SACE Stage 2 Biology Practice Exam 2025 – The Comprehensive All-in-One Guide to Exam Success!

Positive feedback in biological systems is characterized by its ability to amplify the initial response or stimulus. This means that when an event occurs, positive feedback enhances the process, leading to an increased output or result. An example of positive feedback can be observed during childbirth, where the release of oxytocin increases the intensity and frequency of contractions until the baby is born. The system continues to escalate the response until a specific endpoint is reached.

In contrast to this, processes that inhibit the original stimulus or stabilize the system reflect negative feedback mechanisms. Negative feedback works to counteract changes in the system, providing a stabilizing effect. Additionally, negative feedback loops are involved in maintaining homeostasis, contrasting with the amplifying effect of positive feedback. Therefore, the hallmark of positive feedback is its role in intensifying the response rather than suppressing it or creating stabilizing feedback loops.