How did we Get Here? Mk.2 (Part 1)

After a stretched out and stressful exam period I'm finally back!! Hi again guys!

I realise I've kept you all waiting for far too long since the last post and so I've spent a few days reading up and researching to make this a good one, some of you may remember that a few months ago I released a post called "How did we get here" which told the story of how humans reached all the far corners of the Earth. Now this was back when I was revising for exams and I had no time so honestly, although the routes and general information is right, there's probably one or two mistakes, and I personally feel that it was a bit weak and lacked something.

But today I will correct that. Having spent days reading and watching various YouTube content, I'm fairly proud to present How did we Get Here Mk 2: Evolution.

To call the story of human evolution long is one hell of an understatement. Because technically our story starts as soon as the big bang happened. But let's fast forward a little to Africa in the Miocene era, a brief 13 million years ago, because this is where the story of the homo genus begins.

A lot of people say that we evolved from chimps, which is completely wrong. However, we did evolve from monkeys, somewhere between 13 million years ago (the Miocene era) and 4 million years ago (the Pliocene era), an ancient monkey species split into different species, the most notable of which are the homo (human) genus and the pan (chimpanzee) genus. So we didn't evolve from chimps, we merely evolved alongside them. It is thought to have been a long and difficult process but eventually resulted in the two species diverging largely by the time that the Pliocene era rolled around, but first, an important ancestor. Sahelanthropus.

Sahelanthropus is an important discovery because it is such an early point on our timeline. We have found extremely few parts of it, a partial skull (called Toumaï, "hope of life" in the dialect indigenous to the region of Chad where it was discovered), some jawbone and some teeth. While this isn't much to go on, we have managed to discover that it had a brain around 4 times smaller than our own and it has so many chimp - like characteristic that some experts argue that it should be classed as a member of the pan genus.
(see right - a cast of a Sahelanthropus skull)

At the moment Sahelanthropus' role remains a mystery mainly because we don't know when the human - chimp divergence occurred. Therefore, there is the possibility that it could be an early homo, an early pan or a common ancestor of both of them. As there is no general consensus yet, there's very little that I can say so let's fast forward to the late Miocene 6.1 million years ago to Orrorin, a controversial and disputed potential human.

Orrorin tugenensis (or just Orrorin) was postulated to be a species of homininae. Generally, the australopithecines are considered to be the human ancestors, but recently this has threatened their position by being a viable candidate for an even earlier ancestor of humans between the australopithecines and the human - chimp divergence. The fossils which we have discovered (pictured left) are currently being held in a secret bank vault in Nairobi, Kenya.

Now let’s get back to people, specifically, Australopithecus afarensis. This is one of the longest lived species of early human - like apes lasting from 3.85 to 2.95 million years ago. It is also extremely famous because of its discovery in 1974 where it was instantly assumed to be the missing link between the homo genus and the monkey like ancestors. The fossil discovered was nicknamed "Lucy" by Donald Johanson, after the Beatles song "Lucy in the Sky with Diamonds". This fossil turned out to be several hundred pieces of bone, making up 40 percent of the Australopithecus's skeleton and has been toured around the US although it now resides in the National Museum of Ethiopia.

This early hominin species lived primarily in Eastern Africa, and although it may have ventured a little according to fossil record, it didn't really seem to be in any hurry to colonise the world. This however changed with later species as Australopithecus Africanus (the first early apelike species to be classified as hominin) was discovered at 4 separate sites in southern Africa, the most famous of which being Taung in 1924 at which the "Taung Child" was discovered. A large variety of Australopithecus species eventually evolved and spread out around Africa where they continued to develop. However, it is important to note that these creatures were nothing like the humans we see today or even the cavemen that we picture, being our evolutionary predecessors, they were still much closer to apes than the homo genus.

So this seems to be where I'm going to leave off, to summarise, creatures like Sahelanthropus existed before the homo - pan divergence, although as we don't know exactly what species diverged or when it happened, we have trouble pinning down the exact time and saying what came when for this time period. Eventually, the species did in fact separate and evolved into animals such as Orrorin tugenensis which might have been a direct ancestor of humans and also the Australopithecus genus who we currently think were our direct predecessor. Eventually the Australopithecus genus spread out across large sections of Africa as the Pliocene era was coming to a close about 3 million years ago.

This post is getting fairly long and I still have about 2 or 3 million years of human evolution to cover so I'm going to leave this post here for now and hopefully release part 2 in the next day or two. I hope you guys enjoyed reading this, it feels pretty great to be back!

See you soon!