Eine kleine wissenschaftliche Diskussion gefällig?

Eine "Erklärung" von Kreationisten für die nicht-existenten wissenschaftlichen Veröffentlichungen ihrerseits ist, dass eine Art weltweite Verschwörung von Wissenschaftlern das Erscheinen evolutionskritischer Artikel unterdrückt. Funde würden nur im Licht der Evolutionstheorie betrachtet und ausgewertet, ohne andere Deutungsmöglichkeiten zuzulassen.

Ein schönes Gegenbeispiel ist die Geschichte von Homo floresiensis, oder dem "Hobbit"-Menschen. 2003 wurde ein relativ vollständiges Skelett (etwa 18000 Jahre alt) in einer Höhle auf einer kleinen indonesischen Insel namens Flores gefunden, von Wissenschaftlern, die auf der Suche nach menschlichen Spuren waren, um mehr über die Migration unserer Vorfahren von Asien nach Australien zu erfahren. Der Fund wurde 2004 in Nature veröffentlicht (Brown et al., A new small-bodied hominin from the Late Pleistocene of Flores, Indonesia. Nature 431, 1055-1061). Nach der Analyse des Skelett kamen die Forscher zu der Ansicht, dass das 1 m große Skelett zu einer neuen Menschart gehörte, die von Homo erectus abstammte, wobei inbesondere auch das geringe Gehirnvolumen (380 cm²) für eine ursprünglichere Form sprach.

The combination of primitive and derived features assigns this hominin to a new species, Homo floresiensis. The most likely explanation for its existence on Flores is long-term isolation, with subsequent endemic dwarfing, of an ancestral H. erectus population. Importantly, H. floresiensis shows that the genus Homo is morphologically more varied and flexible in its adaptive responses than previously thought.

[Quelle: Brown et al. 2004]

Weil Wissenschaflter aber kritische Geister sind, entgegen den Behauptungen, wurde das eben nicht sofort von allen abgenickt. Im Gegenteil. Alternativ wurde das Skelett als Überrest einer Pymäenform, also Homo sapiens, gedeutet und das kleine Gehirn (es wurden noch Überreste von sieben weiteren Skeletten in der Höhle gefunden, aber nur einen vollständigen Schädel) auf eine Krankheit wie Mikroenzephalie zurückgeführt. Auf Konferenzen muss es hoch hergegangen sein. Das Ganze mündete in der Veröffentlichung von drei Artikeln in Science, einer bei Falk et al. (The Brain of LB1, Homo floresiensis. Science 8 April 2005: Vol. 308. no. 5719, pp. 242 - 245), dem Kommentar dazu von Martin et al. (Comment on "The Brain of LB1, Homo floresiensis". Science 19 May 2006: Vol. 312. no. 5776, p. 999) und der Erwiderung von Falk et al. (Response to Comment on "The Brain of LB1, Homo floresiensis". Science, gleiche Ausgabe).

Falk 2005: The brain of Homo floresiensis was assessed by comparing a virtual endocast from the type specimen (LB1) with endocasts from great apes, Homo erectus, Homo sapiens, a human pygmy, a human microcephalic, specimen number Sts 5 (Australopithecus africanus), and specimen number WT 17000 (Paranthropus aethiopicus). Morphometric, allometric, and shape data indicate that LB1 is not a microcephalic or pygmy. LB1's brain/body size ratio scales like that of an australopithecine, but its endocast shape resembles that of Homo erectus.

Martin 2006: Endocast analysis of the brain Homo floresiensis by Falk et al. (Reports, 8 April 2005, p. 242) implies that the hominid is an insular dwarf derived from H. erectus, but its tiny cranial capacity cannot result from normal dwarfing. Consideration of more appropriate microcephalic syndromes and specimens supports the hypothesis of modern human microcephaly.

Falk 2006 (Response): Martin et al. claim that they have two endocasts from microcephalics that appear similar to that of LB1, Homo floresiensis. However, the line drawings they present as evidence lack details about the transverse sinuses, cerebellum, and cerebral poles. Comparative measurements, actual photographs, and sketches that identify key features are needed to draw meaningful conclusions about Martin et al.'s assertions.

