Phylum Mollusca | Diversity in Living Organisms | Biology | Grade 9 | Telangana | Khan Academy
In this video, we dive into the fascinating world of Phylum Mollusca — the group that includes snails, mussels, octopuses, and even giant squids! Ever picked up a seashell and wondered who once lived inside it? Discover how molluscs, with their soft bodies, protective shells, and unique body divisions, survive and thrive in oceans, rivers, lakes, and even on land. We explore their body structure, the roles of the head–foot, visceral mass, and mantle, and how their gills, nephridia, open or closed circulatory systems, and well-developed nervous systems help them function. From snail gliding to the powerful jet propulsion of squids and octopuses, this video breaks down how molluscs move, breathe, feed, and reproduce. You'll also learn how octopuses solve puzzles and why molluscs are among Earth’s most adaptable animals. Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now! (add course link here) Timestamps: 0:00 – Introduction to Molluscs 0:17 – Meaning of “Mollusca” 0:26 – Diversity & Examples 0:37 – Habitat of Molluscs 0:58 – Body Structure & Shell 1:04 – Head-Foot, Visceral Mass & Mantle 1:29 – Symmetry & Triploblastic Body 1:57 – Coelom & Haemocele 2:18 – Shell & Variations 2:40 – Organ System Level of Organisation 3:00 – Complete Digestive System 3:15 – Circulatory System (Open & Closed) 3:41 – Respiration Through Gills 3:54 – Excretion Through Nephridia 4:02 – Nervous System: From Simple to Advanced 4:36 – Locomotion in Molluscs 5:03 – Jet Propulsion 5:06 – Sexual Reproduction & Larval Stage 5:25 – Summary of Key Features 6:01 – Closing: Seashells and Molluscs Khan Academy India is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We have videos and exercises that have been translated into multiple Indian languages, and 15 million people around the globe learn on Khan Academy every month. Support Us: https://india.khanacademy.org/donate
