Question

Structural organisation in animals attains different levels as a cell - organ - organ system. What is missing in this chain? Mention the significance of such an organisation.

Answer 1

Structural organisation in animals:

Structural organisation in animals can be studied in the following way starting from the lowest level:-
Cell→ tissue→ organ→ organ system

Tissue:

Tissue is missing from the structural organisation given in the question. A group of similar cells having a common origin and a specific function is called tissue. Each tissue has specific functions. Tissues group together to form organs.

Significance:

Multicellular animals cannot directly exchange nutrients from the surroundings. They have diverse functions like ingestion, digestion, excretion, respiration, reproduction etc. All these functions must be carried out efficiently for the survival and growth of these organisms. The structural organisation helps in bringing out an effective “division of labour” as each tissue is specialised for a particular function. This enhances the effectiveness of the complex functions of these animals.