Who was the first human?

Several years back, a good friend asked a question that stumped me: Who was the first human? Actually, he didn’t pose the question quite that way. I don’t remember his exact words to be honest, but he basically wanted to know when the first human was born?

As you might guess, we were discussing evolution at the time. My friend is college educated and had previously worked as a public school teacher. I had always assumed he understood and embraced widely accepted scientific theories like evolution and natural selection.

You can imagine I was quite surprised with his inquiry. It was something I expected a teacher to understand. I was a bit taken back and stumbled over my answer. I remember being frustrated that I couldn’t answer his question in a short, concise manner.

Looking back, I realize his question was not meant to be a stumper. I think he was open minded, but unconvinced about evolutionary theory, despite his education, and was hoping I could explain it in a way that made sense. I remember at some point in the discussion he mentioned monkeys. I think he was struggling with the idea that one day we were swinging through the trees and the next we were solving quadratic equations.*

A difficult question

The problem with answering a question like the one my friend posed is that it is difficult to agree on what a human actually is. This might sound bizarre, but consider the following.

Most people think modern man (Homo sapiens) is a species all to itself. However, we are only one member of the genus Homo. There were once other members of our genus, such as Homo neanderthalis (Neanderthals) and Homo erectus, among others. Sadly, they have all died out. Technically then, Neanderthals were humans, since they were members of our genus. In fact, there is considerable evidence that the people we typically think of as “humans” mated with Neanderthals in western Europe around 40,000 years ago.** This could only have happened if Neanderthals were closely related to us. Indeed, most people living today have Neanderthal DNA that can be identified.

I doubt if my friend was considering Neanderthals when he asked when the first human existed. So you can see there’s a discrepancy in people’s ideas of what a human actually is. How can you say when a thing first existed if you can’t even agree on what that thing is?

Mind-numbing.

Evolution is a gradual process

Before we get to an answer to my friend’s profound question, consider one other thing: Given the spectrum below, where is the point that yellow becomes orange?

First Human Spectrum

It’s not an easy thing to pinpoint is it? “Orange” is a vague and arbitrary description. What you consider orange, someone else might consider yellowish-orange or orangish-red. If I asked multiple people to point orange out, I would surely get multiple answers.

So what does this have to do with the human timeline? The point is that evolution is a gradual process. Just like the change from yellow to orange is gradual and an absolute change unidentifiable, so is the splitting off of one species from another or the change from one species to a new one.***

So can we have an answer, please?

Based on the fossil record, we can place the first appearance of modern humans (entities most lay people would consider “human”) about 100,000 to 200,000 years ago. This would be the safest answer to my friend’s question. However, if we include Neanderthals, then we are looking at least 500,000 years back. And if you want to include all species of Homo, then you are looking at more than a couple of million years ago, going all the way back to the split from a human-like primate named Australopithecus.****

Special thanks to paleontologist Michael Kirby for reviewing and contributing to this post.

* You might already know that humans didn’t evolve from monkeys. It is a common misconception, although we do share an earlier primate ancestor.

** There is a recent study (2016) indicating sapiens might have mated with neanderthals as far back as 100,000 years ago. Read more about this.

*** There are actually two types of evolution: cladogenesis and anagenesis. The former is the splitting or branching that produces two new species from a common ancestor. These branching events can be pinpointed in time, if provided with enough evidence; and is one of the things palaeontologists strive to do. Anagenesis is the evolution of a single species into a new species through gradual changes over time, but no splitting.

**** There is a very famous member of the Australopithecus family you may have heard of named Lucy. Read more about Lucy.

 

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