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...

Diversity patterns the broad picture The current consensus

The 1970s and 1980s witnessed a veritable boom of publications which documented the diversity patterns of life during earth history, the pace of large-scale evolution. Yet the achievements of the late Jack Sepkoski clearly stand above those of all others at that time. His 1981 curve (O Figure 16.2) of Phanerozoic diversity patterns of marine families (and subsequent refinements down to the genus level Sepkoski 1996) is one of the most often reproduced figures in the paleontological literature...

East African Rift Valley

If we look at the geographical distribution of early hominids in Africa, we recognize that many of the famous sites are aligned in a chain along eastern Africa from Ethiopia via Kenya and Tanzania, to Malawi in the southeast. Localities like Hadar, Middle Awash, Omo, Lake Turkana, Olduvai, Laetoli, and others have yielded a great number of hominid specimens during the last 50 years. These sites are positioned in a geological megastructure, the EARV (O Figure 11.1). The EARV extends about 6,400...

Eocene Oligocene transition

In a diagram of Phanerozoic extinction intensities, the Eocene-Oligocene transition period barely stands out as an important event, and yet this time marked the most significant episode since the extinction of the dinosaurs (Prothero 1994). The Eocene was a time of warm temperatures, with widespread tropical forests, archaic mammals, and reptiles occurring above the arctic cyrcle (Prothero 1994 Ivany et al. 2003). Within a time period of 10 Myr, this greenhouse'' world shifted to icehouse,''...

A formal characterization of selectionist explanation and the issue of units of selection

The precise characterization of adaptation has been the focus of a large controversy in biology, and the philosophy of biology, about what exactly is likely to be adapted. Wynne-Edwards (1962) claimed that groups and populations were sometimes adapted. This meant that natural selection worked in favor of groups or populations, which sounds contradictory to the fact that individuals are the entities subsisting and spreading through selection. Williams (1966) gave a forceful defense of selection...

The scope of natural selection

Evolutionary theory puts together the Tree of Life claim, and the Selection principle however, these two statements are not logically connected. We can imagine a possible world where there is selection and not one Tree of Life Lamarckism gives a picture of the opposite possible world. The question then is the relationship between the two claims to what extent is the Tree of Life accountable for by natural selection This question was present but quite attenuated in Darwin since he thought of...

Recognition of paleosols

Paleosols are often distinctive and strikingbands of red clay (Bt horizon), calcareous nodules (Bk horizon), or coal (O horizon) in sedimentary and volcanic sequences (O Figure 13.2). Three general classes of observations are especially helpful in paleosol recognition root traces, soil horizons, and soil texture (Retallack 1997). Kenyan Miocene paleosols have been given field names using local Luo and Turkana languages. These pedotypes are objective field mapping units for paleosols their...

Paleoanthropology and politics three symptomatic events

The misapplication of the Darwinian biological theory known as social Darwinism has been intensively discussed in another context (M hlmann 1968 Zmarzlik 1969 Altner 1981a, b M ller-Hill 1988 Hofstadter 1995 Hawkins 1997 Dickens 2000 Junker 2004 Ho feld 2005b). It is well known that this biological ideology became highly influential after the World War I and especially during the period of National Socialism in Germany. That paleoanthropology was no free zone of research stems from different...

Paleosols as trace fossils of ecosystems

Nyanzapithecus

Australopithecus afarensis is known from body fossils, such as the partial skeleton Lucy (Johanson et al. 1982), as well as from trace fossils, such as the footprints of Laetoli (Leakey and Harris 1987). The soils of A. afarensis also are known, especially at the first family'' site near Hadar, Ethiopia (Radosevich et al. 1992). Here a troop of at least 13 individuals, young and old, died, rotted, and were partially disarticulated, before being interred in flood deposits on a crumb-structured...

The Cambrian radiation and its prelude

The tracking of the appearance and early diversification of the animals in the fossil record (0 Figure 16.6) is at present one of the fields in paleontology where extremely rapid progress is made. New input came especially from molecular Major events during the latest Neoproterozoic and the Cambrian. After Erwin 2001 systematics (Adoutte et al. 2000 Giribet 2002 Pennisi 2003 Halanych 2004 Peterson et al. 2004) and through precise, absolute dating of fossiliferous Late Neoproterozoic and Early...

Devonian to Carboniferous expansion of land flora

The earliest vascular land plants are known from Late Silurian strata. Colonization of the terrestrial environment, at least in moist lowlands, obviously happened rather quickly, and within only 45 Ma, all major land-plant lineages and organizational grades (except for flowering plants) developed (Niklas 1997, 2004 Willis and McElwain 2002). All the morphological adaptations including a protective outer covering (waxy cuticula) against desiccation, stomata to allow gas diffusion, specialized...

