VI. Earth Life Emergence: Development of Body, Brain, Selves and Societies
8. Multiple Ancestries of Homo Sapiens
Evolutionary schemes and complex system perspectives are also being employed by the fields of primate studies, archaeology and anthropology to better explain how simians became hominids and social humans. This multiplex emergence is considered to occur through a co-evolution of increasing brain size, dexterous tool making and especially social interactions facilitated by novel language abilities. These diverse citations report reconstructions of the meandering, interlinked pathway. No longer a linear march to homo sapiens, it is replete with branching and interbreeding. Who then is late collaborative humankind to finally commence on this retrospective? What is a self-revealing genesis universe trying to learn and achieve through our phenomenal education, witness and co-creation?
, . Neanderthal Code. http://channel.nationalgeographic.com/episode/neanderthal-code-3228. A two hour program first shown on the National Geographic Channel on September 21, 2009 which along with a well done scientific dramatization makes a revolutionary claim. Until now the Neanderthal race was thought to have gone extinct under pressures from smarter, more linguistic Cro Magnon, “modern man” peoples. Neanderthals were thus relegated as inferior and not ancestral. But now recent DNA sequencings from Neanderthal bones can be compared with homo sapiens DNA, and since the two hominids could interbreed, we 21st century human folks really ought to consider ourselves as a hybrid. For example, a FoxP2 “language gene” thought to be unique to us, is also found in the Neanderthal genome. A main commentator and authority is Erik Trinkaus, who with Ian Tattersall and others present a fascinating case that rather than lineages dying off, in fact they may often meld into each other and form such a synthesis.
Ackermann, Rebecca, et al. The Hybrid Origin of “Modern” Humans. Evolutionary Biology. Online October, 2015. University of Cape Town, RSA and University of Georgia, USA archeologists and geneticists advise that based on the latest genomic findings the many hominid lineages actually engaged in ubiquitous interbreeding. Rather than a distinct genera, homo sapiens arises from and expresses a diverse genetic exchange between earlier species.
Anton, Susan, et al. Evolution of Early Homo: An Integrated Biological Perspective. Science. 345/45, 2014. Senior anthropologists Anton, Center for the Study of Human Origins, NYU, Richard Potts, Human Origins Program, Smithsonian Institution, and Leslie Aiello, Wenner-Gren Foundation, provide a synoptic update based on a confluence of fossil findings, instrumental abilities, and holistic vistas as our primate and hominid ancestry project becomes ever more filled in.
Until recently, the evolution of the genus Homo has been interpreted in the context of the onset of African aridity and the expansion of open grasslands. Homo erectus was considered to be a bona fide member of the genus Homo, but opinions diverged on the generic status of earlier, more fragmentary fossils traditionally attributed to Homo habilis and Homo rudolfensis. Arguments about generic status of these taxa rested on inferred similarities and differences in adaptive plateau. However, there was near-universal agreement that the open-country suite of features inferred for Homo erectus had evolved together and provided the adaptations for dispersal beyond Africa. These features foreshadowed those of more recent Homo sapiens and included large, linear bodies, elongated legs, large brain sizes, reduced sexual dimorphism, increased carnivory, and unique life history traits (e.g., extended ontogeny and longevity) as well as toolmaking and increased social cooperation. (Abstract)
Atkinson, Quentin. Phonemic Diversity Supports a Serial Founder Effect Model of Language Expansion from Africa. Science. 332/346, 2011. “Clinal,” from the quote, means “a gradual change in a trait or in the frequency of a trait within a species over a geographical area.” By clever, peer-approved, insights, a University of Auckland cognitive anthropologist finds that changes in human genomes as peoples migrated out of Africa to populate the earth are quite paralleled by linguistic diversities along the way. And circa 2011, we wonder Whom now looks back over this fantastic voyage, able to quantify gene and word, unto what great realization and purpose.
Human genetic and phenotypic diversity declines with distance from Africa, as predicted by a serial founder effect in which successive population bottlenecks during range expansion progressively reduce diversity, underpinning support for an African origin of modern humans. Recent work suggests that a similar founder effect may operate on human culture and language. Here I show that the number of phonemes used in a global sample of 504 languages is also clinal and fits a serial founder–effect model of expansion from an inferred origin in Africa. This result, which is not explained by more recent demographic history, local language diversity, or statistical non-independence within language families, points to parallel mechanisms shaping genetic and linguistic diversity and supports an African origin of modern human languages. (Abstract, 346)
Avise, John and Francisco Ayala. In the Light of Evolution IV: The Human Condition. Proceedings of the National Academy of Sciences. 107/Supplement 2, 2010. An Introduction to papers from a Sackler Colloquium on the latest reconstructions of pathways from primates to hominids to homo sapiens. A distinguished array includes “Gene-Culture Coevolution in the Age of Genomics” by Peter Richerson, Robert Boyd and Joseph Henrich; “Bioenergetics, the Origins of Complexity, and the Ascent of Man” by Douglas Wallace; and “Working Toward a Synthesis of Archaeological, Linguistic, and Genetic Data for Inferring African Population History” by Laura Scheinfeldt, Sameer Sol and Sarah Tishkoff.
