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Table of Contents
Introduction
General Analysis
Philosophy and Theory: Historic
Theory and Methods: Modern
- Genetics
- Geochronology
- Archaeology
Case Studies
1) Pliocene Pongid Ancestors
- Australopithecus
3) Java Man
4) Pekin Man
- Neanderthals
- Modern Man
General Discussion
Conclusion
References
Introduction to Physical Anthropology:
Overview of Interpretations of Human Origins
With Case Studies Detailing Archaeological Evidence
Introduction
Stuart (1969, p. 9) notes the inscription “What is Past is Prologue” at the entrance to the National Archives in Washington, D.C. as equally applicable “to the entire span of human life on earth.” In order for us to understand man’s present as well as to help guide his future, the “knowledge and lessons of this long past are essential” (Stuart 1969, p. 9). The geographic origin of Hominidae is generally accepted as Africa; however, the origin of anatomically modern humans or Homo sapiens has not been conclusively determined and is still disputed by anthropologists.
Anthropology is a sub-discipline of archaeology and encompasses two major research categories based on human variation, culture and biology (Hammond 1964; Kelso 1970; Nitecki and Nitecki 1994). Physical anthropology represents the branch of archaeology that is responsible for investigating the evolutionary origin and progression of man from past to present. Physical anthropology investigates biology as well as variation, and is not as structurally differentiated as cultural anthropology (Kelso 1970). Kelso (1970, p. 1) further separates physical anthropology into two major subcategories; identifying human paleontology as the investigation of “variability among man’s ancestors,” and human heterography [human biography] as the investigation of “biological variation among living populations.”
Students of physical anthropology generally have an opportunity to investigate human morphology through study of the fossil record, taxonomy, evolution, genetics, contemporary variation, and adaptation (Kelso 1970). Regardless of research specialization, the top question considered by human anthropology is “where did humans originate?” (Nitecki and Nitecki 1994, p. 1). Secondary questions that are more subject to disagreement among scholars include “who they were, and when they appeared” (Nitecki and Nitecki 1994, p. 1). As definitive answers to these questions have not yet been found, the field of physical anthropology continues in its pursuit of answers to questions regarding man’s past.
General Analysis
The sections below provide an introduction and overview of basic philosophies theories, and methods utilized in the pursuit of human origins. While mentioned briefly in my overview, historic and modern creationist theories will not be discussed in detail. I will be limiting my overview to philosophies, theories, and methods of a scientific nature. However, out of respect for creation theories in general, I would like to call attention to the following insight offered by Birdsell (1972, p. xiii):
…the controversy between religion and science is moderating. There is no conflict between the natural sciences and religion, for natural sciences are based on orthodox materialism, which does not concern itself with the supernatural… the area of disagreement between religion and science focuses on a single central point, the origin of life. Most natural scientists ultimately explain this in materialistic terms, and as a consequence of the very nature of matter and the planetary environment. Those who may reject this view for reasons of faith may take some consolation in the idea that life has not yet been produced in the laboratory, and even if it had, the creation of living molecules would not necessarily prove that life had been created in the same fashion four billion years ago…The reader of faith may conclude that the depth of this intervening time makes the exact origin of life on this planet essentially unknowable…In [any] case, the sweep of organic evolution has a grandeur which compels the individual to some sense of personal humility.
Philosophy and Theory: Historic
Eckhardt (1979, p. 26) reminds us that evolution was a “revolutionary idea” and was a disturbing concept to many, particularly to those of prominent religious orders. Change is readily apparent for most modern cultures, ranging from exposure to technological conveniences to familiarity with genetic engineering. However, technological advances and cultural innovations took place at a much slower pace in earlier centuries. This likely contributed to the inability of many people to accept new ideas such as biological change or evolution through time (Eckhardt 1979).
Philosophies and theories based on evolutionary processes appear in recorded history as early as 611 B.C. (Eckhardt 1979). Anaximander of Greece proposed that living creatures had arisen from a primordial mud covering the earth; with plants and lower animals appearing first, followed by human evolution from a fish-like ancestor (Eckhardt 1979).Aristotle studied the observations of earlier philosophers, but based his own generalizations on personal observation (Eckhardt 1979). Aristotle initiated an early system of classification with designations equivalent to that of our more modern genus and species, well before the advent of Mendel and Linnaeus (Eckhardt 1979).
John Ray, followed later by Linnaeus, assisted in establishment of the formal science of taxonomy (Eckhardt 1979). Linnaeus’ system of binomial nomenclature is still in use today. A French contemporary of Linnaeus, de Buffon (1707-1778), was skeptical of the popular creationist view that each species was individually created by a supernatural being (Eckhardt 1979). de Buffon suggested that geologic processes, including climate, exerted a major influence on species development and subsequent adaptations (Eckhardt 1979).
Lamarck (1774-1829) challenged the static taxonomy of his day, emphasizing a changing natural world and the existence of transitional species (Eckhardt 1979). Evolutionary concepts proposed by Lamarck included: 1) life forces result in a morphology ideal to a specie’s needs; 2) new wants in animals give rise to new movements that in turn produces a new morphology; 3) the size of body parts in animals corresponds to degree of use; 4) changes occurring in parent individuals are transmitted to offspring (Eckhardt 1979). The idea that bits of a parent animal are transmitted to offspring (pangenesis) is reported by Eckhardt (1979) as having been common among nineteenth century biologists.
