If society A had the concept of only Love marriages and society B had the concept of only Arranged marriages, what will be evolved of those societies? How will they look after couple of centuries? How will they look after couple of thousand years?
This topic looks like a phd theis topic. That means I don’t have any knowledge in this topic 
But Everybody is a suman for his own blog and thus I am writing whatever are my half backed ideas/assumptions on this topic. if interested please follow and dare to leave a comment
Beauty:
Obviously Love marriages will lead us to more beautiful people in the process of evolution. Love marriages require attraction. Beauty in male and female will decide on their success to get partners and thus their success to pass on their own gene pool to next generation, which may include the genes of their beauty. But what is beauty. That is very interesting question. Beauty is in the beholders eyes. But now a days beauty is almost decided/promoted/dictated by our media. Thus whatever may our media promote as beauty irrespective of its actual worthiness will be evolved in next generations. Ofcourse there are artificial methods followed to keep one beautiful in the aura of terms and conditions of current fashion/trend. With the use of technology the genes may not be much important. May be simply rich will be successful to pass on their gene. Thanks to democracy and population control and ban to polygamy in most of the societies, now everybody has fair chances to pass on their gene pool. But it will only slow down evolution. It may take more centuries for best promoted genes to over-flow in society. Now coming to Arranged marriages. As beauty had less importance in arranged marriages, though it is one of the criteria for most of the times, other issues will eclipse this. For example money, caste, social status, previous generations, etc.. etc.. will play important role in match-fixing. Thus the evolved societies may not improve much in terms of beauty. If you want a beautiful society after n generations, encourage Love marriages
Caste
Love marriages doesn’t bother about caste. thus a society can not maintain this caste based social structure if there are all Love marriages. To me the compulsory factor for a society to be based on caste based is Arranged marriages. Caste being good or bad is not in the scope of this blog post. But the point I want to stress is arranged marriages are sole reason for a society to have caste based structure.
Male domination
For a society to be male dominated an arranged marriage is a must requirement. Where a society is predominantly Love marriage then women have to proove themselves always. which will evolve better, independent women in future and there will be equality among women and men.
Family Bonds
As long as we have to be rised by our parent until 15 years or 30 years Family bonds may not have much change. The marriage structure may not be P1 factor for family bonds to be healthy. when Government starts breeding and feeding human child in labs then we won’t have any family in the society.
yatha
yatha
ప్రేమ వివాహాలు, పెద్దలు కుదిర్చిన వివాహాలు - పరిణామ క్రమంలో ఏమి జరుగుతుంది ? (Read this on my Telugu Blog)