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Encephalization

Encephalization

1. Encephalization is defined as the amount of brain mass exceeding that related to an animal's total body mass. And quantifying an animals encephalization has been argued to be directly related to that animal's level of intelligence. Williams[http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WN2-45WYMG6-9&_coverDate=04%2F30%2F2002&_alid=345187568&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=6950&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=cb9acecb46bd950701b34eb5bb5e94ee] has recently argued that the most accurate means for quantifying the encephalization of humans and other adult primate species requires the use of Lapicque's universal exponent of 0.28 in Snell's equation of simple allometry. Since Lapicque's slope was derived from various vertebrate groups, this equation may potentially be universally applicable for determining relative adult vertebrate encephalization and intelligence.

References

1. Williams MF., Primate encephalization and intelligence.Med Hypotheses. 2002 Apr;58(4):284-90. 2. Jerison H. J. Paleoneurology and the evolution of the mind. Scientific American 1976; 234: 90-101. 3.Tobias P. V. The Brain in Hominid Evolution. New York and London: Columbia University Press, 1971. 2. Encephalization refers to the tendency for a species toward larger brains through evolutionary time. Anthropological studies indicate that bipedalism preceded encephalization in the human evolutionary lineage after divergence from the chimpanzee lineage. Compared to the chimpanzee brain, the human brain is larger and certain brain regions have been particularly altered during human evolution. Most brain growth of chimpanzees happens before birth while most human brain growth happens after birth (see: Heterochrony). In 2004, Dennis Bramble and Daniel Lieberman proposed that early Homo were scavengers that used stone tools to harvest meat off carcasses and to open bones. They proposed that humans specialized in long-distance running to compete with other scavengers in reaching carcasses. It has been suggested that such an adaptation ensured a food supply that made large brains possible. More encephalized species tend to have longer spinal shock duration.

References

# See Figures 1 and 2 of "Molecular insights into human brain evolution." by J. Bradbury in PLoS Biology (2005) volume 3 page e50. ([http://www.pubmedcentral.gov/articlerender.fcgi?tool=pubmed&pubmedid=15760271 Full text online]) # "Endurance running and the evolution of Homo" by D. M. Bramble and D. E. Lieberman in Nature (2004) volume 432 pages 345-352.

Antropology

Anthropology (from the Greek word άνθρωπος, "humane") consists of the study of humankind (see genus Homo). It is holistic in two senses: it is concerned with all humans at all times, and with all dimensions of humanity. A primary trait that traditionally distinguished anthropology from other humanistic disciplines is an emphasis on cross-cultural comparisons. This distinction has, however, become increasingly the subject of controversy and debate, with anthropological methods now being commonly applied in single society/group studies. In the United States, anthropology is traditionally divided into four sub-disciplines:
- physical anthropology, which studies primate behavior, human evolution, and population genetics; this field is also sometimes called biological anthropology.
- cultural anthropology, (called social anthropology in the United Kingdom and now often known as socio-cultural anthropology). Areas studied by cultural anthropologists include social networks, diffusion, social behavior, kinship patterns, law, politics, ideology, religion, beliefs, patterns in production and consumption, exchange, socialization, gender, and other expressions of culture, with strong emphasis on the importance of fieldwork, i.e living among the social group being studied for an extended period of time;
- linguistic anthropology, which studies variation in language across time and space, the social uses of language, and the relationship between language and culture; and
- archaeology, which studies the material remains of human societies. Archaeology itself is normally treated as a separate (but related) field in the rest of the world, although closely related to the anthropological field of material culture, which deals with physical objects created or used within a living or past group as mediums of understanding its cultural values. More recently, some anthropology programs began dividing the field into two, one emphasizing the humanities and critical theory, the other emphasizing the natural sciences and empirical observation.

Historical and institutional context

:Main Article: History of anthropology The anthropologist Eric Wolf once characterized anthropology as the most scientific of the humanities, and the most humanistic of the sciences. Understanding how anthropology developed contributes to understanding how it fits into other academic disciplines. Contemporary anthropologists claim a number of earlier thinkers as their forebearers and the discipline has several sources. However, anthropology can best be understood as an outgrowth of the Age of Enlightenment. It was during this period that Europeans attempted systematically to study human behavior. Traditions of jurisprudence, history, philology and sociology developed during this time and informed the development of the social sciences of which anthropology was a part. At the same time, the romantic reaction to the Enlightenment produced thinkers such as Herder and later Wilhelm Dilthey whose work formed the basis for the culture concept which is central to the discipline. These intellectual movements in part grappled with one of the greatest paradoxes of modernity: as the world is becoming smaller and more integrated, people's experience of the world is increasingly atomized and dispersed. As Karl Marx and Friedrich Engels observed in the 1840s: :All old-established national industries have been destroyed or are daily being destroyed. They are dislodged by new industries, whose introduction becomes a life and death question for all civilized nations, by industries that no longer work up indigenous raw material but raw material drawn from the remotest zones; industries whose products are consumed, not only at home, but in every quarter of the globe. In place of the old wants, satisfied by the production of the country, we find new wants, requiring for their satisfaction the products of distant lands and climes. In place of the old local and national seclusion and self-sufficiency, we have intercourse in every direction, universal interdependence of nations. Ironically, this universal interdependence, rather than leading to greater human solidarity, has coincided with increasing racial, ethnic, religious, and class divisions, and new – and to some confusing or disturbing – cultural expressions. These are the conditions of life with which people today must contend, but they have their origins in processes that began in the 16th century and accelerated in the 19th century. Institutionally anthropology emerged from natural history (expounded by authors such as Buffon). This was the study of human beings - typically people living in European colonies. Thus studying the language, culture, physiology, and artifacts of European colonies was more or less equivalent to studying the flora and fauna of those places. It was for this reason, for instance, that Lewis Henry Morgan could write monographs on both The League of the Iroquois and The American Beaver and His Works. This is also why the material culture of 'civilized' nations such as China have historically been displayed in fine arts museums alongside European art while artifacts from Africa or Native North American cultures were displayed in Natural History Museums with dinosaur bones and nature dioramas. This being said, curatorial practice has changed dramatically in recent years, and it would be wrong to see anthropology as merely an extension of colonial rule and European chauvinism, since its relationship to imperialism was and is complex. Anthropology grew increasingly distinct from natural history and by the end of the nineteenth century the discipline began to crystallize into its modern form - by 1935, for example, it was possible for T.K. Penniman to write a history of the discipline entitled A Hundred Years of Anthropology. At the time, the field was dominated by 'the comparative method'. It was assumed that all societies passed through a single evolutionary process from the most primitive to most advanced. Non-European societies were thus seen as evolutionary 'living fossils' that could be studied in order to understand the European past. Scholars wrote histories of prehistoric migrations which were sometimes valuable but often also fanciful. It was during this time that Europeans first accurately traced Polynesian migrations across the Pacific Ocean for instance - although some of them believed it originated in Egypt. Finally, the concept of race was actively discussed as a way to classify - and rank - human beings based on inherent biological difference. In the twentieth century academic disciplines began to organize around three main domains. The "sciences" seeks to derive natural laws through reproducible and falsifiable experiments. The "humanities" reflected an attempt to study different national traditions, in the form of history and the arts, as an attempt to provide people in emerging nation-states with a sense of coherence. The "social sciences" emerged at this time as an attempt to develop scientific methods to address social phenomena, in an attempt to provide a universal basis for social knowledge. Anthropology does not easily fit into one of these categories, and different branches of anthropology draw on one or more of these domains. Drawing on the methods of the natural sciences as well as developing new techniques involving not only structured interviews but unstructured "participant-observation" – and drawing on the new theory of evolution through natural selection, they proposed the scientific study of a new object: "humankind," conceived of as a whole. Crucial to this study is the concept "culture," which anthropologists defined both as a universal capacity and propensity for social learning, thinking, and acting (which they see as a product of human evolution and something that distinguishes Homo sapiens – and perhaps all species of genus Homo – from other species), and as a particular adaptation to local conditions that takes the form of highly variable beliefs and practices. Thus, "culture" not only transcends the opposition between nature and nurture; it transcends and absorbs the peculiarly European distinction between politics, religion, kinship, and the economy as autonomous domains. Anthropology thus transcends the divisions between the natural sciences, social sciences, and humanities to explore the biological, linguistic, material, and symbolic dimensions of humankind in all forms.

Anthropology in the U.S.

