14 DAY TRIAL // A newly proposed idea on how early humans and their ancestors evolved states that massive volcanic eruptions early on in the planet's history, coupled with the parting of the first continent, Pangaea, may have played a crucial role in the development of these species. The idea is highly debated in the international scientific community at this point, and both proponents and critics defend their point of view fervently, LiveScience reports.
The widely accepted proposal on the origins of primates, early humans, and their common ancestors is that these species originated from a small portion of Africa. From this “Cradle of Civilization,” our ancestors spread out in successive migration waves, to a point where they succeeded in colonizing the entire world. This is also one of the fundamental differences between us and great apes, some suggest. We live all over the place, even at the poles, while primates only live freely in tropical or subtropical regions of the Americas, Africa and Asia.
Buffalo Museum of Science researcher Michael Heads, one of the proponents of the new theory, argues that this Cradle of Life idea has many flaws, not the least of which being the fact that early humans might have had to sail across the Mozambique Channel to reach Madagascar, or somehow pass the Atlantic Ocean, to get to South America. He argues that this type of what he calls “imaginary migrations” has absolutely no foundations in the biological pieces of evidence available at this time. The idea, he adds, results in “all sorts of contradictory centers of origin,” including Africa, America and Asia, which of course cannot be. The theory itself holds that there was only one Cradle of Life.
Heads suggests that the early ancestors of primates were in fact fairly widespread across Pangaea, more than 185 million years ago, and that they were already present by that time in swaths of land that would later become Central-South America, Africa, India and Southeast Asia. Flying lemurs, tree shrews, and the plesiadapiformes (extinct creatures of Eurasia and the Americas) all lived at the same time, Heads argues. He believes that the catalyst for change came in the form of massive volcanic eruptions, cataclysmic tectonic plate movements and continental splits. These are the factors that he holds responsible for the separation of primate species into different lineages.
But critics to this idea say that primate ancestors couldn't have lived on Pangaea that many millions of years ago. Stony Brook University primatologist John Fleagle explains that fossilized pieces of evidence place the earliest known ancestors to about 56 million years ago, whereas genetic data hints that they were alive between 80 to 116 million years ago. But none of these records supports Heads' theory, the expert adds. The researcher's idea is “inconsistent with all other evidence we have about the timing of major events in primate evolution,” Fleagle adds.