The Best Prediction Ever: Darwin and the Founder Effect

After our 2050 predictions project, I wondered, what’s the upper limit for excellence in prediction?

The very best predictions are so far ahead of their time that they answer questions no one is even asking. Predicting in 1921 that Adolf Hitler would start WWII would be prophetic, but by 1935 this was on enough people’s minds that there was bound to be someone taking the correct position (no disrespect to Mr. Churchill).

Einstein’s (and Newton’s!) gravitational lens or Mendeleev’s periodic trends are strong candidates, but I say the best prediction of all time was made by Charles Darwin in 1871. Now, Darwin made a number of famous predictions around that time, for example:

• Present organisms will be shown to have evolved from different earlier organisms, i.e. the Theory of Evolution.
• Most of the fossil record will be discovered and will demonstrate a history of increasingly complex organisms. ^[1]
• The (then largely undiscovered) fossil record will have fossils of intermediate organisms called “transitional forms”.
• This evidence will show modern Humans and Apes evolved from a common ancestor.

But the prediction I’m thinking of goes even further than that—in fact, it wasn’t even accepted as scientific consensus until 2003!

The full prediction, including the prerequisites, is:

Present organisms evolved from past ones, and the fossil record will be discovered to show this, including in-between organisms called transitional forms, demonstrating that humans and apes have a common ancestor and…

..this common ancestor lived on the continent of Africa.

Darwin’s Greatest Prediction Ever is all of the above-listed predictions combined, plus the Recent African Origin or “Out of Africa” model of human evolution.

This, by a guy who didn’t even know about germs.^[2] How was he able to make such a prediction?

Tracing the Founder Effect Backwards

In population genetics, the Founder Effect happens when a small group of “founders” start a new population that is not representative of the original sample. For example, the Indian state of Gujarat only has ~5% of the Indian population, but Gujaratis emigrated in such disproportionate numbers that nearly 1 in 10 Indian Americans have the Gujarati surname Patel (vs. ~0.5% in India).

This gets really interesting once you realize that the founder effect leads to homogeneity, and therefore you can look at the originating population to find more variation. This applies not only to genetics, for example:

• In China, you’ll see the widest variety of tea. There’s a stereotype that East Asians are green tea drinkers while the rest of the world drinks black tea, but actually, the Chinese invented black tea (they just call it “red tea”) and even have a semi-oxidized tea, oolong. However, the fact that black tea travels better means it became disproportionately popular in far-off lands.
• The closer you get to the Middle East, the more divergent the Christian traditions are. While nearly 90% of worldwide Christians are either Protestant or Catholic (largely thanks to exportation via colonialism), nearer to Christ’s birthplace you’ll find ancient and distinct traditions like the Ethiopian Orthodox Tewahedo Church and the Maronite Church.
• Listen to the accents of these American women, one from near Seattle and the other from near Miami (~2700 miles apart). To me, they are hardly distinguishable and either of them could be from anywhere in the US. However, with these English women from East Sussex and West Midlands County (~150 miles apart), the difference is obvious even to an American and makes evident where the language originated.^[3]

Now hopefully it’s clearer how Darwin made The Best Prediction Ever. From The Descent of Man:

It is, therefore, probable that Africa was formerly inhabited by extinct apes closely allied to the gorilla and chimpanzee; and as these two species are now man's nearest allies, it is somewhat more probable that our early progenitors lived on the African continent than elsewhere.

Darwin saw that the greatest variety of hominids was found in Africa, so reasoned that Africa was the origin of all hominids, including us.^[4]

Thanks to Uri and Kaamya for feedback on drafts of this.