Anthropology in the United States was pioneered by staff of the Bureau of Indian Affairs and the Smithsonian Institution's Bureau of American Ethnology, such as John Wesley Powell and Frank Hamilton Cushing. Academic Anthropology was established by Franz Boas, who used his positions at Columbia University and the American Museum of Natural History to train and develop multiple generations of students. Boasian anthropology was politically active and suspicious of research dictated by the U.S. government or wealthy patrons. It was also rigorously empirical and skeptical of over-generalizations and attempts to establish universal laws. Boas studied immigrant children in order to demonstrate that biological race was not immutable and that human conduct and behavior was the result of nurture rather than nature. Drawing on his German roots, he argued that the world was full of distinct 'cultures' rather than societies whose evolution could be measured by how much or how little 'civilization' they had. Boas felt that each culture has to be studied in its particularity, and argued that cross-cultural generalizations like those made in the natural sciences were not possible. In doing so Boas fought discrimination against immigrants, African Americans, and Native North Americans. Many American anthropologists adopted Boas' agenda for social reform, and theories of race continue to be popular targets for anthropologists today. Boas's first generation of students included Alfred Kroeber, Robert Lowie, and Edward Sapir. All of these scholars produced richly detailed studies which were first to describe Native North America. In doing so they provided a wealth of details used to attack the theory of a single evolutionary process. Their focus on Native American languages also helped establish linguistics as a truly general science and free it from its historical focus on Indo-European languages. The publication of Alfred Kroeber's textbook Anthropology marked a turning point in American anthropology. After three decades of amassing material the urge to generalize grew. This was most obvious in the 'Culture and Personality' studies carried out by younger Boasians such as Margaret Mead and Ruth Benedict. Influenced by psychoanalytic psychologists such as Sigmund Freud and Carl Jung, these authors sought to understand the way that individual personalities were shaped by the wider cultural and social forces in which they grew up. While such works as Coming of Age in Samoa and The Chrysanthemum and the Sword remain popular with the American public, Mead and Benedict never had the impact on the discipline of anthropology that some expected. Boas had planned for Ruth Benedict to succeed him as chair of Columbia's anthropology department, but she was sidelined by Ralph Linton and Mead was limited to her offices at the AMNH.

Anthropology in Britain

Whereas Boas picked his opponents to pieces through attention to detail, in Britain modern anthropology was formed by rejecting historical reconstruction in the name of a science of society that focused on analyzing how societies held together in the present. The two most important names in this tradition were Alfred Reginald Radcliffe-Brown and Bronislaw Malinowski, both of whom released seminal works in 1922. Radcliffe-Brown's initial fieldwork in the Andaman Islands was carried out in the old style, but after reading Émile Durkheim he published an account of his research (entitled simply The Andaman Islanders) which drew heavily on the French sociologist. Over time he developed an approach known as structural-functionalism, which focused on how institutions in societies worked to balance out or create an equilibrium in the social system to keep it functioning harmoniously. Malinowski, on the other hand, advocated an unhyphenated 'functionalism' which examined how society functioned to meet individual needs. Malinowski is best known not for his theory, however, but for his detailed ethnography and advances in methodology. His classic Argonauts of the Western Pacific advocated getting 'the native's point of view' and an approach to field work that became standard in the field. Malinowski and Radcliffe-Brown's success stem from the fact that they, like Boas, actively trained students and aggressively built up institutions which furthered their programmatic ambitions. This was particularly the case with Radcliffe-Brown, who spread his agenda for 'Social Anthropology' by teaching at universities across the Commonwealth. From the late 1930s until the post-war period a string of monographs and edited volumes appeared which cemented the paradigm of British Social Anthropology. Famous ethnographies include The Nuer by Edward Evan Evans-Pritchard and The Dynamics of Clanship Among the Tallensi by Meyer Fortes, while well known edited volumes include African Systems of Kinship and Marriage and African Political Systems.

Anthropology in France

Anthropology in France has a less clear genealogy than the British and American traditions. Most commentators consider Marcel Mauss to be the founder of the French anthropological tradition. Mauss was a member of Durkheim's Annee Sociologique group, and while Durkheim and others examined the state of modern societies, Mauss and his collaborators (such as Henri Hubert and Robert Hertz) drew on ethnography and philology to analyze societies which were not as 'differentiated' as European nation states. In particular, Mauss's Essay on the Gift was to prove of enduring relevance in anthropological studies of exchange and reciprocity. Throughout the interwar years, French interest in anthropology often dovetailed with wider cultural movements such as surrealism and primitivism which drew on ethnography for inspiration. Marcel Griaule and Michel Leiris are examples of people who combined anthropology with the French avant-garde. During this time most of what is known as ethnologie was restricted to museums, and anthropology had a close relationship with studies of folklore. Above all, however, it was Claude Lévi-Strauss who helped institutionalize anthropology in France. In addition to the enormous influence his structuralism exerted across multiple disciplines, Lévi-Strauss established ties with American and British anthropologists. At the same time he established centers and laboratories within France to provide an institutional context within anthropology while training influential students such as Maurice Godelier and Francoise Heritier who would prove influential in the world of French anthropology. Much of the distinct character of France's anthropology today is a result of the fact that most anthropology is carried out in nationally-funded research laboratories rather than academic departments in universities.

Anthropology after World War Two

Before WWII British 'social anthropology' and American 'cultural anthropology' were still distinct traditions. It was after the war that the two would blend to create a 'sociocultural' anthropology. In the 1950s and mid-1960s anthropology tended increasingly to model itself after the natural sciences. Some, such as Lloyd Fallers and Clifford Geertz, focused on processes of modernization by which newly independent states could develop. Others, such as Julian Steward and Leslie White focused on how societies evolve and fit their ecological niche - an approach popularized by Marvin Harris. Economic anthropology as influenced by Karl Polanyi and practiced by Marshall Sahlins and George Dalton focused on how traditional economics ignored cultural and social factors. In England, British Social Anthropology's paradigm began to fragment as Max Gluckman and Peter Worsley experimented with Marxism and authors such as Rodney Needham and Edmund Leach incorporated Lévi-Strauss's structuralism into their work. Structuralism also influenced a number of development in 1960s and 1970s, including cognitive anthropology and componential analysis. Authors such as David Schneider, Clifford Geertz, and Marshall Sahlins developed a more fleshed-out concept of culture as a web of meaning or signification, which proved very popular within and beyond the discipline. In keeping with the times, much of anthropology became politicized through the Algerian War of Independence and opposition to the Vietnam War; Marxism became a more and more popular theoretical approach in the discipline. By the 1970s the authors of volumes such as Reinventing Anthropology worried about anthropology's relevance. In the 1980s issues of power, such as those examined in Eric Wolf's Europe and the People Without History - were central to the discipline. Books like Anthropology and the Colonial Encounter pondered anthropology's ties to colonial inequality, while the immense popularity of theorists such as Antonio Gramsci and Michel Foucault moved issues of power and hegemony into the spotlight. Gender and sexuality became a popular topic, as did the relationship between history and anthropology, influenced by Marshall Sahlins (again) who drew on Lévi-Strauss and Fernand Braudel to examine the relationship between social structure and individual agency. In the late 1980s and 1990s authors such as George Marcus and James Clifford pondered ethnographic authority, particularly how and why anthropological knowledge was possible and authoritative. This was part of a more general trend of postmodernism that was popular contemporaneously. Currently anthropologists have begun to pay attention to globalization, medicine and biotechnology, indigenous rights, and the anthropology of Europe.

