Chapter 7:
Transportation in Animals and Plants

Class 7 Science | CBSE Curriculum

Learn Circulatory system, blood components, heart, excretory system, xylem, phloem, transpiration, and transport mechanisms explained with more than 100 practice questions.

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Quick Revision: Transportation in Animals and Plants

  • Blood Components: Plasma (fluid), RBCs (haemoglobin for oxygen transport), WBCs (immunity), Platelets (clotting).
  • Blood Vessels: Arteries (thick walls, carry blood away from heart), Veins (thin walls, valves, carry blood to heart), Capillaries (exchange site).
  • Heart: 4 chambers (2 atria, 2 ventricles); pumps blood; heartbeat = 70-80/min in adults.
  • Pulse: Throbbing in arteries; pulse rate = heart rate.
  • Excretion: Removal of metabolic wastes. Human excretory system: Kidneys → ureters → bladder → urethra.
  • Waste Products: Humans (urea), Fish (ammonia), Birds/Lizards (uric acid).
  • Plant Transport: Xylem (water + minerals upward), Phloem (food bidirectionally).
  • Transpiration: Loss of water vapor through stomata; creates suction pull; cools the plant.
  • Root Hairs: Increase surface area for absorption.
  • Dialysis: Artificial filtration of blood when kidneys fail.

Chapter Summary:

Transportation in Animals and Plants explains how essential substances move within living organisms. In animals, the circulatory system—comprising blood, blood vessels, and the heart—transports oxygen, nutrients, and wastes. Blood contains plasma, red blood cells (with haemoglobin), white blood cells (defense), and platelets (clotting). Arteries carry blood away from the heart (thick walls), veins return blood (valves prevent backflow), and capillaries enable exchange. The human heart has four chambers, beating 70-80 times per minute, producing a pulse felt in arteries.

Excretion removes metabolic wastes. The human excretory system includes kidneys (filter blood), ureters, urinary bladder (storage), and urethra. Waste products vary: ammonia (aquatic animals), urea (humans), uric acid (birds/reptiles). Dialysis replaces kidney function when needed.

In plants, xylem transports water and minerals from roots upward; phloem transports food from leaves to all parts. Transpiration (water loss through stomata) generates suction pull for water movement. Root hairs increase absorption surface. Understanding these transport systems reveals how organisms maintain homeostasis and survive.