Successive discovery of the paleoanthropological background

In Darwin's time, it was already evident that the scarce evidence of hominin life in the past does not allow the neglect of any clues. We need all available sources to reconstruct our evolutionary history, and these interpretations rely overwhelmingly on fossils. These latter are obviously mute; for this reason, one has to formulate hypotheses about the biological and phylogenetical role of the extinct taxa, and the only reliable approach to increasing our knowledge of the lost worlds is to compare them with recent sets of well-known phenomena.

This scientific process started very soon after the fulguration (sensu Popper) of the pre-Darwinian interpretation of fossil specimens as documents of species of former times and Darwin's evolutionary theory. The systematic search for phylogenetic forerunners of recent taxa began. The most dramatic part of the Darwinian paradigm focused on the question of how humans evolved from archaic primates. What did the hypothetical species transitional between apes and man look like? When, where, and how did the missing link live, a term created in 1861 by Asa Gray (Shipman and Storm 2002). Darwin's evolutionary theory of natural selection did not automatically provide an answer to that question, and Darwin himself was cautious enough not to give a premature answer. But he had provided a new framework in which all these questions could be answered. While the public longed for strong proof of human evolution, Darwin gathered all available arguments for more than 10 years. Finally he published his brilliant anthropological volumes The Descent of Man and Selection in Relation to Sex (1871) and The Expression of Emotions in Animals and Man (1872). Both books deal with human evolution and particularly with sexual selection, whose enormous evolutionary impact was first understood only around 100 years later, when the sociobiological paradigm emerged (Wilson 1975; Vogel 1982; Miller 1998; Voland 2002; Voland and Grammer 2002).

During the 1860s, Darwin's ideas were widely popularized. However, there emerged much scientific skepticism at that time as the laws of heredity worked out by Gregor Mendel (1822-1884) in 1865 remained unknown until the twentieth century. Beside Darwin's British supporters, especially Thomas H. Huxley and Charles Lyell, it were the German geologist and paleontologist Friedrich Rolle (1827-1887) and the zoologist Carl Vogt (1817-1895) who advocated Darwin's theory (Rolle 1863; Vogt 1863).

Even more committed and sarcastic than the "Affenvogt" was Ernst Haeckel (1834-1919), an outstanding German biologist who sagaciously fought against the "ape complex.'' He is best known for his recapitulation law (ontogeny recapitulates phylogeny), a highly controversial assumption. After reading The Origin, he became a powerful and eloquent supporter of evolution. Although Haeckel admired Darwin's theory, concerning his own evolutionary thoughts he remained an orthogradualist, and concerning the concept of the "survival of the fittest,'' a Lamarckian. Haeckel was not really supportive of natural selection as the basic principle of evolution, and his interest in fossils and paleoanthropology was small. He was convinced that due to the intertwining of phylogeny and ontogeny, ontogenetic structures were sufficient evidence for evolution (Haeckel 1898, 1902, 1905, 1922; Heberer 1965, 1968b, 1981; Hofifeld and Breidbach 2005; Kleeberg see www).

Despite misunderstanding many of Darwin's thoughts, Haeckel inspired the public and colleagues with his enthusiasm for evolution and animated the debate. As he was highly motivated by his anti-Christian attitude, his influence in science faded, especially when he created his monistic theories and dabbled in esoteric fields (Hofifeld 2005b; Kleeberg see www). He gave paleoanthropology an essential impulse by publishing the first phylogenetic tree (O Figure 1.4) that

O Figure 1.4

First pedigree designed by Ernst Haeckel

O Figure 1.4

First pedigree designed by Ernst Haeckel

included humankind. Darwin commented on this: "Ihre Kühnheit läßt mich jedoch zuweilen erbeben, aber, wie Huxley bemerkte, irgend jemand muß eben kühn genug sein und einen Anfang machen, indem er Stammbaume entwirft'' (Darwin's letter to Haeckel, November 12, 1868) (Schmitz 1982). As the scarce fossil record only allowed a very hypothetical pedigree, there was much courage needed indeed. Haeckel postulated a forerunner species Pithecanthropus alalus—a speechless ape-man—a missing link, which he believed lived during the Pliocene in Southeast Asia or Africa. Within an orthogenetic pedigree, he posited a primitive species—which he named Homo stupidus—between this "ape-man" and the recent H. sapiens. Around 30 years later, fossils were found in the postulated Asian region by the Dutch physician Eugene Dubois (1858-1940), which roughly fitted the expectation of a Pithecanthropus (Bergner 1965).

