DOCSLIB.ORG

Technology and Human Brain Evolution

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Technology and Human Brain Evolution Volume 15, Number 2 Bulletin of the General Anthropology Division Fall , 2008 ated by the recognition that primate eco- Successful Teaching Tools and Brain Size logical and technological adaptations are socially learned, and that multiple inter- Cultivating the Teaching Technology and Human Brain acting causes and constraints will need Moment Evolution to be considered in any full explanation of human brain evolution. In short, tech- By Elizabeth Chin* By Dietrich Stout nology is social, and the early specula- Occidental College University College London tions of Darwin and Engels continue to eaching, for me, is fundamentally Mastery over nature began with look remarkably current. about facilitating an atmosphere the development of the hand, with Tin which students are able to labour…the development of labour The earliest direct evidence of homi- learn, and creating opportunities for all necessarily helped to bring the mem- nid technological activity, and thus social of us to broaden our understanding of bers of society closer together by in- interaction, comes from stone tools and what learning is and how it can be ac- creasing cases of mutual support and cut-marked bones dating back as much complished. Because my classroom is a joint activity, and by making clear the as 2.6 million years at Gona (Ethiopia). space in which learning is collaborative advantage of joint activity to each in- The ensuing ~2.4 million years of the Lower Paleolithic witnessed a technologi- and processual as opposed to authori- dividual. In short, men in the making cal progression from simple ‘Oldowan’ tarian and outcome oriented, students arrived at the point where they had stone chips to skillfully shaped something to say to each other—first often have to rethink many of their as- ‘Acheulean’ bifacial cutting tools, accom- labour, after it and then with it speech sumptions about knowledge and learn- panied by a nearly threefold increase in ing, teaching and education. I want stu- —these are the two most essential hominid brain size from the top end of dents to learn how to learn, to come away stimuli under the influence of which the ape range to the bottom end of the from their learning experiences with the the brain of the ape gradually modern human range. This coincidence ability to apply their problem-solving, changed into that of man. of two of the most striking trends in hu- man evolution certainly suggests a rela- Frederick Engels Teaching continued on page 5 tionship, but is it one of cause, conse- The Part Played by Labour in the quence, or mere corollary with other, Transition from Ape to Man 1883 In This Issue more fundamental factors? To address such questions, we need to know exactly ool-use and tool-making have long what it is we are trying to explain about Chin on Page 1 been seen as “prime movers” in the modern human brain. Teaching Strategies T a uniquely human evolutionary package linking bipedalism, dexterous The brain: what needs to be Stout on hands, articulate language, culture, and explained? Brain Development and Page 1 a large brain (Darwin 1871, Holloway Technology 1969, Washburn 1960). The 1980s and veryone knows that human brains 90s saw a major reappraisal of this or- Eare “big,” but what does this actu- Paleoanthropology Page 8 thodoxy, with influential “Machiavellian ally mean? Whales and elephants have Intelligence” (Byrne and Whiten 1988) absolutely larger brains and mice have Film and Video Page 11 and “Social Brain” (Dunbar 1998) hy- relatively larger brains, yet few people potheses explaining large brains as a re- want to conclude that these animals are Useful Ethnographies Page 14 sponse to the demands of group living more intelligent than us. Actually, the re- rather than ecological or technological lationship between brain and body pressures. In the past decade, however, changes systematically with size (is “al- this sharp distinction has been moder- Brain continued on page 2 Brain continued from page 1 in many studies to correlate with mam- shifts in developmental timing. On the lometric”), and this fact has been used malian social group size and/or complex- other hand, selection may sometimes to develop measures of brain size that ity. have acted more directly on particular do put humans on top. For example, brain functions, in which case one would Harry Jerison’s famous Encephalization Such allometric approaches provide expect a more “mosaic” pattern of spe- Quotient (EQ) compares observed brain a neat solution to the problem of com- cific structural, micro-structural and even size with expected brain size as predicted paring brains, but there may still be a molecular adaptations. It is likely that from an allometric (slope=0.67) regres- problem with simply factoring absolute both kinds of processes helped to shape sion of brain size on body size. Another size out of the equation. As Terrence the modern human brain. method is to compare the size of differ- Deacon (1997) has emphasized, larger ent structures within the brain, based on