There is a rank order for males and one for the females. Second ranking wolves are commonly called betas. Lower ranking wolves are actually more commonly given numbers for their rank. The alphas have the most stable position and have been known to hold their rank their entire life. Rank changes in lower ranking wolves are far more common and in the wild recent evidence suggests that most lower ranking wolves will actually leave their pack by three years of age.
Wolves maintain their position through ritualized postures.
Fights are very rare. Basically wolves will most commonly use the least amount of force to reinforce their position or discipline wolves who are pushing or testing to see if they can overtake another wolf's position.