Meanwhile a focus of research was the phenomenon of the Ice Ages and the discovery of Upper Paleolithic man and Ice Age cultures (Trinkaus and Shipman 1993; Sackett 2000). Although human fossils were rare at the time of Darwin's revolutionary discovery, there was much evidence from animal bones, molluscs, sediments, and other materials to give insight into ancient populations. Further, there were ever-increasing indications of long-term fluctuations in the earth's climate. Geologists, like Agassiz, Geike, and Lyell as well as Brückner and Penck, established a Pleistocene framework of successive glaciations, and archeologists strove to establish the antiquity of human ancestry through the association of stone tools with extinct animals. The geological research resulted in the Alpine model, a chronological system of glaciations that gave a framework for the ongoing discovery of Neanderthal fossils.

As biological, anthropological, geological, and archeological data came together within the frame of the evolutionary theory during the second half of the nineteenth century, many scientific societies were founded, which supported all kinds of scientific research.

Rudolf L.C. Virchow (1821-1902), a famous German physician and anthropologist sensu lato, best known for his guiding research in cellular pathology and comparative pathology, was a universal scientist and liberal politician who founded the German Society of Anthropology, Ethnology, and Prehistory in 1869 (Degen 1968; Andree 1976; Schipperges 1994; Goschler 2002; Trumper 2004). He included humankind in the historicization of nature and came to the conclusion that H. sapiens was "Post-Historie" (Goschler 2002 p 322). For that reason, he was highly skeptical about the validity of Darwinian theory concerning our own species and doubted the phylogenetic classification of the species H. neandertha-lensis, as the Irish zoologist William King had dubbed the skeleton from the Kleine Feldhofer Grotte (Stringer and Gamble 1993; Trinkaus and Shipman 1993; Schmitz and Thissen 2000). Due to his "pathologist view,'' he interpreted the Neanderthal-derived features or apomorphies as pathological features resulting from arthritis; further from the erroneous information that the skeletal remains were associated with polished stone tools (an indicator for the Neolithic), he concluded that the Neanderthal man must have lived in recent times (Schott 1979). Thus, not all human fossils known at that time were accepted as convincing evidence of our ancestry, especially given their widely uncertain dating.

Neither Virchow nor Haeckel pushed paleoanthropologies research, the former from misinterpretation of the facts and skepticism on Darwin, the latter from his conviction that ontogenetic research delivers sufficient information to demonstrate phylogenetic evolution. Virchow's interest was much more in prehistoric anthropology and ethnology, from the point of view of the decoupling of natural and cultural evolution. The retrograde view that a missing link does not exist was admired by the Christian church, and when Pithecanthropus erectus, the so-called "Java Man,'' was described, he thought that the bones represented a giant gibbon.

Virchow's skeptical attitude concerning Pithecanthropus as well as his critical interpretation of the Neanderthal fossil as a pathological individual lessened the biological impact of a premature "palaeoanthropology" during the second half of the nineteenth century (Triimper 2004). This holds true for the English and French scientific scenes as well. Although the physician Paul Pierre Broca (1824-1880), the founder of the Societe d'Anthropologie de Paris in 1859, was a pioneer of comparative anatomy and anthropology, he never accepted the Neanderthals as fossil documents. His interest was in understanding the patterns of variation in order to understand the significance of anatomical differences. For this reason, he became one of the first to use statistical concepts in establishing anthropology as a scientific discipline in contrast to medical science. In 1882, his French colleagues Quatrefages and Hamy published Crania ethnica, a monograph which exemplifies the huge interest in recent cranial variation that dominated the anthropological discipline.

Eduard Lartet (1801-1871) was the first to describe the primate genera Dryopithecus and Pliopithecus, but much more important was his discovery of signs of prehistoric art made by early humans. The fossil ivory carving of La Madeleine, found in 1864, was presented at the world exhibition in Paris 1867 and raised tremendous interest.

In the following period, neither the discoveries of human fossils from La Naulette in Belgium nor those of Pontnewyydd (Wales), Riveaux (Southern France), Sipka, Mladec, and Brno (Czech Republic) were able to convince the European scientific community of the human antiquity. Even the analysis of the Spy fossils, which had been discovered in Belgium in 1886, did not slow the rejection of evolutionary thoughts. Trinkaus and Shipman (1993 p 132) summarized: "The man of the Neander Valley remained without honour, even in his own country.''

