The Utopian- A rEvolutionary Blog

In the halls of academia researchers are often more concerned about protecting their intellectual property than publishing the truth. Blogging offers a way to respect previous research, mine the information glut, and quickly publish the results. This blog is an experiment in gathering, documenting, associating, and presenting important information about human evolution using only a browser, the internet, and copy/paste techniques. These are not "my" words. I am only the editor.

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Location: United States

I have a BS degree in Wildlife from O.S.U. but most of my education comes from self study. I don't watch much TV because I don't think subjecting myself to all the materialistic and social propaganda is healthy. You can't view the world clearly if you put blinders on. My conclusions about the literature I cite on this website will be confined to the comments section. Please read those comments if you want to see the insights I have gained from my personal study. An interesting thing happened when I began this experiment. I discovered that bolding the important points of the research I was citing produced a rough summary of the information I could scan quickly, and also provided a easily referenced outline I could use to associate data from different sources using multiple browser windows. This led to a number of personal insights. Learning how to use blogs to data mine effectively can contribute greatly to the spread of global knowledge, and reduce the "information glut" that has accumulated.

Saturday, April 02, 2005

Scientist Warning to Humanity

Human beings and the natural world are on a collision course. Human activities inflict harsh and often irreversible damage on the environment and on critical resources. If not checked, many of our current practices put at serious risk the future that we wish for human society and the plant and animal kingdoms, and may so alter the living world that it will be unable to sustain life in the manner that we know. Fundamental changes are urgent if we are to avoid the collision our present course will bring about.

Our massive tampering with the world's interdependent web of life -- coupled with the environmental damage inflicted by deforestation, species loss, and climate change -- could trigger widespread adverse effects, including unpredictable collapses of critical biological systems whose interactions and dynamics we only imperfectly understand. Pressures resulting from unrestrained population growth put demands on the natural world that can overwhelm any efforts to achieve a sustainable future. If we are to halt the destruction of our environment, we must accept limits to that growth. No more than one or a few decades remain before the chance to avert the threats we now confront will be lost and the prospects for humanity immeasurably diminished.

Wednesday, February 23, 2005

Creative Commons

I just want to say that I truly support the idea of the free dissemination of intellectual information, and that I truly lament the various forms of copyrights and patents that are being put on so-called intellectual property. I also lament the collusion of universities in licensing the results of scientific research, and thus violating the project of the free dissemination of knowledge that is their reason for existence. So I consider it an important act to release these books under a Creative Commons type of license.

Friday, February 18, 2005

Thoughts on the Origins of Bipedality

Bipedality, the ability to walk upright using only the lower limbs, is the most ancient of all characteristics that distinguish humans from apes. Bipedality deprives us of speed and agility and all but eliminates our ability to easily climb trees. We must propel our body with two limbs instead of four, and we are generally unable to use the hip and back as parts of our propulsive muscle system.

During its earliest evolution, bipedality is thought to have been a very costly form of locomotion. However, a reproductive advantage must have fallen to those in each generation that walked more frequently in a bipedal posture. Many theories have been developed to try and explain the evolutionary success of bipedality.

The main goals in any evolutionary game are to eat, stay alive, and reproduce. The edge was not speed because most four-legged animals move faster than humans. It was not efficiency because moving on two legs uses no more nor less energy than moving on four legs unless one is traveling a long distance. If this is the case, the number of calories that are expended for travel are lower in a biped than in a chimp walking on four legs or an antelope on four legs.

Even a rise of several degrees in body temperature, from 98.6° to 107° F, poses a special threat to the human brain, leading rapidly to convulsions, hallucinations, permanent neural damage, and sometimes death. Because of its large size, the brain itself generates lots of heat, which can accumulate to dangerous levels if not dissipated. Fortunately, like the engine of a car, the brain has a radiator to protect it from overheating - a network of tiny veins that originate in the scalp and face.

Unlike modern humans, apes lack a venous radiator. The evolution of bipedalism necessitated changes in blood circulation and may have laid the groundwork for its emergence. An examination of fossil skulls, however, reveals that a venous radiator did not arise immediately. It is absent in the earliest-known hominid (Australopithecus afarensis) and in some of its successors, the "robust" australopithecines. Brain size remained conservative in these species. But a prototype radiator is present in the "gracile" australopithecines. This is most evident in the greater number of holes in the skull, called emissary foramina, to accommodate emissary veins. I therefore conclude that the gracile australopithecines gave rise to our own genus.

Beginning about two million years ago, the number of emissary foramina in the genus Homo began to increase dramatically. Brain size also began to increase rapidly in this group, and these trends continued in tandem until the time of the Neanderthals (about 100,000 years ago). The evolving venous radiator apparently removed a major constraint on the increase of brain size.

Humans are not the only large-brained animals that evolved cranial radiators. Some fifty million years ago, the terrestrial ancestors of whales (including dolphins) began a major change in posture and locomotion that culminated in their becoming exclusively adapted to an aquatic habitat. Like humans, whales have evolved large, highly convoluted brains that generate potentially damaging heat.

Hominids, or humanlike primates, first appeared in Africa five to seven million years ago, when that continent's climate was becoming increasingly arid and large tracts of woodland and savanna were replacing the unbroken canopy of the equatorial forest. While the ancestors of chimpanzees and gorillas remained in the moist forests, the hominids started to exploit the more open, drier habitats. The intense sunshine in the new environment, combined with a scarcity of drinking water, must have severely challenged the ability of early hominids to regulate their body temperature.

Most savanna mammals possess special physiological mechanisms to cool the brain - notably the carotid rete, a network of fine arteries near the base of the brain, coupled with venous circulation through the muzzle. Humans, apes, and monkeys, however, lack these features. The first hominids could have prevented damaging elevations of brain temperature only by keeping their entire body cool. Walking on two feet - the unique mode of terrestrial locomotion that is widely recognized as the first key development in hominid evolution - conferred precisely these benefits.

Bipedalism dramatically reduces exposure to direct solar radiation during the middle of the equatorial day. Bipedalism also raises most of the body well above the ground, so that the skin contacts cooler and faster-moving air currents. This favors heat dissipation through convection.

Scientists have long reasoned that one of the most obvious and unusual human features, the loss of insulating body hair, is an adaptation to the hot savanna. Although follicles are still densely distributed over most of the human body, the hairs they produce are so short and fine that the underlying skin is exposed directly to the flow of air, promoting the shedding of excess heat by convection. The problem with this hypothesis has always been explaining why humans differ from other savanna mammals, which have retained dense coats of hair.

