Evidence for Biological Evolution

In 2015, the On the Origin of Species the masterpiece by Charles Darwin was voted the most influential academic book in history. The biology bombshell edged out works by notable authors such as William Shakespeare and Stephen Hawking just to name a few. Darwin’s famous book stirred up controversy virtually from the moment it was published due to its implications for religion and the origin of human beings.

Despite the controversy, the theory of evolution by natural selection has been validated time and time again and is the bedrock of modern biology and medicine.  From its initial proposition by Charles Darwin and Alfred Russell Wallace in the mid 19th century, this groundbreaking scientific theory has elicited the most venomous opposition unlike any other scientific theory in human history, but why?

The challenges were not long in coming, all of a sudden one scientific theory amongst many became the focus of so much vitriol, and the first of many legal challenges and shenanigans  began with The Scopes Trial in 1925 and culminated during the Kitzmiller V. Dover trial in 2005. An attempt to sneak creationism into a science classroom was promptly rebuffed by the US courts.

In the meantime, the evidence for biological evolution keeps piling up. Through the discovery of DNA and Genetics we now know about our kinship with all life on earth. We now know we are more closely related genetically to chimpanzees and bonobos. The evidence from our microbiome,the plethora of endosymbiotic relationships with microbes  we can now see in virtually all organisms on earth,the sometimes  fortuitous viral infections that have shaped our species-endogenous retroviruses and transposons otherwise known as jumping genes, have all played pivotal roles in the evolution of all organisms on earth.

We now know that we once shared our planet with other branches of the homo genus and we interbred with them and the remnants of these dalliances reside in our genome. We have discovered that our ancestors mated with Neanderthals  and left their imprint in some modern humans. We know another archaic hominin know as Denisovans left their genetic fingerprint in Australian Aborigines, East Asians and Melanesians. We have managed to identify an EPAS1 gene inherited by Tibetans from Denisovans that confers an advantage for living at High Altitudes as well as genetic variants for keratin filaments derived from Neanderthals inherited by at least 80% of Eurasians. What has now become clear from the emerging field of Paleogenetics is that our species is just one of a myriad of hominins that once roamed our planet. We have revealed evidence of archaic hominin admixture in all modern humans including Africans.

The most recent research indicated that the Yoruba genome shows evidence of admixture with an unknown archaic population. The Iwo Eleru skull discovered in Ondo state in Nigeria in 1965 displays a mosaic of modern and archaic anatomical features and this new data has led scientists to expect to find more evidence of archaic admixture in Africa. What the genetic evidence suggests is that the emergence of modern humans is more complex than we ever imagined

Some ground breaking work by Svante Paabo of the Max Planck Institute of Evolutionary Anthropology in Leipzig and David Reich of Harvard continues to reveal the fascinating and intriguing story of the Genus to which we belong.

The story of modern humans reveals a veritable thicket that involves numerous hominin species mingling with each other, but for reasons unknown we are the only ones left. It is now generally accepted that modern humans arose in Africa, and some left to explore and discover the rest of the world.

You go back far enough and we are all African, I find the notion that we are all so closely knit to be incredibly humbling and truly poetic in its simplicity,and this is not only profound but empowering.

Tavian Oladapo
A singer/songwriter, a keen science enthusiast and is currently employed in the Microbiology Department in the NHS Trust in London.

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