Cuvier (1769-1832) discredited Lamarck’s theories, but at the same time believed the earth was of a very young geologic age (Eckhardt 1979). Support for this concept was garnered from the conclusions of Usher, an Irish Archbishop who determined through a chronological sequence that the earth was created approximately 4004 B.C. (Eckhardt 1979). Although Cuvier is responsible for derailing evolutionary concepts of his predecessors, he was also responsible for initiating the study of paleontology through use of fossils (Eckhardt 1979).
Fossils had been recognized since the 1500’s, with Aristotle also recognizing the fact that fossils represented the remains of once-living creatures (Eckhardt 1979). Cuvier’s era resulted in the beginning of systematic, large-scale excavations for fossils and the discovery that the earth’s “geologic deposits were not of uniform composition” (Eckhardt 1979, p. 32). Cuvier is also credited with establishment of the catastrophe theory, which was later disproved by the same geologic evidence he and his students had discovered (Brace and Montagu 1977; Eckhardt 1979).
As fossil evidence was re-examined by succeeding geologists, the evidence discovered by Cuvier also resulted in abandonment of the idea that the earth was relatively young (Brace and Montagu 1977; Eckhardt 1979). In 1830 Lyell proposed that the same processes that existed during the formation of the earth’s species were still evident, and could be used to construct approximate ages for the earth and its species (Eckhardt 1979). Lyell determined that the age of the earth needed to be measured in hundreds of millions of years, rather than simply thousands (Eckhardt 1979).
Darwin (1809 to 1882) revived the concept of evolution using a “plausible theory of how natural processes could bring about transformations in organisms as well as in their environment” (Eckhardt 1979, p. 34). Basic observations contributing to Darwin’s theories include: 1) parent organisms typically produce numerous offspring; 2) the number of adults in the following generation remains approximately the same as for the preceding; and 3) no two organisms are identical as there is variation among individuals (Eckhardt 1979). Wallace (1823-1913) came to similar conclusions nearly simultaneous to Darwin; however, Darwin’s two decades of observations supported both sets of conclusions (Eckhardt 1979).
Within the same time period, Mendel (1822-1884) proposed his theories of heredity based on rigorous scientific experimentation (Brace and Montagu 1977; Eckhardt 1979). Additional discoveries shortly followed in related biological fields, including the identification of the cell as the basic unit of life (Eckhardt 1979). De Vries proposed his theory of mutation in 1901, while the chromosome theory of inheritance was proposed by Sutton in 1902 (Eckhardt 1979). Population genetics emerged as a new field of study in the 1930’s and 1940’s. Eckhardt (1979, p. 39) notes the combination of ”chromosome theory of inheritance and population genetics formed the core of the genetic theory of evolution.”
Armed with the tools represented by paleontology and genetics, anthropologists began to make many new and important discoveries relating to human origins. As the scientific community moved into the 20th century many new theories have been alternately advanced, substantiated, discredited, formed, and reformed in light of not only emerging archaeological evidence but in response to increasing technological ability and to advances in genetics and related fields.
Theory and Methods: Modern
While many theories of modern human origin may be postulated, (Nitecki and Nitecki 1994) note that only two major theoretical positions have been commonly recognized in recent years: 1) “modern humans evolved more or less simultaneously from earlier, nonmodern populations throughout the occupied world;” and 2) “modern humans emerged in a circumscribed geographic region and subsequently replaced nonmodern populations elsewhere.” Although both theories and a number of corresponding sub-theories have been substantiated to one degree or another by archaeological and genetic evidence, the definitive geographic origin(s) of anatomically modern humans remains undetermined.
The lack of substantive data regarding human origins has been summarized by Hammond (1964, p. 5) as follows: “Naturally, many problems of a secondary nature have been solved but neither the new data nor the improvement in techniques has provided any effective advance in the understanding of the evolutionary process.” Hammond (1964, p. 5) continues as follows: “It is a fact that among scientists today there is less agreement than there was fifty years ago concerning the Phylogenetic links between man and the rest of the Primates.” Hammond (1964) provides the insightful observation that this is not due to a lack of adequate investigation, but to the complexity of problems presented as paleontological and genetic studies continue to open new doors. Lewin (1998) similarly remarks that new finds result in new questions relating to the evolutionary puzzle.
Regardless, three major divisions of study and/or field efforts continue to shed light on original questions regarding the origins and course of human evolution, as well as on newly discovered complexities, anomalies, and disjunct discovery. These major divisions are introduced below under the headings of genetics, geochronology, and archaeology. While these research divisions may be pursued individually, they obviously overlap in both scientific content and potential scholarly application.
a. Genetics
Inheritance is generally utilized to identify transfers from one generation to the next. Inheritance can be divided into two realms: 1) cultural inheritance, represented by “skills, knowledge, and material attributes” transmitted from one group to another; and 2) genetic inheritance, represented by transmission of “gene-containing reproductive cells” (Eckhardt 1979, p. 72-73). Cultural transmission is extra-somatic or separate from the body and can be transmitted in any generational direction (Eckhardt 1979). Genetic transmission is traditionally one directional, from parent to biological offspring (Eckhardt 1979).