In environments where mammals are exposed to strong solar radiation, the coat acts as a shield, reflecting and reradiating heat before it reaches the skin. For most mammals, the loss of this insulation would create more problems that it would solve. For a biped, in contrast, a naked skin saves water because so little skin surface is exposed to the sun. Mainly the head and upper shoulders are exposed, and these can be protected by the retention of a relatively small amount of hair cover. Bipedalism and the strategy of cooling the whole body (rather than just the brain) probably explain why humans evolved a naked skin, while other savanna mammals of comparable size did not.

Thursday, February 17, 2005

Human Evolution

Charles Darwin made three proposals that he thought, together, could explain the process of species transformation or evolution. They are the theories of natural selection (1859), sexual selection (1868) and pangenesis (more commonly called Lamarckian selection, 1871).

Natural selection is the first and most powerful of the selective processes. Sexual selection, Lamarckian selection (or the adopting of acquired characteristics), and additional selective processes outlined in this work, were created by the branching evolution of the selective processes themselves. In other words, not only do species evolve, but so do the processes behind species creation - a meta evolution.

Recent discoveries in neuropsychology evocatively support a side branch of contemporary evolutionary theory, heterochronic theory, which covers the study of neoteny in human evolution. There is a powerful body of evidence that suggests that Darwin’s third theory, pangenesis, makes way for an understanding of the etiology of neurological disorders in human beings as evidenced in recent discoveries of human hormonal structures and neurological anomalies.

There is powerful evidence that it was in periods of great climactic change that our ancestors made their greatest physical and societal evolution. Humanity's origin my have risen from a period when, during a time of food scarcity, the female hominids choose males inclined toward supplying the community (including his own unknown progeny) with food. Chimp behavior can suggest how the female hominid may have gone about choosing the father of her child, for it is with the premise that the early hominid female participates in choosing her copulation partner, just as in chimpanzee society, that this theory begins to fall into place.

Briefly, we are proposing that for two million years, up to approximately 100,000 to 40,000 years ago, hominid evolution was driven by the criteria females used to select males for their procreation partners (Tanner, 1981) included males who were increasingly cooperative, social, and less aggressive (Young 1971). Males with these characteristics were more inclined to succeed in a promiscuous social environment (Morgan, 1877;Margulis & Sagan, 1991) and more likely to be responsive to the needs of women with infants and children helpless for long periods. These characteristics were evidenced by males with less testosterone (T) than the more aggressive males.

By choosing males with low T, females are prolonging the developmental and maturation rates of their male progeny. In humans the relative levels of testosterone (and probably estrogen) in males and females is the primary hormonal intermediary between the eight environmental cues and relative rates of maturation. By prolonging growth, whether explained by heterochronic concepts of neoteny (Montagu, 1955, 1989; Gould, 1977) (prolonging child features into adulthood) or by hypermorphosis (Shea, 1989; McKinney and McNamara, 1990) (prolonging all developmental stages), one of the net results is increased brain and cranium size (Riska & Archley, 1985). Prolonging growth rates is achieved in humans by lowering T. Accelerating growth, in effect condensing developmental stages, is achieved by raising T.

The bonobo are more neotenous than the chimpanzee, and humans, more neotenous than the bonobo. The influence of neoteny results in a more socialized male, an increased emphasis on sex, yet a decrease in aggression. These are behaviors associated with neotenous evolution that when reinforced by sexual selection can explain how the human species evolved, an explanation supported by patterns revealed by the neuropsychological literature.

For the first two million years of hominid evolution males and females had developed an increasingly androgenous (Hassler, 1992), promiscuous dance and song driven culture (Knight, 1991). When a fully linear language appeared, female and male evolutionary trajectories diverged. There was a further shift to an aggressive male, high T frame of reference enforced by patriarchal societal criteria in sexual selection. In this emerging polygynous culture males chose females for their low T docility and for those characteristics evidencing high fertility. Females that looked and acted young were more likely to be chosen to have progeny. Males now choose females for their neotenic features (Jones, 1995).

It is in a patriarchal context that much of the sociobiological (Chagnon & Irons, 1979; Buss, 1989) and evolutionary psychological (Barkow et. al., 1992) criteria for natural and sexual selection in humans makes sense. Patriarchal society could control the kind of male that would have the opportunity to procreate. Female infanticide is patriarchal culture's method for keeping only high T males in the procreation pool. Shift theory suggests that female infanticide, the culturally encouraged killing of female infants, is one of the manifestations of sexual selection in a cultural context. Female infanticide can now be understood as a form of cultural preservation.

Monday, February 14, 2005

Apes of Wrath

Some female primates use social bonds to escape male aggression. Can women?

Researchers have observed various male animals-including insects, birds, and mammals-chasing, threatening, and attacking females. The males of many of these species are most aggressive toward potential mates, which suggests that they sometimes use violence to gain sexual access.

Jane Goodall provides us with a compelling example of how males use violence to get sex. In one of several scenarios, males gather around attractive estrous females and try to lure them away from other males for a one-on-one sexual expedition that may last for days or weeks. But females find some suitors more appealing than others and often resist the advances of less desirable males. Males often rely on aggression to counter female resistance. Goodall thinks that a male uses such aggression to train a female to fear him so that she will be more likely to surrender to his subsequent sexual advances.

Similarly, male hamadryas baboons, who form small harems by kidnapping child brides, maintain a tight rein over their females through threats and intimidation. If, when another male is nearby, a hamadryas female strays even a few feet from her mate, he shoots her a threatening stare and raises his brows. She usually responds by rushing to his side; if not, he bites the back of her neck. By repeating this behavior hundreds of times, the male lays claim to particular females months or even years before mating with them. When a female comes into estrus, she solicits sex only from her harem master, and other males rarely challenge his sexual rights to her.

These chimpanzee and hamadryas males are practicing sexual coercion: male use of force to increase the chances that a female victim will mate with him, or to decrease the chances that she will mate with someone else. But sexual coercion is much more common in some primate species than in others. Orangutans and chimpanzees are the only nonhuman primates whose males in the wild force females to copulate, while males of several other species, such as vervet monkeys and bonobos, rarely if ever try to coerce females sexually.

These dramatic differences between species provide an opportunity to investigate which factors promote or inhibit sexual coercion. For example, we might expect to find more of it in species in which males are much larger than females-and we do. However, size differences between the sexes are far from the whole story. Chimpanzee and bonobo males both have only a slight size advantage, yet while male chimps frequently resort to force, male bonobos treat the fair sex with more respect. Clearly, then, although size matters, so do other factors.