In the motherlands of evolutionary thinking, France and England, Paleolithic archeology dominated the paleoanthropological discussion and began taking shape as an organized scientific field of research in the 1860s. Sackett (2000 p 38) puts it this way: "... discovering the Paleolithic became a matter of empirically demonstrating that human remains and artefacts could be found in association with the remains of extinct animals belonging to the deep time of earth history.''

Progress was for the first time possible through the scientific recognition of the Pleistocene geological epoch, i.e., the interpretation of fossils within a solid geological background. Although Cuvier and Lyell had done indispensable scientific work to understand the past, the first assumed that the changes came about by a series of revolutions, while the second, although he had major objections to Cuvier's theory of catastrophism, was no evolutionist either. The challenging question for the evolutionists was how to provide empirical data concerning the existence of "diluvial'' and "antediluvial'' early human populations. As these workers had to rely on the research of the paleontologists and the archeologists, paleoanthropological science was becoming multidisciplinary even at this early stage. The evidence from the Paleolithic record was mainly from data from stream gravel terraces, rock shelters, and bone caves. As Sackett (2000 p 42) mentions, from the 1820s until 1859 there was a series of discoveries in France (especially in the Perigord), England (Paviland bone cave near Swansea, Wales; Kent's Cavern, near Torquay, Devonshire), and Belgium (Engis near Liege). The research resulted in the assignment of Pleistocene fauna to deep geological times, but it did not support evolutionary thinking due to the many alternative explanations available. The consequent question was whether actual human remains existed in association with Pleistocene animal fossils and undoubted artifacts. The immediate question of human antiquity came up with the discussion of the fossils from the Neanderthal in Germany and Darwin's evolutionary theory. Most of the geologists and paleontologists remained skeptical; they saw no proof of a high antiquity of humankind from evidence from the bone caves or gravel terraces. One reason for their skepticism resulted from the archeological work of Jacques Boucher de Perthes, director of customs at Abbeville, France, whose empirical evidence was much doubted. As consequence of his having "... found much too much,'' as Sackett (2000 p 45) puts it, the Bible continued to dominate everyday metaphor; and ironically enough, the successful archeological research in the Near East, Egypt, and Palestine solidified the traditional view that humankind was unique and doubtless recent. In spite of many convincing facts— as retrospectively gauged—from archeology, the social establishment of the mid-nineteenth century maintained the older view.

An opportunity for change came in 1858, when Brixham Cave near Torquay on the Devon Coast was discovered, and outstanding scientists like Hugh Falconer (1808-1865), Charles Lyell, Richard Owen (1804-1892) supervised excavations there. William Pengelly (1812-1894), a local schoolteacher and geologist, was able to gather, by a new method of layer-by-layer excavation, thousands of animal bones including those of hyena, cave bear, rhinoceros, and reindeer. The impact of these fossils on the question of human antiquity would have been zero if Pengelly had not found undeniable artifacts, which he described as "knives''. These chipped stones from Brixham Cave challenged the received opinion about human antiquity in 1859. While the belief in human antiquity of the excavator and some colleagues was confirmed by the association of fossil bones and the hand-axes, others like Owen did not agree and thought that the animals had not become extinct until geologically modern times.

New aspects came into the stagnating discussion when the implements of the Brixham Cave were compared to the finds at Abbeville and Amiens, which had been excavated by Boucher de Perthes. The ultimate convincing facts came when the English team, digging in the Somme terraces, was able to document a hand-axe in place in a fossil-bearing stratum at St Acheul. This was the turning point as Pengelly, Prestwich, and Lyell were then able to convince the British establishment of the antiquity of humankind. The French scientific community, which had contradicted Boucher de Perthes' interpretations for many years, now no longer rejected the idea of human antiquity. However, some French scientists, like the zoologist Isodore Geoffrey St Hilaire (1805-1861) or Eduard Lartet (1801-1871), had been more or less convinced about human antiquity before, but the discovery of human teeth intermixed with fossils of cave bear and hyena in a cave near Massat in southern France brought about final acceptance. Lartet published the ultimate proof in 1860. He described cut-marks on fossil bones that had been made by stone tools when the bones were still fresh. This was the essential evidence of contemporaneity of humans and extinct animals, and it signaled the start of intensified geological research. The glaciological research aimed at structuring the Pleistocene epoch helped to put the human antiquity into a chronological frame; and the amalgamation of archeological and geological facts brought up a new era that started with Lyell's first edition of his famous Geological Evidences for the Antiquity of Man (1863). The coming together of diverse aspects of the cultural and natural sciences ultimately yielded an innovative conception of man and his origin (Daniel 1959, 1975; Trinkaus and Shipman 1993; Sackett 2000; Murray 2001).

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