A new, fascinating study suggests that all modern humans descend from an “Adam and Eve” couple who lived sometime between 100,000 and 200,000 years ago – but also that 90 per cent of all animal species in the world today similarly come from parents who lived in that time frame:
Mark Stoeckle at Rockefeller University and David Thaler at the University of Basel reached this striking conclusion after analyzing the DNA “bar codes” of five million animals from 100,000 different species. The bar codes are snippets of DNA that reside outside the nuclei of living cells – so-called mitochondrial DNA, which mothers pass down from generation to generation.With each reproduction, errors creep into the bar code, as they do when you repeatedly photocopy a document. By measuring the accumulated errors – the blurriness or “diversity” among the bar codes – scientists are able to infer the passage of time.
That’s how Stoeckle and Thaler concluded that ninety percent of all animal species alive today come from parents that all began giving birth at roughly the same time, less than a quarter-million years ago. “This conclusion is very surprising,” Thaler avers, “and I fought against it as hard as I could.”
What caused animal life on Earth to be almost completely renewed such a short time ago? For now, it remains a mystery.
It’s possible something far more powerful than H-bombs decimated life and only a single set of parents for each species survived to live and procreate another day. But the last major extinction event we know about – the one that snuffed out the mighty dinosaurs – happened a full 65 million years ago.
It’s also possible there is something in nature that limits the size of an animal population. Perhaps it’s some built-in evolutionary process that when a population gets too big, it crashes and must restart itself from scratch.
In their report, published in Human Evolution, Stoeckle and Thaler offer other possible explanations, including, Thaler explains, “ice ages and other forms of environmental change, infections, predation, competition from other species and for limited resources, and interactions among these forces.” Whatever the explanation, he adds, the takeaway is this: “all of animal life experiences pulses of growth and stasis or near extinction on similar time scales.”
Creationists will no doubt take it as an indirect evidence of a supernatural intervention along the lines described in Genesis, even if not according to its literal timelines. Something curious has certainly taken place at some point in time in a reasonably recent geological history – whether it was something catastrophic, like an asteroid or a comet strike, which were responsible for the previous mass extinctions (Permian and Jurassic) or something more gradual, like the climatic processes, which likely contributed to the extinction of the megafauna around 10,000BC, remains to be established by those following in Stoeckle’s and Thaler’s footsteps.