Thread: applying probabilty at reprodution implies humanitycantexist

1. lets see it this way, girls are purely matrilineal lines and boys purely patrilineal ones

i finally solved the way to find the chances a boy keeps an exclusivily patrilineal line in the future:

if the population is to keep he will have two counting childs which each will have another two and so on

so lets consider a coin toss game, a tail is a boy and a head a girl

the game to find the chances is simple:

toss a coin two times and for every tail you get two extra tosses, you keep playing till you run out of tosses

thise are your chances of having a patrilineal line in the future

but the tossing game in the end can be reduced or simplified to:

you have one toss and for every tail you get an extra toss, you keep playing till you run out of tosses and lose

exactly for the boys in here your chances to get a patrilineal line in the future are 2 elevated to the number of generations

now if even the hole globality dont have the chances to keep a patrilineal line in the case of boys and a matrilineal in the case of girls, humanity cant exist in 64 generations

so is it human reproduction a myth or probability fails in this case

2.

3. I think incest solves that one for you!!

4. Isn't this like the third or fourth time you've posted this exact same thing?

5. His father posted the last one.

6. i posted it again because no one helps me to find the chances a person has to have a patrilineal line into the future

the chances someone has a patrilineal line into the future is one if we suppose humnaity survives

so chances a person has that line should be one in 6 billion

but how do you arrive to this figure from a tossing the coin game in which for every tail you get two extra tosses and keep playing till you run out of tosses and lose

game appliable to suppose each person has two offspring

7. well obviously not everyone has 2 offspring do they

QED

8. There's also the problem of trying to apply this to an infinite situation, whereas the real world is finite but of indeterminate timespan (we know the universe won't last forever).

9. Originally Posted by MagiMaster
There's also the problem of trying to apply this to an infinite situation, whereas the real world is finite but of indeterminate timespan (we know the universe won't last forever).
Don't you mean "we know the Universe will last forever"?

10. Originally Posted by MagiMaster
(we know the universe won't last forever).
Who is "we" and how do you know this?

11. althought the problem is complex it can be simplified:

if the population is to keep its number people will have an average of two children neglecting the ones who die without reproducting

12. AFAIK, no current theory in physics predicts an infinite universe that isn't empty after a finite period of time (trillions plus years maybe, but still finite).

The other problem with your model is that it ignores how people would change their behavior if there was somehow too few men.

13. Originally Posted by luxtpm
so is it human reproduction a myth

yup.. it's just a fairytale we tell you kids to keep you behaving "you'll never get a gal if you act like that" and all

I really don't get your line of thinking at all, there seems to be lots of faults

You seem to have decided only men can reproduce (for each man you get two extra throws). You've forgotten a woman is also neccessary

you also seem to have missed the point that we can in fact have more than two kids. If by some miracle the population starts to dwindle, people will have half a dozen kids and we will thrive again

If we have 10 men and one woman, the woman will be constantly pregnant and there will be lots of siblings. while this would initially lead to incest (as written in that unholy pile of rot the Bible) after a few generations enviromental influences would alter the genepool enough to iron out the flaws

with 10 woman and one man, the man will be constantly impregnating multiple woman. there will be less incestual impact but again it will be sorted.

I honestly have no idea where you've come up with this 'myth'
Men are Xy, women are Xx
babies are mix the Xx and Xy combine and form either
XX
Xy
xX
xy
so theres a clear 50/50 chance of boy or girl

so yes if everyone had two kids, there would be cases where both were boys, however there would also be cases where both are girls. IT EVENS OUT

for example, the population is currently tilted slightly towards women, about 60/50. in a few generations it will bounce the other way

you've also forgotten to take Identical twins, twins, triplets, quadruplets etc. Transexuals, homosexuals and mutants into your 'equation'

14. The question of what the chances are that a particular person will have a line of male descendants of a certain length is valid, but to generalize from that to whether or not humans will continue to exist is not. Think of what a no answer to the second question would mean in this case. It would mean a generation of all women, a chance. Not only is that incredibly unlikely, but it still wouldn't end things since women would just have to marry/take/mate with older men.

15. Originally Posted by luxtpm
so is it human reproduction a myth or probability fails in this case
Probability does not fail, you do.

16. Originally Posted by MagiMaster
The question of what the chances are that a particular person will have a line of male descendants of a certain length is valid, but to generalize from that to whether or not humans will continue to exist is not. .
we all descend from an unbroken line of males

if someone today doesnt develop an unbroken linage of males noone can exist in the future

same for females

17. Originally Posted by luxtpm
Originally Posted by MagiMaster
The question of what the chances are that a particular person will have a line of male descendants of a certain length is valid, but to generalize from that to whether or not humans will continue to exist is not. .
we all descend from an unbroken line of males

if someone today doesnt develop an unbroken linage of males noone can exist in the future

same for females
Please think before you continue the debate. Your reasoning makes no sense, especially this:
but the tossing game in the end can be reduced or simplified to:

you have one toss and for every tail you get an extra toss, you keep playing till you run out of tosses and lose
How did you get to this conclusion?