Politics of anthropology

Anthropology's traditional involvement with nonwestern cultures has involved it in politics in many different ways. Some political problems arise simply because anthropologists usually have more power than the people they study. Some have argued that the discipline is a form of colonialist theft in which the anthropologist gains power at the expense of subjects. The anthropologist, they argue, can gain yet more power by exploiting knowledge and artifacts of the people she or he studies while the people she or he studies gain nothing, or even lose, in exchange. An example of this exploitative relationship can been seen in the collaboration in Africa prior to World War II of British anthropologists and colonial forces. More recently, there have been newfound concerns about bioprospecting, along with struggles for self-representation for native peoples and the repatriation of indigenous remains and material culture. Other political controversies come from American anthropology's emphasis on cultural relativism and its long-standing antipathy to the concept of race. As mentioned above, Boas was a well-known social reformer whose activism and anthropological teaching went hand in hand. The development of sociobiology in the late 1960s was opposed by cultural anthropologists such as Marshall Sahlins, who argued that these positions were reductive. While authors such John Randal Baker continued to develop the biological concept of race into the 1970s, the rise of genetics has proven to be central to developments on this front. As genetics continues to advance as a science, biological anthropologists such as Jonathan Marks have continued to refine their opposition to folk notions of race while addressing recent developments in biology. Finally, anthropology has a history of entanglement with government intelligence agencies and anti-war politics. Boas publicly objected to US participation World War I and the collaboration of some anthropologists with US intelligence. In contrast, many of Boas' anthropologist contemporaries were active in the war effort in some form, including dozens who served in the Office of Strategic Services and the Office of War Information. In the 1950s, the American Anthropological Association provided the CIA information on the area specialities of its members, and a number of anthropologists participated in the U.S. government's Operation Camelot during the war in Vietnam. At the same time, many other anthropologists were active in the antiwar movement and passed resolutions in the American Anthropological Association (AAA) condemning anthropological involvement in covert operations. Anthropologists were also vocal in their opposition to the war in Iraq although their was no consensus amongst all practitioners of the discipline. Professional anthropological bodies often object to the use of anthropology for the benefit of the state. Their codes of ethics or statements may proscribe anthropologists from giving secret briefings. The British Association for Social Anthropology has called these scholarships ethically dangerous and divise For example, the British Association for Social Anthropology has condemned the CIA's Pat Roberts Intelligence Scholars Program, which anonymously funds anthropology students at US universities in preparation for those students to spy for the United States government. The AAA's current 'Statement of Professional Responsibility' clearly states that "in relation with their own government and with host governments... no secret research, no secret reports or debriefings of any kind should be agreed to or given." Anthropology is the study of human diversity--diversity of body and behavior, in the past and present. Anthropology consists of four subfields or subdisciplines: Physical anthropology--studies the diversity of the human body in the past and present. It includes how we acquired the structure of our body over time, that is human evolution, as well as differences and relationships between human populations today and their adaptations to their local environments. It also sometimes includes the evolution and diversity of our nearest relatives, the primates (apes and monkeys). Cultural anthropology--studies the diversity of human behavior in the present. This is what most anthropologists do and what most of the public sees when they look at "National Geographic" magazine or the "Discovery" channel on TV. Cultural anthropologists travel to foreign societies (although it is possible to do anthropology on your own society!), live among the people there, and try as much as they can to understand how those people live. Archaeology--studies the diversity of human behavior in the past. Since it studies how people lived in the past, these people are not available for us to visit and talk to...or at least, not people who are currently living in the same way that their ancestors did in the past. Therefore, archaeologists must depend on the artifacts and features that the people produced in the past and attempt to reconstruct their vanished way of life from those remnants of their culture. Linguistic anthropology--studies the diversity of human language in the past and present. While language is naturally a part of culture, it is such a huge topic that anthropologists have separated it into its own area of study. Linguistic anthropologists are concerned about the development of languages, perhaps even back to the first forms of language, and how language changes over time. They are also interested in how different contemporary languages differ today, how they are related, and how we can learn about things like migration and diffusion from that data. They also ask how language is related to and reflects on other aspects of culture. Other sciences study humans too, of course. History, economics, psychology, sociology, even biology and chemistry can study humans. How is anthropology different? The answer is the anthropological perspective, that is, the way that anthropology approaches the subject and thinks about or studies humans and their behavior. The anthropological perspective has three components: (1) cross-cultural or comparative--anthropology investigates humans in every form that they take. We are interested to see the entire spectrum of human bodies and behaviors, trying to learn the range of humanity--all the ways that we can be human. By seeing humans in their every manifestation, and comparing those manifestations to each other, we can ask what is possible for humans and what is necessary for humans. (2) holistic--anthropology tries to relate every part of culture to every other part. We understand that the various parts of culture are connected to each other and that certain combinations tend to occur or not to occur (for example, there are no hunting and gathering cultures that traditionally lived in cities...that's just impossible!). We are also interested in how a people's cultures is connected to their environment; again, without high technology, you are not going to see farming or cities in the middle of the desert or the arctic. (3) relativistic--this is the most profound yet controversial part of the anthropological perspective. Relativism means that the rules or norms or values of a culture are relative to that specific culture. In other words, say, monogamy may be normal or preferred in one culture, but polygamy may be normal or preferred in another. The point is that different cultures believe different things or value different things or even mean different things with perhaps identical-looking behaviors or objects. In one culture, waving your hand might be a greeting, and in another culture it might be an insult. When you go to another culture, or even just interact with another culture (for example, when you are doing international business), you cannot assume that other people understand things the same way you do. In fact, you should assume that they don't! And you certainly should not judge or evaluate them from your own culture's perspective--if you were in a headhunter society, you might think they were horrible people for keeping heads in their house, but if they came to visit you, they might think you were a horrible person for not having heads in your house! The point is that, if we want to understand other people properly, we must see what their behaviors or words or concepts mean to them, not what they would mean to us. Meaning is relative to the culture that creates that meaning. This is not to say that all things are true or even that all things are good. Some things are true (like the world being round) no matter what people think; those are facts. And "good" is a value judgment, so it has no place in anthropology. What we are saying in relativism is that all value judgments are made from cultural perspective, and if you were to take a different cultural perspective, you would understand or judge the exact same phenomenon in the exact opposite way! How does anthropology study culture? One other way that anthropology is unique among the sciences that study humans is by its emphasis on "fieldwork'" You cannot get to know another culture just by reading about it or watching movies about it. At best, you could learn what other people have already discovered, but you could not learn anything new. So anthropology requires actually going to that society and living with and living like that society as much as possible. This is called participant observation. This depends crucially on making friends with people in the society, who will teach you and include you in their activities--and informant. Then, as much as possible, you will try to eat their food, speak their language, and live their lives, often actually residing with a family in that society. It is not easy work, and it is not always fun, but there is no better way to learn.

Anthropological fields and subfields

- Biological anthropology (also Physical anthropology)
- Forensic anthropology
- Paleoethnobotany
- Cultural anthropology (also Social anthropology)
- Applied anthropology
- Cross-Cultural Studies
- Cyber anthropology
- Development anthropology
- Environmental anthropology
- Economic anthropology
- Ecological anthropology
- Ethnography
- Ethnomusicology
- Gender
- Human behavioral ecology
- Medical anthropology
- Psychological anthropology
- Political anthropology
- Anthropology of religion
- Public anthropology
- Urban anthropology
- Visual anthropology
- Linguistic anthropology
- Synchronic linguistics (or Descriptive linguistics)
- Diachronic linguistics (or Historical linguistics)
- Ethnolinguistics
- Sociolinguistics
- Archaeology

External links

- [http://www.aaanet.org/ The American Anthropological Association Homepage] - the webpage of the largest professional organization of anthropologists in the world.
- [http://www.worldcatlibraries.org/wcpa/ow/09dbb3346fc1c2a4.html Race] - a book by John Randal Baker discussing the origins of racial classification and oppositions to the concept.
- [http://www.antropologi.info Anthropology.Info]
- [http://www.thenation.com/doc.mhtml?i=20001120&c=2&s=price Anthropologists as Spies] - an article by David Price examining the relationship between American Anthropology and US intelligence services.
- [http://news.bbc.co.uk/2/hi/uk_news/education/4603271.stm Pat Roberts Intelligence Program] - a BBC article on the program
- [http://www.antropologi.info/blog/anthropology Social and Cultural Anthropology in the News] - (nearly) daily updated blog
- [http://www.anthrobase.com Anthrobase.com] - Collection of anthropological texts
- [http://www.cybercultura.it Cybercultura] - Collection of web resources about anthropology of cyberspace
- [http://www.anthropology.net Anthropology.net] - A community orientated anthropology web portal with user run blogs, forums, tags, and a wiki.

Chimpanzee

Pan troglodytes
Pan paniscus Chimpanzee, often abbreviated to chimp, is the common name for two species in the genus Pan. The better known chimpanzee is Pan troglodytes, the Common Chimpanzee, living in West and Central Africa. Its cousin, the Bonobo or Pygmy Chimpanzee (Pan paniscus), is found in the forests of the Democratic Republic of the Congo. The boundary between the two species is formed by the Congo River.

Lifespan

Chimpanzees rarely live past the age of 50 in the wild, but have been known to reach the age of 60 in captivity.

Chimpanzee differences

Anatomical differences between Common and Pygmy Chimpanzees are slight, but in sexual and social behaviour there are marked differences. Common Chimpanzees have an omnivorous diet, a troop hunting culture based on beta males led by a relatively weak alpha, and highly complex social relationships; Bonobos, on the other hand, have a mostly herbivorous diet and an egalitarian, matriarchal, sexually promiscuous culture.