animals live in a larger world. Because In some respects the human brain is the idea that some parts of the brain are they tend to live longer and encounter just what you might expect from a large concerned mostly with bodily regulation more environmental variability, larger bodied, long-lived, omnivorous primate. (e.g. brainstem) while others are more animal have both the motive and the op- It is large in relation to other primate “cognitive” (e.g. neocortex). The clas- portunity to rely on flexible learned be- brains, has a relatively large neocortex, sic example of this is Robin Dunbar’s haviors instead of hard-wired instincts. takes a long time to develop, and sup- Neocortex Ratio, which has been found Larger brains must also be organized dif- ports some pretty complex socio-eco- ferently from small brains. Geometrically logical behaviors. Much the same might General increasing numbers of potential connec- be said of omnivorous pigs and bears in Anthropology tions and distances between neurons relation to their more specialized rela- pose communication problems that re- tives. Increased body size and the tran- quire new integrative solutions—includ- sition to a more diverse, higher quality Editors David McCurdy ing the kind of flexible associative diet probably does a lot to explain the Patricia C. Rice mechanisms commonly thought of as “in- rapid increase in hominid brain size seen Conrad Kottak telligent.” So perhaps we shouldn’t be over the past 2 million years. However, Column Editors too surprised that gorillas seem smarter humans have carried these trends to Constance P. deRoche than capuchin monkeys despite having extremes well beyond allometric expec- Lede Pedersen lower EQs. Within primates at least, tations, and also display some very in- General Anthropology ISSN 1537-1727 is pub- there is growing evidence that absolute teresting “mosaic” types of adaptations lished semiannually by the Gerneral Anthropol- brain size is a better predictor of cogni- (Rilling 2006, Sherwood, Subiaul, and ogy Division of the American Anthropological Association. © 2008 by the American Anthro- tive ability than EQ or Neocortex Ratio Zawidzki 2008). Of particular note are: pological Association. All Rights Reserved.The (Deaner et al. 2007). 1) disproportionate expansion of higher- goal of General Anthropology is to provide use- ful, timely, and readable information and ideas order parietal, temporal, and prefrontal from the four fields of anthropology and ap- But this still leaves us wondering why association cortices, 2) increased asym- plied anthropology. All requests for reprints and whales and elephants aren’t more intel- metry between left and right hemi- copyright permission should be sent to journalsrights@oxon. blackwellpublishing. com ligent than humans (at least according spheres, 3) increased connectivity of or by mail: Wiley-Blackwell Permissions Con- to our standards). Obviously size isn’t temporal and frontal lobes, and 4) troller, Blackwell Publishing Ltd., PO Box 805 everything, and the answer may have changes in the histology of occipital vi- 9600 Garsington Road, Oxford OX4 2ZG, United Kingdom something to do the greater density of sual cortex and medial prefrontal cor- cortical neurons in humans and the rela- tex. In a development that would sur- Correspondence should be sent to David tively high conduction velocity of primate prise Darwin and Engels not at all, these McCurdy, 1731 Princeton Avenue, St. Paul, MN, 55105, (651) 698-8492, Fax (651) 696-6324, cortical fibers (Roth and Dicke 2005). human neural specializations correspond e-mail [email protected]; or Patricia Brain size alone may be useful as a rough pretty closely to distinctive human tech- Rice, Dep Soc & Anth, West Virginia U, index of cognitive ability, but it is also nological, linguistic, and cultural capaci- Morgantown, WV 26506, (304) 293-5801, Fax (304) 293-5994, e-mail [email protected]. important to consider how and why par- ties. Conrad Kottak, 3742 Johns island, SC 29455, ticular brains got big. In many cases brain [email protected] size increases might be a product of se- Technology, language and culture Publications Board lection on body size, life history variables, Eric Lassiter [email protected] or perhaps a generalized “information y 2.6 million years ago, hominids had Celeste Ray [email protected] processing capacity.” From this one Bbegun to make simple stone cutting Emily Schultz [email protected] tools that were most likely used to process Tad Schurr [email protected] would expect a predictable pattern of Susan Sutton [email protected] allometric increase throughout the whole animal carcasses and access meat. brain, most likely produced by simple Although these tools were simple, they Page 2 General Anthropology were skillfully made. Experiments have visual field and the perception of the Linguistic communication is itself is shown that modern apes (bonobos) can three-dimensional form from relative a very complex activity that involves indeed fracture stone to make sharp cut- motion cues, and may be newly evolved many different parts of the brain, but ting edges, but that ten years of practice in humans.
