How does buck's living situation change in the story? (excerpt from the call of the wild)

Buck's living situation changes over and over again throughout the story. First he is in a cozy home, well loved and taken care of. Then, after he is stolen, he is made to stay in a crate and is not fed or treated well. He again moves to Canada where he is trained as a sled dog. Here, his living conditions improve but he still has to work hard and train, moving again to a place where he has to move heavy loads. He moves again and again, having to adapt to different living situations and having to work different types of jobs until finally he becomes free in the wild.