“Who Is Killing the Great Chefs of Europe?” was one of those top-notch mystery comedies from 1978. Who killed the ancestors of modern day humans isn’t quite so funny, but it’s still a top-notch mystery. I propose one rather unconventional answer, our creator ‘gods’, the extraterrestrials.
Modern humans (Homo sapiens) evolved from other primates, most probably from chimpanzee stock in Africa when DNA relationships are analysed. We have a 98% compatibility with chimpanzee DNA. However, there was a long chain of in-betweens twixt chimpanzees and modern humans, the two key transitions being a bipedal gait (Australopithecus) and tool use (Homo). The interesting things are that while all the in-betweens have gone extinct, the ancestral primate stock didn’t; the transition to modern humans was so fast that it reeks of artificial selection, not natural. Are the in-between extinctions and the extremely rapid transition to modern humans linked?
Review: 4.5 billion to 5 million years ago.
Divide the roughly 4.5 billion year history of Planet Earth into say five million year segments. Now imagine yourself 4.5 billion years ago jumping from one segment to the next. Even given a five million year leap, would you notice much change per leap? No, you wouldn’t. You’d notice a little change, yes, but hardly anything drastic or major. That applies as you jump from segment to segment – a little change, a little more change, even a little more change as you get further and further removed from your starting point. The composition of the atmosphere slowly, ever so slowly changes; life begins and single celled critters emerge. After many, many segment leaps, these evolve simple multi-celled critters, etc. But change is so gradual that it’s hardly perceptible from one segment to the next. The exception would be when there’s been a mass extinction event, so if you jump from 70 million years ago to 65 million years ago, yes you’d notice that, oops, where are the dinosaurs? Then things settle back down again to very slow but very sure rate of change.
Now about 90 leaps of five million years each will bring you to roughly a time five million years ago. Observe carefully the landscape, atmospheric composition, and the various life forms. If you’re in Africa you just might notice the early stirrings of the hominoid branch that will ultimately lead to us. Now do that final leap. Jump that final segment. Is the resulting change major or minor? If you answered yet again ‘minor’, put on your dunce cap. That change is the most major of all the incremental five million year leaps. Now doesn’t that strike you as odd? It’s always been a relatively slight incline of change, now all of the sudden the slope skyrockets.
Review: 5 million to 500,000 years ago.
Now divide that final five million year segment into say ten parts of 500,000 years each. Perform that same incremental jump. Not all that much changes from one 500,000 year block to the next one to the next one. But that last leap from 500,000 years ago to the present – well, there’s that exponential slope again. There a huge change from that final 500,000 years ago to the present. At the start, there were no Homo sapiens. At the end, well just look around you – billions of Homo sapiens all around you.
Review: 500,000 to 50,000 years ago.
Divide that final 500,000 year block into ten segments of 50,000 years each. By the time you reach the last of those 50,000 year blocks, a lot of Homo species have come and gone, with only a couple left - Homo neanderthalensis and of course Homo sapiens, and in isolated Java, Homo floresiensis.
Review: 50,000 to 10,000 years ago.
Consider that final 50,000 year block. At the start, Homo sapiens exist, but there’s no civilization to speak of. But we do have the first of two relative sudden advances. 50,000 years ago, give or take, modern humans ‘invented’ culture. Cave art and rock paintings appear; also carved figurines; humans began to bury the dead along with grave goods.
Now divide that final 50,000 block into five parts of 10,000 years each. At the end, with only 10,000 years left to go, we now have only one hominoid species left, Homo sapiens. In just that final 10,000 year period, you’ll see the transition, in that relative short period of time, in diverse parts of the world; humans go from a nomadic hunter-gatherer existence to domestic settlements.
Review: 10,000 to 1000 years ago.
If you divide that final 10,000 year block into ten parts, then you go from civilization to a technological civilization.
Review: 1000 to 200 years ago.
Divide that final 1000 block into say five parts, and you go from a technological civilization to a high-tech civilization, and the progress is still undergoing an exponential expansion.
Okay, let’s return back to roughly 5 million or so years ago, perhaps a shade more.
Somewhere around 8 to 6 million years ago, our lineage split off from the chimpanzee lineage. Our lineage is composed of lots of links, about 20 species known so far, some direct (like your grandparents and parents); some just branches off the main and aren’t direct (like your cousins, aunts and uncles).
Here are the starting links in that chain that we know about.
Sahelanthropus tchadensis came on the African scene about 7 to 6 million years ago. We’re not sure if this hominoid species was a parent or a cousin.
Orrorin tugenensis was slightly more recent, dating to roughly 5.8 million years ago. Again, parent or cousin isn’t clear.
Ardipithecus ramidus and Ardipithecus kadabba were known to strut their stuff 5.8 to 4.3 million years ago and are credited with being in a direct linear chain to ourselves.
