One example of disturbances in the internal environment that can act as a stimulus to a feedback mechanism is ovulation. The estrogen, a hormone released by the ovaries, operates as a positive feedback loop stimulation. The information is sent to the brain, which causes the hypothalamus to release gonadotrophin-releasing hormone (GnRH) and the pituitary to release a luteinizing hormone (LH) in response to stimulation. The rise of these hormones will trigger the secretion of more estrogen, which will also trigger the release of more GnRH and LH. The surge of these hormones triggers the release of follicle-stimulating hormones, causing ovulation (Feedback mechanism, 2022).
Another example is fruit ripening. When a fruit on a tree ripens, it releases ethylene gas through its skin and causes the nearby fruits to ripen. As the nearby fruit ripens, it will also emit ethylene gas and drive the rest of the fruit in the tree to ripen in a wave-like action.
Reference
Feedback mechanism (2022). Biology Online. Retrieved September 13, 2022, from https://www.biologyonline.com/dictionary/feedback-mechanism