History of human interaction

Although Africans have had contact with chimpanzees for millennia, the first recorded (Western) contact of humans with chimps was made by Europeans scouting Angola at some point during the 1600s. The first use of the name "chimpanzee", however, did not occur until 1738. The name is derived from an Angolan Bantu language term "Tshiluba kivili-chimpenze", which is the local name for the animal and translates loosely as "mockman" or possibly just "ape". The colloquialism "chimp" was most likely coined some time in the late 1870s. Science would eventually take the 'pan' occurring in 'chimpanzee' and attribute it to Pan, a rural ancient Greek god of nature. Biologists would apply Pan as the genus name of the animal. Chimps as well as other apes had also been purported to have existed in ancient times, but did so mainly as myths and legends on the edge of Euro-Arabic societal consciousness, mainly through fragmented and sketchy accounts of European adventurers. Apes are mentioned variously by Aristotle, as well as the Bible. European scientists were bemused when chimpanzees first began arriving on the European continent as a result of these ancient descriptions, which often falsely purported that chimpanzees had horns and hooves. The first of these early trans-continental chimpanzees came from Angola and was presented as a gift to the Prince of Orange in 1640 and was followed by a few of its brethren over the next several years. Scientists who examined these rare specimens were baffled and described these first chimpanzees as "pygmies" of some kind or another, but did manage to note the animals' distinct similarities to humans. The next two decades would see a number of the creatures imported into Europe, mainly acquired by various zoological gardens as entertainment for visitors. Darwin's theory of evolution (published in 1860), as it did in most life science fields, would spur scientific interest in chimpanzees and led to numerous studies of the animals in the wild and captivity. The observers of chimpanzees at the time were mainly interested in the behaviour as it related to that of humans. However, this was not as strictly and benignly scientific as it sounds, with much attention being focused on whether or not the animals had traits that could be considered 'good' and the intelligence of chimpanzees was often significantly exaggerated. At one point there was even a scheme drawn up to domesticate chimpanzees in order to have them work at various menial tasks (i.e. factory work). By the end of the 1800s there was still very little factual scientific information regarding chimpanzees established. The creatures were still very much a mystery to humans. The 20th century would see a new age of scientific research into chimpanzee behaviour, generally free from the human egotism and patronizing attitude that had marred the previous era of studies. The most progressive studies that emerged were spearheaded primarily by Wolfgang Köhler and Robert Yerkes, both of whom were renowned psychologists. Both men and their colleagues established laboratory studies of chimpanzees focused specifically on learning about the intellectual, particularly the problem-solving abilities, of chimpanzees. This typically involved basic, practical tests where laboratory chimpanzees were required to demonstrate problem-solving abilities in order to solve basic tests which required a fairly high intellectual capacity (such as how to solve the problem of reaching an out of reach banana). Notably, Yerkes also made extensive observations of chimpanzees in the wild which also added tremendously to the scientific understanding of chimpanzees and their behaviour. Yerkes studied chimpanzees until World War II, while Köhler concluded five years of study and published his famous Mentality of Apes in 1925 (which is coincidentally when Yerkes began his analyses), eventually concluding that "chimpanzees manifest intelligent behavior of the general kind familiar in human beings... a type of behaviour which counts as specifically human" (1925).

Taxonomic relationships

The genus Pan is now considered to be part of the subfamily Homininae to which humans also belong. Biologists believe that the two species of chimpanzees are the closest living evolutionary relatives to humans. Their common ancestor branched off from its latest common ancestor with us as recently as four to seven million years ago, and they have about 95 to 98 percent of their DNA in common with humans. It has even been proposed that chimpanzees should be recategorized in the genus Homo as well. The argument for this is that other species have been reclassified to belong to the same genus on the basis of less genetic similarity than that between humans and chimpanzees. However, it is very important where the differences in the genome appear. The study published by Clark and Nielsen of the Cornell University in the Science in December 2003 highlights differences related to one of humankind's defining qualities — the ability to understand language and to communicate through speech, also in the genes for smell, in genes that enable humans and chimps to metabolize amino acids and in genes that may affect the ability to digest various protein. The fact that many chimpanzees have been taught to use hundreds of sign language words, and have sometimes passed on this knowledge to their offspring, indicates that "language" may not be such a major divider between humans and other hominids. See the history of hominoid taxonomy for more about the history of the classification of chimpanzees.

Fossils

Many human fossils have been found, but chimpanzee fossils had not been described until 2005. Existing chimpanzee populations in West and Central Africa do not overlap with the major human fossil sites in East Africa. However, chimpanzee fossils have now been reported in Kenya. This result indicates that both humans and members of the Pan clade were present in the East African Rift Valley during the Middle Pleistocene.

References

- "First fossil chimpanzee." by S. McBrearty and N. G. Jablonski in Nature (2005) Sep 1, Volume 437 pages 105-108. .
- Goodall, Jane. (1986) The Chimpanzees of Gombe: Patterns of Behavior.
- Pickrell, John. (September 24, 2002). [http://news.nationalgeographic.com/news/2002/09/0924_020924_dnachimp.html Humans, Chimps Not as Closely Related as Thought?]. National Geographic.

External link

- [http://chimp.st-and.ac.uk/cultures/intro.htm Chimpanzee Cultures Online] Category:Apes Category:Wildlife of Africa ja:チンパンジー属

Homo (genus)

Homo sapiens
See text for extinct species. Homo is the genus that includes modern humans and their close relatives. The genus is estimated to be between 1.5 and 2.5 million years old. All species except Homo sapiens are extinct; the last surviving relative, Homo neanderthalensis, died out 30,000 years ago, although recent evidence suggests that Homo floresiensis lived as recently as 12,000 years ago. A minority of zoologists consider that the two species of chimpanzees (usually treated in the genus Pan), and maybe the gorillas (usually treated in the genus Gorilla) should also be included in the genus based on genetic similarities. Most scientists argue that chimpanzees and gorillas have too many anatomical differences between themselves and humans to be part of Homo. The genus Homo is most closely related to Kenyanthropus platyops, which is likely to be an ancestral species. Through that species, Homo is next most closely related to the group of extinct species in the genera Paranthropus and Australopithecus, whose evolutionary branch split off from the proto-Homo line some 5 million years ago. The word homo is Latin for "man", in the original sense of "human being". The word "human" itself is from Latin humanus, an adjective cognate to homo, both derived from PIE "Earth".

Species

- Homo habilis (Handy Man)
- Homo rudolfensis (Rudolf Man)
- Homo ergaster (Working Man)
- Homo erectus (Upright Man)
- Homo floresiensis (Flores Man — discovered 2003)
- Homo antecessor (Explorer Man)
- Homo heidelbergensis (Heidelberg Man)
- Homo neanderthalensis (Neanderthal Man)
- Homo rhodesiensis (Rhodesia Man)
- Homo cepranensis (Ceprano Man)
- Homo georgicus (Georgia Man)
- Homo sapiens (Wise Man; modern humans) H. heidelbergensis and H. neanderthalensis are closely related to each other and have been considered to be subspecies of Homo sapiens, but analysis of mitochondrial DNA from H. neanderthalensis fossils suggests that the difference is great enough to count as a separate species. H. rhodesiensis and H. cepranensis are also more closely related to each other than to the other species.

References

- Serre et al. (2004) — No evidence of Neandertal mtDNA contribution to early modern humans. PLoS Biology 2:313–7.

