Shapes in the Great Tree |
Abstract
The tree, with its branches and roots, is an old, powerful and pervasise metaphor in genealogy. But traditional genealogical trees, even the largest and deepest ones, are only very partial and often biased local maps, spanning a handful of recent human generations, a tiny part of a long human history. And humanity itself is only a short and very recent branch of the long evolution of life on Earth, a continuous process spanning billions of years.
The Tree of Life is not a tree
We are all cousins. Not only all of us humans, but all of us living creatures on this planet. At least that's the main lesson to bring home from any introduction to phylogenetics, even if many details of the story are still unclear. Somewhere on Earth, billions of years ago, there lived some of our monocellular common ancestors, and part of their genetic code has been copied over and over through a number of generations which defy our imagination.
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They can't see the Tree for the branches
Of the above state of affairs, many newcomers to genealogy, and even more ancient ones, don't seem to be fully aware. Or maybe they don't buy the narrative built up by centuries of scientific enquiry. In any case, they have hard time understanding, and accepting, what a Single Tree approach to genealogy is all about. Aware of this difficulty, WikiTree communication tries hard to shift the user's perspective from "my tree" to "our tree", but such efforts are unfortunately often misunderstood.
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A slice in the tree : Seven generations around 1900
Let's face it : the intertwined roots of the Great Tree are lost in the depth of time, and its branches keep growing and crossing each other towards an unpredictable future. Both tips are forever out of reach, and all we can explore in our genealogical research is but a thin slice of a few centuries in a story of billions of years. But all the life streams flowing from the distant sources are passing through any slice of time, and if we focus on the geometry of such a slice while keeping in mind the big picture it is cut from, what can we see, and what does it tell us about the tree at larger scales?
Using WikiTree to explore those seven generations, the first figure to be aware of is the distribution of profiles over time in the data base. As of 2021, over 95% of WikiTree profiles were born post-1700, and almost 80% of them post-1800. The second figure to bear in mind is that 1800s profiles in WikiTree, in the current state of affairs, represent less than 1% of the world population during the same period. Nevertheless, even in this very partial state of affairs, shortest paths linking two of those post-1800 profiles, as computed by the Connection Finder, rarely venture pre-1700, and often stay post-1800, using a lot of transversal paths via spouses, siblings, in-laws, cousins of cousins. Adding even a small amount of the remaining 99% can only provide more transversal bridges and shortcuts to the existing paths, and reduce the mean distances. It is not too bold a conjecture to say that all people in those seven generations could be connected without need to go further back in the past. The Connect 1900 project is exploring such a conjecture, adding to the traditional vertical exploration of the tree the transversal relationships (siblings, spouses and in-laws), looking in all four directions to expand "circles", as defined by the 100 Circles project. |
Watch out for crossovers
Circular exploration of generations around 1900 uncovers a geometry of endogamic clusters linked by rare but crucial (pun intended) crossovers. The endogamic clusters are geographical, social, ethnic, religious, economic ... or any mixture of the above ingredients. The main geographical clusters in WikiTree are in North America, hence the most obvious crossovers are immigrants from anywhere to America, and this is an obvious bias to the geometry of WikiTree. Behind the main American cluster are hiding national and regional clusters in Europa, South Africa, Australia, New Zealand. A notable and particular cluster is the European aristocracy, known to be very endogamic, but nevertheless crossed by many connection paths, even those linking commoners.
See also : Circles and Bridges of Suzanne Gardahaut (1900-1992) (more examples to be added) |
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The Shape of Things to ComeOf course we can't see further in the future than in the past, and obviously even less. But like in the famous novel by H.G.Wells, we can have a try at anticipating how the next slices of the Great Tree could look like, based on past and recent trends. One of the most noticeable of those trends in the 1900s and early 2000s has been the continuing decrease of both geographical and social endogamy. This trend was already visible around 1900s in the Western World, as said in the previous section, but it has now become global. Here is a short list of relevant resources about it.
Even if the majority of unions in the world even today are still endogamic, the proportion of crossovers has been steadily growing, each one shortening the distances between endogamic clusters, and we are globally getting closer and closer to each other in the great family network.
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© 2021 Bernard Vatant - last update : 2021-12-08