Auch interessant in dem Zusammenhang sind die beiden News of the week-Artikel, die zu dieser Kontroverse in der gleichen Science Ausgabe (2006) erschienen sind. Um einen Eindruck zu vermitteln:

Jean-Jacques Hublin of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who has seen the original specimens, finds the scaling arguments "quite convincing." But Martin's arguments are provoking a sharp response. Falk calls Martin's claims "unsubstantiated assertions" and adds that her team is surveying microcephalics to learn more. And bones from several small individuals have now been recovered from Flores, notes William Jungers of Stony Brook University in New York. He says that Martin's explanation implies that the island was home to "a village of microcephalic idiots." He adds that "there are precious few 'scaling laws' out there" and that examples of unusual scaling are not unexpected.

[Quelle: Culotta, But is it pathological?. Science 19 May 2006: Vol. 312. no. 5776, p. 983]

At a recent meeting here,* two anatomists presented analyses suggesting that the original hobbit skeleton may not be female, as first described, and that its shoulders differ from those of modern people and hark back to an ancient human ancestor, Homo erectus. That detail and others bolster the notion that an H. erectus population on the island evolved into the dwarf form of H. floresiensis, anatomist Susan Larson of Stony Brook University in New York said in her talk at the meeting.

Other researchers' opinions about almost every aspect of the hobbits, however, continue to run the gamut. Many are impressed with Larson's analysis. "I support Larson's observations … [and see] evidence of a faint phylogenetic signal" connecting the finds with H. erectus, says paleoanthropologist Russell Ciochon of the University of Iowa in Iowa City, who calls the skeleton from Flores "a very important link to our past." But a few researchers still find the whole tale too tall to swallow. In a Technical Comment published online this week by Science, paleoanthropologist Robert D. Martin of the Field Museum in Chicago, Illinois, and colleagues argue that the single skull is that of a modern human suffering from microcephaly (see sidebar). And even some researchers who are reasonably convinced that the fossils do not represent diseased modern people caution that the sample size for the shoulder bones is one. "It's always nicer to have more than one individual" to hang a hypothesis on, says Eric Delson of Lehman College, City University of New York.

[Quelle: Culotta, How the Hobbit Shrugged: Tiny Hominid's Story Takes New Turn. Science 19 May 2006: Vol. 312. no. 5776, pp. 983 - 984]

Ebenfalls 2006 erschien ein weiterer Artikel, diesmal in PNAS (Jacob et al., Pygmoid Australomelanesian Homo sapiens skeletal remains from Liang Bua, Flores: Population affinities and pathological abnormalities. PNAS September 5, 2006: vol. 103, no. 36, 13421-13426; Volltext frei), der ebenfalls die Pygmäen-Mikroenzephalie-Hypothese unterstützte.

Liang Bua 1 (LB1) exhibits marked craniofacial and postcranial asymmetries and other indicators of abnormal growth and development. Anomalies aside, 140 cranial features place LB1 within modern human ranges of variation, resembling Australomelanesian populations. Mandibular and dental features of LB1 and LB6/1 either show no substantial deviation from modern Homo sapiens or share features (receding chins and rotated premolars) with Rampasasa pygmies now living near Liang Bua Cave. We propose that LB1 is drawn from an earlier pygmy H. sapiens population but individually shows signs of a developmental abnormality, including microcephaly. Additional mandibular and postcranial remains from the site share small body size but not microcephaly.

Anfang dieses Jahres ging die Geschichte in eine neue Runde.

Gong! The latest round in the "hobbit" wars is under way. This week, a research team presented new data it says support the contention that a diminutive, small-brained hominid found on the Indonesian island of Flores truly represents a new species. The study, published online by the Proceedings of the National Academy of Sciences (PNAS), directly contradicts a paper published by skeptics last August in PNAS [Anm.: Das ist der Artikel von Jacob et al.; das Datum der gedruckten Ausgabe ist später als die Online-Veröffentlichung], which argued that the hobbit was a modern human with a severe deformity called microcephaly (Science, 25 August 2006, p. 1028). The new study compares the hobbit's puny brain to nine microcephalic brains and finds that the hobbit does not resemble them.

[Quelle: Balter, Small Brains, Big Fight: 'Hobbits' Called New Species. Science 2 February 2007: Vol. 315. no. 5812, p. 583]

Der Artikel, auf den sich dieser News of the week-Artikel bezieht, ist wieder von Falk et al. (Brain shape in human microcephalics and Homo floresiensis. PNAS February 13, 2007. Vol. 104 no. 7: 2513-2518).

