09/13/2025                                                                            
                                    
                                                                            
                                            GENEALOGY & FAMILY HISTORY 
I am a family historian.  My Mom & Dad left me with outlines of their family trees, with names and national origin of our direct ancestors going back to about 1700.  But few details. 
When they passed in 1986, I started researching these names to learn more about their birth, life, marriage, death and their families.  In the 1980s & 90s I searched many libraries, genealogical collections, the National Archives (NARA) and even searched the LDS Main Library in Salt Lake City.  
I spent countless hours, scrolling through miles of microfilm, microfiche and thousands of genealogy books and family histories tracing my four grandparents back to their origins, to find my family ancestors. Compiled family histories already done by other genealogists and related to my family speeded my research. 
By 1990 I had become an intermediate genealogist. I had traced my four grandparents by surname from America back to the 1600s in England, Ireland, Scotland and Germany.  I had found their birth and death and marriage certificates, land holdings, military service records, wills, letters, newspaper articles and even some of their photos. 
All this I did BEFORE the internet made so many more documents available. 
By 1992 more genealogical collections and documents were published online and I expanded my family history on Ancestry.com. 
I now have around 2,500 ancestors and their relatives recorded by name on my Ancestry Tree (fully sourced and documented).  I've written in proper genealogical style my four grandparents' Family Genealogies with source documentation. 
I have identified about 200 names as my direct ancestors.  
How many direct ancestors could I possibly have? 
Using a simple calculator, I took the raw number of my direct ancestors from my 2 parents to my 4 grandparents to my 8, 16, 32, 64 . . . great and greater grandparents back to 1776. Well, if I take just the numbers of direct ancestors back to 1776, it would be 286 great-grandparents!
I continued on calculating to some 30 generations to the year 1066, the Battle of Hastings. 
Mathematically, the number by 1066 was over 33,000,000 direct ancestors. (!)
This is a humbling fact of our human genealogy.  Did the world get more population as we go back in time? 
I wondered: If I continued back in time, it appeared the world population was getting larger!?!?  But we have the idea from Adam & Eve that the population grew larger with each year, each decade going forward to modern times?!?!  How to explain this amazing contradiction? I puzzled for years. 
I could only deduct that:
"When the number of our direct ancestors going back in time, reached the same number as the world population at that time, then that was the time when we humans began to be all directly related to each other."
Of course, there were many inter-family 'marriages' in history, (cousins marrying cousins) but that does not seem significant to explain such huge numbers of direct ancestors. 
So, if world population increased going forward in time, as it is now doing, when was this time in history that equaled the number of our direct ancestors?
To me, this is empirical mathematical proof that we humans are all, indeed, related to each other!
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Today I asked "Google's AI" the question: "What year in time was it when the number of our direct ancestors equaled the world population?"
Their answer: 
"A single person's number of direct ancestors can theoretically equal the world population sometime in the Middle Ages, around 1200 A.D.. However, this is not a hard-and-fast date due to what's known as "pedigree collapse," where ancestral lines overlap. 
The ancestral paradox
The paradox arises from a simple calculation: The number of your direct ancestors doubles every generation you go back.
2 parents (1 generation back)
4 grandparents (2 generations back)
8 great-grandparents (3 generations back)
At an average of 30 years per generation, this doubling causes the number of ancestral slots in your family tree to exceed the global population within 30–40 generations.
For example, at 30 generations back (roughly 900 years ago), [1125] a person would have over one billion ancestral slots, a number that surpasses the world's actual population at that time. 
Pedigree collapse is the reason why
This paradox is resolved by a phenomenon called "pedigree collapse," where your family tree is not a perfectly branching structure. 
Instead of each ancestral slot being a unique individual, many are filled by the same people because your ancestors were often related to each other, even if distantly.
Because humans have historically lived in smaller, isolated groups, intermarriage among cousins and other relatives was common.
This means that as you go back in time, your genealogical tree collapses on itself, and the number of your unique ancestors is far fewer than a simple exponential calculation would suggest. 
A population bottleneck may also be involved
Another factor in the small number of actual ancestors is that humanity experienced a population bottleneck, particularly between 900,000 and 800,000 years ago, when the number of breeding individuals dropped to as few as 1,280. This means every person alive today is descended from a very small number of ancient ancestors."                                        
                                    
                                                                        
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