Another "Oldest Homo" Contender Alleged
Not again: another jawbone is making the rounds in the human-evolution saga.
It’s just part of a jawbone, but some paleoanthropologists said it’s the oldest member of our genus, and the usual suspects in the media went into action, writing it up uncritically.
- Oldest known member of human family found in Ethiopia (New Scientist)
- Oldest Human Fossil Found, Redrawing Family Tree (National Geographic)
- ‘First human‘ discovered in Ethiopia (Pallab Ghosh in the BBC News)
- Fossil pushes back human origins 400,000 years (Ann Gibbons in Science Magazine)
- Earliest Human Species Possibly Found in Ethiopia (Charles Q. Choi in Live Science)
- Jaws, Not Brains, Define Early Human Species (Charles Q. Choi in Live Science)
- Photos: Earliest Known Human Fossils Discovered (Jeanna Brynner in Live Science)
- Discovery of jaw by ASU team sheds light on early human ancestor (press release from Arizona State)
- Earliest known fossil of the genus Homo dates to 2.8 to 2.75 million years ago (PhysOrg)
The rest of the media outlets usually just echo sources like this. We’ve been through this so many times before (“oldest ancestor found…rewrites human family tree” etc.); what is it this time?
It’s always best to examine the source. This time the announcement stems from a paper in Nature, “Reconstructed Homo habilis type OH 7 suggests deep-rooted species diversity in early Homo” from Fred Spoor’s group working in Ethiopia. In the figures, we find one fragmentary jaw, with the caption saying, “As preserved, marking individual parts that were adjusted in the reconstruction.” The researchers also “reconstructed” in a computer model the fragmentary pieces of the type specimen of Homo habilis, found in the 1960s by Louis and Mary Leakey. To their credit, most of the media showed photos of the jawbone, without (so far) drawing full-bodied artwork of some ape-like creature. They are saying, however, that it represents an important link between Lucy and Homo habilis. The BBC News wrote in a surfeit of emotion:
Could Lucy’s kind – which belonged to the species Australopithecus afarensis – have evolved into the very first primitive humans?
“That’s what we are arguing,” said Prof [Brian] Villmoare [U of Nevada].
But the fossil record between the time period when Lucy and her kin were alive and the emergence of Homo erectus (with its relatively large brain and humanlike body proportions) two million years ago is sparse.
The 2.8 million-year-old lower jawbone was found in the Ledi-Geraru research area, Afar Regional State, by Ethiopian student Chalachew Seyoum. He told BBC News that he was “stunned” when he saw the fossil.
“The moment I found it, I realised that it was important, as this is the time period represented by few (human) fossils in Eastern Africa.”
If history is any guide, all the emotion will be quickly spent when the next team somewhere else in Africa claims a better specimen that will make this one obsolete. So what do the discoverers say in the paper, where emotion is supposed to be suppressed in favor of objectivity?
Spoor et al. issue caveats like these: “…there is no consensus over the respective groupings….” They took a “partial skull” of a specimen dubbed Homo habilis (“handy man”) and tried to relate it to their new jawbone.
This partial skull and hand from Olduvai Gorge remains pivotal to evaluating the early evolution of the Homo lineage, and by priority names one or other of the two taxa. However, the distorted preservation of the diagnostically important OH 7 mandible has hindered attempts to compare this specimen with other fossils. Here we present a virtual reconstruction…. We find that this shape variability is not consistent with a single species of early Homo. Importantly, the jaw morphology of OH 7 is incompatible with fossils assigned to Homo rudolfensis and with the A.L. 666-1 Homo maxilla. The latter is morphologically more derived than OH 7 but 500,000 years older, suggesting that the H. habilis lineage originated before 2.3 million years ago, thus marking deep-rooted species diversity in the genus Homo. We also reconstructed the parietal bones of OH 7 and estimated its endocranial volume. At between 729 and 824 ml it is larger than any previously published value, and emphasizes the near-complete overlap in brain size among species of early Homo. Our results clarify the H. habilis hypodigm, but raise questions about its phylogenetic relationships. Differences between species of early Homo appear to be characterized more by gnathic [jaw] diversity than by differences in brain size, which was highly variable within all taxa.