Luminescence

Since its introduction by Daniels et al. (1953) luminescence dating has gradually developed into a powerful chronometric technique, particularly for quartz- and feldspar-bearing materials (Aitken 1985, 1998). In the meantime, luminescence dating has significantly contributed to paleoanthropology. As to the techniques of luminescence dating, one distinguishes between thermoluminescence (TL) and optically stimulated luminescence (OSL). For the latter, the term optical dating'' is also used....

Bolks fetalization hypothesis its successors and critics

Fetal Cranial Development

Forever young Many contributions have emphasized the relevance of phylo-genetic conclusions from ontogenetic information (Minugh-Purvis and McNamara 2002). One of the most influential books on developmental change and (human) evolution is Stephen Jay Gould's Ontogeny and Phylogeny (1977). Tuttle's (1978 p 287) review of this book was not rhapsodic Perhaps the author attempted too much in this chubby volume Time will tell whether it is in fact a hemicentennial classic as implied on the dust...

Heterochrony in human evolution a compilation

Repetitio est mater studiorum or as Schwartz (1999 p ix) commented '' it would be foolhardy to cling unreservedly to a particular set of models and hypotheses without at least occasionally questioning their very bases.'' In Sudden Origins, Schwartz reconsidered and discussed inter alia the different interpretation of the Taung child. While Raymond Dart was influenced by ideas of neoteny and concluded that his fossil occupied a missing link-position, Sir Arthur Keith drew a totally different...

Electron spin resonance

Electron spin resonance (ESR) dating is also based on the accumulation of radiation-induced energy in minerals and thus has close links to luminescence dating. Although first attempts to exploit the ESR phenomenon for dating go back to the 1960s (Zeller et al. 1967), as a dating method it did not flourish before the 1980s and is still being developed. The ESR method permits age determination up to few million years, far beyond the range of the luminescence methods, and covers the whole...

Fossils hypotheses controversies and approaches

In the early beginning of paleoanthropology the main question was quite simple is there a fossil record which proves the existence of our ancestors from ancient times The protagonists of paleoanthropology soon recognized the need for a sophisticated empirical approach. The best basis for such a development existed in France, where Pierre Marcelin Boule (1861-1942), a qualified geologist, paleontologist, and archeologist, unified in persona all necessary attributes to establish a...

Taxic versus the transformational approach to homology

The phylogenetic literature that deals with species, taxa, as well as with homologs, is replete with dismissals of taxa, or homologs, as natural kinds, for these are considered abstract entities, like sets, or classes (Hull 1999). The same is true of properties (attributes), which are dismissed as universals that cannot be instantiated by evolutionary entities (Grant and Kluge 2004). Hey (2001 p 153) for example dismisses property cluster kinds as polythetic classes, where a polythetic class is...

Historical Overview of Paleoanthropological Research

This chapter provides a comprehensive scientific historical overview on paleoanthropology as a multifaceted biological discipline. A terse compendium on pre-Darwinian theories of evolution is followed by a historical report of the paradigmatic change by Darwin's perspective on life processes from a teleological to a teleonomic view. Focusing on the fossil discoveries in Europe and later on in Asia and Africa and the different methodological approaches, it becomes obvious that as opposed to...

Info

Fortunately, sediments sometimes contain biological factors, faunal and floral remains, in different stages of preservation. The appearance of animal remains in a sedimentary matrix depends on its so-called taphonomic history. The taphonomy (Efremov 1940) includes the two processes, biostratinomy and diagenesis, that describe the pathway from a carcass to a fossil. Biostratinomy (Weigelt 1927) deals with everything that happens to a carcass after an animal's death, before the...

Zoogeography of African Pliocene Hominini

Whether or not the common ancestor of later Hominidae was indeed of Eurasian dryopithecine-like morphology and origin, our African ancestors and relatives changed from being generalized apes to more sophisticated apes with tools over a period of a few million years, only becoming really recognizably human with the earliest appearance of the H. erectus lineage at around 1.8 Ma. This transition included shifts to an upright stance and fully bipedal walking and a massive increase in relative and...

Methods for the study of paleosols

Just as soil individuals pedons are studied as soil columns in soil pits, paleosols are studied in columnar stratigraphic sections of the sort also used in sedimen-tology and stratigraphy O Figure 13.3 . Grain size is emphasized because it is important to soil formation, as weathering transforms sand and silt grains to clay. A graphical representation of grain size profiles conveys important information on the abruptness of horizon transitions. Color from a Munsell chart should also be...

References

Andrews P, Van Couvering JAH 1975 Palaeo-environments in the East African Miocene. In Szalay FS ed Approaches to primate paleobiology. S Karger, New York, pp 62-103 Andrews P 1996 Paleoecology and hominid palaeoenvironments. Biol Rev 71 257-300 Anhuf D, Frankenberg P, Lauer W 1999 Die postglaziale Warmphase vor 8000 Jahren. Eine Vegetationsrekonstruction fur Afrika. Geograph Rund 51 454-461 Bancroft H 1932 A fossil cyatheoid stem from Mount Elgon, East Africa. New Phytol 33 241-253 Bancroft H...