Axtell, R., et al. Population Growth and Collapse in a Multiagent Model of the Kayenta Anasazi in Long House Valley. Proceedings of the National Academy of Sciences. 99/7275, 2002. The reconstruction of the social morphology and dynamics of an ancient culture by means of complex systems principles.
Our model closely reproduces important spatial and demographic features of the Anasazi in Long House Valley from about A.D. 800 to 1300. To “explain” an observed spatiotemporal history is to specify agents that generate - or grow - this history. By this criterion, our strictly environmental account of the evolution of this society during this period goes a long way toward explaining this history. (7278)
Barras, Colin. Losing the Plot. New Scientist. August 26, 2017. A news report about how recent fossil finds along with novel abilities to reconstruct ancient genomes is changing and erasing the olden branching diagrams of hominid speciation. In their place, new evidence of extensive interbreedings, e.g. Neanderthal and Cro Magnon, reveal much more blended pathways.
Barrett, Louise and Peter Henzi. The Social Nature of Primate Cognition. Proceedings of the Royal Society B. 272/1865, 2005. Over the past decade, a “social brain hypothesis” has come to the fore whereof cerebral enlargement in primates was most driven by communal demands, especially the need for Machiavellian deception and exploitation. The authors here argue that this view is to narrow and other factors such as behavioral coordination and tolerance are equally important. Drawing on advances in evolutionary economics, cognitive science and neurophysiology, a more general theoretical framework is then proposed to include notions of embodied and distributed cognition, namely “thinking as a group.”
Bentley, Alexander and Herbert Maschner, eds. Complex Systems and Archaeology. Salt Lake City: University of Utah Press, 2003. As noted in this section’s introduction, after expanding the study of prehistoric and early human habitation into an evolutionary basis, scholars are now realizing that complexity principles are equally at work. This work explores aspects such as scale-free networks, agent-based modeling, power law distributions, and self-organization, all of which seems in need of a common terminology and synthesis.
Bentley, Alexander and Stephen Shennan. Cultural Transmission and Stochastic Network Growth. American Antiquity. 68/3, 2003. A long article that studies how nonlinear science can apply to and explain, for example, the development of Neolithic cultures in central Europe. Elemental nodes are households whose dynamic interaction can be evaluated through changing pottery design motifs. In our website perspective, the universal principles are likewise at work in humankind’s emergence.
Boehm, Christopher. Interactions of Culture and Natural Selection among Pleistocene Hunters. Levinson, Stephen and Pierre Jaisson, eds. Evolution and Culture. Cambridge: MIT Press, 2005. On the initial occasion of an egalitarian social morality by a precarious meld of altruistic tendencies along with punitive sanction and positive reward. Upon reflection, from an organically developing universe arises a natural ethics that might finally leaven and guide an increasingly complex, yet quite violent world civilization.
Boughner, Julia, and Campbell Rolian, eds. Developmental Approaches to Human Evolution. Hoboken, NJ: Wiley-Blackwell, 2016. Wherein the evo-devo reunion is expanded to a vital, consequent “anthropo” phase. A Foreword by Gunter Wagner is followed by chapters such as Chondrocranial Growth, Developmental Integration and Evolvability in the Human Skull by Neus Martinez-Abadias, et al, Origin, Development, and Evolution of Primate Muscles by Rui Diogo and Bernard Wood, Evolving the Developmental Cortex by Christine Charvet and Barbara Finlay (search), and Growing Up Fast, Maturing Slowly: The Evolution of a Uniquely Modern Human Pattern of Brain Development by Philipp Gunz. The Evolutionary Biology of Human Neurodevelopment: Evo-Neuro-Devo Comes of Age by Bernard Crespi (search) and Emma Leach goes on to report how the quality of neural connectivity affect one’s mental state whence autism is due to not enough while schizophrenics have too many.
Developmental Approaches to Human Evolution encapsulates the current state of evolutionary developmental anthropology. This emerging scientific field applies tools and approaches from modern developmental biology to understand the role of genetic and developmental processes in driving morphological and cognitive evolution in humans, non-human primates and in the laboratory organisms used to model these changes.