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Isn't arranged marriage against the principle of natural selection & evolution?

Monday, November 2, 2009
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Ketan said...


If you've talking of Darwinian kind of natural selection, then arranged marriage does not go against the concept of 'natural selection'. But if it leads to restriction of 'crossing' to a small gene pool (inmating/consanguinity), then it would somewhat slow down the 'rate' of evolution.

I'm assuming your query was purely in biological context.


PS: Why did you post a question that does not allow me to write a longer comment? :( But if you ask me for an elaboration, I would get to write longer comments! ;)

Srishti said...

Oye! We're just studying this in school! Heredity and Evolution. You know, now I understand everything so much better, after entering the Tenth.

Wait. Arranged Marriage DOES go against 'natural selection'?
Doesn't it? I think it does. :\
And since arranged marriages are arranged within the caste or religion, it would lower the rate of evolution.
Woww. This is so cool. I get it now.
Except the part where Ketan says it does not go against the concept of natural selcetion.

Abhinav said...

No its not.. earlier it was Natural Selection but eventually it evolved into a system of arrangement!

Although history has a bad habit of repeating itself so we might have to go through this cycle again!

wise donkey said...

There are plenty of society where the concept of arranged marriages doesn't exist..how have they evolved..

Stupidosaur said...

I don't know what exactly you term as Darwinian kind of natural selection, or even what it officially is. But my

impression over the years due to various references to Darwin stuff, or modifications in my own head that it will

have to consist of two things at least:

1) when a creature is born, whether it survives its natural lifespan and atleast up to fertile adulthood or not.
2) if it does, whether its genes pass to the next generation through appropriate mate/any mate at all, or not.

Maybe you are talking only of the first point. Thats one stage of natural filtering.

Arranged marriage comes in at the second filtering point above (according to me).

What I understand is, that in the wild, creatures choose their mate based on various instinctive criteria. Symmetry

and health of potential mate indicates how well it itself is surviving. So one with better looks is chosen. Of

course I do not overrule mental and emotional compatibility. Being a reptile I do not subscribe to the haughy human

notion that other 'lower animals' do not think or feel as much as us. And even if they do think and feel lesser

than us, its perfect level for them and their first person sense of existence and feeling could be very similar to

humans. A circle with a smaller radius is still a complete circle.

Again, getting back on track, out of the ones which are 'surviving equally well', the attraction of one specimen is

most towards the other which is probably most suitable combination genetically. This is achieved through various

external mechanisms such as attraction towards scent of more genetically compatible specimen, etc. Or at least

thats what I read.

In arranged marriage, anyone and everyone will get married. So...
1) The genes that would have otherwise never passed to the next generation do pass!
2) The combination may not be as good as that by the natural attraction and choice.
So I would tend to think that the progeny has more chance of being weaker in arranged marriage than otherwise.

So natural selection and evolution are hampered. Of course, as Ketan & Srishti said, there is the additional aspect

of 'arranged marriage' happening in same 'community', further reducing the size of gene pool and potential genetic

combinations. Every hopeless being will also get unnaturally selected.

Ketan, so as I explained above, I think it does 'slow down' evolution in the words that you put it. Now if wind

drag slows down the car's motion, obviously wind is against the car's motion. So arraged marriage is against

evolution and natural selection. So by
"If you've talking of Darwinian kind of natural selection, then arranged marriage does not go against the concept

of 'natural selection'.", you are precontradicting what you said later :P. Of course being close to academics, you

must realise that even if the question seems to warrant a small answer, long answer is actually expected if thats

the only question in the paper.Elaborate out your mind's content to your heart's content ;)

Stupidosaur said...

Abhinav, I didn't understand what you said. Could you please repeat yourself? Oh wait, that wouldn't make you

history, would it? (History repeats itself ;) )

@WMD (Wise madam donkey ;) )

This is just a thought which I have elaborated in this comment above though not in the post. I have not done a statistical survey. I do not even know globally speaking which exact countries/communities practice more arranged marriage and which the other kind. However do share such info if you have it. Though my knee jerk response is that the countries where arranged marriage is not currently predominant are termed as 'developed countries'. Though always open to debate if you brings in facts. Of course, not saying that must be the only reason for their being 'developed'.

Side thoughts:

Did countries with arranged marriage concept majorly get colonised by the others?

If universe is finally going to end due to some reason or other (eg heat death of universe, big crunch, ever increasing entropy, whatever), did the universe create 'life' in some parts with the hope that the life might evolve fast enough to give rise to superbeings who can solve and prevent this impending death of universe?

Stupidosaur said...


Even I didn't understand why Ketan said that.

BTW yes, 10th is cool. Enjoy!

Somehow I enjoyed it more than previous school years and later college years!

Of course reasons for not enjoying college as much were specific to me. Enjoy ahead!

wise donkey said...

universe is too creepy.. u know about 2 of saturn moons, janus and something else..their orbit ought to make them collide. know what they do..they rise and fall..so yeah, be ready for the aliens..or earth could just switch off the gravity and throw us off, and continue her revolution..

i liked the invaders point..see a donkee like me likes to think about it.. so will mull over it..

PS please avoid wmd or wdm.
wd is fine..and u have to strain your fingers less..

wise donkey said...

after rereading ur comments..

maybe the instinct exists even in arranged marriages..(i need others help to reproduce..)
there is a difference between arranged marriage and forced marriage..

whether arranged or unarranged..no one is going to look at the entire gene pool and there is bound to be limitations..

