Coordination in living organisms can be broadly categorized into two types:
nervous coordination and chemical coordination.
In this form of coordination, specialized cells or glands release hormones, signaling molecules that stimulate or inhibit various body cells or tissues. Target cells must possess receptor molecules to respond to these signals. It’s prevalent in simpler organisms like plants and smaller animals.
Most animals exhibit nervous coordination, powered by neurons. Neurons generate rapid electrochemical signals upon stimulation, facilitating swift communication within the body. This advanced form of coordination suits animals with complex anatomies and behaviors.
Aspect | Chemical Coordination | Nervous Coordination |
Mode of Communication | Hormones (signaling molecules) | Electrical impulses (nerve signals) |
Speed of Transmission | Slower, gradual responses | Very rapid, near-instantaneous |
Target Cells | Requires specific receptors | Direct contact with neurons |
Range of Influence | Widespread, systemic effects | Precise, localized responses |
Duration of Effect | Long-term stability | Short-term, immediate effects |
Examples | Endocrine system in humans | Central and peripheral nervous systems |
Lower life forms such as prokaryotes, protozoa, algae, fungi, and plants employ chemical coordination as a vital regulatory mechanism. This intricate system relies on signalling molecules, often hormones, to govern essential functions including motion, growth, metabolism, and reproduction. For instance, the “touch me not” plant swiftly closes its leaves when touched, showcasing its prompt response to external stimuli. Other reactions, such as growth and reproduction, hinge on hormones produced by specialized cells and transported to target organs through diverse pathways. Similarly, the “sunflower” plant’s remarkable sunward movement is attributed to phytohormones called Auxins, which trigger gradual but deliberate cell expansion in shaded regions, optimizing exposure to sunlight.