In some species, females remain in their birth communities their whole lives, joining forces with related females to defend vital food resources against other females. In such "female bonded" species, females also form alliances against aggressive males. Vervet monkeys are one such species, and among these small and exceptionally feisty African monkeys, related females gang up against males. High-ranking females use their dense network of female alliances to rule the troop; although smaller than males, they slap persistent suitors away like annoying flies.

Females in other species leave their birth communities at adolescence and spend the rest of their lives cut off from their female kin. In most such species, females do not form strong bonds with other females and rarely support one another against males. Both chimpanzees and hamadryas baboons exhibit this pattern, and, as we saw earlier, in both species females submit to sexual control by males.

This contrast between female-bonded species, in which related females gang together to thwart males, and non-female-bonded species, in which they don't, breaks down when we come to the bonobo. Female bonobos, like their close relatives the chimpanzees, leave their kin and live as adults with unrelated females. Recent field studies show that these unrelated females hang out together and engage in frequent homoerotic behavior, in which they embrace face-to-face and rapidly rub their genitals together; sex seems to cement their bonds. Examining these studies in the context of my own research has convinced me that one way females use these bonds is to form alliances against males, and that, as a consequence, male bonobos do not dominate females or attempt to coerce them sexually. How and why female bonobos, but not chimpanzees, came up with this solution to male violence remains a mystery.

Female primates also use relationships with males to help protect themselves against sexual coercion. Among olive baboons, each adult female typically forms long-lasting "friendships" with a few of the many males in her troop. When a male baboon assaults a female, another male often comes to her rescue. In return for his protection, the defender may enjoy her sexual favors the next time she comes into estrus. There is a dark side to this picture, however. Male baboons frequently threaten or attack their female friends-when, for example, one tries to form a friendship with a new male. Other males apparently recognize friendships and rarely intervene. The female, then, becomes less vulnerable to aggression from males in general, but more vulnerable to aggression from her male friends.

As a final example, consider orangutans. Because their food grows so sparsely, adult females rarely travel with anyone but their dependent offspring. But orangutan females routinely fall victim to forced copulation. Female orangutans, it seems, pay a high price for their solitude.

Decreasing women's vulnerability to sexual coercion, then, may require fundamental changes in social alliances. Women gave voice to this essential truth with the slogan SISTERHOOD IS POWERFUL-a reference to the importance of women's ability to cooperate with unrelated women as if they were indeed sisters. However, among humans, the male-dominant social system derives support from political, economic, legal, and ideological institutions that other primates can't even dream of. Freedom from male control-including male sexual coercion-therefore requires women to form alliances with one another (and with like-minded men) on a scale beyond that shown by nonhuman primates and humans in the past. Although knowledge of other primates can provide inspiration for this task, its achievement depends on the uniquely human ability to envision a future different from anything that has gone before.

Saturday, February 12, 2005

Wading for Food: The Driving Force of the Evolution of Bipedalism?

"The recent discovery of sahelanthropus tchadensis has brought into focus once more questions about the factors which may have led some ape clades to begin to evolve those most distinguished human traits: large brain size and bipedality. This find, the oldest putative hominid yet, as well as recent nutritional studies have both strengthened the idea that human evolution occurred in water-side rather than arid, open savannah grassland habitats."

"Evidence is accumulating that suggests that the large human brain is most likely to have evolved in littoral and estuarine habitats rich in naturally occurring essential fatty acids. This paper adds further weight to this view, suggesting that another key human train, our bipedality, might also be best explained as an adaptation to a water-side niche."

"Evidence from apes in the wild show that though preferring to keep dry, they do go into water when driven to do so by hunger and tend to do so bipedally. A new empirical study of captive bonobos found them to exhibit 2% or less bipedality on the ground or in trees but over 90% when wading in water to collect food."

"The paleo-habitats of the earliest known bipeds, and all the evidence reviewed here (as is that of the newly discovered Sahelanthropus), is consistent with the hypothesis that wading contributed to the adaptive pressure towards bipedality."

"One tricky question remains: If a water-side habitat was the original driver both for a bipedal way of locomotion and for an increase in brain size, why did bipedality evolve so much earlier than large brains? The large brain capacity of Homo is a, relatively, recent phenomenon according to the fossil record and only really begins with Homo erectus and then accelerates more recently with Homo sapiens. If hominids have been living in water-side habitats all along, why did larger brains not evolve long ago?"

http://allserv.rug.ac.be/~mvaneech/Fil/Verhaegen_Language_
SpeculationsScienceTechnology.html

The aquatic ape theory (AAT) of Sir Alister Hardy (1) states that a few million years ago human ancestors spent a considerable part of their day swimming and diving in a river, lake or sea, and, at least partially, consumed aquatic food. The AAT is supported by the presence of our thick subcutaneous fat layers, by our lack of body hair and by several other features that are absent in non-human primates, but widespread among aquatic mammals (1-13).

The ability to speak is a uniquely human characteristic. Innumerable attempts to explain it have been made but the question of how language emerged is not yet solved. Recently, it has been suggested that the origin of speech was facilitated by our aquatic past (5,14). All aquatic mammals "voluntarily" control their breathing. When surfaced they open the airway passage whenever they want to inhale air, and they can hyperventilate and then close the airway passage when they intend to dive. The subtle "voluntary" control of breathing and airway closure in mammals in general is a pre-adaptation for speech (15,16).

Aquatic mammals can close the airway entrances much more completely than land mammals, thus avoiding being drowned by water entering the lungs, and they have a very refined voluntary control of mouth, nose and throat passages.

Modern man has a very special anatomy of the airway entrances that is not incompatible with a previous semi-aquatic lifestyle. He has a smaller mouth which can be closed more efficiently (24) and, presumably, the wet mucosa of our fleshy lips allows a better fit than the dry skin of the lips of non-human primates. In other primates, the tongue is generally flatter and somewhat less mobile than in humans (ref. 16, p.625). Our nasal cavity is elongated by an external nose (ref. 25, Figure 159) and narrowed by strongly developed inferior conchae, which often cause even complete obstruction in some humans (11,26,29). The nasal cavity can be disconnected from the throat by muscles that raise the velum (probably also in apes) (5).

Our primary motor projection cortex is much larger than that of apes, mostly due to the expansion of the areas for the musculature of mouth, throat and breathing, i.e. the latero-inferior section of Area 4 (see Figure 1). Just in front of that enlarged Area 4 lies Broca’s Area. It is a typically human structure indispensable for speech generation, and can be distinguished histologically from all other human cortical areas (ref. 30, pp.5-12).