Why should noone exist in the future? As long as children are born, your concerns are blatantly false.
Or do you fear that one gender can die out? Why do you think it should happen?

18. i got that one wrong thats why i ask for help`

i dont think humanity will die out nor one gender die out

but the thing is that getting an unbroken line of males into the future is damn hard

yet the probaility for this to happen is one or humanity just wouldnt exist since a male descends from an unbroken lines of males and a female from an unbroken line of females

is like nature is playing a gambling game in which theres a o.5 chance to win but nature using an strategy gets a chance of 1 yet gets paid as if the chance is 0.5

19. Your error is in the sentence I cited.
toss a coin two times and for every tail you get two extra tosses, you keep playing till you run out of tosses
can't be simplified to
you have one toss and for every tail you get an extra toss, you keep playing till you run out of tosses and lose

but what are the chances to win at this game which i think are the same to get an unbroken line of males supposing pulation keeps so everybody has an average of two children neglecting the ones who die without reproducting:

toss a coin two times and for every tail you get two extra tosses, you keep playing till you run out of tosses

imo if the whole humanity starts playing this game seems unlikely that in a trillion years theres a single player left who hasnt run out of tosses

21. There are three possibilities with each round:
50% chance for one tail. You have two tosses again so nothing changes.
25% chance for no tails. Game over.
25% chance for two tails. Now you have four tosses.

So for each round you have 50% chance for two tosses in the next round, 25% chance for no tosses and 25% chance for four tosses.

As you can see, the average number of tosses in the population remains the same.

22. Originally Posted by luxtpm
toss a coin two times and for every tail you get two extra tosses, you keep playing till you run out of tosses

imo if the whole humanity starts playing this game seems unlikely that in a trillion years theres a single player left who hasnt run out of tosses
oh, I think that I finally got what you mean! You mean that with each round, some "players" are removed? But that's exactly why we can trace human lineage to only some 50000 years ago. It does not mean that only one (wo)man was alive, it means that all others have lost all their tosses.

http://en.wikipedia.org/wiki/Mitochondrial_Eve

23. all right lets concentrate on females

there are now 3 billion females, lets see the chances a gambler female from today has of getting an unbroken line of females in x number of generations

there are 3 posible outcomes on the offspring:

male, female, a draw, the gambler keeps playing
male male this gambler has lost

female female, the gambler has won this hand

so we can see that with this example every generation a thrird of original female gamblers are removed

so when theres only one original female gambler left after countless generations apparently she has no way to lose since she would be the mithocondrial eve?

this is really confusing

so you see of 3 billion females you keep dividing by 3 for every generation and when you get to one thats the age mithocondrial eve should have

but consider it a gambling game:

a female can win draw or lose by having two girls, one boy and one girl or two boys

so chances of winning or losing for a female are 50% percent for every generation

but with the gambling method nature uses it grants that at least one girl of the 3 billion there are now is gonna win it all posible that theres to win, remember a girl is a win and a boy is a lose and all and every girl in the world in the future will descend from this winner gambler girl

what nature does, seems to me, is like if a crowd of people goes to the casino and by a coomon startegy have a cahnce of braking the bank of 1

24. MM, MF, and FF aren't equally likely. MM and FF are 25%, but MF is 50% (you have to count FM too).

There's another error. The average number of children is only approximately 2. In fact, it's more than 2, or the total population wouldn't be changing.

Let's assume there are 4 billion females and it really is 2 children each. In one generation, there would be 8 billion kids, 4 billion males and 4 billion females, and the same thing would happen the next generation.

If you look at it from the perpective of a single female, it works out like Twit of wit said, and the expected value is (.25 * 0) + (.5 * 1) + (.25 * 2) = 1. So, on average, every female would expect to contiue their line indefinitely, and those that drop out are exactly balanced by those that get 2 chances.

25. luxtpm:I don't want to be rude, but this is tiresome. You lack even the most basic mathematic skills. Please talk about this with your math teacher or someone similarly suitable.

26. As someone working on becoming a professor (of Computer Science, though that's fairly math heavy), I don't mind trying to teach people when I understand the question myself, but they have to be willing to learn or nothing I can do will make a difference. (It's still worth arguing a bit though, for the sake of the lurkers.)

27. Originally Posted by lux
but the thing is that getting an unbroken line of males into the future is damn hard
Genghis Khan figured it out - so no worries, it's covered: http://www.forbes.com/2007/02/25/gen..._0301khan.html

28. of course i know little maths but that doesnt refrain me from asking questions and trying to find answers

for example what are the chances my fathers original surname lasts 100 generations applying the tossing the coin game?

edit:

thats a very interesting article

as i see it khan was a gambler with a lot of cash which increased his chances

29. Some quick calculations, which I haven't double checked, suggest that the chances that your last name will carry on 100 generations given exactly 2 kids per generation is about 3.7%. You should check this yourself.

Of course, this does not say anything about the chances of it happening in general, since the chances for those seperate lines wouldn't be independent events, at least not when you start getting to the scale of the whole population.

30. Booms wrote:

with 10 woman and one man, the man will be constantly impregnating multiple woman. there will be less incestual impact but again it will be sorted.
I like this consideration. 8)

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