Geological Background of Early Hominid Sites in Africa

Hominid remains are rare elements in the fossil record. Probably the small population sizes of early hominids, in combination with preservation constraints, limit the probability of a higher frequency of fossil discoveries. The early evolution of mankind appears to be a Pan-African story, even though the distribution pattern of remains concentrates on eastern and southern Africa. More recent findings from the Chad Basin in central Africa demonstrate that fossil hominid remains are not...

Arabia

In contrast, the possibility of hominin dispersions through the Arabian Peninsula and the Levant, either across the Sinai Peninsula or the Bab-el-Mandeb Straits at the south of the Red Sea, is indicated by the mixed Afro-Eurasian nature of the fauna of the region since the later part of the Pliocene and in particular by the Early Pleistocene deposits at 'Ubeidiya in Israel Tchernov 1992 Turner 1999b Belmaker et al. 2002 . Late Pliocene African elements, chiefly bovids and giraffids, are known...

Basis of stable isotope tools

The stable light isotopes of principal interest as environmental proxies are the isotopes of hydrogen, carbon, nitrogen, and oxygen. In all cases, the chemistry of the different isotopes of an element remains the same as chemical properties are controlled by electron configuration. Among these light isotopes, the mass difference owing to one or two extra neutrons is sufficient to cause a small, but predictable, difference in the rates of chemical reactions or physical processes. If the starting...

Epistemological parsimony The Wagner algorithm

In September 1965 two articles on phylogeny and parsimony appeared. Wilson 1965 introduced a consistency test for phylogenies based on contemporaneous species.'' His null hypothesis was that all characters that are used for a phyloge-netic analysis are unique and unreversed. In order to pass Wilson's consistency test, the taxa defined by these characters must be nested and these nested conditions must persist as new species are added to the tree. Colless 1966 was concerned that more than one...

Taxonomy and classification without phylogeny an outdated remnant or a practical necessity

There is an increasing shift in taxonomy toward modifying the directives on how to name organisms to reflect genealogical relationships. However, despite the fact that most systematists would agree that the hierarchical system of names in biology should be governed by phylogenetic hypotheses instead of by intuitive similarity, the increasing pressure of phylogenetic demands on the naming processes results in intrinsic conflicts in systematics. Phylogenetic analyses have not been conducted for...

Paleosols as proxies of paleoprecipitation

Climatic zonation of soils was a key element in the Russian origins of soil science Jenny 1941 , and a variety of relationships between particular soil features and climatic variables can be applied to East African paleosols in order to reconstruct Carbon isotopic S13Corg depth profiles of Kenyan Miocene pedotypes, showing strong surface humification in grassland paleosols Chogo and Onuria pedotypes , subsurface humification in Alfisols Tut and mixing in vertic Inceptisols Chido . Carbon...

Embryological data and its phylogenetic implications

It is now more than a century since embryological studies the Reichert-Gaupp theory, refuted by Otto 1984 demonstrated the homology of the mammalian malleus and incus with the articular and quadrate bones which formed the ancestral jaw joint of gnathostomes. This tremendous transition can be traced in fossils by comparing basal synapsids through therapsids to early mammals. A fetal mammal shows that the angular tympanic , articular malleus , and quadrate incus develop in the same positions they...

Karl Ernst von Baer and Gallus domesticus the beginnings of comparative embryology

Nineteenth-century comparative embryology lies at the origin of evolutionary developmental biology or, more briefly, evo-devo. Von Baer's and Haeckel's works are the most popular examples of that period, and these authors' laws describing the general development of organismic form are of great interest. Karl Ernst von Baer, a pupil of Ignatius Dollinger, a professor at Wiirzburg, is known as the founder of embryology as a scientific endeavor. Although representatives of German transcendentalism...

Von Baer and Haeckeloutmoded

The fancy term evo-devo biology represents an emerging field Gould 2002 Carroll 2005 that has been specially featured in semi-popular journals such as PNAS 2000 or Nature 2003 . It refers to the quest by evolutionary biologists to understand how organisms change shape and form. Hall 2002 p 8 explained that evolutionary developmental biology is more than a name for an emerging subfield of biology. It is a reflection of a level of analysis, synthesis, and understanding not possible through the...

Postcranial ontogenetic data and the origin of primates

Stafford and Thorington 1998 and Hamrick 2001 presented important data on the hand proportions in developing and adult mammals. Using a ternary plot Hamrick 2001 , relative metacarpal, proximal, and intermediate phalanx lengths among fossil and extant taxa deliver an elegant possibility of distinguishing primates from other archontan mammals. Primates differ from flying and gliding mammals in having much longer proximal phalanges relative to their metacarpals and are unique among the sampled...