Final answer:
Ophelia's character development in 'Hamlet' transitions from compliant and demure to apparently mad, with the pivotal event of her father's death leading to her emotional breakdown and tragic drowning.
Step-by-step explanation:
Ophelia undergoes significant transformation over the course of Shakespeare's Hamlet. Initially, she is obedient and dutiful, complying with her father Polonius's wishes and spurning Hamlet at his behest.
However, the plot event of her father's death triggers a drastic change, as she descends into apparent madness, symbolized by her erratic singing and gifting of flowers, representing a loss of innocence and descent into emotional turmoil. Her eventual death by drowning cements her transformation as a tragic figure enveloped by the consequences of the machinations around her, unable to exert control over her destiny.