Weird History Uh Oh... The Theory That Humans Originated In Africa Is Rapidly Falling Apart  

Cleo Egnal
56.5k views 10 items

It is commonly accepted that humanity's ancestors evolved in – and migrated out of – east Africa from a region that has been dubbed the "cradle of humanity" for its foundational role in human evolution. However, a newly discovered footprint in Crete could complicate the standing human evolutionary narrative.

It's theorized that the footprint might have belonged to a human precursor that lived 5.7 million years ago, which would mean that humans were wandering around continents other than Africa for much longer than archaeologists originally thought. This new theory of human evolution is not the first piece of evidence to try to debunk the standing "cradle of humanity" theory, which has been around since the mid-20th century, but it is significant in helping researchers craft the most accurate model of human evolution possible.

Let's Get The Science Jargon Out Of The Way

Let's Get The Science Jargon O... is listed (or ranked) 1 on the list Uh Oh... The Theory That Humans Originated In Africa Is Rapidly Falling Apart
Photo: hairymuseummatt/Wikimedia Commons/CC BY-SA 2.0

When talking about human ancestry, the terminology can easily get a bit jumbled. There are humans; there are Homo sapiens; there are Neanderthals; there are about 15-20 known early human species. Because of this plethora of terms, it can get a bit confusing to know what people mean when they invoke certain species in explanations of how evolution is theorized to have worked.

The important ones to know are those that involve human lineage, and those all lead up to what we call Homo sapiens, the modern and only surviving human species. 

Before Homo sapiens were hominids, whose surviving species members are the great apes. Neanderthals were hominids' ancestors, and they are extinct whereas hominids still exist. 

Oh, and of course, you can't forget that the most modern humans are Homo sapien sapiens, because that extra 'sapien' really lets you know we modern humans mean business. 

The Footprint Seen 'Round The World (Well, In Crete)

The Footprint Seen 'Round ... is listed (or ranked) 2 on the list Uh Oh... The Theory That Humans Originated In Africa Is Rapidly Falling Apart
Photo: Grand Canyon NPS/flickr/CC-BY 2.0

Authors of a 2017 study claim to have found a footprint in Crete that belonged to a bipedal human ancestor about 5.7 million years ago. The footprint was of a creature that walked on two feet, had no claws, had inner toes that were longer than its outer ones, and had a big toe that was in line with the rest of the toes (rather than attached at the side) – the conclusion is that this footprint likely belonged to a human ancestor. 

As Crete was still a part of the Greek mainland – and hospitable climate existed all the way from Africa to the Mediterranean – it makes sense that these early humans could have made the journey much earlier than previously thought. They also could have developed these traits independently, according to the researchers making the controversial claims.

Unfortunately, a lack of further footprints from more evolved species leads some to conclude the journey did not end well for our ancestors. 

The Out Of Africa Model Of Human Evolution Started With Darwin And Has Widely Been Accepted

The Out Of Africa Model Of Hum... is listed (or ranked) 3 on the list Uh Oh... The Theory That Humans Originated In Africa Is Rapidly Falling Apart
Photo: GrrlScientist/flickr/CC-BY 2.0

Charles Darwin was a naturalist famous for his theories on evolution, and he was the one who first proposed the idea, in the 19th century, that humans originated in Africa. He knew that there were apes in Africa; he had read then-contemporary anatomical studies that suggested humans and apes shared the same ancestor; and he put two and two together.

More advanced genetics confirmed Darwin's theory decades later, but they also highlighted some questions: namely, how and when did humanity's ancestors depart Africa; how many dispersal waves were there; and where did they go? The reason the footprint found in Crete is viewed as "controversial" is that it attempts to poke holes in the answers to these questions, answers that are widely accepted as the truth. 

The Out Of Africa Theory Is The Dominant Model Of Human Origin And Migration

The Out Of Africa Theory Is Th... is listed (or ranked) 4 on the list Uh Oh... The Theory That Humans Originated In Africa Is Rapidly Falling Apart
Photo: Unknown/Wikimedia Commons/CC BY-SA 3.0

The Out Of Africa theory, when boiled down, essentially contends that all human beings descended from a single group of early humans who originated in Africa and spread to Europe and Asia over time. This is the most widely accepted model for how human beings came to be, as well as how, where, and when they dispersed from Africa. This theory also holds that there is a clear line of migration that goes from Africa into Asia, then Europe, and then the rest of the world much later.