Demographic Collapse, or Why We're All Related

There's an interesting article I found via the browser that discusses recent research on demographic collapse. It makes the case that everyone currently living shares an ancestor 2,000-3,000 years ago. Moreover:

It doesn’t get any less weird when you look at it from the other angle: While you more than likely have four distinct grandparents and eight distinct great-grandparents, past a certain number of generations back, your number of ancestors stops growing exponentially, because they start being the same people. By the time a couple who married in 1450 in Holland, has had a few hundred descendants over the span of several generations, those people are distantly related enough that some of them start marrying (and, yes, reproducing with) each other.

I have found one instance of third cousins marrying in my family tree.


  1. Interesting point! Certainly something to think about. Welcome to GeneaBloggers :)

  2. I think that this is an interesting topic and think that it would be interesting if records existed since time began. I would love to be able to research my family history "beyond the bend", so to speak. In other words, to the point that it stops growing exponentially and starts narrowing back down.

    My husband's paternal grandmother and my paternal grandmother had the same surname- Fowler. Both were born in the same county in South Carolina. However, I have found no common ancestor between us in the 400 or so years that I have researched of our families. I know that it has to be there; I just need to look harder.

    It is definitely an adventure. :)

    I am a new follower of your blog, via the Feedly Reader. We have at least one research interest in common, the surname James. Have a great day!

  3. Saw your blog listed at Geneabloggers, congratulations. From my own experience We Are All Related. I have several ancestors that have more than 100,000 descendants in a span of 400 years. I have done research for friends and usually by the 8th generation we have a common ancestor.

    Take care,

    Moises Garza
    We Are Cousins - My personal blog about Northeastern Mexico and South Texas Genealogy

    Mexican Genealogy - Blog where anyone with Mexican roots can get started with their family genealogy and history.

  4. I learned about your blog via Geneabloggers.
    Reading it, it struck me that the Hartman name sounds very Dutch. Being Dutch myself, I was very much interested. I also have a blog with many genealogical subjects. One of my posts shows a survey of foreign genealogical blogs/sites showing Dutch origin surnames. The URL is http://www.patmcast.blogspot.com/2012/05/dutch-ancestors.html. The idea is to try and establish contacts between people who have an interest in the same surname. There are numerous cases in The Netherlands where people emigrated centuries ago without leaving a trace in Dutch archives. With my blog I try to bring Dutch and foreign (mainly US/CAN) genealogists together.
    Therefore, I like to have your permission to show your site in my a.m. blog unless of course you are certain the Hartman surname is not of Dutch origin.
    I look forward to your reaction!
    Kind regards,