Load more

Recommended publications
  • COVID-19 and Human Rights: We Are All in This Together
    COVID-19 and Human Rights We are all in this together APRIL 2020 Human rights are critical – for the response and the recovery They put people at the centre and produce better outcomes Human rights are key in shaping the pandemic response, both for the public health emergency and the broader impact on people’s lives and livelihoods. Human rights put people centre-stage. Responses that are shaped by and respect human rights result in better outcomes in beating the pandemic, ensuring healthcare for everyone and preserving human dignity. But they also focus our attention on who is suffering most, why, and what can be done about it. They prepare the ground now for emerging from this crisis with more equitable and sustainable societies, development and peace. Why are human rights equip States and whole societies to respond to so important to the threats and crises in a way that puts people at the centre. Observing the crisis and its impact COVID-19 response? through a human rights lens puts a focus on how it is affecting people on the ground, partic- The world is facing an unprecedented crisis. ularly the most vulnerable among us, and what At its core is a global public health emer- can be done about it now, and in the long term. gency on a scale not seen for a century, Although this paper presents recommenda- requiring a global response with far-reaching tions, it is worth underlining that human rights consequences for our economic, social and are obligations which States must abide by. political lives.
    [Show full text]
  • The Natural Science Underlying Big History
    Review Article [Accepted for publication: The Scientific World Journal, v2014, 41 pages, article ID 384912; printed in June 2014 http://dx.doi.org/10.1155/2014/384912] The Natural Science Underlying Big History Eric J. Chaisson Harvard-Smithsonian Center for Astrophysics Harvard University, Cambridge, Massachusetts 02138 USA [email protected] Abstract Nature’s many varied complex systems—including galaxies, stars, planets, life, and society—are islands of order within the increasingly disordered Universe. All organized systems are subject to physical, biological or cultural evolution, which together comprise the grander interdisciplinary subject of cosmic evolution. A wealth of observational data supports the hypothesis that increasingly complex systems evolve unceasingly, uncaringly, and unpredictably from big bang to humankind. This is global history greatly extended, big history with a scientific basis, and natural history broadly portrayed across ~14 billion years of time. Human beings and our cultural inventions are not special, unique, or apart from Nature; rather, we are an integral part of a universal evolutionary process connecting all such complex systems throughout space and time. Such evolution writ large has significant potential to unify the natural sciences into a holistic understanding of who we are and whence we came. No new science (beyond frontier, non-equilibrium thermodynamics) is needed to describe cosmic evolution’s major milestones at a deep and empirical level. Quantitative models and experimental tests imply that a remarkable simplicity underlies the emergence and growth of complexity for a wide spectrum of known and diverse systems. Energy is a principal facilitator of the rising complexity of ordered systems within the expanding Universe; energy flows are as central to life and society as they are to stars and galaxies.
    [Show full text]
  • Microremains from El Miron Cave Human Dental Calculus Suggest A
    Journal of Archaeological Science 60 (2015) 39e46 Contents lists available at ScienceDirect Journal of Archaeological Science journal homepage: http://www.elsevier.com/locate/jas Microremains from El Miron Cave human dental calculus suggest a mixed planteanimal subsistence economy during the Magdalenian in Northern Iberia * Robert C. Power a, , Domingo C. Salazar-García b, c, d, e, Lawrence G. Straus f, g, Manuel R. Gonzalez Morales g, Amanda G. Henry a a Research Group on Plant Foods in Hominin Dietary Ecology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany b Department of Archaeology, University of Cape Town, Cape Town, South Africa c Departament de Prehistoria i Arqueologia, Universitat de Valencia, Valencia, Spain d Aix Marseille Universite, CNRS, Ministere de la culture et de la communication, LAMPEA UMR 7269, 13090 Aix-en-Provence, France e Department of Human Evolution, Max-Planck Institute for Evolutionary Anthropology, Leipzig, Germany f Department of Anthropology, University of New Mexico, Albuquerque, NM, USA g Instituto Internacional de Investigaciones Prehistoricas de Cantabria, Universidad de Cantabria, Santander, Spain article info abstract Article history: Despite more than a century of detailed investigation of the Magdalenian period in Northern Iberia, our Available online 13 April 2015 understanding of the diets during this period is limited. Methodologies for the reconstruction of Late Glacial subsistence strategies have overwhelmingly targeted animal exploitation, thus revealing only a Keywords: portion of the dietary spectrum. Retrieving food debris from calculus offers a means to provide missing Upper Palaeolithic information on other components of diet. We undertook analysis of human dental calculus samples from Archaeobotany Magdalenian individuals (including the “Red Lady”) at El Miron Cave (Cantabria, Spain), as well as several Palaeolithic diet control samples, to better understand the less visible dietary components.
