The significance of cellular signaling in organisms lies in its role in communication between cells and in coordinating various biological processes. Signaling pathways enable cells to respond to external stimuli, facilitating essential functions such as growth, immune response, and metabolism. Through complex interactions involving hormones, neurotransmitters, and receptors, cellular signaling maintains homeostasis and regulates development. Dysregulation of these signaling pathways can lead to diseases such as cancer or diabetes, emphasizing the importance of understanding cellular communication for advancements in healthcare and medicine.