Both cultural transmission and genetic transmission have played important roles in human evolution, with physical anthropology concentrating on the genetic aspects. Chromosomal studies allow scientists to study not only the genetic makeup of living subjects, but to explore potential genetic relationships with other organisms past and present (Eckhardt 1979). Genes, the material necessary for genetic transmission, are segments of chromosomes containing DNA codes. Similarities between organisms of different species can be determined directly through study of amino acid sequences (Eckhardt 1979). For example, humans and chimpanzees share identical amino acid sequences in at least five proteins (Eckhardt 1979). Relationships between organisms of different species may also be indirectly studies through nucleic acid sequences (Eckhardt 1979).
Phenotype refers to an organism’s appearance and physical characteristics, such as in the case of human individuals with red hair (Eckhardt 1979). Genotype refers to an organism’s genetic makeup, and is fixed at the time of fertilization of an embryo. Individual aspects of phenotype or genetic makeup (e.g. blood type, recessive genes for inherited diseases) are now routinely analyzed through blood and tissue samples (Brace and Montagu 1977; Eckhardt 1979). Some genetic characteristics are routinely expressed in a subsequent generation [dominant genes], while other characteristics may appear only under certain conditions or combinations [e.g. recessive genes] (Eckhardt 1979; Waits 2004).
La Barre (1954) reminds us “for all its spectacular variety, mankind is obviously a morphological and genetic unity.” Hammond (1964, p. 136) in speaking of human notes “evolution of man is a natural process hat has transcended itself,” and that only when initial life emerged from inorganic matter has there been a comparable event in history. Hammond (1964, p. 136) also notes that genes are the “raw materials” with which natural selection works through mutation and sexual recombination and that these factors have apparently “led to the emergence” of anatomically modern humans or Homo sapiens.
Populations composed of groups of organisms belonging to the same species are the units of biological evolution routinely used by anthropologists (Eckhardt 1979). Such units are greater in size than an individual family, but smaller than the overall “size” of a particular species. Within the context of evolution, a population is a “group of organisms that breed with one another” (Eckhardt 1979, p. 102). However, breeding population boundaries are not necessarily absolute. Higher organisms tend to diffuse between populations, with the frequency determined largely by geographic mobility (Eckhardt 1979).
Brace and Montagu (1977) report that evolution can occur under a variety of settings, including but not limited to natural selection, genetic drift, specialization, and mutation. Natural selection is an aggregate of environmental forces that affect a species chance for survival (Brace and Montagu 1977). Often referred to as survival of the fittest, natural selection presumes that individuals within a species that are better fitted to survive in the face of environmental difficulty will leave more progeny behind than less fit individuals (Brace and Montagu 1977; Waits 2005).
Genetic drift is responsible for random genetic variation, and occurs in relation to the amount of influence any particular organism within species will have on succeeding generations (Brace and Montagu 1977). Specialization is represented by both specialized (adaptation) and unspecialized (adaptability) responses of a species (Brace and Montagu 1977). While commonly considered to be limiting, specialization may result in unique adaptations to set conditions (Brace and Montagu 1977). Adaptability can be achieved in one of two ways: 1) possession of morphological features that allow the organism to survive under a wide variety of conditions; or 2) possession of the genetic potential to produce variants that can survive in the face of changing conditions (Brace and Montagu 1977).
Evolutionary studies of human populations past and present are confounded by cultural boundaries as well as geographic boundaries (Eckhardt 1979). Important advances and breakthroughs occurred in the 1990’s in relation to primate evolution, and such scientific advances continue to the present day. Findings relating to human evolution still make news headlines before fading into the relative obscurity of academia. For example, a recent news brief included in a Twin Falls, Idaho newspaper indicated that the genetic trait for red hair in humans has now been traced as far back as Neanderthal populations (Times News 2007).
An article just released in December 2007 by the Associated Press [AP] calls attention to a genetic study by Harpending (2007) at the University of Utah. Harpending (2007) indicates human evolution is occurring at a greater rate than in prehistoric times, with many different changes occurring in African, Asian, and European populations. The AP report by Schmid (2007) calls attention to several important findings reported by Harpending:
Rapid population growth has been coupled with vast changes in cultures and ecology, creating new opportunities for adaptation…The past 10,000 years have seen rapid skeletal and dental evolution in human populations, as well as the appearance of many new genetic responses to diet and disease.
b. Geochronology
Eckhardt (1979) notes that strong evidence of geologic age is extremely important to the determination of evolutionary sequences. As we know different populations of a given lineage may evolve at different rates, obtaining as accurate a dating as possible is critical for valid research assumptions. Accurate determination of the relative age of fossil remains has also been responsible for exposing a number of forgeries and fraud perpetrated in the anthropological world, including but not limited to the Piltdown forgery exposed in the 1950’s (Brace and Montagu 1979).
Relative dating is a process based on geologic strata and operates under the assumption that later populations cannot be ancestral to earlier populations (Eckhardt 1979). Absolute dating [also known as chronometric or radiometric dating] is a quantitative measure of time with respect to known scales (Eckhardt 1979). Klein (1994, p. 7) notes, “It would be difficult to overstate the importance of radiocarbon dating to the archaeology of the last 40,000 years or of radiopotassium dating to our understanding of the earliest phases of human evolution, before 500,000 years ago.” Other dating methods include Thermoluminescence Dating [TL], which can be applied to artifacts such as burned flint; and Electron Spin Resonance [ESR] that can be applied to surfaces such as ancient dental enamel (Klein 1994).
