Surprised? Once you go through this post you won’t be! As I mentioned in my last post, I love to relate history with geology, and that is exactly what I am going to do here. At first it seems like there is no link between the two widely different subjects- History and Geology. However, when we take a closer look we do see that geology – the history of earth – has influenced the history of mankind ever since the species was born. We know how tsunamis, earthquakes, volcanoes and floods have affected our lives. Had there been no Himalayas to source the rivers of Indus and Ganges, the great ancient Indian civilizations would have never existed. But what I am speaking about in this post has much greater influence in shaping our history. Had the orientations of our landmasses, shaped by plate tectonics, been different, the history of mankind would have been totally different. A slight reorientation of plates and it would have been the Africans, and not the Europeans, leading the world.
We know that the landmasses have moved through time and had been in different location and orientation in the past (see image above). The movement of these landmasses is explained by plate tectonics. Africa, thanks again to plate tectonics, happens to be in the right position to enjoy tropical and sub-tropical climate in which life flourished. It is this environment in which our ancestors were born. Had the plate-tectonics been different, we might not have been born, and had Africa been at a different place it might not have been linked to any other continent for our ancestors to migrate. It is hard to predict if we would have evolved in the same fashion in that closed area, but that is a different topic. What is interesting is the fact that it is the Eurasians, and not the Africans (where human beings originated) or the Native Americans and Australians (where they migrated later), who became the most ‘civilized’. One explanation is that the Africans enjoyed the best living conditions and as the human population increased the weaker tribes were thrown out. These weaker tribes migrated to new areas (see figure below) where they had to fight with unknown dangers. In that process they changed and became civilized. For the Africans, on the other hand, there was no need to change. But why then the Americans and Australians, who migrated even further than the Eurasians, were also left behind? One reason could be that they killed all the large mammals and hence there were no mammals to domesticate (to plough their fields and carry their loads). Apart from agriculture, it was the domesticated animals that helped in the progress of mankind. But is there another bigger factor that we have ignored – the shape of the landmasses?
The two greatest inventions of all times, without which there would probably have been no difference between the ‘Old World’ Eurasians and the ‘New World’ Americans and Australians, are wheels (5000 years ago) and writing (3500 years ago). Wheels have been invented independently in both Eurasia and Mexico, but why is it that the wheels in Eurasia spread rapidly from the Mediterranean to South-East Asia while the one in Mexico never spread? Writing was independently invented in both Eurasia and Mesoamerica, but why again did it spread and developed in Eurasia and not in America? The answer lies in the shape of the landmasses.
Before trying to answer that let’s recapitulate two things from our school geography-
- Climate varies in the north-south direction.
- The tropical and subtropical climates are best suited for agriculture because there’s plenty of rain.
|Long axis of continents|
Thus, a landmass having a longer east-west axis in the tropical and sub-tropical zone will have greater and continuous agricultural land. Now, if we take a look at the world map, the only continent having a long east-west axis is Eurasia, thanks again to plate tectonics. It meant a huge, continuous agricultural land from southern Europe through Middle-East, India, China to South-East Asia. Spread of food production through this east-west axis was much easier than spreading from Mexico to America or from South-East Asia to Australia where the climate changed rapidly over short distances. Now, let’s recollect the two greatest inventions of all times – Wheel and Writing. They improved because they were used rigorously in Eurasia along that east-west axis. Wheel was used to transport food for trading and writing was used to maintain records, effectively transfer messages and for royal propaganda. Faster spread of agriculture also helped in rapid spread of writing, technology, metallurgy and empires across Eurasia. This easy diffusion acted as a catalyst in the progress of human civilization in Eurasia while other continents failed to catch up. Had plate tectonics played its trick and rotated Africa by 90 degrees and placed its long axis in the tropical-subtropical zone, pushing Asia further north under extreme cold climate, our history would have been totally different!
Diamond J. (2005). Guns, Germs and Steel. Vintage books.