My maths are wrong here: if I have 2 parents, they have 2 each, then their's 2; won't i have 1000s?

Answer 1

I think I see a different question you're asking.

You're saying that the number expands exponentially as you go back more and more generations ... but how can that be if the population of the world was smaller long ago?

I.e. if I go back 35 generations, then wouldn't that be 2^35 ancestors, or 34,359,738,368 (34 billion) people?! That's almost six times the number of people alive on the planet today (6 billion). How does that math fit with the fact that there were *fewer* people back then?

The answer, of course, is that this math only holds true based on the taboos of who is marrying or mating with whom. Yes, siblings don't (usually) mate. Nor do first cousins. And rarely second cousins. But once you get past 5 or 6 degrees of separation, the taboos against interbreeding start to disappear and our knowledge of who we're related to gets fuzzier. Your parents could have common ancestor only 7 or 8 generations back and not know it ... or not consider it a problem even if they did know it. Go back 10 or 12 generations and they probably have several ancestors in common. (This is especially true if both your parents are (for example) of European descent.) Go back a few generations more and *all* your mothers ancestors are also your father's ancestors ... and at that point the list stops growing.

Was that your question?

Answer 2

You have 2 parents.
They EACH have/had 2 parents.
(2x2)=4
Thus giving you 4 grandparents.
Your grandparents EACH had 2 parents.
(4x2)=8
That gives you a total of 8 GREAT-Grandparents
They EACH had 2 parents.
(8x2)=16.
Giving you 16 GREAT-GREAT-Grandparents.

Each generation back is x2 for more grandparents. Not to include their brothers/sisters and go back about 10-15 generations and your pretty much related to almost anyone you can think of. (Ok a little further but still then its all irrelavent)

But to have 1000 grandparents you would have to go back 8 generations to give you a total of 1022 grandparents (Of some great or great great +). It would be 1024 ancestors but taking away 2 for your parents its 1022.

Answer 3

not quite,because eventually they pass away,and your parent's parents are not your parents,they are your grandparents,and so on and so on.Although this latest fact may sometimes not always be the case,different cultures have there own ways,eg.Your uncle could possibly marry your oldest sister,making your kids have an auntie that is really there 2nd auntie at the same time,and it gets more complicated if she has a child,does that make it your nephew/niece or a cousin?forget the maths for now there are other issues in the world to be concerned about.Nice question though.

Answer 4

In earlier times, it was more usual for cousins to marry, reducing the number of different ancestors, as people who are already related share whole branches of a family.

Answer 5

Of course you do. You have millions or billions of ancestors; so does everyone on Earth. It's just a matter of going far enough back.