An objective ancestry test for fossil bones
by Joseph Mastropaolo
By the look of the curve of a fossil toe bone and the slant of its joint surface,
recent reports concluded that it was from an ancestor of apes and humans, Ardipithecus
ramidus kadabba, that walked on two legs. The question arose as to whether
there might be a simple method yielding objective evidence to bridge the gap between
those scant subjective determinations and that far-reaching conclusion. Accordingly,
an objective, valid, reliable and calibrated correlational method of substantiating
that conclusion was devised and successfully tested. For monkey (baboon), ape (chimpanzee)
and human, similar were the ape and monkey, dissimilar were the human and monkey
and most dissimilar were the ape and human. The monkey and ape similarities to human
bone were less than for an anatomically different bone. The fossil toe bone had
scant similarity to humans, dissimilarity to monkeys and most dissimilarity to apes
with the dissimilarities to monkeys and apes like those for an anatomically different
bone. The results of this objective ancestry test contradicted the conclusion that
Ardipithecus ramidus kadabba was an ancestor of apes and humans
that walked on two legs. Instead, these objective analyses provided evidence
that apes are similar to monkeys, but monkeys and apes have no similarity to humans.
Figure 1. The toe bone of Ardipithecus ramidus kadabba. Left foot,
digit 4, phalanx 1, plantar view, shown with sidelines A and B, proximal and distal
lines D and E, central axis C, and perpendicular distances from the central axis
to the bone borders laterally and medially at each decile of its length, 0.1 to
0.9.
Amongst other fossils, Haile-Selassie reported a left, fourth digit, phalanx 1,
toe bone 31.9 mm long designated Ardipithecus ramidus kadabba, AME-VP-1/71,
5.2 Ma. He reported:
‘AME-VP-1/71 shows a mosaic of features shared with both apes and A. afarensis.
The proximal pedal phalanges of A. afarensis are unique in combining both
strong phalangeal curvature (similar to apes) with a dorsally canted proximal joint
surface (similar to later hominids). The dorsal orientation of this surface in AME-VP-1/71
may therefore constitute important evidence of a unique pedal morphology in this
specimen similar to that in Hadar.’1
The interpretation given by Robinson was, ‘This toe bone (AME-VP-1/71) proves
the creature walked on two legs. … How apes became human. Ardipithecus ramidus
kadabba. What a new discovery tells scientists about how our oldest ancestors
stood on two legs and made an evolutionary leap.’ His artist’s conception
on the cover of Time was an upright chimpanzee-like creature with blue
eyes.2 Except for the blue
eyes, it bore a striking resemblance to the Piltdown forgery of 1912–1952.3
It is not clear that length was the only objective measurement made on AME-VP-1/71,
but if it was, then the question arose as to whether there might be a simple method
to yield objective evidence to bridge the gap between those scant subjective determinations
and that far-reaching conclusion.
Accordingly, an atlas of primate gross anatomy by Swindler and Wood was obtained
to scan the renderings of the comparable bone in baboons, chimpanzees and humans.4 If AME-VP-1/71 tested intermediate
between chimpanzees and humans and resembled least baboons, then the conclusions
of Haile-Selassie and Robinson would have objective support. The conceptual design
of this test was to objectively determine for each bone a central axis and the deviations
from it to the lateral and medial bone borders at decile distances from the proximal
to the distal end. For each bone in the same order, these deviations in tenths of
millimetres would be tabulated and correlated. A high correlation between two bones
would indicate a high degree of similarity.
Methods
For a plantar or dorsal view, from proximal to distal, a straight sideline was drawn
joining the lateral-proximal extreme of the bone with the lateral-distal extreme.
The same was done for the medial extremes. See A and B of Figure 1.
To determine the central axis, a straight line was drawn perpendicular to the medial
sideline such that it provided a tangent to the proximal extreme of the bone then
crossed the lateral sideline. See D of Figure 1. The same was done for the distal
extreme of the bone. See E of Figure 1. Between A and B, D and E were divided in
half to determine the course of the central axis of the bone. See C of Figure 1.
From the bone’s proximal to distal extremes, the central axis was divided
into deciles. See 0.1 to 0.9 of Figure 1.
Figure 2. Phalanx 1, 2 and 3 from Spalteholz, 1900, p. 146. The
correlation between phalanx 1 and 2 was 0.657 and between 1 and 3 it was 0.271.
