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Myth №14: Missing link is not found yet...

After publishing “Myths about human evolution” we received dozens of letters in which our readers suggest their own variants of myths “for debunking". Among various misconceptions a leading place rightfully belongs to the “Missing Link” myth. It usually sounds as following: Scientists have been looking for a missing link for over 100 years, but still failed to present one...

Figure 1. Pithecanthropus in the center. (Sculpture of V. A. Vatagin).
					Figure 2. Chimpanzee to the left. (engraving of Tulp, 1641).
					Figure 3. Cro-Magnon man to the right. Source: http://www.arthursclipart.org/p
Figure 1. Pithecanthropus in the center. (Sculpture of V. A. Vatagin).
Figure 2. Chimpanzee to the left. (engraving of Tulp, 1641).
Figure 3. Cro-Magnon man to the right. Source: http://www.arthursclipart.org/p

The term “missing link” was first used in the XIXth century. For example, Ernst Haeckel suggested that some kind of intermediate type of creature – pitekantrop - should have existed in our evolutionary line between a human being and his ancestor – an ancient ape. Such creature had not been found yet for the time being (Pic. 1).

Missing link term is frequently used now, mostly by journalists and in popular literature. Specialists understand perfectly that formation of Homo sapience species is a long process, and as evolution is continuous, it is obvious that there were MANY SPECIES between a modern human and our ancestral ape living about 10 mya. These species were slowly, one by one, discovered by anthropologists for the last 100 years. As a result we see not just a link, but a chain of intermediate species.

That is why a specialist would always ask: “A missing link between who and who?” 

Figure. 2. Incomplete and simplified scheme of human evolution.
Figure. 2. Incomplete and simplified scheme of human evolution.
  • Between a human and an ape? Too vague, it could be e.g. any of Australopithecus species...
  • Between Homo sapience and pitekantrop (Homo erectus)? In this case it is Homo heidelbergensis, who lived about 500 000 thousand years ago.
  • Between Homo erectus and Australopithecus?  It is Homo habilis, who lived about 2 mya
  • Between a quadrupedal and a bipedal ancestor? Ardipithecus, 4.5 mya.
  • Common ancestor of a human, chimp and gorilla? Nakalipithecus, 10 mya
  • Common ancestor of apes? Proconsul, more than 15 mya
  • Common ancestor of all primates? Purgatorius, end of Cretaceous period.

And so on … (See here) 

A statement that a “missing link has was not found” became a misconception in 1970ies, when basic material about all mane stages of human evolution was accumulated. 

At the end of the XXth, beginning of the XXIst century, with a description of an “early Australopithecus” group, the missing link problem absolutely lost its value. Nowadays we find not simply “missing links”, but intermediate species, “links between links”. Findings are so numerous, that their amount now becomes a problem for anthropologists, as dealing with such a number of material is increasingly more difficult.

Meanwhile, new species of fossil hominids are found quite often.

For example, only in 2010 three new species were discovered: 

  • Australopithecus sediba (a typical “missing link between links”, not yet a human, but already not quite an Australopithecus
  • Homo gautengensis (most ancient hominid from South Africa)
  • Mysterious “Denisovan man”, (who does not yet have a Latin name) 
Figure 3. “Traditional” and modern scheme of human evolution.
Figure 3. “Traditional” and modern scheme of human evolution.

Clearly, each new finding, each new described species, makes human evolutionary picture more detailed... and more complex (see Pic. 3 and also here). But these are the rules of scientific investigation! 

Imagine we have forms A and C, and a “missing link” between them:

А ? ? ? С

Now let’s assume that we have found this “missing link” B:

А ? B ? C

Good enough? Nope, it is not! If we are dealing with a continuous sequence - now we have TWO missing links:

А ? ?  ? B ? ? ? C

But an ordinary person being far from scientific debates cannot be satisfied with such situation. People like to solve simple tasks (e.g. guessing letters in Wheel of Fortune), but do not handle existence of complex problems well. Problems, which cannot be solved in a minute, in an hour, in a day and, moreover, in years. Popular mentality requires primitive solutions. And “Missing link” brand is perfect for that role.

That is the reason journalists are always eager to inform that “the missing link is finally found!” as soon as paleoanthropologist report on finding a new human ancestral species. 

And people not familiar with anthropology get surprised: What, again?!

A little note. About 70 years ago, when such findings were not that numerous, the situation seemed relatively not complicated. First there lived Australopithecus, who was the ancestor of pitekantrop; then there was Neanderthal, and so on. When more fossils were discovered, it became clear that there were a lot of bipedal anthropoid species living on our planet.  For example, several species of Australopithecus were wondering across Africa about 2-4 mya. And you can be sure, more new species we have no idea about right now, will be discovered soon! Obviously, one of Australopithecus was an ancestor to the line eventually leading to modern humans. At the same moment, they obviously could not all be our ancestors. So, which of Australopithecus is our actual ancestor? Or maybe there were several of them (as many primate representatives can interbreed forming new hybrid species...)?    

Figure 4. Where are you, grandfather?
Figure 4. Where are you, grandfather?

Imagine, that you have found a dusty box of yellowish family pictures in an attic corner of your old house (let us assume you have one)... Some people in old suits, ladies in beautiful dresses... Everything here: familiar traits of their faces, atmosphere, and the very place where you found the pictures suggest these are your relatives. You definitely know your grand grandparents are among these people, but beside them, some others too, their cousins and second cousins and so on... If pictures had a single person, things were easy. But as there are many of them, you do not know for sure which one of them is your grand grandfather. There are several possible candidates.

Fig 5. Models are changing.
Fig 5. Models are changing.

A person not involved in science might think that scientists tend to “overthink” this problem. Does it happen only in anthropology? Now we know that Earth is not an ideal sphere, its shape is more complicated (see Pic. 5). The first atomic model by J.J. Thompson (so called “Plum pudding model”, see Pic. 5) was really far from what we got used to see.

Models become more complex, but their basic principles are not going anywhere, only details are debatable. Earth is a sphere, although not a perfect one. The road from an ancient ape to a modern human was long and complicated, but its benchmarks are known and human ancestor progression is studied better than any other. We would obviously like to found ALL links in ancestral line, but such variety is not seen even in Bible.  

Alexander Sokolov, Stanislav Drobyshevskiy

Translated by Olga Vasileva

Editor of English version: Ella Jones

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