The initial mass of the star determines what the star will become and the life expectancy of the star. The more massive a star's core is the more inward pressure there is. Therefore larger mass stars can develop much higher internal temperatures. More massive star's have shorter lives. Second, it allows for fusion of heavier elements.
More massive stars have the ability to evolve farther than their low mass brethren.
The Evolution of A One Solar Mass Star Lets examine the evolution of a one solar mass star in detail. The development of the star truly begins with the collapse of a bit of interstellar gas and dust due to its own mass. Recall that as a gas collapses it heats up. When the central part of the protostar reaches about 8 million degrees Kelvin fusion begins and the protostar becomes a star. Stars the size of the sun fuse Hydrogen into Helium via the proton-proton chain.