Any correlation amongst AME-VP-1/71 bone and human, monkey, or ape phalanx 1 toe
bones equal to or less than 0.657 was considered as dissimilar as for an anatomically
neighboring bone. Any correlation equal to or less than 0.271 was considered as
grossly dissimilar as for a bone anatomically two bones away.
From the central axis at each decile, the perpendicular distance to the lateral
border of the bone was measured in tenths of millimetres. The same was determined
to the medial border of the bone.
For each bone, for each decile proximal to distal, all the lateral distances were
tabulated in order followed by all the medial distances. These scores approximated
the bone contours and when treated by the correlational r they took on
the attributes of proportionalities thereby permitting comparisons regardless of
image magnification. The correlational r expressed the mathematical magnitude
of the similarity from 0.0, no similarity, to 1.0, perfect in similarity.
This test was validated by determining the correlation of the bone with itself at
a different magnification. This test should be independent of image magnification
and the correlation should approach 1.0.
This test also was validated by determining the correlation of the same bone in
two different atlases. Given atlases with perfect fidelity, this test ought to be
independent of the atlas employed and the correlation ought to approach 1.0.
The criterion for similarity was that a correlation exceed the correlation between
the phalanx 1 toe bone and its anatomical neighbour, the phalanx 2 toe bone. A correlation
equal to or less than that was considered as dissimilar as a bone for an anatomically
neighbouring bone. A correlation equal to or less than the one between the phalanx
1 and phalanx 3 toe bones was considered as grossly dissimilar as a bone for an
anatomical neighbour two bones away. See Figure 2.
Figure 3. The baboon, Papio cynocephalus, toe bones, plantar view,
as shown in Swindler and Wood.4
Figure 4. The chimpanzee, Pan troglodytes, toe bones, plantar view,
as shown in Swindler and Wood.4
The Ardipithecus ramidus kadabba AME-VP-1/71 bone was correlated with the
baboon (Papio cynocephalus) bone (see Figure 3), the chimpanzee (Pan troglodytes)
bone (see Figure 4), and the human (Homo sapiens) bone (see Figures 5 and
6). The baboon, chimpanzee and human bones also were compared to each other.
Results
The plantar view of bone AME-VP-1/71 as shown in Nature correlated 0.975
with the same bone at 2.26 greater magnification. That suggested that this test
was independent of any magnification or reduction in the photographic images of
the fossil. The photograph of AME-VP-1/71 shown in Time correlated 0.983
with the same image at double the magnification. This result confirmed that magnification
did not significantly affect the correlation and additionally demonstrated that
the test was reliable and calibrated for the effects of magnification.
The dorsal view of the fourth digit, phalanx 1, human toe bone shown in Swindler
and Wood correlated 0.906 with the same human bone in Spalteholz.5 That suggested that the atlas employed would lower
the correlation to about 0.9. However, the plantar views correlated 0.764 and that
lack of agreement between views seemed worthy of further investigation. To illumine
the cause of the disparity, plantar and dorsal views were correlated for each atlas.
For the Spalteholz atlas, the plantar and dorsal views correlated 0.936 whereas
for the Swindler and Wood atlas their plantar and dorsal views correlated 0.605.
That suggested that the cause of the lower correlation between atlases for the plantar
views was the lower reliability of the plantar view in the Swindler and Wood atlas
compared to the Spalteholz atlas. This result suggested that the atlas employed
lowered the correlation to about 0.906 for the reliable views.
The phalanx 1 toe bone was correlated 0.657 with the phalanx 2 toe bone and 0.271
with the phalanx 3 toe bone.5 For this study, a correlation of 0.657
or less was considered dissimilar and a correlation of 0.271 or less grossly dissimilar.
See Figure 2.
The AME-VP-1/71 bone shown in Nature was from a left foot but it was compared
to the same bone in the right foot because the atlases did not show the left foot.
The baboon, chimpanzee and human S&W correlations were made with the Swindler
and Wood atlas whereas the human S correlations were made with the Spalteholz atlas.
Accordingly, the plantar view of AME-VP-1/71 correlated 0.575 with the baboon bone,
0.491 with the chimpanzee bone, 0.743 with the human S&W bone, 0.613 with the
human S bone. The baboon and chimpanzee bones were correlated 0.856. These results
suggested that the AME-VP-1/71 bone had some similarity to humans, less to baboons
and least similarity to chimpanzees. However, all of those similarities were lower
than the baboon-chimpanzee similarity. The lack of higher correlations with humans
and chimpanzees and the chimpanzee correlation out of the evolutionary order suggested
further research.