Some of the dates obtained through TL and ESR procedures indicate that modern or near-modern human populations existed as recently as 120,000 to 80,000 years ago in what is now Israel (Klein 1994). Klein (1994) report that TL and ESR dating efforts support a fundamentally African origin for modern human morphology. TL and ESR processes have also revealed that Neanderthal populations may have cohabited specific geographic regions for up to four millennia after the appearance of anatomically modern humans; presumably as Neanderthals were better adapted to surviving in an increasingly cold climate (Klein 1994).
However, as with any scientific procedure, a dating process is subject to misinterpretation or error. Klein (1994) point out a number of cases underlining the need for caution in interpreting dates obtained through TL and ESR. For example, teeth “tend to accrue uranium form ground water” that can result in significant increases in annual radiation dosage rates (Klein 1994). Based upon the possibility of errors, some argue that assumptions that Neanderthals and anatomically modern human overlapped in some regions are incorrect As Klein (1994) points out, further development of geochemical processes that can provide an independent means for verifying dating obtained by TL or ESR will be incredibly useful to anthropologists.
c. Archaeology
Archaeological evidence in the form of fossils and other material is more than ancient bones; a fossil is any item that provides us with direct information about organisms that lived in the past (Kelso 1970). However, as Klein (1994, p. 10) points out, “human paleontologists and geneticists often barely mention the archaeological evidence for modern human origins, perhaps because they believe it is too ambiguous or subjective.” Klein (1994, p. 10-11) also provides the following excellent discourse on the value of archaeology to the study of human evolution:
Certainly, some archaeological evidence has been poorly collected and analyzed, and some interpretations are plainly flawed by a lack of logical rigor or good sense. However, archaeological data have the unquestionable advantage of being relatively abundant… reliable patters can be detected using fundamentally the same principles for evaluating incomplete or contradictory evidence that are successfully employed in judicial cases.
Klein (1994) goes on to note that archaeology contributes to the understanding of human evolution in two important ways: 1) archaeology helps to elucidate behavioral differences between modern and non-modern humans; and 2) archaeology illustrates approximate appearances of modern humans in different regions and whether or not the appearance was gradual or abrupt. These determinations contribute to our understanding and efforts to determine whether or not modern humans originated in a single geographic area or concurrently in numerous areas (Klein 1994).
Birdsell (1972) reports that two major characteristics of the fossil record make archaeological evidence particularly useful in studying human evolution. The first characteristic is that man appears to have evolved comparatively rapidly during the first three million years of the Pleistocene (Birdsell 1972). Examples include the fact that brain size approximately tripled during this time period (Birdsell 1972). The second major characteristic is moderate radiation of man during the Pleistocene resulted in a greater variety of populations than exists currently on the earth. (Birdsell 1972). Birdsell (1972) provides the observation that one of the best bases for utilizing the fossil record is the capability it offers for comparison of similarities in form across time as well as in relation to local and regional geography.
It is interesting that some authors (e.g. Brace 1997) have published rather bold assumptions based entirely on archaeological evidence, even though this evidence is considered by anthropologists to be incomplete. Brace (1997) makes the following assertion:
…if one turns to the evolutionary dynamics by which modern form is produced, it is obvious that what is involved is simply a reduction in the degree of robustness both in faces and teeth and in the postcranial skeleton a Hrdlička perceived two generations ago. The change in life ways that allowed such reductions to occur is clearly indicated in the archaeological record.
Brace (1997) further elaborates on his position by noting that such evidence is clearly indicative of in situ evolution rather than an African origin for anatomically modern humans.
Most authors remain much more cautious, presenting or at least discussing alternative theories rather than boldly espousing a single theory on the basis of incomplete evidence. Such caution is exemplified by the writing of Cann and others (1994, p. 146) who note, “We remain puzzled by exactly what caused the break in the transition from our archaic ancestors to anatomically modern people.” Lewin (1998, p. 130) similarly notes, “The overall evolutionary pattern of primates remains still unsettled.”
Case Studies:
Archaeological Evidence From Around the Globe
The field of archaeology continues to provide unique opportunities to delve into man’s physical or evolutionary past. Technological advances not only assist with field discovery, but in the evaluation of existing evidence using new methodologies. Although light is continually being shed on previous archaeological finds and theoretical assumptions, new field discoveries continue to reveal additional puzzles for which anthropologists have no answers.
The Case Study sections below provide details of field discovery, chronology, and a evolutionary evidence from five major archaeological groupings: 1) Pliocene Pongid Ancestors; 2) Australopithecus; 3) Java Man; 4) Pekin Man; 5) Neanderthals; and 6) Modern Man.
1) Pliocene Pongid Ancestors
Hammond (1964) reports it has taken approximately two million years for humans to become “human.” The actual date of transition from “ape to man” is unknown, but Hammond reports several lines of evidence under consideration in the early 1960’s pointed to Africa as the site of human origin. However, Hammond (1964, p. 67) notes if the similarities between humans and apes indicate a common ancestry, then “the problem arises as to how such a generalized ape could have adapted to the bipedal, carnivorous ecological niche which the early hominids appear to have occupied and which distinguishes them sharply from all known apes.”
