People vote with their ballots: time, attention, money, and sex.
It's basically a world full of individuals campaigning to earn business, to teach, to preach, to solicit romance, and to influence others. Each individual has evolved their own style of campaign to accomplish their goal. Some are aggressive, others are passive, and some adapt their strategy to each situation. Either way, in a social environment, politics are the way we interact with one another (as opposed to one's lack of political concern on a deserted island).
In the animal kingdom there exists a social pecking order, or status. This status governs the responsibilities of each member of the animal community. This animal 'caste' system has often been described by anthropologists using Greek letters to establish the following order: Alpha, Beta, Gamma, Sigma, and Omega (with the likelihood of many more). The characteristics that describe each Greek letter in alphabetic pack order tend to differ slightly from each observer's perspective; however, using the voting statistics determined by social interactions one is able to draw their own political conclusions...
Alpha class individuals are generally favored to lead based upon perceived genetic traits that favor dominance and power, such as height, size, intellect, and physical strength. They are the recognized 'best', or champions of the pack. In the animal kingdom, the Alphas earn the privilege of mate choice selection. In other words, because of their perceived genetic advantages within their environment, they can pretty much mate with whomever they desire. Animals instinctively breed with those that will favor their offspring's gene pool with traits that will benefit future progeny (Classic Darwinism).
Beta class individuals equally possess many or all of the favored genetic traits; however, they do not seem as concerned with leadership as their Alpha counterparts; instead choosing to pursue a path less fraught with competition. They still command a healthy selection of mate choices without the burden of battling for dominance and leadership of the pack. Their selection of mating options, while still great, are fewer in comparison to those of the Alpha.
The characteristics that surround Gamma, Sigma, and any other class (with the exception of Omega) are more loosely defined and subject to discord among the scientific community. Basically, these classes do not fit into Alpha, Beta, or Omega categories, but still hold enough distinction to have their ranks. Mate selection preferences are difficult to determine as there are many nebulous factors that contribute to these individuals class designation.
The Omega class (the last letter in the Greek alphabet) are composed of the lowest order of individuals in a social grouping. These beings do not possess the commonly desired attributes for genetic propagation within a given environment. They are often outcasts that occupy the lowest rung on the social ladder. Their mate selection is often limited and restricted to their own kind.
It appears that the politics of caste discrimination are biologically rooted in our animal evolution. In other words, our species is competing within itself for the genetic evolution of the strongest, fittest, and most dominant genes (within a given environment). We reward these traits with continued support by our 'vote' as counted by where we give our time, attention, money, and sex.
Animals are able to mimic those belonging to another social class for the benefit of social gain; however, the constant charade must be extremely convincing in order to fool the social constituency (in humans we call them politicians). If the 'act' is found fraudulent, then the social masses usher the charlatan to their deserving classification. Many individuals choose this path in order to improve their circumstance (which is understandable), but at the expense of polluting the genetic pool with their fraudulent genes. This can be likened to an individual who masks their true appearance with deceptions about their character or through physical alterations such as plastic surgery. While upon initial observation these individuals may fool a prospective mate, their true nature will eventually out itself as seen by passing on their 'flawed' DNA to successive offspring.
I guess the bottom line here is that as humans we must accept that we are political creatures and not immune from the harsh reality that is our ingrained discrimination. When we accept our nature, we can then seek to improve our collective circumstance by using our abundant intellect to override our baser instinct to judge others and focus on a win/win solution for brothers and sisters of all classes. It is important to understand that these caste borders are an imaginary construct to which we allow ourselves to be bound.
Unlike other animals, we possess the free will to change our circumstance at any time. We can seek an education that will sharpen our minds or travel to experience culture and perspective. We can make conscious decisions to better ourselves such as diet and exercise. We possess the power to connect spiritually with one another through the bonds of Love. In these ways (mind, body, and spirit), we can rise above our imprisonment of social classification.
In order to steer the evolution of human beings, it is clear that it will require the leadership of Alpha individuals, who are naturally selected by virtue of sexual politics. Their participation will be necessary to provide protection, guidance, and compassion to those tragically bound to the state of hopelessness. Like a Lion watching over his pride, or a shepherd looking after his sheep.