Are there “missing links” in the human family tree?


Creationist and and intelligent design writers frequently emphasize “gaps” in the fossil record, and, in particular, claim that there are “missing links” in the human family tree between “apes” and humans. So what are the facts here? Is there indeed an unbridgeable “gap” between apes and humans?

Hardly. To appreciate how far the study of prehuman fossils has come, even in the 1990s it was generally thought that the first hominins (the group that includes modern humans and their extinct predecessors) appeared about four million years ago, and then descended in a fairly “linear” fashion to Homo ancestors who left Africa about one million years ago, some of which subsequently became the Neanderthals, a relatively brutish and not-very-smart species who were, in turn, replaced by Homo sapiens about 30,000-50,000 years ago.

A new, more complicated family tree

But we now know that this picture was too simplistic. The full history of prehuman species is significantly more complicated, with numerous branches that may or may not have led to modern humans. What’s more, emerging evidence has shown that there were more of our “cousins” living on the planet within the past million years. In addition to the Neanderthals, a branch known as Denisovans has been discovered that, based on actual DNA analysis, is distinct from both human and Neanderthal lineage, yet some of its DNA lives on today in human DNA — see DNA. Yet another branch is Homo floresiensis, popularly known as the “hobbit” fossil, which may have survived until as recently as 18,000 BCE (although there is still debate on whether or not it is a non-human specimen). Recent updates on these developments are available in two Scientific American articles [Harmon2013; Wood2014] and in a 2015 New York Times article [Zimmer2015b].

Here is a “family tree” graphic, from the September 2014 Scientific American (although it does not include some more recent discoveries):

Creationists’ classification of prehuman fossils

Creationist writers, who deny that there are any “transitional” fossils, typically deal with prehuman fossils by classifying them as either “ape” or “human.” However, these writers have not been able to agree as to which fossils should be classified “ape” or “human.” Here is a chart of creationist classification of some prehuman fossil specimens, based on a similar chart in [TalkOrigin2009]:

Creationists’ Classifications of Prehuman Fossils

Specimen Brain cavity
size (cc)
Cuozzo1988 Gish1985 Mehlert1996 Bowden1981
ER 1813 510 cc Ape Ape Ape Ape Ape Ape Human
Java 940 cc Ape Ape Human Ape Ape Ape Human
Peking 915-1225 cc Ape Ape Human Ape Human Human Human
ER 1470 750 cc Ape Ape Ape Human Human Human Human
ER 3733 850 cc Ape Human Human Human Human Human Human
WT 15000 880 cc Ape Human Human Human Human Human Human

In the above table, the column headers denote different creationist publications — see [Cuozzo1988; Gish1985; Mehlert1996; Bowden1981; Gish1979; Menton1988; Taylor1992; Baker1976; Taylor1995; Lubenow2004; Taylor1996; Line2005].

The utter disagreement in this table as to whether fossils are “ape” or “human” is moot testimony to the fact that there is no clear delineation — all are related in a family tree. As biologist Kenneth Miller observes, “Ironically, validation of our common ancestry with other primates comes directly from those [creationists] who are most critical of the idea.” [Miller2008, pg. 95].

Some recent findings

What’s more, recent studies continue to identify even more interesting hominin fossils (“hominin” species means prehuman species that are either in the line of descent that led to humans or at least are closely related to humans). Here are just four examples, within the last year or two. More are listed at Prehuman fossils.

  1. Oldest prehuman DNA. In a surprising new development, announced in December 2013, researchers at the Max Planck Institute retrieved DNA from an ancient hominin fossil 400,000 years old found in Spain. It is easily the oldest specimen ever to have its DNA analyzed. These researchers had expected the specimen to be a forerunner of Neanderthals, but its DNA more closely resembles that of the Denisovan lineage, mentioned above. This raises the possibility that the Spanish specimen might belong to yet another branch of ancient prehumans, or even the remnant of Homo Erectus, which originated roughly 1.8 million years ago but was thought to be extinct more recently. Either way, researchers are puzzled and excited by the new discovery [Callaway2013b; Zimmer2013b]. For additional discussion of DNA evidence for evolution, see DNA.

  2. Complete Neanderthal genome from one toe bone. In December 2013, a team of researchers led by Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany announced that they had extracted the entire genome of a 130,000-year-old Neanderthal from a single toe bone found in a cave in Siberia. Sarah Tishkoff of the University of Pennsylvania commented on this development by saying, “Twenty years ago, I would have thought this would never be possible.” This data, together with other recent studies, has established that humans, Denisovans (see previous item) and Neanderthals represent three different branches on a common tree that diverged roughly 600,000 years ago, but that there has been significant genetic sharing through interbreeding since then [Zimmer2013c].
  3. 3.3 million-year-old tools in Kenya. In May 2015, a team led by Sonia Harmand of Stony Brook University reported finding tools at a site in Kenya that are estimated to be 3.3 million years old, the oldest date so far for any hominin tools. The researchers believe these tools were made by a species known as Kenyanthropus platyops [Wilford2015a].
  4. New prehuman species contemporary with Lucy. Just when it seemed that the prehuman family tree could not get any more complicated, in May 2015 a team led by Yohannes Haile-Selassie of the Cleveland Museum of Natural History announced the discovery of a jaw in Ethiopia that belonged to a distinct prehuman species that lived between 3.3 and 3.5 million years ago. They dubbed the species Astralopithecus deyiremeda. As paleoanthropologist Carl Ward of the University of Missouri explained, “I’m so excited about these discoveries, I’m driving my friends crazy.” [Zimmer2015b].


Although these and other findings have destroyed the previously held scientific notion of a neat, linear descent through a sequence of well-defined ancient hominin species, they have also utterly destroyed the creationist view that there are no “missing links.” As Carol Ward of the University of Missouri School of Medicine noted in the February 2013 issue of Scientific American, “What we’re glimpsing in the fossil record is but a flicker of the ancient diversity.”

Indeed, there is an embarrassment of riches — so many specimens have been found in the past decade or two that the only challenge is clearly establishing their positions in the family tree, i.e., deciding which are distinct species and which are simply varieties of a single species, and which are truly in the direct line that leads to modern humans and which are evolutionary dead ends. Thus claims of “missing links” or “gaps” are only valid in the sense that when one transitional fossil is found, this creates two more “gaps” — one on each side of the new fossil!

What’s more, as can be readily seen from the examples mentioned above, those writers who still advance the “missing link” or “gap” line to criticize evolution cannot take refuge in ignorance. Most of the recent hominin fossil findings have been widely publicized, not only in scientific journals, but also in news sources such as The New York Times, Scientific American, National Geographic and New Scientist, which are available at many grocery stores and also online. Even a quick Internet search yields numerous easily accessible and very readable articles on these discoveries.

For additional discussion, see Prehuman fossils.

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