Can someone explain to me negative and positive feedback??

Question

i have homework over the summer from my ap bio class that i'm taking next semester, and in this chapter, we're learning about negative and positive feedback. i've read through the chapter over and over and still don't seem to understand quite fully what they are. can someone please explain those terms to me?? thank you!! =]

Answer 1

negative feedback is when the end product of a process slows down the process

positive feedback is when the end product speeds up the process

Answer 2

If an increase in the output loops back to cause an increase in the input, the system is supposed to have a positive feedback.  As you can see, it will eventually cause disequilibrium or breakdown of the system.

On the other hand, if an increase in the output loops back to cause an decrease in the input, the system is supposed to have a negative feedback.  This will eventually bring stability and equilibrium.

Driving a car is a good example of negative feedback.  If the car goes too much towards right, you slightly steer it towards left.  And vice versa.  This brings stability to the whole process.

You can Google it and get a ton of definitions and examples./

Answer 3

An example of a negative feedback loop would be having the pituitary gland decrease it's production of hormones which in turn effect the thyroid gland.  the effect on the thyroid hormones would be to keep blood calcium levels within normal ranges.  This is a negative loop as it stops or slows down a process.  An example of a positive feedback loop (of which there are very few) would be the pituitary glands continued production of the hormone oxytocin to keep the labor process going until such time as the baby is born.  this is not a process you would want to stop, hence it's a positive (ongoing) loop.

Hope this helps.