Intro
Have you ever wondered why Balkans look different from Sub-Saharan Africans, for instance? Or what exactly created the genetic differences that we can see with the naked eye between modern humans today? Whether you are curious to know the answer to these questions or you have a general idea of the topic, in this article I will present to you a very cool theory that gives us an explanation of how this complex phenomena occurred.
Toba the volcano
There was once a volcano that scientists today named Toba. It has erupted numerous times in the past however, approximately 74,000 years ago, it erupted so viciously that almost wiped out all of mankind. In order to comprehend the scale of the hazard, Toba released magma nearly twice the volume of Everest and the eruption was more than 5,000 times as large as the 1980 eruption of Mount St Helens in the USA. According to modern scientific theories, the eruption has caused a drop of 10°C and a decade-long ‘volcanic winter’. Moreover, the eruption particles from this eruption blocked out life-giving sunlight and absorbed a great deal of the water present in the atmosphere, thus a drier climate emerging. As at the time humans were hunter-gatherers and their prey was suffering from this situation as well, there was a significant decline in the human population.
Taking these matters into consideration, it is little said that our ancestors had to live through extremely tough conditions and a great deal of them lost their lives at the time.
Impact
At some point, you may ask yourself how come this eruption caused the genetic differences we know today. In a nutshell, the eruption has created a ‘genetic bottleneck’, as the population was reduced to a few scattered thousands (though the population is not estimated to have been particularly numerous then) in dispersed refugia. Trying to get through these difficult times, humans were forced by circumstance to emigrate wherever. As colonies developed independently from one another, they have sown the seeds for the genetic differences between modern humans when these groups left their homes behind. Surprisingly, humans managed to resume their lives quickly after the eruption. Of course, it is important to note that several other factors have contributed to what sets us apart today, such as natural selection, discovered by Darwin.
Alternative theories
It is paramount to also understand that this theory has not been reached by consensus and is criticized to this day by certain scientists. Firstly, some believe that the ecological aftermath has been overestimated and there would have actually been a drop of 2.5°C in the atmosphere, (which is still a lot) lasting just a few years. Moreover, it has been argued that the effects were regional and did not create such a dramatic climate shift. According to the theory above, massive deforestation would have been one of the effects of the eruption however, when a professor at the University of Oxford searched the soil for such traces, he could find none. Nevertheless, there are ongoing debates on the topic, as it a difficult task to find evidence from that time.
Conclusion
Seemingly, the divergence of races is both a fast and slow phenomena. Regardless of whether the eruption had a catastrophic effect or not, genetic differences require a significant amount of time to develop. Nowadays, Toba the volcano is Lake Toba in Sumatra, Indonesia and it’s a way nicer place to visit than the place it was a while ago. :)
Anyhow, it is very possible that, in the far future, humans will be strikingly different from us today, as evolution has always existed and will always do.
Bibliography:
‘Human Origins’, by New Scientist
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