Basic assumptions for an evolutionary break resulting in development of an early pongid ancestor potentially required geographic isolation, speciation, and ecological divergence of an early ape population from its neighbors (Hammond 1964). Fossil evidence available to Hammond (1964) shows that the bone structure of pre-australopithecines or other early hominines indicates a possible transition from an ape origin (e.g. reduction in jaw size from Dryopithecines through Gigantopithecus). Kelso (1970) notes the essential differentiation between pongids and Hominids as being bipedal with an erect posture; however, as Kelso also notes, this determination remains problematic when determinations are based on teeth and other skull fragments such as the jaw.
A reconsideration of early fossils originally determined to be pongid in nature or that were subsequently discovered and determined to be Hominid in nature include Ramapithecus, Bramapithecus, Sivapithecus, and Paleosimia (Kelso 1970). Kenyapithecus was discovered by Leakey in 1962, and further supports the antiquity of Hominids over what was previously believed (Kelso 1962). Leakey has also found evidence that the Miocene form of Kenyapichacus was tool using; however, Kenyapithacus had not been determined as being unique or as being an African form of Ramapithecus at the time of Kelso’s publication in 1970.
2) Australopithecus
South Africa has provided the majority of pieces to date fitting the human evolutionary puzzle. The first Hominid specimen, labeled as Australopithecus, was discovered by science in the late 1920’s (Hammond 1964). The first skull was of an infant, and many discounted the original find of what few believed to be a primitive human (Brace and Montagu 1979). However, later discovery of adult remains in South Africa renewed scientific interest in Australopithecus (Brace and Montagu 1979).
Hammond (1964) describes Australopithecines as intermediate between earlier small-brained pongids and later large-brained bipedal hominids. By 1964 (Hammond), over 300 specimens from approximately 100 individuals had been found in South Africa. Less than a dozen specimens had also been discovered in East Africa and the Far East (Hammond 1964). Kelso (1970) reports that fossil evidence shows Australopithecus walked erect. Hammond (1964) describes the skull of Australopithecus as follows:
…a dolichocephalic skull with a good hominine shape. A distinct, low forehead is present and the vertex rises well above the level of the brow ridges. The latter are poorly developed and the postorbital constriction is moderately developed. The face is fairly wide, the nasal region is slightly raised above the surrounding level of the face, which is distinctly prognathous. The skull is gracile, without any heavy bone or strong development of ridges or crests. The mandible is robust with a moderately high ramus and an almost vertical chin region. The dentition is morphologically very similar to that of early hominines.
Birdsell (1972) notes that Australopithecines existed prior to human use of fire, and there is some debate over what methods might have been employed to obtain safety at night in their prehistoric cave shelters. One theory is that cave entrances were blocked at night with barricades of thorny brush much as is still done by some Africans today (Birdsell 1972). Bones of food animals have been found with fossil remains of Australopithecus (Birdsell 1972, p.263) along with fossil evidence also indicating that Australopithecus may have been a “head hunter.” Fossil evidence has also been utilized to deduct hunting methods, including but not limited to hypotheses that Australopithecus was essentially right-handed and may have engaged more often in scavenging than initiating kills of large or dangerous animals. However, this hypothesis is debatable as evidence found at Olduvai Gorge indicates Australopithecus used clubs to kill baboons and also fashioned hunting or defensive “weapons” from antelope bone (Birdsell 1972).
3) Java Man
Java Man is known from fossil remains found in the Djetis beds (Lower or early Middle Pleistocene) and the Trinal beds (Middle Pleistocene) in Java (Hammond 1964). Remains were first discovered by Dubois in the late 1920’s, with continued finds into the 1930’s and beyond (Hammond 1964). Although no tools have been found in strata with Java Man remains, Hammond (1964) reports that Java Man is the earliest specimen of mankind about whom we have any substantial knowledge. Java Man also apparently overlapped with earlier “man-apes” as fossil remains of both have been found together (Hammond 1964). Kelso (1970) notes that although fossil strata are unequal in content, Java Man appears to have preferred warm climates.
Hammond (1964) reports that male and female skulls of Java Man are visibly differentiated. Hammond (1964, p. 87) also reports the following description of Java Man:
This most ancient man was about the same size as ourselves, judging from his thigh bones…His femur shows he walked upright, and his head shows the same, by the position of its base and of the foramen magnum…the neck was stout and strong, with its muscles spread well across and up the back of his skull…The skull itself was tremendously heavy and thick, in contrast to the South African man-apes; and the still-large face and jaw threw the skull forward, much farther off balance than in our own head. The jaws, generous in size, contained the largest teeth yet found in the skull of any kind of “man” (euhominid)…Java Man’s face was fairly projecting, as the above might suggest, although his lower jaw was long, rather than deep, with its more human, smaller, molar teeth.
Birdsell (1972) notes that since the 1930’s, evolutionary theory has been influenced by the emerging science of genetics. Even though Java Man’s skeletal remains were widely scattered and often obtained from strata of a mixed nature (e.g. stream deposits), genetics would have been consistent across the population (Kelso 1970; Birdsell 1972). This allows for the determination from one or more small samples that the original organisms were genetically related.