External links

- [http://www.talkorigins.org/faqs/homs/species.html Hominid species]
- [http://www.modernhumanorigins.com/ For more details, including photos of fossil hominids + modern apes' skulls]
- [http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma/Chordata/Synapsida/Eutheria/Primates/Hominoidea/Hominidae.htm Mikko's Phylogeny archive] Category:Apes

Spinal shock

Spinal shock is an initial period of “hypotonia” that can result from damage to the motor cortex or other brain regions concerned with the activation of motor neurons. Since many of the descending motor nerves cross the midline, spinal shock originating from damage on one side of the brain (such as damage due to a stroke) can often be detected as reduced muscle activity on the contralateral side of the body. Loss of muscle function tends to be most severe in the arms and legs. Some control of trunk muscles is often preserved because of remaining brainstem pathways and spinal circuits that control midline musculature. Category: Neurology

Nature journal

Nature is one of the oldest and most reputable scientific journals, first published on 4 November 1869. Although most scientific journals are now highly specialized, Nature is idiosyncratic (along with other journals such as Science and PNAS) in still publishing original research articles across a wide range of scientific fields. In most fields of scientific research, many of the most important new advances each year are usually published as articles or letters in Nature. In astronomy and physical cosmology, most of the serious advances are published in specialist journals, but a short letter is often published in Nature for publicity purposes, in particular to get attention from the mainstream media. Research scientists are the primary audience for the journal, but article summaries and accompanying articles make many of the most important articles understandable for the general public. Toward the front of each issue are editorials and news and feature articles on issues of general interest to scientists, including current affairs, science funding, business, scientific ethics and research breakthroughs. There are also sections on books and arts. The remainder of the journal consists mostly of research articles which are often dense and highly technical. Having an article published in Nature is very prestigious, and the articles are often highly cited, leading to promotions, grant funding, and attention from the mainstream media. Because of these positive feedback effects, competition among scientists to publish in high-level journals like Nature and its closest competitor, Science, can be very fierce. Natures impact factor for 2004 was 32.182 (from Thomson/ISI). As with other professional scientific journals, articles undergo rigorous peer review before publication, in which other scientists, chosen by the editor for expertise with the subject matter but who have no connection to the research under review, will read and critique articles before publication. However, in the case of Nature, submitted articles undergo an initial screening procedure by the editor. They are only sent for review if it is decided that they deal with a topical subject or are sufficiently ground-breaking in a particular field. As a consequence, the majority of submitted articles are rejected without review.
Publication
Nature was founded in 1869 by Sir Joseph Norman Lockyer, an astronomer and physicist best known as the co-discoverer of helium. Lockyer was also the first editor of the journal from its founding until 1919. In Natures mission statement, it says: :It is intended, FIRST, to place before the general public the grand results of Scientific Work and Scientific Discovery; and to urge the claims of Science to a more general recognition in Education and in Daily Life; and, SECONDLY, to aid Scientific men themselves, by giving early information of all advances made in any branch of Natural knowledge throughout the world, and by affording them an opportunity of discussing the various Scientific questions which arise from time to time. Nature is a weekly journal edited and published in the United Kingdom by Nature Publishing Group, a subsidiary of Macmillan Publishers which in turn is owned by the Georg von Holtzbrinck Publishing Group. Nature has offices in London, New York City, San Francisco, Washington, D.C., Boston, Tokyo, Paris, Munich, and Basingstoke. Nature Publishing Group also publishes other specialized journals including Nature Neuroscience, Nature Biotechnology, Nature Methods, Nature Clinical Practice, Nature Structural & Molecular Biology and the Nature Reviews series of journals. Each issue of Nature is accompanied by the [http://www.nature.com/nature/podcast/index.html Nature Podcast] presented by Naked Scientist, [http://www.thenakedscientists.com/HTML/Who_we_are.htm Chris Smith]. The podcasts feature highlights from the issue and interviews with the articles' authors and the journalists covering the research.

Nature family of journals

In addition to Nature itself, there are three families of Nature-branded journals published by the Nature Publishing Group: :Nature research journals: :
- Nature Biotechnology :
- Nature Cell Biology :
- Nature Chemical Biology :
- Nature Genetics :
- Nature Immunology :
- Nature Materials :
- Nature Medicine :
- Nature Methods :
- Nature Neuroscience :
- Nature Physics :
- Nature Structural and Molecular Biology :Nature Review journals: :
- Nature Reviews Cancer :
- Nature Reviews Drug Discovery :
- Nature Reviews Genetics :
- Nature Reviews Immunology :
- Nature Reviews Microbiology :
- Nature Reviews Molecular Cell Biology :
- Nature Reviews Neuroscience :Nature Clinical Practice journals: :
- Nature Clinical Practice Cardiovascular Medicine :
- Nature Clinical Practice Endocrinology & Metabolism :
- Nature Clinical Practice Gastroenterology and Hepatology :
- Nature Clinical Practice Neurology, Nature Clinical Practice Nephrology :
- Nature Clinical Practice Oncology :
- Nature Clinical Practice Rheumatology :
- Nature Clinical Practice Urology

Relation to open science publishing

As of 2005, Nature has only partially responded to the challenge from the Public Library of Science and its supporters, who in 2001 signed a petition calling for all scientists to pledge that from September of 2001 they would discontinue submission of papers to journals which did not make the full-text of their papers available to all, free and unfettered after a six-month period from publication. Nature's response was to allow authors to self-archive their original submission, after an embargo date, for example on the arXiv.org e-print archive.

External links

- [http://www.nature.com/nature/ The Nature website]
- [http://www.nature.com/nature/first/ An electronic version of the first issue from 1869]
- [http://www.nature.com/reviews/index.html The Nature Reviews website]
- [http://www.nature.com/clinicalpractice/ Nature Clinical Practice website] Category:Scientific journals ko:네이처 ja:ネイチャー

Human evolution

Human evolution is the process of change and development, or evolution, by which human beings emerged as a distinct species. It is the subject of a broad scientific inquiry that seeks to understand and describe how this change and development occurred. The study of human evolution encompasses many scientific disciplines, most notably physical anthropology and genetics. The term 'human', in the context of human evolution, refers to the genus Homo, but studies of human evolution usually include other hominids, such as the australopithecines.

History of paleoanthropology

The modern field of paleoanthropology began with the discovery of 'Neanderthal man'; and evidence of other 'cave men' in the 19th century. The idea that humans are similar to certain great apes had been obvious to people for some time, but the idea of the biological evolution of species in general was not legitimized until after Charles Darwin published On the Origin of Species in 1859. Though Darwin's first book on evolution did not address the specific question of human evolution— "light will be thrown on the origin of man and his history," was all Darwin wrote on the subject— the implications of evolutionary theory were clear to contemporary readers. Debates between Thomas Huxley and Richard Owen focused on the idea of human evolution, and by the time Darwin published his own book on the subject, Descent of Man, it was already a well-known interpretation of his theory— and the interpretation which made the theory highly controversial. Even many of Darwin's original supporters (such as Alfred Russel Wallace and Charles Lyell) balked at the idea that human beings could have evolved their apparently boundless mental capacities and moral sensibilities through natural selection. Since the time of Carolus Linnaeus, the great apes were considered the closest relatives of human beings, based on morphological similarity. In the 19th century, it was speculated that our closest living relatives were chimpanzees and gorillas, and based on the natural range of these creatures, it was surmised humans share a common ancestor with African apes and that fossils of these ancestors would ultimately be found in Africa. It was not until the 1920s that fossils other than neanderthalensis were discovered. In 1924, Raymond Dart described Australopithecus africanus. The type specimen was the Taung Child, an australopithecine infant discovered in Taung, South Africa. The remains were a remarkably well-preserved tiny skull and an endocranial cast of the individual's brain. Although the brain was small (410 cm³), its shape was rounded, unlike that of chimpanzees and gorillas, and more like a modern human brain. Also, the specimen exhibited short canine teeth, and the position of the foramen magnum was evidence of bipedal locomotion. All of these traits convinced Dart that the Taung baby was a bipedal human ancestor, a transitional form between apes and humans. Another 20 years would pass before Dart's claims were taken seriously, following the discovery of more fossils that resembled his find. The prevailing view of the time was that a large brain evolved before bipedality. It was thought that intelligence on par with modern humans was a prerequisite to bipedalism. The australopithecines are now thought to be the immediate ancestors of the genus Homo, the group to which modern humans belong. Both australopithecines and Homo sapiens are part of the tribe Hominini, but recent data has brought into doubt the position of A. africanus as a direct ancestor of modern humans; it may well have been a dead-end cousin. The australopithecines were originally classified as either gracile or robust. The robust variety of Australopithecus has since been reclassified as Paranthropus. In the 1930s, when the robust specimens were first described, the Paranthropus genus was used. During the 1960s, the robust variety was moved into Australopithecus. The recent trend has been back to the original classification as a separate genus.

