The fight between Buck and Spitz is a perfect example of survival of the fittest because it is a example of what it actually is. Buck and Spitz both wanted leadership over the pack, and Buck was tired of Spitz bossing him around, so they fought to the death. The winner deserved to be the leader because they conquered the other dog.
This cell shows Buck when he dreams of the cavemen. Buck has dreams of his ancestors being with and accompanying the cavemen. If his ancestors survived through an unknown number of generations, as dogs that survived, so could Buck. It shows that his ancestors were survivors and so is he.
This shows when Buck is leading the pack and is just following his instincts and not even thinking about what he is doing, and he is leading, and Spitz comes out of a shortcut and takes Buck's precious kill of the rabbit. This shows that whoever is the craftiest, smartest (fittest) will be the one that succeeds in life.
This cell is all about when Buck was beaten by Hal and even though he was in pain, he decided that no matter what, he wasn't going on and that he wouldn't get up and pull for the people, even if they beat him to death. Which they were very close to doing. This shows that he is stronger than the rest and is willing to take a beating to prove that he doesn't take orders without his consent.
When Buck was chasing the moose it was a perfect example of survival of teh fittest. Buck was determined to defeat and kill the moose even though it was a lot bigger and stronger than him. He figured out ways that he could take down the beast without the risk of harming himself, which shows that he is cunning, a skill that is necessary for survival
This cell is about Buck´s triumph when the wolves ¨initiated¨ him to see if he could join them. He didn't just pass but he took down everyone that came at him. This is survival of the fittest because if he wasn't fit to join the wolves pack, they would have killed him on the spot and moved on. This shows the cruelty the wild has and how Buck has survived and thrived through it all.