In order to use the voluntary airway control for the vocal apparatus, our ancestor must have been able to register and interpret his own sound production (feedback, cf. motor theory of speech production) (31,32). This was certainly improved by the evolution of the arcuate fasciculus (see Figure 1), a typically human neural pathway between Broca’s Area and Wernicke’s Area (33).

Compared with a chimpanzee’s brain, our association areas are enormously large. These areas are found in the temporal, preoccipital, parietal and inferior frontal lobes (see Figure 1). The cortex of these areas can be distinguished histologically from the other cortical areas and even from Broca’s Area (ref. 30, pp.5-12). This suggests that Broca’s Area and the association areas evolved separately (respectively in Phases II and IV?). In my interpretation, most association areas evolved after the breathing and air-holding function of the enlarged Area 4 and Broca’s Area had been integrated with sound generation (Phase III). The new association areas amplified the possible applications of the sound-producing apparatus.

There are indications, I think, that our ancestors returned to a more terrestrial habitat not earlier than two million years ago (in a cooler and drier period of the Pleistocene? see ref. 11). In the hominid fossil record, the great expansion of the association areas seems to begin about two million years ago, with the genus Homo (34,35). The limited brain enlargement of Homo habilis could correspond broadly with the enlargement of Area 4, Broca’s area (34), the arcuate fasciculus and Wernicke’s Area; that of Homo erectus with a further association cortex enlargement.

The relatively small size of the brain of the australopithecines (possibly without a real Area of Broca (34)) could be explained by their dwelling or having dwelt in inland semi-aquatic habitats (e.g. gallery forests), and not in littoral habitats (11). If early Homo lived at the sea coasts, he had to dive deeper and longer than his freshwater cousins, so the voluntary control of this airway muscles became more important. Brain enlargement is a striking feature of many cetaceans. Conceivably, the support of the body (and brain) weight by the surrounding water allowed sea mammals to obtain large brains.

Concerning the relation of language and thought, I assume that a simpler (non-verbal) sort of thinking already existed in our pre-aquatic ancestors, but the great unfolding of human cognitive abilities became possible only after the acquisition of proper input/output organs for the brain. Hence, our great communicational capacities may not have evolved thanks to our large brain; rather the opposite seems true: large association areas only became usable with our voluntary sound production.

Of Lice And Men: Parasite Genes Reveal Modern & Archaic Humans Made Contact

"A University of Utah study showing how lice evolved with the people they infested reveals that a now-extinct species of early human came into direct contact with our species about 25,000 years ago and spread the parasites to our ancestors."

"The study found modern humans have two genetically distinct types of head lice. One type is found worldwide and evolved on the ancestors of our species, Homo sapiens. The second type is found only in the Americas, evolved on another early human species (possibly Homo erectus) and jumped to Homo sapiens during fights, sex, sharing of clothes or perhaps cannibalism."

"Alan Rogers, a co-author of the study and professor of anthropology at the University of Utah, says: “The record of our past is written in our parasites.” The analysis of lice genes also confirmed two other key developments in human evolution. First, it verified studies showing how and when various species branched off the family tree of primates and humans. Second, it confirmed the “out of Africa” theory that the population of Homo sapiens mushroomed after a small band of the early humans left Africa sometime between 150,000 and 50,000 years ago."

"Transmission of the second type of lice from a now-extinct human species to Homo sapiens may have happened during mating, so Reed plans a study of pubic or crab lice – which only spread sexually – to confirm or disprove that possibility. Clayton says evidence of contact between two species of humans is surprising because “Homo erectus has long been thought to have gone extinct hundreds of thousands of years ago,” although recent studies suggested Homo sapiens might have had contact with Homo erectus in Asia 50,000 years ago."

"Reed says: “Not only did modern humans live contemporaneously with close cousins such as Neanderthals, but also with more archaic hominids such as Homo erectus, a species that we have not shared a common ancestor with for over a million years. Reed wonders if contact with our species proved fatal."

“When scientists first determined that we (Homo sapiens) were contemporaneous with Neanderthals (Homo neanderthalensis) in Europe, it was suspicious that our contact with them immediately preceded their extinction,” Reed says. “Our study has provided evidence that we had contact with Homo erectus in Asia just prior to the extinction of that species as well. Did we cause the extinction of two other species of humans?”

"The researchers found the family tree of the lice closely mirrors the previously published family tree of humans and their primate ancestors. That was consistent with the well-known phenomenon that any single species or lineage of lice (like other parasites) tends to stick only to one species of host and rarely jumps to other hosts."

"Some of the findings conflict with two major theories of human evolution – the “replacement model” and “multiregional model” and instead fit best with a third theory known as the “diffusion wave model.”

"(1) The replacement model says that after primitive human ancestors first left Africa about 2 million years ago, a second wave spread out from Africa sometime after 150,000 years ago and certainly by 50,000 years ago, and then replaced other now-extinct species of early humans in Africa, Asia and Europe without breeding with them."

"Clayton says that model doesn’t fit the louse data because if Homo sapiens from Africa replaced archaic humans elsewhere without interacting with them, the type of lice on archaic humans would have gone extinct with their hosts instead of jumping to modern humans."

"(2) The multiregional model says early humans from Africa and elsewhere in the world mated with other each other, so Homo sapiens gradually evolved in many regions worldwide. But if so much interbreeding occurred, the two groups of lice probably would not have remained genetically distinct for the last 1.18 million years, Rogers says."

"(3) The diffusion wave model falls between the other two theories. Like the replacement theory, it says modern humans arose in Africa and spread across the world, Rogers says. Like the multiregional theory, it says those early humans mated with humans elsewhere. The diffusion wave theory adds a new twist, namely, that the genes of humans spreading from Africa came to dominate the modern human genetic blueprint because when they mated with archaic humans, the children were less fit."

"The new study confirmed several events in primate and human evolution. The researchers found chimp lice and human lice diverged roughly 5.6 million years ago, consistent with previous evidence that chimps and human ancestors diverged from a common ancestor about 5.5 million years ago."

"The study also supports the controversial view that there was a “bottleneck” or reduction in the global Homo sapiens population to only about 10,000 people about 100,000 to 50,000 years ago. Rogers and others have proposed the bottleneck may have occurred because of a mass die-off of early humans due to a globally catastrophic volcanic eruption. Others believe the population bottleneck seen in human genes happened because only a small group of human ancestors left Africa in the second wave 150,000 to 50,000 years ago,"

"The new study used the mutation rate in lice and comparisons of genetic differences among lice to find a similar population bottleneck in the group of head lice that infested early Homo sapiens, but no such bottleneck in the population of the lice on the archaic human species. That means archaic humans didn’t go through the same population shrinkage and thus must have spread their lice to Homo sapiens sometime after 50,000 years ago. Rogers speculates contact occurred 25,000 or 30,000 years ago."

