This little page came about after I recently connected a few missing links, and combined them with some older research done by others in my wife's McKee line. This tree takes us back to my wife's 15th great grandfather. He (Patrick McKie), was born in or near the year 1500 in Cumloden, Minnigaff, Kirkcudbright, Scotland. It wasn't until about 1855 or so that her 5th great grandfather, David McKee, came to the US, and settled near Pittsburgh, in what would become the city of McKeesport, which is named after him.
I also found another descendent of Patrick. Our common ancestor was born in 1577. He is my wife's 11th cousin, once removed! It was then that I began to wonder how large a family tree could be. I have seen trees that included well over 100,000 individuals, thinking that this is the ultimate in the number of leaves on the tree. After doing a couple of calculations, I found that even those large trees only begin to scratch the surface!
Below are two tables. The first showing how many grand parents my wife would have, if we could go back those 17 generations as we did with the McKee line:
Number of Grandparents
Using the above family example, 17 generations. This table is easy:
You have 2 parents, each of them having two parents (total 4 grandparents)
They each have 2 parents (Total 8 great grand parents)
So simply put, each generation back doubles the number of direct ancestors. You then have to add them to the accumulated number from the other generations.
Generation # Relationship No. in generation Accumulated Total 1 Parents 2 2 2 Grand Parents 4 6 3 Great Grandparents 8 14 4 2 X Great grandparents 16 30 5 3 X Great grandparents 32 62 6 4 X Great grandparents 64 126 7 5 X Great grandparents 128 254 8 6X Great grandparents 256 510 9 7X Great grandparents 512 1,022 10 8 X Great grandparents 1,024 2,046 11 9 X Great grandparents 2,048 4,094 12 10 X Great grandparents 4,096 8,190 13 11 X Great grandparents 8,192 16,382 14 12 X Great grandparents 16,384 32,766 15 13 X Great grandparents 32,768 65,534 16 14 X Great grandparents 65,536 131,070 17 15 X Great grandparents 131,072 262,142 We were so pleased and proud of our selves when we found my wife's 15th great grandparents.
Two down, - - - 131,070 to go!!!
This next little project gets even more mind boggling. This is to illustrate how many direct descendants a 15th great grandfather would have, if everything being the same over the course of the time until now. I'm not a mathematician, so I'll keep the formula simple.
Lets suppose every generation has an average of three children. Why Three? I don't know, the math is easy. If anything, these numbers below are conservative. Families is the 19th century and prior had many more than three.
(Our family record is 17 kids, but that took my 4th great grandfather almost 40 years and 4 wives!)
Some generations had only one child that reached maturity, or never married and had children. More recent generations had 2, 3 or 4. If we used an average of 4 or 5 kids, it might be a more realistic number, but as you will see 3 is plenty!
Each generation "turns over" ever 30 years. The real number in 29.52, but like I said, keep it simple!
The average life span is 60 years. This is quite longer now, but in 17th century scotland the life expectancy was probably 45. It may average out to 60. This is used to figure living descendants in the last column.
For this example, I'll start the year at 1500.
OK, Here goes:
|Generation #||Year||Children of each descendant||New grandchildren per generation||Total direct descendants||Total living descendants|
When I tell people I have about 9,500 in my family tree database,
I usually get a "Wow!", and I usually feel like it is coming along quite
well. I has taken me 4 years to accumulate my list of names.
At that rate, I'll be done with this tree in 72,495 years, but then there
would then be over 2,400 new generations!!!!!
Then I can start on my other lines!