Periodically, we publish essays from Professor Andrew Lyon‘s Honors 389 course “The Science Blender”, which is the basis for Schmid College’s Grand Challenges Initiative. In HON 389, students are asked to reflect on different aspects of tackling a grand challenge. In this essay, student’s were asked to research and analyze an interdisciplinary breakthrough of their choosing.
Life stays in motion. We as humans kept our natural intuitions and instincts to stay together, to socialize, and to depend on one another. These characteristics have stayed constant through the ages. The prevailing theory among scientists is that everything human originated on the continent of Africa between 156,000 and 200,000 years ago. Genetic and archeological evidence suggest that migrations of modern humans out of Africa began at least 100,000 years ago. And the wave of migration from Africa steadily spilled out to the entire globe for tens of thousands of years. However, most humans outside of Africa have likely descended from other human groups who left the continent more recently, from 40,000 and 70,000 years ago .
As a scientist, you have to ask: why did they leave? Wouldn’t the first humans stem from where the conditions were most desirable for human life? One would assume that natural instinct tells a species to find the most favorable conditions for survival. But somehow humans ended up in the northern state of Alaska, and in the tundra-ridden Russia, where survival takes more energy than in other places around the globe.
A major recent scientific breakthrough that encompasses the fields of geography, anthropology, and genetics has surfaced. According to researchers at the University of Hawaii at Manoa, the first humans that originated on the continent of Africa were coaxed into migrating up the Arabian Peninsula because of the Earth’s rotation. The change in rotation caused a dramatic modification to weather patterns that forced the human ancestors to leave Africa. The Earth’s weather patterns are dependent on the rotation of the earth and every 21,000 years the Earth experiences slight changes in orbital and rotational patterns called the Milankovitch cycles .
The researchers developed a computer simulation that tracked these changes in orbit and solar radiation and how they affected rainfall, temperature, sea levels, glacial ice, vegetation, carbon dioxide levels, and global modern human migration patterns over the past 125,000 years. Research tells the scientists that heavy rainfall in the northern Arabian Peninsula made that area habitable for humans. This model also suggests that modern humans should have arrived nearly simultaneously in southern China and Europe about 80,000 to 90,000 years ago .
This discovery is recent, and is significant because the effect that Earth’s wobble had played a huge role in humans’ dispersal across the planet and most likely also played a big role in our evolution and adaptation. Climates and geographies shaped us, and as always, Mother Nature had decided our fate.
 Choi CQ. Earth Wobbles May Have Driven Ancient Humans Out of Africa[Internet]. LiveScience. 2016 Sep 21 [cited 2016 Sep 22]. Available from http://www.livescience.com/56188-humans-left-africa-due-to-earth-wobbles.html
 Lamb R. Is Africa the cradle of humanity?[Internet] HowStuffWorks. 2009 May 11 [cited 2016 Sep 22]. Available from http://science.howstuffworks.com/life/evolution/africa-cradle-humanity1.htm