Final answer:
The feedback mechanism that leads to further deviation from an original value or range is positive feedback. In contrast, negative feedback works to reduce excess and maintain homeostasis. Examples include body temperature regulation and blood clotting, with the latter potentially causing overshoot if negative feedback is delayed.
Step-by-step explanation:
The feedback mechanism that causes a variable to deviate farther from its original value or range is known as positive feedback. Unlike negative feedback loops, which serve to reduce an excessive response and keep a variable within its normal range, positive feedback amplifies the conditions of a system. Positive feedback results in a change in the system's state, driving it further away from the state of equilibrium. One of the most well-understood negative feedback mechanisms in biology is the regulation of body temperature. When body temperature rises, mechanisms such as sweating are activated to cool the body down, thereby bringing the temperature back within a normal range.
An example of positive feedback is the process of blood clotting. When a blood vessel is damaged, substances are released that attract more platelets to the site of the injury. This, in turn, causes more substances that attract platelets to be released, thus amplifying the clotting process until the damage is sealed. Overshoot can occur in biological systems when there is a delay in negative feedback, leading to an exaggerated response that exceeds the target state or normal range, similar to overshooting a turn when driving if the driver's reactions are delayed.
In summary, negative feedback loops are critical in maintaining homeostasis by opposing changes to a system, whereas positive feedback loops drive the system away from its initial state, sometimes resulting in overshoot if not properly controlled or in the absence of timely negative feedback.