In other words, there are surprises aplenty, and there remains ample wiggle room to concoct a variety of tales. Ewen Callaway, in the same issue of Nature, calls it a “messy history” below his flashy headline, “Ethiopian jawbone may mark dawn of humankind.” Be sure to read the subtitle: “A 2.8-million-year-old mandible and a digital model of a key fossil paint a complicated picture of the genus Homo.”
Those who grew up with the Leakey stories plastered on covers of National Geographic may be shocked at Fred Spoor’s account of their work on so-called Handy Man:
But Homo‘s origins are increasingly confusing, as a reanalysis of 1.8-million-year-old fossil specimens, reported in Nature, demonstrates. In the early 1960s, a team led by palaeoanthropologists Louis and Mary Leakey found a deformed lower jaw, hand and partial skull in Olduvai Gorge, Tanzania.
“It was reported in a very informal way in Nature: ‘Sir: I found a bone and I’m showing you a picture now. Goodbye,’” says Fred Spoor, a palaeoanthropologist at University College London. The Leakey team later designated the remains as a new species that they called Homo habilis, meaning the handy man. They contended that members of the species had made stone tools that had been discovered nearby years earlier.
But the material was so sparse that all manner of other fossils were later designated H. habilis.
“It’s how I cut my teeth as a palaeoanthropologist — working with the mess that is Homo habilis,” says Lieberman. “It became very clear that there was too much variation to accommodate just one species.”
And yet just last year, others claimed that all the species dubbed Homo were members of one species, remember? (see 1/03/14, also 10/18/13). So it depends on which expert you ask whether this or that bone is “primitive” or “derived” and which ones deserve to be put in this bin instead of that bin. Callaway sums it up this way:
The two reports confirm that ‘early Homo‘ species showed lots of variation, yet none stands out as an obvious ancestor of H. erectus, says Lieberman. “The question on everybody’s mind is what happened at this transition to the origin of early Homo and in early Homo,” he says. “We just don’t understand what’s going on.”
You wouldn’t get that from reading the suggestive headlines. New Scientist ended this way far below its confident-sounding headline:
But as Villmoare admits, his find throws up more questions than it answers. What did the early Homo look like? How did it behave? To probe these questions, he has the somewhat unlikely dream of uncovering more fossils from the same creature of a similar age on his next dig in Ethiopia.
“In archaeology there is no sure thing,” he says. “All you can do is hope.”
In Science, by contrast, Ann Gibbons has her story tied to global warming: “climate change sparked intense periods of speciation,” she infers from another “expert.” And her hope is stronger: “Stay tuned,” her ending expert says. Choi in Live Science quotes Spoor: “You can see how the whole human lineage could derive from Australopithecus afarensis based on the 2.8-million-year-old Ledi-Geraru jaw.” It just takes the ever-hopeful eyes of imagination.
Update 3/05/15: PhysOrg says that a study found “significant facial variation” among pre-Columbian South Americans – yet they were essentially contemporaneous, and all members of one species: Homo sapiens. This shows that variation does not imply evolution. Ann Ross at NC State, who examined archaeological sites across South America, says, “for a long time, the conventional wisdom was that there was very little variation prior to European contact. Our work shows that there was actually significant variation.” The work “may affect a lot of hypotheses regarding New World anthropology,” PhysOrg says.
This gets so tiresome. It’s what happens when nobody outside the paradigm gets a voice. Secular reporters in mainstream media are like inbred imbeciles, incapable of thinking outside the box. If they had human brains working properly, they would know their view is self-refuting, because it attributes their thoughts to blind, unintelligent processes of chance. Out of non-intelligence, only nonsense comes.
So don’t concern yourselves with the details of this bone and Spoor’s “corrected” computer model of broken bits of skull. It will all be passe once the next rival team holds up their holy relic as evidence for man’s emergence from nonsense. The fear of the Lord is the beginning of wisdom. Logically, this means that the Darwinians are headed backward behind the starting line.