Re: Homo erectus: racial variants of Homo sapiens?
Jim Foley (email@example.com)
10 Jan 1997 00:29:08 GMT
[this article is being posted on behalf of Alex Duncan]
In article <32D4491D.23D8@fast.net>, A Pagano <firstname.lastname@example.org> wrote:
>The following is posted on behalf of David Buckna <email@example.com>:
>Today evolution survives, not so much as a theory of science, but as a
>philosophical necessity. Good science is always tentative and
>self-correcting, but this never really happens in the case of evolution.
>Regardless of the scientific data, the idea of evolution as a valid concept
>is not open to debate. Students are allowed to ask "HOW did evolution
>occur?", but never "DID evolution occur?". Which is a more objective
>question: "What were the ape-like creatures that led to man?" or "_Did_ man
>evolve from ape-like creatures?"
Nothing could be further than the truth. Any course that attempts to deal
with evolution in a serious manner will begin by presenting the evidence that
supports evolutionary ideas, and then demonstrate why evolutionary theory is
the only practical means of explaining the evidence (note -- this is not due
to instructor bias, it is simply the way things are). If this is not
addressing the question "does evolution occur?", then I don't know what
would. However, the statement above addresses a more serious point. The
evidence supporting the great age of the earth and the descent of all extant
life forms from a common ancestor is so overwhelming that to address the
question "did evolution occur?" is somewhat akin to asking "is the earth a
sphere?" The answer to the second question is presented by providing a
picture of the earth from space. The first question is not so easily
answered, but the evidence for evolution is so powerful that -- when
presented correctly -- it is equivalent to the picture of the earth from
space. The ONLY people who deny this are either ignorant of the facts, or
have a tremendous religious bias against examining the facts honestly.
>On December 9 archeologist and paleo-anthropologist Mary Leakey died at age
>83. Although Leakey was convinced that man had evolved from ape-like
>ancestors, she was equally convinced that scientists will never be able to
>prove a particular scenario of human evolution. Three months before her
>death, she said in an interview: "All these trees of life with their
>branches of our ancestors, that's a lot of nonsense." Associated Press (AP)
>Dec. 10, 1996.
Mary Leakey is certainly entitled to her opinion. The fact is that the
phylogenetic methodology used in paleoanthropology has advanced in leaps and
bounds since Mary Leakey was an active scientist. Phylogenetics was never
something she seemed very interested in, and a topic about which she never
published a single paper.
Modern cladistic methodology is in fact among the most scientific of
evolutionary methods, as systematic ideas are framed as falsifiable
hypotheses that can be rejected or modified as further evidence is gathered.
The broad agreement between phylogenies based on comparative anatomy and
those based on analysis of nuclear and mitochondrial genomes argues strongly
for the power of modern systematic methods.
I suppose the different phylogenies constructed by various paleontologists
must be somewhat frustrating to intelligent laypeople, and the points of
disagreement are attacked with glee by creationists who have no understanding
of systematic methodology. In this, the attack is somewhat akin to the "no
transitional fossils" argument. There are, in fact, lots of transitional
fossils, but unfortunately not every extant lineage is represented in the
fossil record. There is also broad agreement among systematists about the
relationships between fossil hominids, and extant apes and humans.
Creationists seize upon the points of disagreement as if those sound the
death-knell for evolutionary ideas. In this, they highlight their
misunderstanding of science. It would be suprising and disturbing if
paleoanthropologists all agreed on every detail of a particular phylogenetic
scheme. The fact that disagreement and controversy exists suggests that we
have a healthy science on our hands. There are different ways of looking at
data and different ways of analyzing it.
Virtually all paleoanthropologists agree on a number of points. Homo erectus
and Homo habilis sensu lato are respectively more distant sister-taxa of Homo
sapiens. The australopithecines are more closely related to humans than to
any extant apes. The robust australopithecines form a clade.
Australopithecus afarensis is a sister-taxon to a clade containing the other
australopithecines and Homo. Creationists seem to have difficulty addressing
these points of broad agreement, perhaps because they know so little of the
methodology involved that they are incapable of providing a relevant
critique. Creationists are certainly capable of discovering the occasional
anomalous opinion (e.g., Oxnard), however, I have never heard one explain
what it is about the science behind the opinions that they find so
compelling. The reason for this is simple. Creationists are not capable of
evaluating the science behind the opinion.
>With Leakey's words still ringing in my ears, _The New York Times_ reported
>three days later that scientists had re-examined two major fossil sites in
>Java, and found that Homo erectus may have lived there as recently as "27,000
>years ago". (December 13, P.A1) This dating analysis, conducted by McMaster
>University geologists Henry Schwarcz and Jack Rink, will serve to cast
>further doubt on the so-called evidence for human evolution. Why? If it can
>be shown that Homo erectus lived at the same time as modern man, Homo
>erectus may be no more than racial variants of Homo sapiens. That is what
>creationists such as Duane Gish ("Evolution: The Fossils Still Say No!",
>Master Books, 1995) have been saying for decades.