4) Pekin Man
A fossil tooth was located in a Pekin [also known as Peking] drugstore, drawing the attention of regional paleontologists in 1900 (Hammond 1964; Brace and Montagu 1979). Caves in adjacent regions of China yielded bits of quartz and not known from the limestone host rock (Hammond 1964; Brace and Montagu 1979). Individual teeth were located over several years and the finding of another early hominid species Sinanthropus pekinensis was announced in 1926 based on analysis of the teeth (Hammond 1964). Stone tools were later found and preserved, but the Pekin man remains were lost during the subsequent world war (Hammond 1964; Brace and Montagu 1979).
Hammond (1964) notes that Java Man and Pekin Man [also referred to as Peking Man] were similar, with no skeletal difference but with some differences in neck attachment, teeth development, and brain size. Caves associated with the strata in which Pekin Man remains were found include ash, burned bones, and cooking hearths (Hammond 1964; Brace and Montagu 1979). As Hammond (1964) notes, Pekin Man provides the first solid evidence of human fire use for both warmth and cooking. Characteristic tools of Pekin Man included stone choppers, scrapers, and points; animal bones were also apparently used frequently as tools (Hammond 1964).
5) Neanderthals
The first Neanderthal specimens to receive substantial scientific attention in the Old World were discovered in 1856, three years previous to publication of Darwin’s Origin of Species (Kelso 1970). Initially, Neanderthal remains were viewed as possibly modern remains evidencing some type of physical anomaly such as some type of a bone disease that might explain the heavy structure (Kelso 1970). However, as with modern man, there was found to be considerable difference among various Neanderthal specimens (Kelso 1970).
Hammond (1964) notes that controversy surrounded the identity and order of human predecessors in the Middle and Upper Pleistocene. Hammond (1964) also states that although views were obviously changing, many felt Neanderthal man “too brutish to deserve a position of prominence on our family tree.” Some of the controversy stemmed from the accepted ideas at the time of Neanderthal discovery in the late 1800’s that 1) modern man already existed at the same time as the Neanderthals; and 2) the sudden replacement of Mousterian era populations by Upper Paleolithic populations believed to have developed culturally in prior locations (Hammond 1964).
Eckhardt (1979, p. 535-536) describes the quandary of Neanderthal populations in relation to other hominids and more modern man as follows:
From the standpoint of human evolution, the most important disagreement is over the role of Neanderthals…were they direct ancestors that lived all over the Old World for a time, local variants that interbred to a limited extent with more modern-looking contemporaries, or an extinct side branch that contributed no alleles to our gene pools? Because of the controversies surrounding the place of the Neanderthals in hominid evolution, the small sample of their Mindel-Riss and Riss predecessors takes on an importance that may be out of all proportion to its actual size.
Homo sapiens presents the “structural level achieved by the most advanced human populations” (Birdsell 1972, p. 280). This classification was initially reserved for living humans and the most immediate fossil ancestors that were indistinguishable from “modern” human populations (Birdsell 1972). Definitions of what constituted modern man were substantially revised when Neanderthals were moved from the classification of Homo erectus and placed within Homo sapiens. Birdsell (1972, p. 280) reports that the morphological definition of Homo sapiens had to be altered from “small-faced populations” to include “large-faced populations” and “very large brow ridges as well as moderate ones” upon inclusion of Neanderthals. Brace and Montagu (1977) remind us that the bone structure of the face provided the only readily perceptible difference between the Neanderthal and what was commonly referred to as modern man.
Birdsell (1972) notes that at the first level of abstraction, populations of Homo sapiens appeared first in Europe, dominating the Middle Pleistocene. Until approximately 40,000 years ago, following retreat of the Würm ice advance, all European fossil remains are Neanderthal in form (Birdsell 1972). Although a stooping, head-thrusting posture has been popularized for the Neanderthal, this race of Homo sapiens is believed to have been fully erect and is also believed to have walked with an essentially normal gait (Birdsell 1972). Although their disappearance remains a mystery, Neanderthals disappeared from Europe following the end of the first portion of the complex Würm glaciations (Birdsell 1972).
Bones of classic Neanderthals, when accompanied in the strata by stone tools, the industry group is classified as Mousterian (Birdsell 1972). Pointed stone flakes that appear to have served as spearheads, along with scrapers, notched and denticulate flakes, hand axes, and small engraving or boring tools have been found in association with Mousterian groups (Birdsell 1972). Cave living became systematic for Neanderthals with advancing ice sheets, and are routinely found with evidences of charcoal from fires in constructed hearths apparently used for both heat and cooking (Birdsell 1972).
Additional archaeological evidence indicates hides may have been hung on posts to form shelter doorways (Birdsell 1972). The discovery of bone needles indicates that tailoring of fur clothing was likely, as severe climatic conditions necessitated “sophisticated clothing” (Birdsell 1972). Based on archaeological evidence such as the remains of spears, Neanderthals were capable of killing large forms of prey, including extinct forms of big game such as Irish elk, bison, and cave bears (Birdsell 1972).
