First, it is imperative to understand what a system is. A system is "a structured set of components which are related to each other and which operate together as a complex whole." There are several types of systems, with the most common being open and closed systems. Consider the desert in chapter 3. As an example of an open system, that is, one in which both energy and materials pass through the system, the materials passing through are the humans and their chips of stone and roads, while the energy could be the wind blowing through. It becomes a closed system, that is, one in which only energy passes through, when the human intervention ceased, and all that

is left was the wind (although technically grains of sand could be carried out of the system).

The remaining humans also had to adapt to a new world. Many, unfortunately, went insane after witnessing the horrors of the plague. Given time, however, Ish banded together with a solid group of people and, together, they started a new settlement, which they called "the Tribe." Food was not a problem, as the abandoned stores, even having been picked over by ants and rats, still held abundant resources for humans in the form of sealed tin cans. And so they lived, with the comforts of plentiful food and running water. This is a system which is said to be in equilibrium-there is no real change in the system. Unfortunately, Ish knew that they wouldn't be able to just find food in an abandoned store forever, and they needed to learn to fend for themselves. His suspicions were confirmed when suddenly the town reservoir ran dry, and a new source of water had to be found. Over the years, many new streams had become reliable sources of water, so the tribe dug a well in order to get water from the streams into their neighborhood. Thus, though the equilibrium was disturbed by the loss of water, it eventually went back to equilibrium. This leads to the concept of relaxation time- the time it takes for a system to return to equilibrium. By the end of the novel, the Tribe, now around 100 strong, had also learned how to hunt without leftover rifles, start fires without leftover matches, and many other skills. In this case, the equilibrium is known as dynamic, in that while the inputs of food and water increased from the Tribe's burgeoning skills, the equilibrium was slowly moving up instead of standing still, as represented by the growing human population. If the population were to stop growing so quickly and instead had stayed r

Some common words found in the essay are:
Isherwood Williams, Earth Abides, Unfortunately Ish, Charlie Tribe, Tribe Food, feedback occurs, food source, population grew, positive feedback, George Stewart's, rat population grew, positive feedback occurs, rat population, earth abides, lion population, skills equilibrium, system changes, abundant food source, food abandoned,
Approximate Word count = 1237
Approximate Pages = 5 (250 words per page double spaced)