How Many Ancestors Do You Have?
My grandparent ancestors have been in America for around 270 years with 8 generations for my maternal and 9 for my paternal families. That makes the actual number around 25 years per generation. Our ancestors number more than a million in 20 generations with our 16th great-grandparents from roughly the year 1525 if none of them were related through more than one family. At 8 generations you have 254 ancestors in that generation. At 15 generations over 32,000 ancestors in that generation. At 21 generations you have over a million ancestors in that generation with a total of over 2 million total ancestors! Most of our ancestors would be related multiple times in the small farming communities and villages where they would have lived. I have found a number of instances in a few of my family lines which show many common ancestors on both sides of the family making spouses second and third cousins, rarely first cousins although it is known to have occurred. This table assumes you were born in the year 2000.
An interesting story in the Monday July 3, 2006 Journal Gazette newspaper by Matt Crenson discusses the mathematical probability that all living humans today have a common ancestor if you go back 2,000 to 5,000 years. This is discussed in the 2002 book Mapping Human History by Steve Olson. Olson states that if you go back 5,000 to 7,000 years we would all have the same set of ancestors. An interesting observation made was that "every Palestinian has Jews in his past. Every Sunni Muslim in Iraq is descended from at least one Shiite. And every Klansman has African roots."
Year | Generation | Total Ancestors | Surnames | |
---|---|---|---|---|
2000 | 1 |
You |
You |
1 |
1975 | 2 |
2 |
2 parents |
2 |
1950 | 3 |
6 |
4 grandparents |
4 |
1925 | 4 |
14 |
8 g grandparents |
8 |
1900 | 5 |
30 |
16 gg grandparents |
16 |
1875 | 6 |
62 |
32 ggg grandparents |
32 |
1850 | 7 |
126 |
64 gggg grandparents |
64 |
1825 | 8 |
254 |
128 ggggg grandparents |
128 |
1800 | 9 |
510 |
256 gggggg grandparents |
256 |
1775 | 10 |
1,022 |
512 ggggggg grandparents |
512 |
1750 | 11 |
2,046 |
1,024 gggggggg grandparents |
1,024 |
1725 | 12 |
4,094 |
2,048 ggggggggg grandparents |
2,048 |
1700 | 13 |
8,190 |
4,096 gggggggggg grandparents |
4,096 |
1675 | 14 |
16,382 |
8,192 ggggggggggg grandparents |
8,192 |
1650 | 15 |
32,766 |
16,384 gggggggggggg grandparents |
16,384 |
1625 | 16 |
65,534 |
32,768 ggggggggggggg grandparents |
32,768 |
1600 | 17 |
131,070 |
65,536 gggggggggggggg grandparents |
65,536 |
1575 | 18 |
262,142 |
131,072 ggggggggggggggg grandparents |
131,072 |
1550 | 19 |
524,286 |
262,144 gggggggggggggggg grandparents |
262,144 |
1525 | 20 |
1,048,574 |
524,288 ggggggggggggggggg grandparents |
524,288 |
1500 | 21 |
2,097,150 |
1,048,576 gggggggggggggggggg grandparents |
1,048,576 |
Continuing with the newspaper story, by the 13th century we would have 1 billion ancestors and 40 generations ago in the 9th century we would have a trillion ancestors. 1,200 years ago there were only 200 million people on Earth. "Simple division - 1 trillion divided by 200 million - shows that each person back then would appear 5,000 times on the family tree of every single person living today ... It is mathematically inevitable that at some point, there will be a person who appears at least once on everybody's tree."
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