6) Modern Man
Upper Paleolithic cultures that proceed the Neanderthals in Europe remain much of a mystery, but still represent the earliest known “white” race of the region (Birdsell 1972). Emerging around 25,000 years ago, these populations are indistinguishable in skeletal morphology from living Europeans (Birdsell 1972). Stone artifacts allow archaeologists and anthropologists alike to classify these early modern Europeans into three major Paleolithic cultures: 1) Perigordion and Aurignacean (35,000 to 20,000 years ago,); 2) Solutrean (20,000 to 17,000 years ago, producing more specialized stone tools than previous cultures); and 3) Magdalenian (12,000 to 5,000 years ago, with special techniques for producing stone blades from prepared cores).
Birdsell (1972) reminds us that when examining the evolutionary path of man, we must be cognizant of the fact that some lines have apparently changed faster than others. The physical radiation of modern man actually “requires an acceptance of the hypothesis that evolution does not proceed everywhere at the same speed” (Birdsell 1972). Birdsell (1972, p. 330) further notes that there is no way of knowing what genetic bases provided the “superior fitness” demonstrated by modern populations. While the theory of favorable mutations may explain man’s evolutionary advances, Birdsell (1972) reminds us that there is no hard evidence to date that favorable mutation provides the answer.
One of the intriguing issues in dealing with modern man, including living cultures, is the concept of race. When addressing such a question, biological anthropology and social science must of necessity overlap (Brace and Montagu 1979). According to Brace and Montagu (1979) the concept of race stems largely from observable physical traits. The question of race has been aggravated by the fact that modern Christianity identifies humans as descendants of Adam and Eve; historically pictured by Old World religious art as of European build and fair complexion.
North American’s first biological anthropologist, Stanhope Smith of the College of New Jersey [now Princeton University] undertook an evaluation of the concept of race in 1794-1795 while serving as College President (Brace and Montagu 1979). Like his German counterpart Blumenbach, Smith came to the conclusion that environmental factors were responsible for the development of widely variant racial differences such as skin color, facial form, and body build (Brace and Montagu 1979). Although also coming to a rather Lamarckian conclusion (e.g. the environmental factors were directly responsible for human variation rather than selection of favorable gene variants over time), Smith’s contributions were still remarkable in the fact that he published his theories more than 70 years prior to Darwin’s Origin of Species (Brace and Montagu 1979).
Unfortunately for the field of anthropology, Smith’s work was not well received by his college’s Board of Trustees (Brace and Montagu 1979). Smith was forced to resign his presidency, a fellow chemist hired by Smith was dismissed, and a substantial number of college students were suspended at the time (Brace and Montagu 1979). Brace and Montagu (1979) provide the observation that as of their publication, Princeton University has never had another biological anthropologist on its staff. A similar event took place at a California university more than a century later, when in dismissing their university president, the Board of Regents stated “We cannot afford to subsidize intellectual curiosity” (Brace and Montagu 1979).
The definition of race as presented by Brace and Montagu (1979, p. 389) is that race consists of “A human group, members of which can be identified by the possession of distinctive physical characteristics.” As many acts of inhumanity have been practiced in the name of race, it has been advocated that the term should be abandoned (Brace and Montagu 1979). Montagu suggested that in place of “race” we should be using the term “ethnic group.” Indeed, we now find such terms as ethnicity or ethnic origin being used in most modern U.S. forums in place of the term “race.”
Brace and Montagu (1979, p. 387) remind us:
It is the task of biological anthropologists to further the understanding of human evolution. The investigation and interpretation of the hominid fossil record is clearly one of the ways in which this may be accomplished, but another equally important approach is through the consideration of the biological diversity among the living peoples of the world.
General Discussion
The record of mammalian-primate-human evolution has long been defined by fossil remains, largely in the form of bones and teeth (Birdsell 1972). Stigler and others (1975, p. 11) note, “ To understand the significance of the oldest archaeological evidence, the evolutionary background from which human behavior emerged must by considered.”
Stigler and others (1975) report that following World War II, many new archaeological sites have been excavated around the world. New analytical techniques have also opened new horizons on the past, providing an unprecedented range of information, and foundations for sophisticated theoretical frameworks (Stigler and others p. 1).
There are many facets of human biology and culture that have yet to be adequately explained. Even though the world’s major geographic regions have now been surveyed by a variety of scientists, including anthropologists and archaeologists, new discoveries are constantly being made. As technology increases, not only are physical locations and artifacts being found that previously escaped notice, application of genetics and computer models are revealing new insights into human evolution [biology]. In addition, existing artifacts and other historical records continue to be “re-discovered” or made available for research and renewed analysis with updated methodologies.
Wolpoff and others (1994, p. 176) note that two decades before analysis of mitochondrial DNA [mtDNA] was focused on human origins, a number of “extreme theories about modern human origins had developed within the paleoanthropological community.” These theories were largely based on variations due to genetic exchange and on cultural adaptations almost to the complete exclusion of geographic variation (Wolpoff and others 1994). As Wolpoff and others (1994) note, it is more reasonable today in the light of anthropological advances to include Homo erectus within Homo sapiens as these cannot be separated by cladogenesis or any other distinct or otherwise definitive boundary.
