Suppose there were a human society where rules of natural selection apply, but in a faster way, genetics change fast enough to be noticeable after a few generations (a static society with normal genetic speed would work as well).
Add to this traits, physical attributes or skills that are always desirable. Finally, less desirable people do not die, they just go to the bottom of the society, while nice people goes to the top of the ladder.
Question: After some time, will we have a perfect caste system where a person can't move in the hierarchy? Or does this society still have the chance to give opportunities to its members?
Edition 2016-12-30
To improve the question and answer some comments:
First of all, my idea is to find the most basic requirements in order to obtain a stable caste system without the use of force. Therefore:
Traits, physical attributes or skills that are always desirable.
This means that for example, using a stereotype: tall and blond people will always be considered more beautiful in contrast to short and brunette people. Or maybe intelligence always grants the chance to get better jobs.
I suppose that this concept is a must, in order to keep people in their place in the hierarchy.
The concept of "stable caste system"
As @Green realized, my ultimate question goes to find out if it is possible to obtain castes (and finally speciation) starting with typical western social classes. Humans in this world will eventually separate so much that they will eventually become different species?
Less desirable people do not die, they just go to the bottom of the society
If I remove less able people, then I would never have different castes, because the bottom caste will be constantly removed from the pool. That's why I use the word "desirable" instead of "capable", they can survive and transfer their genes to the next generation, but these genes will be unwanted.
This society is isolated, so they can peacefully evolve. I need to speed up evolution, in order to reduce the effect of technology, social changes or even fashion. How much faster has to be evolution? I don't know. Maybe it is part of the question.