Before Homo

- The earliest hominids
- Aegyptopithecus
- Sahelanthropus tchadensis
- Orrorin tugenensis
- Ardipithecus kadabba
- Ardipithecus ramidus
- The Australopithecus genus
- Australopithecus anamensis
- Australopithecus bahrelghazali
- Australopithecus afarensis
- Australopithecus africanus
- Australopithecus garhi
- The Paranthropus genus
- Paranthropus aethiopicus
- Paranthropus boisei
- Paranthropus robustus

The Homo genus

In modern taxonomy, Homo sapiens is the only extant species of its genus, Homo. Likewise, the ongoing study of the origins of Homo sapiens often demonstrates that there were other Homo species, all of which are now extinct. While some of these other species might have been ancestors of H. sapiens, many were likely our 'cousins', having speciated away from our ancestral line. There is not yet a consensus as to which of these groups should count as separate species and which as subspecies of another species. In some cases this is due to the paucity of fossils, in other cases it is due to the slight differences used to distinguish species in the Homo genus. The word homo is Latin for 'person', chosen originally by Carolus Linnaeus in his classification system. It is often translated as 'man', although this can lead to confusion, given that the English word 'man' can be generic like homo, but can also specifically refer to males. Latin for 'man' in the gender-specific sense is vir, cognate with "virile" and "werewolf". The word 'human' is from humanus, the adjectival form of homo.

Homo habilis

H. habilis lived from about 2.4 to 1.5 million years ago (MYA). H. habilis, the first species of the genus Homo, evolved in South and East Africa in the late Pliocene or early Pleistocene, 2.5–2 MYA, when it diverged from the Australopithecines. H. habilis had smaller molars and larger brains than the Australopithecines, and made tools from stone and perhaps animal bones. One of the first known hominids, it was nicknamed 'handy man' by its discoverer, Louis Leakey.

Homo erectus

H. erectus (including H. ergaster) lived from about 1.8 MYA (or from about 1.25 MYA excluding ergaster) to 0.07 MYA. In the Early Pleistocene, 1.5–1 MYA, in Africa, Asia, and Europe, presumably, Homo habilis evolved larger brains and made more elaborate stone tools; these differences and others are sufficient for anthropologists to classify them as a new species, H. erectus. A famous example of Homo erectus is Peking Man; others were found in Asia (notably in Indonesia), Africa, and Europe. Many paleoanthropologists are now using the term Homo ergaster for the non-Asian forms of this group, and reserving H. erectus only for those fossils found in the Asian region and meeting certain skeletal and dental requirements which differ slightly from ergaster. They may have used fire to cook their meat.

Homo ergaster

H. ergaster lived from about 1.8 to about 1.25 MYA. Also proposed as Homo erectus ergaster

Homo heidelbergensis

H. heidelbergensis (Heidelberg Man) lived from about 800 thousand years ago (TYA) to about 300 TYA. Also proposed as Homo sapiens heidelbergensis and Homo sapiens paleohungaricus.

Homo sapiens idaltu

H. sapiens idaltu lived from about 160 TYA (proposed subspecies). Is the oldest anatomically modern human known.

Homo floresiensis

H. floresiensis, which lived from about 12 TYA (announced 28 October 2004 in the science journal Nature)), has been nicknamed hobbit for its small size, probably a result of Island dwarfing. H. floresiensis is intriguing both for its size and its age, being by far the most recent species of Homo that does not lie along the direct evolutionary path of modern humans.

Homo neanderthalensis

H. neanderthalensis lived from about 250 to 30 TYA. Also proposed as Homo sapiens neanderthalensis. There is ongoing debate over whether the 'Neanderthal Man' was a separate species, Homo neanderthalensis, or a subspecies of H. sapiens. While the debate remains unsettled, the prevailing view of evidence, collected by examining mitochondrial DNA and Y-chromosomal DNA, currently indicates that little or no gene flow occurred between H. neanderthalensis and H. sapiens, and, therefore, the two were separate species. In 1997, Dr. Mark Stoneking, then an associate professor of anthropology at Pennsylvania State University, stated: "These results [based on mitochondrial DNA extracted from Neanderthal bone] indicate that Neanderthals did not contribute mitochondrial DNA to modern humans… Neanderthals are not our ancestors."² Subsequent investigation of a second source of Neanderthal DNA confirmed these findings.³ However, supporters of the multiregional hypothesis point to recent studies indicating non-African nuclear DNA heritage dating to one MYA, as well as apparent hybrid fossils found in Portugal and elsewhere, in rebuttal to the prevailing view.

Homo sapiens

H. sapiens lived from about 200 TYA to the present. Between 400,000 years ago and the second interglacial period in the Middle Pleistocene, around 250,000 years ago, the trend in cranial expansion and the elaboration of stone tool technologies developed, providing evidence for a transition from H. erectus to H. sapiens. The direct evidence suggests there was a migration of H. erectus out of Africa, then a further speciation of H. sapiens from H. ergaster in Africa (there is little evidence that this speciation occurred elsewhere). Then a subsequent migration within and out of Africa eventually replaced the earlier dispersed H. erectus. However, the current evidence does not preclude multiregional speciation, either. This is a hotly debated area in paleoanthropology. 'Sapiens' means 'wise' or 'intelligent'.

Additional notes

The origins of humanity have often been a subject of great political and religious controversy (see Creation-evolution_controversy and Hybrid-origin) The classification of humans and their relatives has changed considerably over time (see History of hominoid taxonomy). Speculation about the future evolution of humans is often explored in science fiction as continued speciation of humans as they fill various ecological niches (see adaptive radiation and Co-evolution).

References

#Wolfgang Enard et al. "Molecular evolution of FOXP2, a gene involved in speech and language." Nature, Vol 418 (22 August 2002) p. 870. #[http://www.psu.edu/ur/NEWS/news/Neandertal.html DNA Shows Neandertals Were Not Our Ancestors] #Ovchinnikov, et al. "Molecular analysis of Neanderthal DNA from the Northern Caucasus." Nature 404, 490 (2000). #Crow TJ Ed. The Speciation of Modern Homo Sapiens OUP, Oxford, 2002.

External links

- [http://www.imperial.ac.uk/P3487.htm The human immune system may limit future evolution]
- [http://www.human-evolution.org Human evolution and the future]
- [http://www.andaman.org/book/chapter34/text34.htm Relations of the Homo sapiens]
- [http://www.talkorigins.org/faqs/homs/species.html Hominid Species] at talkorigins.org
- [http://www.psu.edu/ur/NEWS/news/Neandertal.html DNA Shows Neandertals Were Not Our Ancestors]
- [http://www.pbs.org/wgbh/nova/neanderthals/ Neanderthals on Trial] Nova Online - Provided by PBS.
- [http://www.becominghuman.org/ Becoming Human] - Provided by PBS.
- [http://www.mnh.si.edu/anthro/humanorigins/ha/a_tree.html Tree of evolution of Man's fossil ancestors]
- [http://www.evolutionpages.com/FOXP2_language.htm FOXP2 and the Evolution of Language]
- [https://www5.nationalgeographic.com/genographic/atlas.html Atlas of the Human Journey] (National Geographic)
- [http://info.anu.edu.au/mac/Newsletters_and_Journals/ANU_Reporter/_pdf/vol_29_no_01/dogs.html Theory suggets greater role for man's best friend]
- [http://groups.yahoo.com/group/AAT Waterside adaptations in the genus Homo]
- [http://homepage.uibk.ac.at/~c720126/humanethologie/ws/medicus/block1/inhalt.html Theory of Human Sciences (Documents No. 8 and 9 in English)]
- Category:Neogene th:วิวัฒนาการของมนุษย์

Human brain

The human brain is the center of the central nervous system in humans as well as the primary control center for the peripheral nervous system. The brain controls "lower" or involuntary activities such as heartbeat, respiration, and digestion - these are known as autonomic functions. The brain also controls "higher" order, conscious activities, such as thought, reasoning, and abstraction. The human brain is more capable of these higher order activities than any other species.

Overview

Human encephalization is especially pronounced in the neocortex, the most complex portion of the cerebral cortex. Singular among those of all animals, the human brain possesses the largest and most massive neocortex. Humans thus enjoy unique neural capacities, despite the fact that much of the human neuroarchitecture resembles that of more primitive species. Basic systems that alert the nervous system to stimuli, that sense events in the environment, and that monitor the condition of the body are similar in some ways to those of the most basic vertebrates. Human consciousness involves both the extended capacity of the modern neocortex in particular as well as profoundly developed prototypical structures of the brain stem. But the human brain is unique, in part, because it relies on some million billion synaptic connections, making it among the most intricate and densely connected networks among natural and fabricated systems found on Earth.