"The findings provide independent confirmation of the second “out of Africa” event because genetic analysis shows the population of lice – like their Homo sapiens hosts – also dramatically expanded after the bottleneck."

New Ethiopian Fossils Are From 6-million-year-old Hominid Living Just After Split From Chimpanzees

"In all the great apes - and that includes fossil and modern - the large, tusk-like, projecting, shearing canine teeth are used as weapons, and in most of them the main use is in males fighting with other males for access to estrus females," White said. "The earliest hominids lack that adaptation, showing much smaller canines that are not at all chimpanzee-like."

"The implication of this dental difference is that the newly evolved hominids were living in a radically different, less competitive social structure than seen in modern chimps, he said."

"The researchers note two other sites that have yielded fossil hominids from the same 5- to 6-million-year period. One group of fossils found in 2002 in Chad has been named Sahelanthropus tchadensis, while others found at a Kenyan site in 2000 have been dubbed Orrorin tugenensis. All of these fossils are sufficiently similar that they should be included in the same genus as Ardipithecus kadbba, the team argues."

http://www.sciencedaily.com/releases/2000/01/000110142554.htm
Big Bang Theory Of Human Evolution?

"All the available evidence supports an 'Out of Africa' theory, that humans first evolved in Africa about two million years ago, then spread to other regions of the world," says John Hawks, first author of the paper and now an assistant professor of anthropology at the University of Utah. "This original population lived before humans colonized regions outside of Africa. In fact, it was the act of becoming human that made these colonizations possible."

"A second reason for suspecting that a population bottleneck led to a rapid genetic reorganization that started the process of human evolution comes from archeological evidence of a series of behavioral changes suggestive of a new adaptive pattern of hunting, gathering and scavenging. "Body size is a key element in these behavioral changes," the authors note, "because of the locomotor changes that large body size denotes, and the increased metabolic resources it requires." These behavioral changes are far more massive and sudden than any earlier changes known for hominids, they point out.""Many details of subsequent human evolution over the period of the ice ages remain unclear, but one certain finding from both anthropological and genetic data is that there was no later time when the size of the human species became small again," says Hawks.

http://www.sciencedaily.com/releases/2003/08/030807075457.htm
Early Hominids May Have Behaved More 'Human' Than We Had Thought

"Previously skeptical, an Ohio State University anthropologist now supports the idea that the minimal size differences between male and female pre-hominids suggest that they lived in a more cooperative and less competitive society. The evidence centers on the extent of sexual dimorphism – differences in size based on sex --that existed among these early primates and what it suggests about the social structure of these creatures."

"Paleontologists knew that there were minimal size differences between males and females since Homo sapiens evolved but the fossil record is so sparse, they were unsure of whether pre-Homo species showed more of less sexual dimorphism."

"The comparison showed that the sex-based size differences among the fossils at Site 333 were no greater than those for modern humans, suggesting that the same kind of modern social structure with cooperating males also occurred in the days of Australopithecus afarensis."

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Human eating behaviour in an evolutionary ecological context.

"One hallmark trait of human feeding behaviour, complex control of food availability, emerged with Homo erectus (1.9 x 10(6)-200000 years ago), who carried out this process by either increased meat eating or by cooking, or both. Another key trait of human eating behaviour is the symbolic use of food, which emerged with modern Homo sapiens (100000 years ago to the present) between 25000 and 12000 years ago. From this and subsequent social and economic transformations, including the origins of agriculture, humans have come to use food in increasingly elaborate symbolic ways,"

http://www.sciencedaily.com/releases/1999/08/990810064914.htm
Light My Fire: Cooking As Key To Modern Human Evolution

"Fire provided the "spark" for modern human evolution, but not because it allowed our ancestors to eat meat. Rather, it was the ability to cook tuberous roots akin to carrots, potatoes and beets that caused hominids to turn a major evolutionary corner about 1.9 million years ago."

"The researchers link the advent of tuber cooking to changes in body size and tooth size that separated Homo erectus from earlier hominids such as australopithecines, of which "Lucy" is the most famous specimen. They said that tuber cooking could also have brought about basic changes in hominid social structure. The key word is cooking, not tubers."

"The process of human evolution had much to do with food and how it was prepared," said Laden. Australopithecines like Lucy had huge teeth suitable for chewing all day long, and males were much bigger than females. But 1.9 million years ago, things changed. Teeth got smaller, and both sexes increased in size. Females increased in size more than males, and so the size gap between the sexes shrank. Homo erectus had arrived, and cooking of tubers made the difference."

"We strongly suspect hominids began using fire about 1.9 million years ago, when Homo erectus appeared," said Laden. "The evidence for fire this early is a bit tenuous, but once word got out about our idea, we were contacted by colleagues working in East Africa who are about to publish very strong evidence for human-controlled fire at a very early date. In any event, fire wouldn't have worked as a 'spark' to evolution if roots hadn't already been in the diet."

"According to Laden and his colleagues, both Lucy and Homo erectus ate tubers, but Lucy ate them raw. Thus, she and her australopithecine relatives had huge teeth and strong jaws. But with the advent of fire, hominids were able to cook tubers, which softened them, making chewing easier, and increased the amount of available nutrients."

"Teeth no longer had to be huge and suitable for constant chewing. Further, cooking allowed hominids to expand their diets. Many tubers are poisonous unless cooked, so cooking opened up new food sources. The use of tubers may have helped australopithecines expand their range from rainforest to savanna, where tubers were numerous. But cooking foods went beyond this, said Laden, and had profound effects on early human size and social behavior."

"On an evolutionary scale, male primates are limited in reproduction by access to females," said Laden, "but females are limited by access to resources." When cooking increased the supply of calories, females were able to grow to a larger size. At the same time, a decrease in the male-female size difference signalled a change in mating systems."

"Highly polygynous mating systems, such as the harem system of gorillas or the promiscuous mating of chimps, are typically associated with males being much larger than females," said Laden. "When male and female mammals are close in size, pair bonding is the rule. So this change about 1.9 million years ago is probably best explained as a change in mating practices."

"This social change is probably more important than, and was caused by, the expansion of the diet, Laden said. Cooking required changes in how food was prepared. Like living chimps, australopithecines would have eaten food on the spot whenever it was found. But cooking meant bringing food to a common site for processing, where other members of the group--including larger and more dominant individuals--could see it."

