Life : Simple and Complex – Maharashtra Board Class 9 Solutions for Science and Technology (English Medium)
A group of cells which are similar in structure and perform the same function is known as tissue.
- Highly evolved plants and animals are multicellular. These cells work in groups which perform the same function and these groups are called tissues.
- Each tissue is able to perform only a specific function. While in unicellular organisms, a single cell performs all the functions of the body. However, in multicellular organisms, there is division of labour which means each tissue is allotted a specific function.
- For example, in plants, the parenchyma cells store food and water. The xylem transports water and salts from the roots to the other parts of the plant, while the phloem carries prepared food from the leaves to the roots and stem.
- Thus, all the processes necessary for life in plants function smoothly due to division of labour.
- In animals, epithelial tissues perform the functions of protection, secretion and absorption.
- Various types of connective tissues support the framework of the body.
- The fluid connective tissues, like blood, are essential for survival and contain different blood cells which perform different functions.
- Muscular tissue is connected with bones and cartilage and helps in the movement of the body.
- Nervous tissue helps in the transmission of impulses.
- Thus, the complexity of multicellular organisms is made easier due to division of labour.
- Life would not have been possible without such division of labour in tissues.
Differences between striated and unstriated muscles:
- Squamous epithelium
- Apical meristem
- The ciliated columnar epithelium is located in the respiratory tract.
- Kidney possesses cuboidal epithelium.
- Aerenchyma gives buoyancy to the plants.
- Striated muscles are also called voluntary muscles (or unstriated muscles are called involuntary muscles).
- Chlorenchyma contains chlorophyll.
- Meristems (Others are permanent tissues of plants.)
- Epidermis (Others are tissues in animals.)