    [Show full text]
  • How Did Language Begin?
    How did language begin? Written by Ray Jackendoff What does the question mean? In asking about the origins of human language, we first have to make clear what the question is. The question is not how languages gradually developed over time into the languages of the world today. Rather, it is how the human species developed over time so that we — and not our closest relatives, the chimpanzees and bonobos — became capable of using language. And what an amazing development this was! No other natural communication system is like human language. Human language can express thoughts on an unlimited number of topics (the weather, the war, the past, the future, mathematics, gossip, fairy tales, how to fix the sink...). It can be used not just to convey information, but to solicit information (ques- tions) and to give orders. Unlike any other animal communication system, it contains an expression for negation — what is not the case. Every human lan- guage has a vocabulary of tens of thousands of words, built up from several dozen speech sounds. Speakers can build an unlimited number of phrases and sentences out of words plus a smallish collec- tion of prefixes and suffixes, and the meanings of sentences are built from the meanings of the individ- ual words. What is still more remarkable is that every normal child learns the whole system from hearing others use it. Animal communication systems, in contrast, typically have at most a few dozen distinct calls, and they are used only to communicate immediate issues such as food, danger, threat, or reconciliation.
    [Show full text]
  • Human Performance
    Human Performance March 2008 JSR-07-625 Approved for public release; distribution unlimited JASON The MITRE Corporation 7515 Colshire Drive McLean, Virginia 22102-7508 (703) 983-6997 Form Approved REPORT DOCUMENTATION PAGE OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202- 4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES COVERED (From - To) March 2008 Technical 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Human Performance 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER E. Williams et al. 13079022 5e. TASK NUMBER PS 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER The MITRE Corporation JASON Program Office JSR-07-625 7515 Colshire Drive McLean, Virginia 22102 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10.
    [Show full text]
  • What Makes a Modern Human We Probably All Carry Genes from Archaic Species Such As Neanderthals
    COMMENT NATURAL HISTORY Edward EARTH SCIENCE How rocks and MUSIC Philip Glass on Einstein EMPLOYMENT The skills gained Lear’s forgotten work life evolved together on our and the unpredictability of in PhD training make it on ornithology p.36 planet p.39 opera composition p.40 worth the money p.41 ILLUSTRATION BY CHRISTIAN DARKIN CHRISTIAN BY ILLUSTRATION What makes a modern human We probably all carry genes from archaic species such as Neanderthals. Chris Stringer explains why the DNA we have in common is more important than any differences. n many ways, what makes a modern we were trying to set up strict criteria, based non-modern (or, in palaeontological human is obvious. Compared with our on cranial measurements, to test whether terms, archaic). What I did not foresee evolutionary forebears, Homo sapiens is controversial fossils from Omo Kibish in was that some researchers who were not Icharacterized by a lightly built skeleton and Ethiopia were within the range of human impressed with our test would reverse it, several novel skull features. But attempts to skeletal variation today — anatomically applying it back onto the skeletal range of distinguish the traits of modern humans modern humans. all modern humans to claim that our diag- from those of our ancestors can be fraught Our results suggested that one skull nosis wrongly excluded some skulls of with problems. was modern, whereas the other was recent populations from being modern2. Decades ago, a colleague and I got into This, they suggested, implied that some difficulties over an attempt to define (or, as PEOPLING THE PLANET people today were more ‘modern’ than oth- I prefer, diagnose) modern humans using Interactive map of migrations: ers.
    [Show full text]
  • K = Kenyanthropus Platyops “Kenya Man” Discovered by Meave Leaky
    K = Kenyanthropus platyops “Kenya Man” Discovered by Meave Leaky and her team in 1998 west of Lake Turkana, Kenya, and described as a new genus dating back to the middle Pliocene, 3.5 MYA. A = Australopithecus africanus STS-5 “Mrs. Ples” The discovery of this skull in 1947 in South Africa of this virtually complete skull gave additional credence to the establishment of early Hominids. Dated at 2.5 MYA. H = Homo habilis KNM-ER 1813 Discovered in 1973 by Kamoya Kimeu in Koobi Fora, Kenya. Even though it is very small, it is considered to be an adult and is dated at 1.9 MYA. E = Homo erectus “Peking Man” Discovered in China in the 1920’s, this is based on the reconstruction by Sawyer and Tattersall of the American Museum of Natural History. Dated at 400-500,000 YA. (2 parts) L = Australopithecus afarensis “Lucy” Discovered by Donald Johanson in 1974 in Ethiopia. Lucy, at 3.2 million years old has been considered the first human. This is now being challenged by the discovery of Kenyanthropus described by Leaky. (2 parts) TC = Australopithecus africanus “Taung child” Discovered in 1924 in Taung, South Africa by M. de Bruyn. Raymond Dart established it as a new genus and species. Dated at 2.3 MYA. (3 parts) G = Homo ergaster “Nariokotome or Turkana boy” KNM-WT 15000 Discovered in 1984 in Nariokotome, Kenya by Richard Leaky this is the first skull dated before 100,000 years that is complete enough to get accurate measurements to determine brain size. Dated at 1.6 MYA.
