Question

What are the important characteristics of growth? Describe in brief.

Answer 1

Hint: Growth refers to increase in size and entire mass of the body that may lead to structural changes which are permanent. Growth depends on several factors like increase in protoplasm, rate of cell division, rate of cell death and differentiation etc.

Complete answer:
To understand the characteristics of growth, we must first know what growth is.
Growth is physiological, irreversible, permanent increase in size of the entire body or some part of the body or cell. Growth and metabolism go hand-in-hand.

Growth in plants is different from animals and thus unique. Here are the characteristics of plant growth:
- Growth in plants is indeterminate i.e., plants keep growing as long as they live. Unlike animals, where growth takes place up till a certain age. Such kind of growth in plants is unique. There are special cells called meristematic cells which keep dividing continuously.
- Growth in plants is measurable. Increase in protoplasmic content indicates growth, but assessing protoplasmic content is difficult. Increase in fresh weight (organic matter), increase in dry weight, increase in length can be easily measured.
- Growth in plants can be understood by growth rate. Growth rate is an increase in growth per unit time. Growth rate can be geometric or arithmetic.

Growth in plants has phases. This can be understood by taking an example of root. The phases are:
- Meristematic phase: The cells are continuously dividing hence the Cell division phase.
- Elongation phase: The vacuole is enlarged in this phase.
- Differentiation or Maturation phase: The cells get differentiated to perform various special functions.

Growth in animals is different from plants.
- Growth is a slow process which leads to development in animals. With growth, different cells divide and lead to different physiological and behavioral changes in the body.
- In animals there is cell division happening constantly for wear and tear. Cell size and number increase but the increase in body size of the organism is no longer seen.
- Different cells have different life spans and thus dead and injured cells are continuously replaced by the body. Therefore, the rate of cell division differs in body parts.

Note: Growth in plants is different from growth in animals. Certain cells in plants keep dividing till the plant is alive hence they show indeterminate growth. In case of animals, growth ceases after a certain time.