"We propose that cooking opens the door for theft, so among cooking hominids, there would have been cause to cooperate in new ways," said Laden. Females would have been vulnerable to theft by much larger males. This would have resulted in evolutionary pressure for females to form bonds with males, basing their choice on male willingness to cooperate in defending food stores rather than on male size."

"Laden and his colleagues believe this might have led to an important evolutionary novelty of humans: female sexual attractiveness. Unlike humans, other female primates are sexually attractive only around the time of ovulation, as indicated by obvious physical and behavioral changes, Laden said. But women are generally attractive to males, and this is part of the process by which long-term bonds can form between individuals. This would have lessened the benefit many male mammals gain from direct competition for females in heat."

"We don't know if males or females invented cooking, or who did the cooking, but the kind of 'scramble' competition we see in primates would have made a cooking-based strategy impossible, while pair bonding and formation of a sort of family around a hearth would be a stable, evolutionarily sensible strategy," he said."

"All these changes resulted in humans becoming a species that ate a wider variety of foods than their ancestors, formed more stable pair bonds and cooperated in cooking and defending food stores."

Morphological affinities of the Australopithecus afarensis hand on the basis of manual proportions and relative thumb length.

"Our results indicate that A. afarensis possessed overall manual proportions, including an increased thumb/hand relationship that, contrary to previous reports, is fully human and would have permitted pad-to-pad human-like precision grip capability. We show that these human-like proportions in A. afarensis mainly result from hand shortening, as in modern humans."

"Since A. afarensis predates the appearance of stone tools in the archeological record, the above-mentioned conclusions permit a confident refutation of the null hypothesis that human-like manual proportions are an adaptation to stone tool-making,"

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11260704
New hominin genus from eastern Africa shows diverse middle Pliocene lineages.

"A 3.5 Myr-old cranium, showing a unique combination of derived facial and primitive neurocranial features, is assigned to a new genus of hominin. These findings point to an early diet-driven adaptive radiation, provide new insight on the association of hominin craniodental features, and have implications for our understanding of Plio-Pleistocene hominin phylogeny."

Hand of Paranthropus robustus from Member 1, Swartkrans: fossil evidence for tool behavior.

"New hand fossils from Swartkrans (dated at about 1.8 million years ago) indicate that the hand of Paranthropus robustus was adapted for precision grasping. Functional morphology suggests that Paranthropus could have used tools, possibly for plant procurement and processing."

"The new fossils further suggest that absence of tool behavior was not responsible for the demise of the "robust" lineage. Conversely, these new fossils indicate that the acquisition of tool behavior does not account for the emergence and success of early Homo."

Thursday, February 10, 2005

Bonobo Sex and Society

At a juncture in history during which women are seeking equality with men, science arrives with a belated gift to the feminist movement. Male-biased evolutionary scenarios-- Man the Hunter, Man the Toolmaker and so on--are being challenged by the discovery that females play a central, perhaps even dominant, role in the social life of one of our nearest relatives. In the past few years many strands of knowledge have come together concerning a relatively unknown ape with an unorthodox repertoire of behavior: the bonobo

The species is best characterized as female-centered and egalitarian and as one that substitutes sex for aggression. Whereas in most other species sexual behavior is a fairly distinct category, in the bonobo it is part and parcel of social relations--and not just between males and females. Bonobos engage in sex in virtually every partner combination (although such contact among close family members may be suppressed). And sexual interactions occur more often among bonobos than among other primates. Despite the frequency of sex, the bonobo's rate of reproduction in the wild is about the same as that of the chimpanzee. A female gives birth to a single infant at intervals of between five and six years. So bonobos share at least one very important characteristic with our own species, namely, a partial separation between sex and reproduction.

This finding commands attention because the bonobo shares more than 98 percent of our genetic profile, making it as close to a human as, say, a fox is to a dog. The split between the human line of ancestry and the line of the chimpanzee and the bonobo is believed to have occurred a mere eight million years ago. The subsequent divergence of the chimpanzee and the bonobo lines came much later, perhaps prompted by the chimpanzee's need to adapt to relatively open, dry habitats. In contrast, bonobos probably never left the protection of the trees. Their present range lies in humid forests south of the Zaire River, where perhaps fewer than 10,000 bonobos survive.

"If this evolutionary scenario of ecological continuity is true, the bonobo may have undergone less transformation than either humans or chimpanzees. It could most closely resemble the common ancestor of all three modern species. Indeed, in the 1930s Harold J. Coolidge--the American anatomist who gave the bonobo its eventual taxonomic status--suggested that the animal might be most similar to the primogenitor, since its anatomy is less specialized than is the chimpanzee's. Bonobo body proportions have been compared with those of the australopithecines, a form of prehuman. When the apes stand or walk upright, they look as if they stepped straight out of an artist's impression of early hominids."

In both baboons and chimpanzees, males are conspicuously dominant over females; they reign supremely and often brutally. It is highly unusual for a fully grown male chimpanzee to be dominated by any female. Although female bonobos are much smaller than the males, they seem to rule.

"Fruit is central to the diets of both wild bonobos and chimpanzees. The former supplement with more pith from herbaceous plants, and the latter add meat. Although bonobos do eat invertebrates and occasionally capture and eat small vertebrates, including mammals, their diet seems to contain relatively little animal protein. Unlike chimpanzees, they have not been observed to hunt monkeys. Whereas chimpanzees use a rich array of strategies to obtain foods--from cracking nuts with stone tools to fishing for ants and termites with sticks--tool use in wild bonobos seems undeveloped. (Captive bonobos use tools skillfully.)"

Sex, it turned out, is the key to the social life of the bonobo. The first suggestion that the sexual behavior of bonobos is different had come from observations at European zoos. Wrapping their findings in Latin, primatologists Eduard Tratz and Heinz Heck reported in 1954 that the chimpanzees at Hellabrun mated more canum (like dogs) and bonobos more hominum (like people). In those days, face-to- face copulation was considered uniquely human, a cultural innovation that needed to be taught to preliterate people (hence the term "missionary position"). These early studies, written in German, were ignored by the international scientific establishment. The bonobo's humanlike sexuality needed to be rediscovered in the 1970s before it became accepted as characteristic of the species.

Bonobos become sexually aroused remarkably easily, and they express this excitement in a variety of mounting positions and genital contacts. Although chimpanzees virtually never adopt face-to-face positions, bonobos do so in one out of three copulations in the wild. Furthermore, the frontal orientation of the bonobo vulva and clitoris strongly suggest that the female genitalia are adapted for this position.

Another similarity with humans is increased female sexual receptivity. The tumescent phase of the female's genitals, resulting in a pink swelling that signals willingness to mate, covers a much longer part of estrus in bonobos than in chimpanzees. Instead of a few days out of her cycle, the female bonobo is almost continuously sexually attractive and active.