The lack of higher correlations with humans and chimpanzees and the chimpanzee correlation
out of the evolutionary order suggested further research.
Accordingly, another analysis was done with a more distinct plantar image of the
AME-VP-1/71 bone.6 In this
analysis the AME-VP-1/71 bone was correlated 0.615 with the baboon bone, 0.461 with
the chimpanzee bone, 0.761 with the human S&W bone, 0.681 with the human S bone.
Each correlation was slightly higher than the previous analysis with the chimpanzee
correlation slightly lower. The lack of evolutionary sense, the suggestion that
chimpanzees evolved to baboons, persisted and none of these correlations were as
high as the 0.856 baboon-chimpanzee correlation.
This suggested investigating the dorsal view of AME-VP-1/71 and correlating it to
the dorsal views in the atlases. The AME-VP-1/71 bone correlated 0.460 with the
baboon bone, 0.308 with the chimpanzee bone, 0.739 with the human S&W bone,
0.873 with the human S bone. Except for human S bone, the correlations were lower
and in the same order. The baboon-chimpanzee correlation was 0.806. This analysis
yielded no additional clarification.
In a final attempt at clarification, for each bone the dorsal view data were combined
with the plantar view data. For these combined data, the AME-VP-1/71 bone correlated
0.475 with the baboon bone, 0.377 with the chimpanzee bone, 0.729 with the human
S&W bone, 0.722 with the human S bone. The baboon-chimpanzee correlation was
0.820 whereas the baboon-human correlations were 0.329 and 0.549 for S&W and
S, respectively. The chimpanzee-human correlations were 0.197 and 0.332 for S&W
and S, respectively. These combined data confirmed that the AME-VP-1/71 bone had
scant similarity to humans (compare Figure 1 with Figure 2, Phalanx I), was dissimilar
to baboons and most dissimilar to chimpanzees. The monkey was similar to the ape,
dissimilar to the human and the most dissimilar was the ape and human. The ancestral
sequence suggested was not the Haile-Selassie and Robinson monkey-great ape-human
but rather great ape-monkey. These objective analyses identified the Haile-Selassie
and Robinson conclusions as farfetched speculations.
Discussion
Oxnard did complex multivariate statistical analyses and found,
‘Nor, however, can man be described as a mosaic of other forms. In almost
all studies man lies quite separately from the spectra of non-human species ….’ This multi-dimensional method, employing rotations by means of matrix algebra
and a computer, found essentially what the present simpler method found, but the
complex method had no cutoff for similarity, which the present simpler method has.7 This may also give insight
to the concern that a simpler two-dimensional method may fall short on three dimensional
objects. Like errors, shortcomings do not help but rather hinder finding differences
and high correlations. If a simpler method finds what a complex method finds, then
that suggests that all the complexity may not be necessary. This should also clarify
whether or not confounding variables like dimorphism may need special consideration.
If dimorphism were critical, then it would act like error or anything else causing
undue variability and would diminish correlations toward zero rather than allow
a correlation as high as 0.906.
From the 18 scores, the present method approximates the outline of the bone. When
those scores are treated by the correlational r, they
acquire the attributes of proportionalities. If the same bone is magnified, the
proportions remain constant and that is why the r’s for the two independent
magnification trials were so high and so close, 0.975 and 0.983. The bone and its
magnified image have the same contours, and the high correlation indicates a high
degree of similarity. Subjectively, investigators may be confused by size but the
r is not. Had there been no measurement error, the r’s would
have been 1.0, perfect in similarity.
If confounding variables and much error are inherent in the atlas
materials, then the correlations would tend toward zero while losing the power to
discriminate. Contrarily, if the atlases were the product of careful work, then
the correlations should be high and should reliably discriminate. And that is what
was found. Human bone in one atlas compared to another correlated 0.906 and that
for this study was considered high and reliable. The same bone at different magnifications
was 0.975. When tried again with a different image it was 0.983. For this study,
that demonstrated that the test was reliable, it determined consistently, and was
calibrated for the effects of magnification. The test thereby proved valid, reliable
and calibrated, and anyone should be able to reproduce those findings, which means
it is objective as well. That contrasts sharply with the subjective, unquantifiable
method of inspection employed by Haile-Selassie which likely is unreliable and uncalibrated.