    [Show full text]
  • Neanderthal-Human Hybrids Tions Split Approximately 370,000 Years Ago Paul H
    HYPOTHESIS 1 Neanderthal-human Hybrids tions split approximately 370,000 years ago Paul H. Mason1* and Roger V. Short2 (1). Over time, Neanderthals genetically di- verged. Analyses of mitochondrial DNA (mtD- Evidence from studies of nuclear and mitochondrial DNA extracted NA) sequences extracted from Neanderthal from Neanderthal fossils and humans points to fascinating hypotheses fossils suggest that their most recent common concerning the types of interbreeding that occurred between these two ancestry dates back to approximately 250,000 species. Humans and Neanderthals share a small percentage of nuclear years ago (2). DNA. However, humans and Neanderthals do not possess the same mito- Neanderthals inhabited a vast geographi- chondrial DNA. In mammals, mitochondrial DNA is exclusively maternally cal area extending from Portugal to west- inherited. Taking into account an understanding of interspecific hybridity, ern Siberia and from northern Europe to the the available data leads to the hypothesis that only male Neanderthals Middle East until approximately 25,000 years were able to mate with female humans. If Haldane’s Law applied to the ago (3). Recent evidence from DNA extracted progeny of Neanderthals and humans, then female hybrids would survive, from fossil Neanderthal bones reveals gene- but male hybrids would be absent, rare, or sterile. Interbreeding between flow between Neanderthals and anatomically male Neanderthals and female humans, as the only possible scenario, modern humans in the Middle East around accounts for the presence of Neanderthal nuclear DNA, the scarcity of 80,000 to 50,000 years ago as humans spread out of Africa and into Europe and Asia Neanderthal Y-linked genes, and the lack of mitochondrial DNA in modern (4).
    [Show full text]
  • Lieberman 2001E.Pdf
    news and views Another face in our family tree Daniel E. Lieberman The evolutionary history of humans is complex and unresolved. It now looks set to be thrown into further confusion by the discovery of another species and genus, dated to 3.5 million years ago. ntil a few years ago, the evolutionary history of our species was thought to be Ureasonably straightforward. Only three diverse groups of hominins — species more closely related to humans than to chim- panzees — were known, namely Australo- pithecus, Paranthropus and Homo, the genus to which humans belong. Of these, Paran- MUSEUMS OF KENYA NATIONAL thropus and Homo were presumed to have evolved between two and three million years ago1,2 from an early species in the genus Australopithecus, most likely A. afarensis, made famous by the fossil Lucy. But lately, confusion has been sown in the human evolutionary tree. The discovery of three new australopithecine species — A. anamensis3, A. garhi 4 and A. bahrelghazali5, in Kenya, Ethiopia and Chad, respectively — showed that genus to be more diverse and Figure 1 Two fossil skulls from early hominin species. Left, KNM-WT 40000. This newly discovered widespread than had been thought. Then fossil is described by Leakey et al.8. It is judged to represent a new species, Kenyanthropus platyops. there was the finding of another, as yet poorly Right, KNM-ER 1470. This skull was formerly attributed to Homo rudolfensis1, but might best be understood, genus of early hominin, Ardi- reassigned to the genus Kenyanthropus — the two skulls share many similarities, such as the flatness pithecus, which is dated to 4.4 million years of the face and the shape of the brow.
