Let's first look at the difference between the two, as long as we understand the difference between the two, it is natural to understand why some populations of the same species will evolve into flocks of sheep, while others will evolve into lions.
The large number of sheep makes it easy to manage, and a few shepherd dogs can manage a large flock. And sheep do not have the ability to survive independently and do not dare to leave their own herd. As long as the sheep are well fed, they will not ask too much and will do their best to breed and keep the population at a certain number. At the same time, the flock does not need to learn other aspects of knowledge, what it needs is what it is born with, eating, drinking, sleeping, breeding, all these skills do not need to be learned. Therefore, for the ruler, it is the best choice to train all the individuals under it into sheep, no need to educate, no need to give them various reasons, just say what to let them do, if they are not obedient, pull out a few leading sheep and torture them in public to shock all the individuals.
The lion is different, from birth must continue to learn a variety of hunting skills, with the ability to survive independently, for the ruler, if the individuals in his population are all lions, the ruler must be the strongest lion to rule the entire population, and at the same time it must provide a variety of educational environment for the lion, otherwise the whole lion group will not survive. So for a ruler who is not the most capable, the individual below it cannot be a lion.
Comparing the differences between sheep and lions, it is easy to understand why some flocks become flocks and others become lions. It's just that there is a sentence that needs to be added, it is easy for a ruler to rule a flock, but such a flock is also very easy to succumb to when facing a foreign enemy, but this trait is not much different for ordinary individuals in the flock, because whether it is ruled by a ruler of the same race or ruled by a ruler of a foreign race, as long as it is still a sheep, its fate is to be ruled, enslaved, and eaten. There is no other possibility.