Lewin (1998) notes the origin of modern humanity will continue to serves as the subject of scholarly debate. However, new evidence continues to be discovered. Recent events include but are not limited to the discovery of additional fossils at Atapuerca, Spain, new dating procedures for use with fossils previously discovered in Java, and the ability to now extract DNA from the fossilized bones of the world’s first Neanderthal specimen. Each succeeding discovery assists, and will continue to assist, in shedding further light on the question of where humans originated.
Another question that may well be asked is whether or not human evolution has ceased in the context of the present. Eckhardt (1979, p. 573) notes that as of the end of the Pleistocene “humans had attained the major features of modern physical form.” As Eckhardt (1979, p. 573) queries, “Can we conclude, then, that human biological evolution has ceased?” Some anthropologists feel that culture has become so elaborate in some regions of the world as to essentially preclude the need or mechanism for further physical evolution (Eckhardt 1979). However, an opposite opinion may also be well taken; and as Eckhardt (1979) points out, evolution is a continuous process and future trends are theoretically predictable based on the past.
Evolutionary trends have actually been predicted for some human traits. For example, the modern medical practice of increased numbers of births by cesarean sections allows for successful delivery and survival of large-skulled babies; over 17% of which show signs of superior intellect (Eckhardt 1979). Changes in physical stature are another predicted trend, based on improved nutrition as well as improved medical care in many regions of the world (Eckhardt 1979).
As previously described above, human evolution can be shown to be occurring at a greater rate than in prehistoric times, with many different changes occurring in African, Asian, and European populations. The Associate Press report by (Schmid 2007) calls attention to several important findings reported by Harpending; including but not limited to rapid skeletal and dental evolution in human populations and to the appearance of many new genetic responses to diet and disease.
Conclusion
Physical anthropology represents the branch of archaeology that is responsible for investigating the evolutionary origin and progression of man from past to present. Physical anthropology is not as structurally differentiated as cultural anthropology (Kelso 1970). Kelso (1970) separates physical anthropology into two major subcategories; identifying human paleontology, the investigation of human variability; and human heterography, the investigation of biological variation among living populations. Students of physical anthropology generally have an opportunity to investigate human morphology through study of the fossil record, taxonomy, evolution, genetics, contemporary variation, and adaptation (Kelso 1970).
Regardless of academic specialization, the top question considered by human anthropology is “where did humans originate?” (Nitecki and Nitecki 1994, p. 1). Secondary questions that are more subject to disagreement among scholars include “who they were, and when they appeared” (Nitecki and Nitecki 1994, p. 1). As definitive answers to these questions have not yet been found, the field of physical anthropology continues its pursuit of man’s past (Kelso 1970; Eckhardt 1977; Brace and Montagu 1979; Lewin 1998).
Eckhardt (1979, p. 26) reminds us that evolution was a “revolutionary idea” and was a disturbing concept to many, particularly to those of prominent early religious orders. However, philosophies and early theories based on evolutionary processes appear in recorded history as early as 611 B.C. (Eckhardt 1979). Darwin (1809 to 1882) revived the concept of evolution using a “plausible theory of how natural processes could bring about transformations in organisms as well as in their environment” (Eckhardt 1979, p. 34).
La Barre (1954) observes that “for all its spectacular variety, mankind is obviously a morphological and genetic unity.” Hammond (1964, p. 136) notes “evolution of man is a natural process hat has transcended itself,” and that only when initial life emerged from inorganic matter has there been a comparable event in history. Hammond (1964, p. 136) also notes that genes are the “raw materials” with which natural selection works through mutation and sexual recombination and that these factors have apparently “led to the emergence” of anatomically modern humans or Homo sapiens.
Most anthropologists remain cautious in their work, presenting or at least discussing alternative theories of human evolution rather than boldly espousing a single theory on the basis of incomplete evidence. This is exemplified by the writings of Cann and others (1994, p. 146) who note, “We remain puzzled by exactly what caused the break in the transition from our archaic ancestors to anatomically modern people.” Lewin (1998, p. 130) also similarly notes, “The overall evolutionary pattern of primates remains still unsettled.” Maienschein (1997) observes:
This confusion remains one of the most intriguing aspects of scientific study…the ‘past did in fact, happen, and in only one way.’ Yet scientists disagree about what that one way was. They disagree not just about the conclusions or about which theory or answer they like best. They also disagree about how to go about knowing the answer.
I believe that continued caution by researchers is warranted. The fossil record remains incomplete and much of what becomes accepted as fact is still very theoretical in nature. Many intricate hypotheses as well as all manner of assumptions have been made on very limited physical evidence, such as a single section of jawbone or a few fossil teeth. I also believe that irregardless of whether or not we can ever accurately determine man’s beginning and exact path of evolution, routine study coupled with continued field investigation and analysis of existing fossil remains will not only help answer lingering questions but will help us chart a more productive and responsible future.
Eckhardt (1979, p. 576) provides a fitting conclusion through his observation that “the study of human evolution in the past can supply a guide for the future… Our strategy for the future must be rooted in a knowledge of the complexity of our ties with the rest of the natural world.” I believe that in order to chart a productive future for mankind we must of necessity seek an understanding of our past. We must also come to better understand our shared position on the planet with other species in order to be able to balance potentially competitive or exclusive economic views and cultural values at all levels of human society.
References
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