Und nun gibt's eine weitere Untersuchung, die die Deutung des Skelettfunde als neue Art, H. floresiensis, unterstützt.

The diminutive human who lived on the Indonesian island of Flores 18,000 years ago has been called many things: a pygmy, a diseased Homo sapiens, a hobbit. Now, in a report that was the talk of the Paleoanthropology Society's annual meeting here last week, a postdoctoral researcher claimed that the shapes of the fossil's wrist bones are so primitive that it cannot be H. sapiens. "It is definitely not a modern human. It's not even close," paleoanthropologist Matthew Tocheri of the Smithsonian Institution in Washington, D.C., said in his talk. Although some critics still think the bones could be those of a diseased H. sapiens, others who heard Tocheri's report were persuaded. "It's the most convincing evidence so far that it really is something different," says paleoanthropologist Carol Ward of the University of Missouri, Columbia.
[...]
But until the hobbit bones can be compared with a wrist of a microencephalic human, some remain unconvinced. "The wrist bones don't look like those of a normal modern human, but how can we rule out that it's a pathological modern human until we get comparative evidence?" asks paleoanthropologist Robert Martin of the Field Museum in Chicago, Illinois.

Although much work has focused on the fossil's chimp-sized skull (Science, 2 February, p. 583), the new skeletal data are proving convincing to many. Says lower-limb expert Henry McHenry of the University of California, Davis: "It clinches it for me that [the Flores fossil] was not modern."

[Quelle: Gibbons, Hobbit's Status as a New Species Gets a Hand Up. Science 6 April 2007: Vol. 316. no. 5821, p. 34]

Die Geschichte ist damit wahrscheinlich immer noch nicht zu Ende.

Was aber meiner Meinung nach sehr deutlich wird, ist, dass gegenläufige Meinungen keineswegs unter den Teppich gekehrt werden. Eine wissenschaftlich basierte und fundierte Untersuchung wird veröffentlicht, gleichgültig, ob sie kontrovers ist oder nicht. Im Gegenteil, die Diskussion von Daten und Funden ist grundlegender Bestandteil des Prozesses. Die Behauptung, die "etablierte" Wissenschaft würde sich einer kritischen Analyse verweigern, ist absolut gegenstandslos. Sie würde beinhalten, dass sich alle Wissenschaftler über die Bedeutung jedes Fundes einig wären. Wie das Beispiel der Diskussion um den "Hobbit"-Menschen zeigt, ist das keineswegs der Fall.

Wie bei so vielem ist auch hierbei die Darstellung durch Kreationisten mehr als unehrlich. Wäre man sich über Homo floresiensis einig, wäre man unkritisch. Findet eine Diskussion statt, ist die Validität aller Fossilfunde inklusive Evolutionstheorie in Frage gestellt. Beispielsweise schreibt Harun Yahya:

[...] The Nature journal news service that published the discovery of H. floresiensis summarizes the dilemma facing evolutionists in the headline it chose, "Little Lady of Flores Forces Rethink of Human Evolution."

Problems, astonishment, confused statements, a theory in need of a rethink …

Evolutionists' own statements reflect the heavy blow the fossil in question has dealt to the illusory scenario of human evolution. Furthermore, the depiction of these fossils as evidence for evolution in the media shows once again that Darwinism is a belief system kept blindly alive in the face of the facts, since evolutionists still refuse to abandon their theory in the face of the fossil findings that have recently totally demolished the myths they recounted so tirelessly for so many years. Evolutionists gloss over every new blow dealt to their scenarios by new discoveries by saying, in effect, "that means we evolved not in this way, but in that," and still attempt to keep the myth of evolution they support so blindly alive behind a scientific mask.

Und weiter:

The attempt to describe the Flores Man fossils as a separate species to modern man is based on no scientific grounds and constitutes no support for the theory of evolution.

The fact that the "separate species" description of Flores Man launched by evolutionists is being challenged by other evolutionists once again reveals the uncertainty shrouding the evolutionary claims regarding the fossils in question.

[Quelle: Harun Yahya]

MfG,
JLT