Here are the next links in the chain starting with the advent of the bipedal gait.
AUSTRALOPITHECUS (hominoids with an undoubted bipedal gait) had their origins from roughly that 4 to 3 million years ago era, give or take.
*Australopithecus anamersis existed down Africa way some 4.2 to 3.8 million years ago, an apparent ancestor to Australopithecus afarensis.
*Australopithecus afarensis is well known thanks to Lucy (of “in the sky with diamonds” fame). Australopithecus afarensis were around from roughly 3.6 to 3 million years ago though it seems there’s a gap in the fossil evidence of some 200,000 years twixt Australopithecus afarensis and Australopithecus anamersis. When hominoid fossils are as few and far between as they are, such gaps aren’t surprising.
*Australopithecus bahrelghazali has been documented from about 3.5 million years before the present.
*Kenyanthropus (or Australopithecus) platyops (depending on who you talk to) was a contemporary of Australopithecus bahrelghazali and Australopithecus afarensis dated again to 3.5 million years ago.
*Australopithecus africanus: If Australopithecus afarensis faded out of the picture some 3 million years ago, they were replaced by this mob, who reigned from about 3 million to 2.5 million years ago.
*Australopithecus garhi comes upon the scene just as Australopithecus africanus fades away in turn at about 2.5 million years before today.
Our Paranthropus cousins branch off around that 2.5 million year mark. First up was Paranthropus aethiopicus at 2.5 million years ago. Now there is some dispute about names.
*Australopithecus boisei or Paranthropus boisei? Whether parent or cousin, they were around from about 2.3 to 1.4 million years ago, and thus evolved before, and went kaput after, Australopithecus robustus or Paranthropus robustus.
*Australopithecus robustus or Paranthropus robustus? What’s in a name anyway, The fact of the matter is that this African species is dated to 2 to 1.5 million years ago.
HOMO (tool makers) had their origin somewhere from 2.5 to 2 million years ago.
*Homo Rudolfensis (species akin to Homo habilis) inhabited Africa 2.5 to 1.9 million years ago.
*Homo habilis hit the scenes about 2.3 million years ago and lasted until roughly 1.6 million years ago.
*Homo ergaster: In one telling of the tale, Homo ergaster was post Homo habilis but pre Homo erectus and existed from about 2 million years ago to 1 million years ago. Other anthropologists assign the name Homo ergaster just to the African version of Homo erectus. That’s because a hominoid species was about to flee the coup!
*Homo erectus was that species that flew the African coup. It was the first such ancestor of ours to migrate out of Africa (though not all did of course). They ended up in western, eastern, and South-Eastern Asia. Fossil remains have been found in Java for example. Homo erectus survived and thrived more as an Asian species than an African one, surviving until roughly 200,000 years ago in Asia after their 2 million years ago origins in Africa , and as Homo ergaster, died out 800,000 years before their Asian equivalents.
*Homo floresiensis (Java only) was an isolated offshoot of Homo erectus who has the distinction of being our most recent ancestor to go extinct. Homo erectus did so 200,000 years ago, but that isolated community hung on until a very short 12,000 years ago. That’s nearly modern times!
*Homo heidelbergensis: Homo erectus also spawned another out-of-Africa species, Homo heidelbergensis who spread out over Europe from 700,000 to 300,000 years ago, presumably via migration from their ancestors in western Asia .
*Homo antecessor is the Homo erectus species who colonized Europe , sometimes known as another European version of Homo heidelbergensis. Homo antecessor lived in Europe from about 1 million years ago to roughly 300,000 years ago.
*Homo rhodesiensis is the same as Homo heidelbergensis, only the African version. So, presumably Homo ergaster gave rise to Homo rhodesiensis just as the out-of-Africa version of Homo erectus gave rise to Homo heidelbergensis. Like Homo antecessor, Homo rhodesiensis hung around for only 700,000 years – 1 million years ago to 300,000 years past.
*Homo neanderthalensis, being a west Asian and European species is the obvious descendant of those other European hominoids, Homo antecessor and Homo heidelbergensis. Of all our extinct ancestors (600,000 to 35,000 years ago), Neanderthals are the most famous, but we still don’t the exact degree of interaction, even breeding (if possible) between them and the last and final species on the list – us.
*Homo sapiens (takes shape 400,000 to 200,000 years ago, but probably closer to 200,000 than 400,000, at least that’s the consensus. Another consensus is that Homo sapiens were only the second African native to migrate out of Africa after Homo erectus, some 60,000 to 50,000 years ago.
There are probably still lots of undiscovered species that form additional links and branches in the chimp – modern human chain, but the above are enough to illustrate the point. A heck of a lot of our ancestors went extinct – cause or causes unknown.
To be continued…
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