- Cutaneous respiration
- : Breathing through moist skin in water.
- Pulmonary respiration
- : Breathing through lungs on land.
- Three-chambered heart
- : Frog heart with two atria and one ventricle.
- Portal systems
- : Veins that route flow through the liver or kidney first.
- Lymph
- : Tissue fluid with less protein and no red cells.
Try it in two minutes
- Order gut from mouth to cloaca.
- Assign each breathing surface.
- Trace heart to body and back.
Try at home. List human organs matching frog ones.
Frog Excretion, Control and Reproduction
Part of: Frog Organ Systems
Bean kidneys filter through nephrons; males share ducts while females split them; urea leaves as in ureotelic design. Ten cranial pairs wire three-part brains with five senses; glands tune hormones; thousands of eggs meet water sperm and hatch tadpoles that transform.
Why it matters. Shared versus split ducts mark frog sexes. External mating explains huge egg counts.
Key words
- Ureotelic
- : Excreting nitrogen waste mainly as urea.
- Nephron
- : Kidney tubule unit that filters fluid into urine.
- Metamorphosis
- : Change of a tadpole larva into an adult frog.
- Aestivation
- : Summer sleep to escape heat and dryness.
- Hibernation
- : Winter sleep to escape cold and food shortage.
- Cranial nerves
- : Ten pairs of nerves leaving the frog brain.
Try it in two minutes
- Name the kidney units.
- Contrast male with female ducts.
- Order egg to tadpole to frog.
Try at home. Chart frog senses against your own.
What your child will practise
- Cells to Organ Systems: Desert Puzzle (Clue Puzzle)
- Cells to Organ Systems: Desert Quick Fire (Quick Fire)
- Frog Digestion, Respiration and Circulation: Space Puzzle (Clue Puzzle)
- Frog Excretion, Control and Reproduction: Desert Quest (Flip and Match)
- Frog Morphology: Jungle Quick Fire (Quick Fire)
- Quiz: Cells to Organ Systems (8 questions)
- Quiz: Frog Digestion, Respiration and Circulation (8 questions)
- Quiz: Frog Excretion, Control and Reproduction (8 questions)
- Quiz: Frog Morphology (8 questions)