The time when an organism lives has no impact on it's systematic status.
Duane Gish has been saying all kinds of nonsensical things for decades.
For quite some time, Gish has claimed that H. habilis and some H.
erectus are merely apes. Now apparently the creationists want to say
that Gish's "apes" are simply racial variants of H. sapiens. Of course,
the judgement of anyone who mistakes H. habilis or H. erectus for an ape
is clearly suspect. Since Gish has a well-known religious bias that
precludes the reasonable evaluation of scientific ideas, his thoughts on
the matter are irrelevant.
>>From Maclean's magazine (Canada's weekly newsmagazine):
>That would place him [Java Man] in the era of modern humans---and argue
>against an ancestral relationship."If these dates are right," said Philip
>Rightmire, an anthropologist at the State University of New York at
>Binghamton, "the multiregionalists will have to do some fast
>thinking."...The new findings also challenge the rival Out of Africa
>theory. That view holds that modern humans emerged in Africa as recently as
>150,000 years ago and spread around the globe, driving Homo erectus into
>extinction---well before the era pointed to by the new finding.(Maclean's,
>science section,"The origins of man", Dec. 23, p. 69)
>Marvin Lubenow has an M.S.in anthropology and zoology from Eastern Michigan
>University, and teaches at the Institute for Creation Research in El Cajon,
>California. He is also the author of "Bones of Contention: A Creationist
>Assessment of Human Fossils", Baker Book House, 1993. According to Lubenow,
So, Lubenow is a creationist? Well, that would mean that he's already made
up his mind about the way the world works, and decided that no contrary
evidence is going to sway his opinion. In other words, he is not a
scientist, and his opinion on matters of science is worthless. For example,
see his creationist apologia for H. erectus below.
>from the neck down, the differences between Homo erectus and modern humans
>are minor. (Erectus skeletons are usually smaller than moderns, but not
>always.) And while Homo erectus tended to have thicker skulls and smaller
>brains, we now know the human brain's organization is such that small size
>does not affect intelligence (eg. some Australian aboriginees). In fact,
>the actual range in humans is said to be a remarkable 700 to 2200 cubic
Actually, the few known nearly complete H. erectus skeletons are all
surprising large, and would definitely be "above average" in a modern human
population. There are also hints that H. erectus exhibits clinal variation
in stature and body build. Surely someone who is familiar with the fossil
record should know this. The fact that Lubenow is unfamiliar with this fact
would lead me to question any other conclusion he might provide.
It is true that within a taxon, brain size is thought to have no bearing upon
intelligence. However, between taxa, relative brain size is thought to be
the dominant factor determining intelligence. The average cranial capacity
of H. erectus individuals is 300 - 400 cm^3 less than the average cranial
capacity of modern humans. There is definitely overlap between the species.
However, there is also overlap between the cranial capacities of humans and
cetaceans. Does this mean that whales are "racial variants" of H. sapiens?
Very few aspects of H. erectus cranial morphology can be found in modern
humans. Features that characterize the H. erectus skull include very thick
cranial bones; a robust occipital torus; a nuchal plane that is quite large
relative to the occipital plane; a skull that is pentagonally shaped in rear
view, with the broadest point being at about the level of the mastoids;
angular parietals with strong bossing; a sagittal boss or keel; very robust
and continuous supraorbital tori with associated sulcus; receeding frontal;
relatively large temporal fossae; large, robust faces with marked
prognathism; and robust mandibles lacking a mental eminence. Some of these
features do occasionally show up in modern humans, and not all H. erectus are
characterized by all of these features. However, the suite of features
listed above are generally diagnostic of H. erectus skulls. In fact, the
skull of H. erectus is so distinctive that only someone completely ignorant
of cranial morphology could mistake the skull of H. erectus for that of
anatomically modern H. sapiens.
>Lubenow states that other characteristics of Homo erectus
>skulls can be accounted for by poor diet and disease (especially
>rickets),inbreeding, and harsh living conditions, and that most,if not all,
>of these skull-shape characteristics can still be found within the current
There are plenty of modern human populations that suffer from poor nutrition,
disease (including rickets), inbreeding, and harsh living conditions. None
of these populations show features we might associate with H. erectus. And,
for the most part, very few H. erectus remains show any signs of any
pathology whatsoever. The most complete H. erectus skeleton, the "Turkana
Boy" was tall and robust, and shows no signs of rickets or malnutrition.
Both of these illnesses leave characteristic signs of their presence in the
skeleton and dentition. These signs are not apparent in H. erectus (or
Neandertals, for that matter). Among the known reasonably abundant H.
erectus postcranial remains, not a single bone shows the diagnostic
morphology associated with rickets. For Lubenow to suggest otherwise is
indicative of a very poor research strategy. No wonder creationism can't get
published in reputable journals.
Alex Duncan (posted by firstname.lastname@example.org)