I believe the answer to your question is isokinetic, isometric, and isotonic
No. it will continue cycling through the carbon cycle forever
Giraffes and Elephants: Giraffes have adapted a long neck over time letting them eat and access food allowing them to survive. If a dry season was unusually long they would succeed fine because they are able to eat and drink from the trees. Elephants have survived with similar tactics of eating higher up, they have rough skin allowing them to outlast the heat, and only need water after long periods of time.
A change in their food, from trees to grass in the Great Plains.