Perhaps the bonobo's most typical sexual pattern, undocumented in any other primate, is genito-genital rubbing (or GG rubbing) between adult females. One female facing another clings with arms and legs to a partner that, standing on both hands and feet, lifts her off the ground. The two females then rub their genital swellings laterally together, emitting grins and squeals that probably reflect orgasmic experiences. (Laboratory experiments on stump- tailed macaques have demonstrated that women are not the only female primates capable of physiological orgasm.)

Male bonobos, too, may engage in pseudocopulation but generally perform a variation. Standing back to back, one male briefly rubs his scrotum against the buttocks of another. They also practice so-called penis-fencing, in which two males hang face to face from a branch while rubbing their erect penises together.

The diversity of erotic contacts in bonobos includes sporadic oral sex, massage of another individual's genitals and intense tongue-kissing. Lest this leave the impression of a pathologically oversexed species, I must add, based on hundreds of hours of watching bonobos, that their sexual activity is rather casual and relaxed. It appears to be a completely natural part of their group life. Like people, bonobos engage in sex only occasionally, not continuously.

That sex is connected to feeding, and even appears to make food sharing possible, has been observed not only in zoos but also in the wild. Nancy Thompson-Handler, then at the State University of New York at Stony Brook, saw bonobos in Zaire's Lomako Forest engage in sex after they had entered trees loaded with ripe figs or when one among them had captured a prey animal, such as a small forest duiker. The flurry of sexual contacts would last for five to 10 minutes, after which the apes would settle down to consume the food.

There are two reasons to believe sexual activity is the bonobo's answer to avoiding conflict.

First, anything, not just food, that arouses the interest of more than one bonobo at a time tends to result in sexual contact. If two bonobos approach a cardboard box thrown into their enclosure, they will briefly mount each other before playing with the box. Such situations lead to squabbles in most other species. But bonobos are quite tolerant, perhaps because they use sex to divert attention and to diffuse tension.

Second, bonobo sex often occurs in aggressive contexts totally unrelated to food. A jealous male might chase another away from a female, after which the two males reunite and engage in scrotal rubbing. Or after a female hits a juvenile, the latter's mother may lunge at the aggressor, an action that is immediately followed by genital rubbing between the two adults.

Given its peacemaking and appeasement functions, it is not surprising that sex among bonobos occurs in so many different partner combinations, including between juveniles and adults. The need for peaceful coexistence is obviously not restricted to adult heterosexual pairs.

Apart from maintaining harmony, sex is also involved in creating the singular social structure of the bonobo. This use of sex becomes clear when studying bonobos in the wild.

Both bonobos and chimpanzees live in so-called fission- fusion societies. The apes move alone or in small parties of a few individuals at a time, the composition of which changes constantly. Several bonobos traveling together in the morning might meet another group in the forest, whereupon one individual from the first group wanders off with others from the second group, while those left behind forage together. All associations, except the one between mother and dependent offspring, are of a temporary character.

Rather than being male- bonded, bonobo society gives the impression of being female- bonded, with even adult males relying on their mothers instead of on other males. No wonder Kano calls mothers the "core" of bonobo society. The bonding among female bonobos violates a fairly general rule, outlined by Harvard University anthropologist Richard W. Wrangham, that the sex that stays in the natal group develops the strongest mutual bonds.

Bonobos are unique in that the migratory sex, females, strongly bond with same-sex strangers later in life. In setting up an artificial sisterhood, bonobos can be said to be secondarily bonded. (Kinship bonds are said to be primary.) Although we now know HOW this happens--through the use of sexual contact and grooming--we do not yet know WHY bonobos and chimpanzees differ in this respect.

Observers at the Belgian animal park of Planckendael, which currently has the most naturalistic bonobo colony, reported similar findings. If a male bonobo tried to harass a female, all females would band together to chase him off. Because females appeared more successful in dominating males when they were together than on their own, their close association and frequent genital rubbing may represent an alliance. Females may bond so as to outcompete members of the individually stronger sex.

It has been speculated by anthropologists-- including C. Owen Lovejoy of Kent State University and Helen Fisher of Rutgers University--that sex is partially separated from reproduction in our species because it serves to cement mutually profitable relationships between men and women. The human female's capacity to mate throughout her cycle and her strong sex drive allow her to exchange sex for male commitment and paternal care, thus giving rise to the nuclear family.

Although bonobos clearly do not establish the exclusive heterosexual bonds characteristic of our species, their behavior does fit important elements of this model. A female bonobo shows extended receptivity and uses sex to obtain a male's favors when--usually because of youth--she is too low in social status to dominate him.

Human family life implies paternal investment, which is unlikely to develop unless males can be reasonably certain that they are caring for their own, not someone else's, offspring. Bonobo society lacks any such guarantee. Yet no degree of moralizing can make sex disappear from every realm of human life that does not relate to the nuclear family. The bonobo's behavioral peculiarities may help us understand the role of sex and may have serious implications for models of human society.

The Challenge of the Matriarchy By Evelyn Reed

Woman's Evolution, which deals with the hidden history of women, is a feminist book. But it is more than that; it marks a new theoretical turn in anthropology, which in recent years has witnessed a progressive deterioration in its methodology. Let us examine the reasons for this decline and what is required to put anthropology back on the right track.

Anthropology was founded by Morgan, Tylor, and other nineteenth-century evolutionists, who defined the new science as a study of prehistoric society and its origins. The two most important of the numerous discoveries they made were: Primitive society was a collectivise egalitarian system having none of the inequities of modern society, which is founded upon the patriarchal family, private property, and the state. It was likewise a matriarchal society in which women occupied positions of leadership in productive and social life and were held in high esteem.

These features stood in such sharp contrast to the conditions which prevail in patriarchal society that they soon gave rise to controversies which brought about a deep division in anthropological circles. After the turn of the century new trends of thought arose, led by Boas, Radcliffe-Brown, and others, who rejected the method and principal findings of the founding scholars .

These schools abandoned a comprehensive evolutionary approach and substituted in its place empirical and descriptive field studies of contemporary primitive peoples surviving in various parts of the globe. They discarded Morgan's three stages of social evolution - from savagery through barbarism to civilisation - without offering any pattern of progression of their own.

As anthropology became more trivialised, further explorations into the matriarchal epoch and the hidden history of women virtually came to a halt. Students in the universities were taught that Morgan and the other founders of anthropology were "old-fashioned" and "out-of-date." In academic circles the matriarchy became a non-subject.

