Weird History

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

Cleo Egnal
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It is commonly accepted that history of early humans can be traced back to a region in East Africa 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 development in the theory of human evolution is not the first piece of evidence threatening to debunk the current "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 be easily jumbled. There are humans, Homo sapiens, Neanderthals and about 15-20 known early human species. Because of this plethora of terms, it can be easy to get confused when using the names of certain species to discuss human evolution theory. 

The important terms to know are those in the human lineage, which eventually evolved into Homo sapiens, the modern and only surviving human species. The most modern humans are Homo sapien sapiens because that extra ' sapien ' really lets you know we modern humans mean business. 

Before Homo sapiens were hominids, whose surviving species members are the great apes. Neanderthals were hominids' ancestors but are now extinct. 

 

The Footprint Seen 'Round The World' (Well, In Crete)
The Footprint Seen 'Round The ... 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 5.7-million-year-old footprint in Crete that belonged to a bipedal human ancestor. 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 appeared 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 footprints from more evolved species leads some to conclude the journey did not end well for these ancestors. 

The Out Of Africa Model Of Human Evolution Started With Darwin And Has Been Widely 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. Knowing that there were apes in Africa and having read then-contemporary anatomical studies that suggested humans and apes shared the same ancestor, Darwin combined the two ideas.

More advanced genetics confirmed Darwin's theory decades later, but they also brought forth important questions. How and when did humanity's ancestors depart from 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 understanding of 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, Europe, and then the rest of the world much later.