Errors tend to be normally and stochastically distributed about
the true value. For tests of statistical significance, they increase the variability
which is in the denominator of say a t-test thereby giving a ‘t’
too small to be significant. In the case of a correlation, the tendency to scatter
equally above and below the true value yields an r close to 0.00. Therefore,
errors or shortcomings are likely to hinder finding statistical significance or
a high correlation. If statistical significance is found, or if a high correlation
is found, it is in spite of errors or confounding variables not because of them.
Dimorphism or gender is a confounding variable and would have an
effect similar to anything else causing error or variability. It hinders finding
significance or a high correlation. For both atlases, the human sample number and
gender(s) were unknown. For the Swindler and Wood atlas, there were six chimpanzees
and 22 baboons all of unspecified genders. If genders whether in small or large
samples made a significant difference, then the humans probably would not have correlated
as high as 0.906 and the baboons and chimpanzees probably would not have correlated
across species lines as high as 0.820.
A photograph may be taken of a bone, and even if not to scale,
its proportionalities will be the same as the original. From a scale photograph,
a tracing may be made and the same may be said of it. From several preparations,
their tracings may be overlaid and the median may be identified and used in an atlas.
If all of the same bones had their shapes quantified and averaged, then the rendering
from those digital data would be very close to the one graphically determined. The
graphical method may be similar to the methods used for atlases and if it were quite
faulty then an r of 0.906 should not have been possible. Perhaps anatomists
deserve more respect than they are usually accorded.
Some investigators assume that atlases may be constructed with
artistic license rather than carefully from dissections. That was not the case for
the atlases used in this study. Swindler and Wood stated in their preface, ‘The
illustrations of Papio and Pan have been drawn from original dissections of twenty-two
baboons and six chimpanzees, and represent composite illustrations based upon the
specimens.’4 Spalteholz stated in the author’s preface, ‘The
illustrations, in all cases, have been faithfully drawn from original preparations,
but at the same time no copy of a definite individual case, but always a composite
from several sections has been made.’5
Figure 5. The human, Homo sapiens, toe bones, plantar view, as
shown in Swindler and Wood.4
The human bones used by Spalteholz in 1900 probably were different from the human
bones used by Swindler and Wood in 1973, yet for the reliable views the r
was 0.906. Let us pretend that the Spalteholz bones were the ancestors of the Swindler
and Wood bones. Let us suppose further that a human and his ancestor is likely to
be correlated about 0.906. Let us call this the top of the scale of similarity.
Now, what is needed is a lower limit of similarity. Any lay person will observe
the significant difference in proportions between phalanx 1 and phalanx 2 and would
easily judge them dissimilar (see Figure 2). That level of dissimilarity had an
r of 0.657. Now, there is objectively established a range of similarity
expected to be between 0.906 and 0.657. If r is lower than 0.657, then
the bones are as dissimilar as a bone for an anatomically different bone. The expectation
is that if there is ancestry, then the bones will be in the range of 0.657 to 0.906.
This was confirmed with humans compared to humans, 0.906, and across species lines
monkeys compared to apes, 0.820. Monkeys and humans, even more so apes and humans,
were as dissimilar as for an anatomically different bone. The method established
those criteria objectively, validly, reliably and with calibration. Scientifically,
that may be considered a higher standard than the subjective inspection that led
to the extravagant claims of Haile-Selassie and Robinson.
This study used the atlases as standards and they worked well. Had the atlases been
faulty, then the correlations would have approached zero in every comparison and
the study would have failed. Had that happened, then there may have been the need
to go out and obtain materials. The human bones and those of chimpanzees and baboons
would have been available for random sampling but not the solitary fossil bone.
Therefore, the sampling approach would have a benefit only if the atlases were unreliable
and if the sampling would have provided more reliable data. Given reliable atlases,
it did not seem a judicious expenditure of resources to duplicate work already adequate
for successful studies.
