0 generations ago - me. 1 ancestor, being myself.
1 generation ago - my parents. 2 ancestors.
2 generations ago - my grandparents. 4 ancestors.
3 generations ago - my great-grandparents. 8 ancestors.
10 generations ago - 1024 ancestors.
30 generations ago - 1,073,741,824 ancestors.
Let's suppose each generation represents 20 years. 20 x 30 = 600. If subtract this from the year I was born in: 1995 - 600 = 1395.
So in 1395, there were 1 billion ancestors of mine (rounding down).
But in 1400, according to Google, there were only 390 million people on Earth.
Where the fuck did all of those 610 million remaining people go in 5 years? Were they killed by the black plague?
No. The answer is simply that there is more to Earth than what InStItUtIoNs oF HiGhEr KnOwLeDgE would have you believe.
Read: https://en.m.wikipedia.org/wiki/Root_race#:~:text=Root%20races%20are%20stages%20in,mainly%20on%20now%2Dlost%20continents.