NCERT Solutions Class 11 Biology Chapter 20 – Download PDF

The class 11 NCERT solutions for biology chapter 20 are provided here so that students can refer to these solutions for better clarification and understanding. It consists of answers to the textbook questions along with extra question and important questions from previous year question papers. This solution provides you with exemplary questions, MCQ’S, locomotion and movement important questions and other exercises that will help you in understanding the topic thoroughly.

This chapter specifically deals with how you move using your limbs and the related muscles and bones. Movement is something that differentiates plants from the animals. Multicellular animals developed movement as a way of getting from point A to point B either to feed or to evade predators. It is also important to adapt to the environment or move to a more favourable environment. Also, evolution played an important role in locomotion. Humans are tetrapod, meaning we got 2 pairs of limbs. This lineage includes almost all vertebrates. Even snakes are considered tetrapods because they evolved from ancestors who had 2 pairs of limbs.

Important concepts of Chapter 20 locomotion movement

1. Types of Movement
2. Muscle
   1. Structure of Contractile Proteins
   2. Mechanism of Muscle Contraction
3. Skeletal System
4. Joints
5. Disorders of Muscular and Skeletal System.

Importance of Locomotion and movement Concept

Locomotion and movement is an important function in animals. They help the organism to find food or acquire prey, evade predators, and find mates. Also, it helps the organisms to migrate and adapt to new and favourable environments. Anatomically speaking, most vertebrates are tetrapods, meaning that they have two pairs of limbs. Humans, cows, horses all are tetrapods as they obviously have 4 limbs. Even animals that seem like they don’t have any limbs like snakes are considered tetrapods because they have ancestors who had four limbs.

This theory was also proved when scientists discovered a fossil of a snake that had 4 small limbs protruding from its body. But scientists have theorized that the limbs were not meant for walking – it was probably used during mating or to hold on to unruly prey.

Humans have several muscles in their limbs, in tandem with bones they provide strength and structure to aid locomotion. There are many muscle types that are adapted to fulfil this function by having specialized cells and tissues suited for the task. Besides this, single cells also move – For instance, did you know that human White Blood Cells can sprout many legs like a millipede and crawl along the walls of the blood vessels towards the site of an injury.

 

(a) Actin and Myosin

(b) Red and white muscles

(c) Pectoral and Pelvic girdle

Q6: Match Column I with Column II :

Answer:

Answer: