Question

What is meant by co-ordination? <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> [Textbook Question 7a pg no.178]

Answer 1

The function of cells, tissues and finally, the organs together as a unit in an organism in order to co-ordinate with its external environment is defined as co-ordination.

It is the functioning together of various organs in an integrated manner to produce a suitable reaction in response to an external stimulus.

• Generally the animals, including human beings, the coordination is done by the nervous system and endocrine system via the help of neurones and various hormones.

• In plants, different plant hormones like auxins, gibberellins, cytokinins, abscisic acid (ABA) and ethylene [which is a gaseous hormone (C2H4)]help in their coordination.

e.g., the division of cells and tissues, parthenogenesis (in case of banana) like processes are governed by auxins and cytokinins. The shape and size of the fruits, the length of the internodes (in case of sugarcane) are governed by gibberellins. The abscision & shedding off of leaves is controlled by ABA while the dominancy or germination of seeds is under the control of ethylene.