Anatomy

synaptic for an animated sequence of slices.]] The normal adult human brain typically weighs between 1 and 1.5 kg (three pounds) and has an average volume of 1,600 cm³ (98 in³). The male brain has approximately 4% more brain cells and 100 grams more brain tissue than the equivalent female brain. During infancy, adolescence and adulthood, females have a higher brain weight to body weight ratio than males. The mature brain consumes some 20% of the energy used by the body, while the developing brain of an infant consumes around 60%. Such heavy energy usage generates large quantities of heat, which must be continually removed to prevent brain damage. A bulbous cerebral cortex is composed of convoluted grey matter internally supported by deep brain white matter and separated by a prominent central fissure. A well-developed cerebellum is visible at the back of the brain. Brain stem structures are almost completely enveloped by the cerebellum and telencephalon, with only the medulla oblongata visible as it merges with the spinal cord. The blood supply to the brain involves several arteries that enter the brain and communicate in a circle called the circle of Willis. Blood is then drained from the brain through a network of sinuses that drain into the right and left internal jugular veins. The brain is suspended in cerebrospinal fluid (CSF) which also fills spaces called ventricles inside it. The dense fluid protects the brain and spinal cord from shock; a brain that weighs 1,500 g in air weighs only 50 g when suspended in CSF. (Livingston, 1965). Fluid movement within the brain is limited by the blood-brain barrier, brain-cerebrospinal fluid barrier and the blood-cerebrospinal fluid barrier. The brain is easily damaged by compression, so the fluid surrounding the central nervous system must be maintained at a constant volume. Humans are estimated to produce about 500 ml or more of cerebrospinal fluid each day, with only about 15 percent of the body's estimated 150 ml of CSF at any given time located in the ventricles of the brain. The remainder fills the subarachnoid space which separates the soft tissues of the brain and spinal cord from the hard surrounding bones (skull and vertebrae). Elevated levels of CSF are associated with traumatic brain injuries and a pediatric disease known as hydrocephalus. Increased fluid pressure can result in permanent brain injury and death. The exceptional size of the human brain resulted in some anatomical compromises. At birth, an infant's skull is as large as it can be without causing undue peril to the mother and child. However, prior to the intervention of modern medicine, childbirth was a dangerous event that frequently resulted in the death of the mother. The difficulty experienced by humans in giving birth is nearly unique in the animal kingdom. Female humans have large pelvic openings to accommodate the birth of large-headed children, but the larger this opening, the more the ability of the mother to run is compromised. At birth, the human skull is rather soft, and it deforms somewhat during its passage through the birth canal, then recovers its shape. This allows it to expand to make room for the brain, which continues to grow, at the same rate as that of an unborn fetus, for an additional year. In all other animals, the growth rate of the brain slows significantly at birth.

Function

childbirth The human brain is the seat of the human mind - the set of cognitive processes related to perception, interpretation, imagination and memories, of which a person might or might not be aware. Beyond cognitive functions, the brain regulates autonomic processes related to essential body functions such as respiration and heartbeat. Extended neocortical capacity allows humans some control over emotional behavior, but neural pathways between emotive centers of the brain stem and cerebral motor control areas are shorter than those connecting complex cognitive areas in the neocortex with incoming sensory information from the brain stem. Powerful emotional pathways can modulate spontaneous emotive expression regardless of attempts at cerebral self-control. Emotive stability in humans is associated with planning, experience and an environment that is both stable and stimulating, especially during early developmental years. The 19th century discovery of a primary motor control area mapped to correspond with regions of the body led to popular belief that the brain was organized around a homunculus. A distorted figure drawn to represent the body's motor map in the pre-frontal cortex was popularly recognized as the brain's homunculus, but function of the human brain is far more complex. The human brain appears to have no localized center of conscious control. Like the brains of other vertebrates, it derives consciousness from interaction among numerous systems within the brain. Executive decision-making functions rely on cerebral activities, especially those of the frontal lobes, but redundant and complementary processes within the brain result in a diffuse assignment of executive control that can be difficult to attribute to any single locale. Mid-brain functions include routing, selecting, mapping and cataloguing information, including information perceived from the environment and information that is remembered and processed throughout the cerebral cortex. Endocrine functions housed in the mid-brain play a leading role in modulating arousal of the cortex and of autonomic systems. Nerves from the brain stem complex where autonomic functions are modulated join nerves routing messages to and from the cerebrum in a bundle that passes through the spinal column to related parts of a body. Twelve pairs of cranial nerves, including some that innervate parts of the head, follow pathways from the medulla oblongata outside the spinal cord. A definite description of the biological basis for consciousness so far eludes the best efforts of the current generation of researchers. But reasonable assumptions based on observable behaviors and on related internal responses have provided the basis for general classification of elements of consciousness and of likely neural regions associated with those elements. Researchers know people lose consciousness and regain it, they have identified partial losses of consciousness associated with particular neuropathologies and they know that certain conscious activities are impossible without particular neural structures. A common myth is that human beings only use ten percent of our brains. This is false; we use our entire brains. The myth likely had its source in an advertisement or a misunderstanding of neurological research in the late 1800s or early 1900s. Some psychics help to prolong this myth by asserting that the "unused" ninety percent of the human brain is capable of exhibiting psychic powers, and can be trained to perform psychokinesis and extra-sensory perception. A less literal interpretation of the statement is, however, valid. It can be reasonably claimed that most people only use a very small fraction of the cognitive potential of their brain, even though all individual brain neurons are busily working. Various cultural inventions enable humans to better utilise their cognitive potential, such as reading, education, solving puzzles, critical thinking, etc.

Study of the brain

critical thinking Although folklore about putatively 90% dormant human brain has proven scientifically unfounded, researchers until the mid 1990s focused on only a small portion of the brain in efforts to understand its computational capacity. Grey matter, the thin layer of cells covering the cerebrum, was believed by most scholars to be the primary center of cognitive and conscious processing. White matter, the mass of glial cells that support the cerebral grey matter, was assumed to primarily provide nourishment, physical support and connective pathways for the more functional cells on the cerebral surface. But research fueled by the interest of Dr. Mary Diamond in the glial structure of Albert Einstein's brain led to a line of research that offered strong evidence that glial cells serve a computational role beyond merely transmitting processed signals between more functional parts of the brain. In 2004, Scientific American published an article suggesting scientists in the early 21st century are only beginning to study the "other half of the brain." For many millennia, the function of the brain was unknown. Ancient Egyptians threw the brain away prior to the process of mummification. Ancient thinkers such as Aristotle imagined that mental activity took place in the heart. Greek scholars assumed correctly that the brain serves a role in cooling the body, but incorrectly presumed the brain to function as a sort of radiator, rather than as a thermostat, as is now understood. The Alexandrian biologists Herophilus and Erasistratus were among the first to conclude that the brain was the seat of intelligence. Galen's theory that the brain's cavities, or ventricles, were the sites of thought and emotion prevailed until the work of the Renaissance anatomist Vesalius. Vesalius to view an animation of the scan from top to bottom.]] The brain is now studied in neurology and psychiatry, and is known to be the organ responsible for the phenomena of consciousness, thought and emotion. Studies of brain damage resulting from accidents led to the identification of specialized areas of the brain devoted to functions such as the processing of seeing and hearing. Brain imaging has allowed the function of the living brain to be studied in detail without damaging the brain. New imaging techniques allowed blood flow within the brain to be studied in detail during a wide range of psychological tests. Functional neuroimaging, including (fMRI), allows researchers to monitor activities in a brain while they are happening (see also history of brain imaging). Molecular analysis of the brain has provided insight into some aspects of what the brain does as an organ, but not how it functions as the seat of human consciousness. Further, the molecular and cell biological examination of brain pathology is hindered by the scarcity of appropriate samples for study, the (usual) inability to biopsy the brain from a living person suffering from a malady, and an incomplete description of the brain's microanatomy. With respect to the normal brain, comparative transcriptome analysis between the human and chimpanzee brain and between brain and liver (a common molecular baseline organ) has revealed specific and consistent differences in gene expression between human and chimpanzee brain and a general increase in the gene expression of many genes in humans as compared to chimpanzees. Furthermore, variations in gene expression in the cerebral cortex between individuals in either species is greater than between sub-regions of the cortex of a single individual. In addition to pathological and imaging studies, the study of computational networks, largely in computer sciences, provided a third key to unlocking many of the secrets of how the human brain functions. A body of knowledge developed for the production of electronic mathematic computational systems provided a basis for researchers to develop and refine hypotheses about the computation function of biological computational networks. The study of neural networks now involves study of both biological and artificial computational systems. A new discipline of cognitive science has started to fuse the results of these investigations with observations from psychology, philosophy, linguistics and computer science. Recently the brain was used in bionics by several groups of researchers. In a particular example, a joint team of U.S. Navy researchers and Russian scientists from Nizhny Novgorod State University worked to develop an artificial analogue of olivocerebellar circuit, a part of the brain responsible for balance and limb movement. The researchers plan to use it to control autonomous underwater vehicles.