    [Show full text]
  • Universal Declaration of Human Rights
    Universal Declaration of Human Rights Preamble Whereas recognition of the inherent dignity and of the equal and inalienable rights of all members of the human family is the foundation of freedom, justice and peace in the world, Whereas disregard and contempt for human rights have resulted in barbarous acts which have outraged the conscience of mankind, and the advent of a world in which human beings shall enjoy freedom of speech and belief and freedom from fear and want has been proclaimed as the highest aspiration of the common people, Whereas it is essential, if man is not to be compelled to have recourse, as a last resort, to rebellion against tyranny and oppression, that human rights should be protected by the rule of law, Whereas it is essential to promote the development of friendly relations between nations, Whereas the peoples of the United Nations have in the Charter reaffirmed their faith in fundamental human rights, in the dignity and worth of the human person and in the equal rights of men and women and have determined to promote social progress and better standards of life in larger freedom, Whereas Member States have pledged themselves to achieve, in cooperation with the United Nations, the promotion of universal respect for and observance of human rights and fundamental freedoms, Whereas a common understanding of these rights and freedoms is of the greatest importance for the full realization of this pledge, Now, therefore, The General Assembly, Proclaims this Universal Declaration of Human Rights as a common standard of achievement for all peoples and all nations, to the end that every individual and every organ of society, keeping this Declaration constantly in mind, shall strive by teaching and education to promote respect for these rights and freedoms and by progressive measures, national and international, to secure their universal and effective recognition and observance, both among the peoples of Member States themselves and among the peoples of territories under their jurisdiction.
    [Show full text]
  • Early Members of the Genus Homo -. EXPLORATIONS: an OPEN INVITATION to BIOLOGICAL ANTHROPOLOGY
    EXPLORATIONS: AN OPEN INVITATION TO BIOLOGICAL ANTHROPOLOGY Editors: Beth Shook, Katie Nelson, Kelsie Aguilera and Lara Braff American Anthropological Association Arlington, VA 2019 Explorations: An Open Invitation to Biological Anthropology is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted. ISBN – 978-1-931303-63-7 www.explorations.americananthro.org 10. Early Members of the Genus Homo Bonnie Yoshida-Levine Ph.D., Grossmont College Learning Objectives • Describe how early Pleistocene climate change influenced the evolution of the genus Homo. • Identify the characteristics that define the genus Homo. • Describe the skeletal anatomy of Homo habilis and Homo erectus based on the fossil evidence. • Assess opposing points of view about how early Homo should be classified. Describe what is known about the adaptive strategies of early members of the Homo genus, including tool technologies, diet, migration patterns, and other behavioral trends.The boy was no older than 9 when he perished by the swampy shores of the lake. After death, his slender, long-limbed body sank into the mud of the lake shallows. His bones fossilized and lay undisturbed for 1.5 million years. In the 1980s, fossil hunter Kimoya Kimeu, working on the western shore of Lake Turkana, Kenya, glimpsed a dark colored piece of bone eroding in a hillside. This small skull fragment led to the discovery of what is arguably the world’s most complete early hominin fossil—a youth identified as a member of the species Homo erectus. Now known as Nariokotome Boy, after the nearby lake village, the skeleton has provided a wealth of information about the early evolution of our own genus, Homo (see Figure 10.1).
    [Show full text]
  • Evolution of Nervous Systems and Brains 2
    Evolution of Nervous Systems and Brains 2 Gerhard Roth and Ursula Dicke The modern theory of biological evolution, as estab- drift”) is incomplete; they point to a number of other lished by Charles Darwin and Alfred Russel Wallace and perhaps equally important mechanisms such as in the middle of the nineteenth century, is based on (i) neutral gene evolution without natural selection, three interrelated facts: (i) phylogeny – the common (ii) mass extinctions wiping out up to 90 % of existing history of organisms on earth stretching back over 3.5 species (such as the Cambrian, Devonian, Permian, and billion years, (ii) evolution in a narrow sense – Cretaceous-Tertiary mass extinctions) and (iii) genetic modi fi cations of organisms during phylogeny and and epigenetic-developmental (“ evo - devo ”) self-canal- underlying mechanisms, and (iii) speciation – the ization of evolutionary processes [ 2 ] . It remains uncer- process by which new species arise during phylogeny. tain as to which of these possible processes principally Regarding the phylogeny, it is now commonly accepted drive the evolution of nervous systems and brains. that all organisms on Earth are derived from a com- mon ancestor or an ancestral gene pool, while contro- versies have remained since the time of Darwin and 2.1 Reconstruction of the Evolution Wallace about the major mechanisms underlying the of Nervous Systems and Brains observed modi fi cations during phylogeny (cf . [1 ] ). The prevalent view of neodarwinism (or better In most cases, the reconstruction of the evolution of “new” or “modern evolutionary synthesis”) is charac- nervous systems and brains cannot be based on fossil- terized by the assumption that evolutionary changes ized material, since their soft tissues decompose, but are caused by a combination of two major processes, has to make use of the distribution of neural traits in (i) heritable variation of individual genomes within a extant species.
    [Show full text]