EagleJCS,

I am not talking about timeframes at all. I'm simply reminding people that each generation doubles the number of ancestors.

Here is a simple family tree. You are at the bottom. You have two parents. This is the first generation.



Each of your parents had two parents. And so on, and so on. This example is only four generations and you have 16 ancestors. 8 male and 8 female.
You can trace your ancestry through any one of these 16 people. And each of them had a different name and may have come from widely different places.

If a great uncle died without children he cannot be your ancestor.

The average time between generations obviously differs depending on how old your ancestors were when they had children, but most genealogists use an average of 20 years between generations.