Myths

The following are some common myths or misconceptions about the mind and brain, perpetuated through common or urban myths, the media, and the promotion of dubious products to consumers (Sala, 1999). A number of practitioners of pseudoscience, new age philosophies, and mystical or occult practices are known to use some of these myths as a part of their belief systems. Also see popular psychology.
- Myth: The human brain is firm and grey. The fresh/living brain is actually very soft, jelly-like and deep red. They do not become firm and grey until they have been preserved with various chemicals/resins.
- Myth: Humans use only 10% or 1% of their brain. Though the brain still holds mysteries that are being studied, every part of the brain is known to have a function. A possible origin of this myth is the fact that only about 10% of the neurons in the brain are firing at any given time. However, if all of your neurons began firing at once, you would not become smarter, but instead suffer an epileptic seizure. In fact studies have shown that the brains of more intelligent people are less active than the brains of less intelligent people, when working on the same problems.
- Myth: Mental abilities are separated into the left and right cerebral hemispheres. Some mental functions, like language production and comprehension, tend to be localized to specific areas in one hemisphere. If this hemisphere is damaged at a very early age, however, these functions can often be recovered by the other hemisphere. Other abilities like motor control, memory, and general reasoning are spread equally across the two hemispheres.
- Myth: Creativity can be easily developed using the simple brainstorming/lateral thinking techniques.
- Myth: Learning can be achieved more powerfully through subliminal techniques. Technically, information that is entirely subliminal cannot be perceived at all. The extent to which subliminal techniques can influence learning depends largely on what level of perception the techniques affect.
- Myth: Hypnosis can lead to perfect recall of details. Not only is this not entirely true, an incompetent or deceptive hypnotist can actually implant memories of events that never occurred.

Brain enhancement

Various methods have been proposed to improve the cognitive performance of the human brain, including pharmacological methods (nootropic drugs), electric stimulation (direct current polarization) and surgery. More advanced methods of brain enhancement may be possible in the future, perhaps including direct brain-computer interfaces. These proposed enhancements are a major focus of Transhumanism.

References

Books

- Simon, Seymour (1999). The Brain. HarperTrophy. ISBN 0688170609
- Thompson, Richard F. (2000). The Brain : An Introduction to Neuroscience. Worth Publishers. ISBN 0716732262
- Campbell, Neil A. and Jane B. Reece. (2005). Biology. Benjamin Cummings. ISBN 0805371710

External links

- [http://www.med.harvard.edu/AANLIB/home.html The Whole Brain Atlas]
- [http://www.sylvius.com Sylvius: 400+ structure neuroanatomical visual glossary; used by over half of U.S. medical schools]
- [http://primate-brain.org High-Resolution Cytoarchitectural Primate Brain Atlases]
- [http://faculty.washington.edu/chudler/facts.html Brain Facts and Figures]
- [http://www.thedoctorslounge.net/studlounge/articles/cerebcirc/index.htm Blood supply of the human brain]
- [http://vadim.www.media.mit.edu/MAS862/Project.html Estimating the computational capabilites of the human brain]
- [http://www.transhumanist.com/volume1/moravec.htm When will computer hardware match the human brain?] – an article by Hans Moravec
- [http://science.howstuffworks.com/brain.htm How the human brain works]
- [http://www.solbaram.org/articles/humind.html More about the Human brain!]
- [http://www.snopes.com/science/stats/10percnt.htm The Ten-Percent Myth], Snopes, by Benjamin Radford, 8 February 2000.
- [http://faculty.washington.edu/chudler/heshe.html Differences between female & male human brains]

Numbered references and notes

# general public reference:
—technical reference: # Khaitovich, P., et al. 2004. "Regional patterns of gene expression in human and chimpanzee brains". Genome Research, 14:1462-1473. refers to four studies of comparative transcriptome analysis prior to publication of the findings in the cited manuscript Category:Central nervous system ja:脳

Category:Evolutionary biology

Evolutionary biology is a subfield of biology concerned with the origin and descent of species, as well as their change over time. evolutionary biology Category:Evolution ko:분류:진화생물학

Gravediggers

Gravediggaz was a hardcore hip hop group from New York City, well-known for their dark sense of humor and abrasive, menacing soundscapes. The group was formed in 1994 and was effectively a "supergroup", bringing together Prince Paul (formerly producer with De La Soul and Stetsasonic), Frukwan from Stetsasonic, Poetic from the Brothers Grimm, and RZA from the Wu-Tang Clan (who at the time of Gravediggaz' formation had only just released their first album). The group are widely credited as being one of the most influential and pioneering groups in the small hip hop subgenre of horrorcore. The group's first album was originally titled Niggamortis; however, the potentially risqué title was changed to 6 Feet Deep for the American market (European versions of the album retained the original title, and also included the bonus track "Pass The Shovel"). Released on August 9 1994, 6 Feet Deep was a mix of over-the-top ghoulish black humor, cartoonish violence reminiscent of the Geto Boys, esoteric references to the Five Percent Nation of Gods and Earths, and gritty, foreboding beats reminiscent of RZA's work with the Wu-Tang Clan. The four members adopted Gravedigga alter-egoes for their work with the group: RZA became RZArecta, Poetic became the Grym Reaper, Prince Paul became the Undertaker, and Frukwan became the Gatekeeper. The three rapping members (without Prince Paul) released a collaborative EP titled "The Hell EP" with UK trip hop artist Tricky in 1995. The second full-length Gravediggaz album, The Pick, The Sickle and the Shovel (released in 1997) was considerably more mature and socially conscious than 6 Feet Deep, and used calmer and more intricate production. Prince Paul played a considerably smaller role in the making of this album, with many of the production duties now taken care of by RZA's Wu-Tang associates (including True Master and 4th Disciple). The Gravediggaz' third album, Nightmare in A Minor, was completed in 2001 and only featured two of the original members, Poetic and Frukwan. This album was their darkest work yet, including many references to Poetic's struggle with colon cancer as well as focusing on the more apocalyptic themes within the teachings of the Five Percent Nation. Although RZA did not take part in the making of the album, some Wu-Tang Clan affiliates such as 4th Disciple, True Master and Beretta 9 were involved. The album was mostly produced by Poetic and Frukwan themselves. Poetic finally succumbed to cancer in July 2001, two months before Nightmare in A Minor was to be released. Frukwan stated in an interview not long after Poetic's death that a new album using leftover Poetic material would be released[http://www.altrap.com/features/interviews/frukwan/frukwan.html], however nothing has so far materialized. It was recently rumored that Shabazz The Disciple, who featured on two tracks on 6 Feet Deep as well as one on The Pick, The Sickle & The Shovel, would fill the role of Poetic in a new formation of the Gravediggaz. Prince Paul, however, has stated he does not wish to be a part of any new version of the group.

Discography

- 1994 6 Feet Deep/Niggamortis
- 1997 The Pick, the Sickle and the Shovel
- 2001 Nightmare in A-Minor, 2002

Singles

- 1994 "Diary Of A Madman"
- 1994 "Nowhere To Run, Nowhere To Hide"
- 1994 "1-800 Suicide"
- 1997 "Unexplained"
- 1997 "The Night The Earth Cried"
- 1997 "Dangerous Mindz"

External links

- [http://www2.arnes.si/~ljzss46/gmain.html Gravediggaz fansite] Gravediggaz Category:Alternative hip hop musicians

House kalorie pozycjonowanie stron praca

Encephalization

References

References

See also

Antropology

Historical and institutional context

Anthropology in the U.S.

Anthropology in Britain

Anthropology in France

Anthropology after World War Two

Politics of anthropology

Anthropological fields and subfields

External links

See also

Chimpanzee

Lifespan

Chimpanzee differences

History of human interaction

Taxonomic relationships

Fossils

References

See also

External link

Homo (genus)

Species

References

External links

Spinal shock

Nature journal

Publication

Nature family of journals

Relation to open science publishing

External links

Human evolution

History of paleoanthropology

Before Homo

The Homo genus

Homo habilis

Homo erectus

Homo ergaster

Homo heidelbergensis

Homo sapiens idaltu

Homo floresiensis

Homo neanderthalensis

Homo sapiens

Additional notes

References

See also

External links

Human brain

Overview

Anatomy

Function

Study of the brain

Myths

Brain enhancement

See also

References

Books

External links

Numbered references and notes

Category:Evolutionary biology

Gravediggers

Discography

Singles

External links