PS : i don't support arranged marriages..just trying to think..

PPS : personally i think if one doesn't submit wholeheartedly to the choice, the marriage is doomed..sort of like the body rejecting a donated heart, even if it needs it for survival..

you need to make the mess, to accept the mess..

Ketan said...

Thanks you Stupidosaur, for letting me write long comments without feeling guilty!

Okay, I did not give a counter-intuitive answer only to prolong the discussion.

My first, 'knee jerk' reaction was to state that it goes against Darwinian natural selection, but on thinking a bit more (for the first time, thanks to you :) ), I realized, arranged marriages wouldn't interfere.

Yes, you're right I had stressed on Darwinian natural selection, precisely in contradistinction with 'natural' as in, according to the organism's 'most native drive'.

'Natural' in context of evolution means, selection by nature, and not the organism. Of course, by nature here we mean the various ecological challenges--including scarcity of food/water, weathering the terrain/climate, being able to evade one's predator, etc.

So obviously, such factors have been totally eliminated from the contemporary human society. They've been replaced by other factors like, income, skills, intelligence, which predict a better life (as against increased survival).

Yes, even in humans, physical factors had and have been important in sexual attraction. For instance, I had read/heard that whatever physical the either sexes find attractive in the opposite gender, would've guaranteed a healthier off spring.

But the point is, in olden days, survival was so difficult that most of the unfit genes (actually, alleles) have already been eliminated. So now basically, the whole of the human gene pool consists of largely fit alleles....

Ketan said...

...And to that, add the fact that survival is lot easier.

So, even the most unfit allele would be fit enough to survive till reproductive age.

But one more thing about fit and unfit is that they're not absolute, but dependent on the environmental conditions. I'm not sure if you've read about a famous observation by Darwin himself of how with industrial revolution, black moths started predominating 'cuz the walls had got covered with soot, which would make them camouflage, whereas, the white ones would become easy prey to lizards! ;)

So, as of now, the most unfit genes, probably those causing diseases like diabetes, heart attacks, various kinds of cancers rarely curtail life to such a degree that the person would not reproduce.

Also, in humans, pheromones (click), the odorants you were talking of, do not play a significant role in sexual attraction. Mainly 'cuz our sense of smell is not that strong.

But there's a huge social factor that you might have overlooked--family planning measures. It ensures that even if two persons are very intimately attracted to each other, they would not produce babies till they actually want. And conversely, especially in an arranged marriage (in India), they would produce children despite not being attracted to each other.

But you know, one factor that you might have not known or overlooked is that selection only ensures that the gene pool gets 'pruned' mainly through elimination of unfit alleles....

Ketan said...

...So, whether this sort of elimination is fast or slow wouldn't affect the rate of evolution much.

What affects the rate of evolution the most is introduction of new mutations in the gene pool, which in turn depends on agents that damage the DNA, like UV rays, radioactivity, cosmic rays, chemical toxins, etc., all of which are totally independent of who marries whom!

To summariz, the respects in which human evolution has changed is:

1. The factors that in the past used to portend fitness, no longer contribute to fitness in the social context. For instance, one running very fast might win a few school-level competitions, but nothing more, whereas, in the past it would have increased chances of survival and successful hunting. But 'natural' attraction is still based on the 'old' factors, which no longer contribute to fitness.

2. Relatively unhealthy humans/incompatible couples are also fit enough to reproduce at the same rate as healthier humans/more compatible humans. This is largely because of 'support systems' like vaccination, and comfortable environment, etc.

3. Family planning ensures almost a fixed number of progeny from a couple irrespective of their mutual physical/emotional attraction/repulsion.

4. The rate of introduction of new mutations, which eventually determines the rate of evolution, is independent of type of marriage....

Ketan said...

...I had mentioned consanguinity (mating of blood relations), only because it increases the incidence of blood cancers and many autosomal recessive disorders (transmitted through non-sex chromosomes), like sickle cell anemia and thalassemias. Also, it would allow for fewer new combinations to form.

But then, very few arranged alliances are actually genetically so close. In fact, I've heard people are not supposed to marry in the same gotra or something like that! :)

I think the Western society is more developed because somehow: democratic governments started earlier --> earlier equality of genders --> liberation of women --> greater say in matters of family size --> smaller families --> lesser population density --> more prosperous societies.

You've not yet replied to my comments on that post yet, where I've tried to explain how population density somewhat governs prosperity by determining the degree of disguised unemployment. :)

And well, Western society embraced democracy earlier because they were much more oppressed by religious+aristocratic class in dark ages as compared to the Indian subcontinent. Okay of course, my conjecture. :)

I'm looking forward to more doubts if you have.


PS: I think my story, 'Residua' where you'd commented pretty much summarizes my take on the humane aspect of this issue.

Abhinav said...

itni see post aur itne bade comments!

haah ye dunia!

wise donkey said...

i remember reading in one of my school textbooks, social revolution is generally initiated by those well off economically..
i would like to think its otherwise..but maybe they developed and then decided to do away with arranged marriages..(reverse corelation)..i was thinking of Japan where the arranged marriages are declining..

btw what about divorce..

PS : the 4 comments on previous post were unintentional..i got the impression comment wasn't published..

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