B-Theories

Homo Naledi: Is This A Human Ancestor?

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Sushmita PathakB-Theories,,,,,,,,,,,,,

Pictures via National Geographic.

13th of September 2013. It was just another regular Friday night for Rick Hunter and Steve Tucker- no, they weren’t partying at some club-they were inside the Rising Star, a remote cave near Johannesburg in South Africa’s Cradle of Humankind, a UNESCO World Heritage site. The Rising star is a highly inaccessible cave with ridiculously narrow passages that would make even the most experienced cavers claustrophobic. Steve and Rick had gone in deep that night.

They knew they were probably crawling into spaces no human had crawled into for a long, long time. What they did not know was that they were about to discover something that would change history forever.

Curiosity about our ancestors has both inspired men and driven them crazy. Most of us, regular people, practically have no time for musings of the sort when there are presentations to be made and targets to be achieved.

But just stop for a moment and think: What are we? Where did we come from? How did it all begin?

We came from the in-between

Modern humans evolved from apes. Let’s go back in time to 4 million years ago – this was the era of the Australopithecus, an ape-like creature that could walk upright. Jump to 2 million years ago- this was the age of the Homo Erectus – our oldest human relative.

Fossil evidence suggests that our genus, Homo, was born somewhere between the Australopithecus era and the Homo Erectus. Somewhere in this glorious period, humankind was born.

Enigmatic: No fossils from our period of origin found yet

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Between the last Australopithecus and the earliest Homo fossils, there is a huge gap of about 1 to 1.5 million years. The key to our origin lies in this critical gap. However, mysteriously, we have never been able to unearth enough fossils belonging to this crucial episode of evolution.

In the 1960s, in Tanzania, the discovery of the remains of a hominin called Homo Habilis had caused quite a lot of excitement in Paleoanthropologists, but the fossils were so scarce that not much could be made of them. They seemed to mock us.

A serendipitous discovery

On that fortunate Friday night, as cavers Rick and Steve squeezed their way into the rising star, they saw some overwhelming rock structures. Rick Hunter took out his video camera and his partner Steve ducked out of the frame and crouched into a nearby crevice.

To Steve’s slight surprise, his feet encountered empty space instead of rock. When he lowered himself further, he discovered that the crevice went on and was actually a narrow chute- a mere gap of 7 to 8 inches. Steve sensed something exciting and called Rick to join him.

Adrenaline levels rose- they’d found a part of the cave that wasn’t even shown on the maps! At the end of their scary descent, they found themselves in a chamber, which is now called the Dinaledi chamber. The roof of this chamber too, like the previous one, was filled with beautiful rock structures. The next moment they saw something on the floor of the cave that took their breath away.

The floor was strewn with bones. Bones that, to Rick and Steve, looked human-like. They could hardly believe their eyes. They reported their findings to Professor Lee Berger, a paleoanthropologist and National Geographic Explorer-in-Residence, who’d been fossil-hunting in South Africa for quite a few years now.

When Berger saw the pictures, he swore. This was something big. The Rising Star Expedition was on.

Fortune and fossils favour the skinny

The chamber’s absurdly narrow entrance meant that only wiry individuals could go down. Berger immediately put out the word on social media: skinny individuals with a background in palaeoanthropology were wanted. In spite of the odd combination of requirements, Berger received quite a lot of applications, mostly women.

By November 2013, after three weeks of painstaking crawling, squeezing and fossil-hunting, the team had managed to bring up a whopping 1,550 pieces of bone and teeth- the most that any single site had ever yielded! Berger knew they were extraordinary, but even he wasn’t prepared for what was about to unfold.

What do the fossils say?

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When Berger had first seen pictures of the fossils, he had been certain that it was either an Australopith or a Homo Habilis specimen. The very first batch of fossils that were fetched included a part of a mandible, the lower jaw bone, with four teeth in it. The bone was smaller than that of the Australopiths and so it was definitely from the genus Homo. The bone was also distinctly curved which suggested that it wasn’t an H. Habilis, who possessed a relatively straight mandible.

If it wasn’t H. Habilis and it definitely wasn’t Australopithecus then what was this creature? Was it a new specimen altogether? Was this the missing piece of the puzzle? For Lee Berger, things had just got serious.

As the expedition progressed, the picture that was slowly coming together was different than anything anyone ever knew. The hands, feet and teeth were human-like, but the trunk was more primitive. It had a small brain (about a third in size of what modern humans have) which implied that it lived early in the Homo tree.

It manifested every attribute that a creature on the cusp of the Australopithecus-Homo transition could imaginably have. You could almost see evolution working on it. They christened it Homo Naledi (Naledi means ‘star’ in the local Sotho language). This was indisputably a new member in our family tree but was it the answer to the dawn of humanity?

What does this imply?

The Dinaledi chamber is perhaps one of the most inaccessible places in the African continent. How then, did so many bones accumulate in such an isolated place? Also, all the fossils found in the chamber are hominin, there is no trace of bird, animal or even rodent fossils which is unusual for a regular excavation.

The logical conclusion is that, if these creatures had wandered on their own, found themselves trapped and eventually died, so would have other smaller animals but that clearly isn’t the case. This only leaves one possibility – they’d been put there on purpose.

This startling implication raises more questions than it answers. Was Homo Naledi disposing of its own members at such a nascent stage? Was Rising Star, in fact, the earliest human burial site? If yes, it would indicate a pretty impressive cognitive ability in spite of a small brain.

All roads lead to Africa

For years now, Berger has believed that the birth of our great race occurred in Africa. Was it here, in South Africa, in the Cradle of Humankind? Or was it in the East where Homo Habilis was found? Or was it both? This monumental discovery gives evolution an altogether new dimension. Perhaps we’ve been wrong all this time. Perhaps there were more than one species evolving simultaneously.

What if evolution wasn’t through a linear family tree but through a braid-like system that ultimately coalesced into one highly intelligent human being?

Homo Naledi’s discovery is an epiphany. There is so much out there waiting to be discovered. We might be closer to understanding the dawn of humanity, but one question will always remain: what other discoveries about our past does the future have in store for us?

Watch this Nova-Nat Geo documentary about the Dawn of Humanity. If this doesn’t give you goose bumps, I don’t know what will.

https://www.youtube.com/watch?v=hzur-ytztWc