A case may be made for postponing the study and the report until an adequate sample of fossils
is found. That is like allowing what is perceived to be the only statistical design
available, sample statistics, to dictate scientific activity. Statistics are meant
to be a tool, not the master. The alternative is to seek or invent a statistical
design that accommodates a sample of one. By making repeated determinations on that
sample of one, which may be considered random samples normally distributed, then
conventional statistical tools may be applied. The statistical universe is that
sample of one and all conclusions apply only to that sample of one. That is exactly
what was wanted for the present study of a sample of one fossil. Now the question
of scientific acceptability arises. To my knowledge this sample of one method was
first reported in the Research Quarterly in 1959 and was again used successfully
and reported in a different protocol in 1967. It is ideally suited to individualized
pilot protocols especially those requiring stringent, multiple controls. It probably
has been used and reported in the literature many times since 1967 and has been
accepted undisputed for generalized application by the scientific community for
more than 40 years. That was the concept used in this study and that is why the
conclusions apply to that fossil as a sample of one and the specified atlases each
treated as if they were samples of one.
Figure 6. The human, Homo sapiens, toe bones, plantar view, as
shown in Spalteholz.5
Haile-Selassie must consider that what he observes as dorsal tilting
may not be objectively and quantitatively established in the life-long bipedal range.
Even if it were in the life-long bipedal range, it is not likely to have only that
similarity and no other. It is not likely to pass a subjective test but fail an
objective test. If it did, then which is to be doubted? The protocol for an experiment
must be repeatable by any scientist in any laboratory and yield the same answer.
Anyone may obtain the results of the present study. Very few have access to the
fossil and although accessible, a better image than that shown in Nature
was not made available. By contrast, the present method is available worldwide.
Haile-Selassie’s is confined to a locked drawer as was done with the Piltdown
forgery of 1912–1952. The verdict ought to be put in the hands of scientists
worldwide. Although available and upon request, Haile-Selassie would not even allow
out a better image than the indistinct one that appeared in Nature.
Haile-Selassie apparently is using his eyes and subjective judgement on the slant
of a joint surface, a joint surface unavailable to the scientific community. Were
it available, a way might be found to do a parallel, objective, valid, reliable,
calibrated test of similarity. It is not available, so scientists denied access
must do the best they can with whatever is available and that is what was done.
It is unfortunate that those with access do not take seriously their responsibility
to the scientific community at large and devise the objective tests themselves.
That they do not, that they make much from such meagre data, that they deny access
to even a better image, and that the results of this modest study are so contradictory
make one wonder whether their purpose is to avoid rather than welcome scientific
scrutiny, acceptance and application. Was the intent instead to proceed directly
from a letter to the editor of Nature1 to the acclaim from a
cover story in Time magazine?2 If they are confident of their
work with nothing to hide, then they should behave like bona fide scientists and
not like those involved in the Piltdown forgery.3
Summary and conclusions
In summary, the results of this objective statistical study suggest that the AME-VP-1/71
bone had scant similarity to human bone, was dissimilar to baboon bone and was most
dissimilar to chimpanzee bone. The baboon bone was similar to the chimpanzee and
dissimilar to human bone. The chimpanzee was most dissimilar to humans. Human bone
had no similarity to monkey or ape bone. Therefore, these objective ancestry analyses
for fossil bones suggest that the conclusion of Haile-Selassie and Robinson, that
Ardipithecus ramidus kadabba was an ancestor of apes and humans that walked
on two legs, is farfetched speculation.
Further reading
Related resources
References
- Haile-Selassie, Y., Late Miocene hominids from the Middle
Awash, Ethiopia, Nature 412:178–181, 2001.
Return to text.
- Robinson, S., Paleontology, one giant step for mankind,
Time 158(3):54–61, 2001. Return to text.
- Walsh, J.E., Unraveling Piltdown: The Science Fraud of
the Century and Its Solution, Random House, New York, pp. 124–125, 1996.
Return to text.
- Swindler, D.R. and Wood, C.D., An Atlas of Primate Gross
Anatomy: Baboon, Chimpanzee, and Man, University of Washington Press, Seattle,
pp. 52–55, 1973. Return to text.
- Spalteholz, W., Hand Atlas of Human Anatomy, Volume I,
S. Hirzel, Leipzig, pp. 146–149, 1900. Return to text.
- Sarfati, J., Time’s alleged ‘ape-man’ trips
up (again)! Journal of Creation 15(3):7–9, 2001.
Return to text.
- Oxnard,C.E., The place of australopithecines in human
evolution: grounds for doubt? Nature 258:389–395,
1975. Return to text.
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