To justify this discrediting of the pioneers it is usually contended that there was "insufficient" documentation on the prior existence of the matriarchy, and, in any case, no one could ever draw any "universal" conclusions about a remote period that was forever closed off from view. This contention is highly ironical since the opponents of the evolutionists have not hesitated to set forth some "universal" theories of their own.

The claim that there is insufficient documentation on the prior existence of the matriarchy is unfounded. The pioneer scholars brought forth a wealth of materials derived from different avenues of investigation. They assembled this data from literary sources as well as from actual observations and field studies on the matrilineal structure still surviving in many regions of the globe. They noticed that wherever matriliny was still in force patriarchal institutions were either nonexistent or only feebly developed. And they drew cogent conclusions from their studies of primitive customs, traditions, myths, and rituals which had survived from the former matriarchal epoch.

Let me pose three most important queries:

Opponents of the matriarchy do not deny the presence of the matrilineal kinship system, since it exists to the present day in many primitive regions. Where did this matrilineal structure come from if not from the ancient matriarchal epoch?

Why has the passage from matrilineal to patrilineal kinship always been in that direction, never the other way around?

Why is the ancient system of matrilineal kinship and descent found nowadays only in primitive regions and never in the advanced patriarchal nations, which have long lost and forgotten their matriarchal origins?

Such is the sad state of anthropology today in the hands and heads of confused and despairing men. They frankly admit that, one by one, the most significant subjects have been degraded to non-subjects and their books reduced to non-books. Are we now to look forward to the final admission that anthropology itself is bankrupt and a non-science?

This is the end result of the wrong course taken more than half a century ago by the anti-evolutionists. It has brought about the stagnation and demoralisation of a once - vigorous branch of social science. What is needed to rescue anthropology from its blind alley? It must return, although on a higher level, to the evolutionist and materialist approach of the pioneer scholars.

That is precisely what I have tried to do in my book Woman's Evolution, which begins with the basic premise of the priority of the maternal clan system or matriarchy. Upon this foundation 1 have been able to develop new theories that explain the meaning and purpose of certain enigmatic institutions of savage society, including the ones so cavalierly disqualified as non-subjects - totemism and kinship.

My own theory on totemism came about, somewhat accidentally, through a closer examination of taboo, which is indissolubly connected with totemism. I could not accept the standard reason given for the primitive taboo - that it was directed against incest. Primitive peoples were ignorant of the most elementary biological facts of life, including how babies are conceived and the inevitability of death. How, then, could they have understood the concept of incest?

Moreover, the taboo was a double taboo, applying to food as well as to sex. In fact, the clause applying to food was the more elaborate and stringent prohibition. Most investigators were aware of this twofold character of the taboo, but because the food prohibition seemed inexplicable, they focused their attention on the sex clause.

Since the taboo is regarded as the oldest prohibition in human history, going back to the primeval epoch, the thought entered my mind that it must have been directed against cannibalism. There was a logic to this surmise which was confirmed by my subsequent researches. Apes in nature are vegetarians; our branch of the primates became meat-eaters only after they became hominids. How could they know, at a time when they were still part ape, that all hominids belonged to a species distinct from all other animals?"

In other words, the earliest hunters had to learn what flesh they could not eat at the very time they were learning how to hunt, kill, and eat flesh foods. This dilemma, stemming from biological ignorance, could only be solved through social and cultural means. To my mind, this explains how the first social regulation in human history - totemism and taboo - developed. It was first and foremost a prohibition against cannibalism, and it began as a protection of the totem-kin.

Totem-kinship marked the dividing line between human flesh that could not be killed or eaten and animal flesh that could. Those who were born of the same horde of mothers and who lived and worked together in the same community were the totem-kin; that is, the human beings, the "people." Outsiders and strangers were non-kin and therefore non-human; they were "animals" which could be killed and eaten. Thus, while totem-kinship began on a small and limited scale, it furnished protection for the in-group, or kin - group - the primal horde.

Subsequently this protection against cannibalism became broader in scope. This was accomplished through the interchange system, usually called "gift-giving," by which different groups began exchanging food and other things with one another. These acts converted them from strangers and enemies (or "animals" in the most primitive concept) into new kinds of kinsmen and friends. These linkages created a network of affiliated clans which ultimately became the large tribe. On this higher cultural level cannibalism dwindled to an occasional ritual until it vanished altogether.

The other clause of the taboo was simply a sex taboo, having nothing whatever to do with incest. As many scholars have pointed out, male sexuality in the animal world - where males fight one another for access to females - is a violent force. Such individualism and competitiveness had to be suppressed since human survival depended upon the closest cooperation of all the members of the group. Thus, it became imperative to overcome animal sexuality and to convert fighting males into the human brotherhood.

This goal was also achieved through totemism and taboo. All males in the totem-kin group were forbidden access to any females of that group. All the older women were classified as the mothers (or older sisters); the women of a man's own generation were his sisters, and the female children were his younger sisters. In this way the antisocial characteristics of animal sexuality were suppressed, and the foundation for the tribal brotherhood was laid. The clan system of social organisation arose as a non-sexual, economic and social association of mothers, sisters, and brothers.

The two clauses of the taboo have an interlocking relationship. Food and sex represent the most imperative hungers in human and animal life; they are the twin driving forces behind the survival of the species. The hunger for food must be satisfied if the organism is to maintain itself., the hunger for sex must be satisfied if the species is to reproduce itself. The double taboo on food and sex therefore represents the earliest social controls over these imperative needs. And without these controls, human organisation could not have gained its start.

Far from being a figment of the imagination of early anthropologists or a non-subject, totemism is in fact one of the most important subjects to be investigated in reconstructing our most ancient history. Totemism and taboo represent the means by which humankind elevated itself out of animality.

Those who have turned away from the matriarchy, however, fail to understand totemism because it was the female sex that instituted it. In the beginning the females were the advantaged sex; they were the mothers, responsible for the survival of the species. Unlike males, who suffered from the biological handicap of incessant striving for dominance over other males, females could band together for the protection of themselves and their offspring. This nurturing, cooperative trait enabled the females to make the great advance from the maternal brood in the animal world to the maternal clan system in the human world.

Then, through the institution of totemism and taboo, the females were able to correct the biological deficiencies of the males. They began by socialising the two basic hungers. They expelled all internal hunting - whether for food or mates - from the group composed of totem-kin mothers, sisters, and brothers. By this means, both cannibalism and fights for dominance were overcome, and males were brought together as the clan brothers. This cooperative association of men - the fratriarchy, as I call it - has no counterpart in the animal world. It represents the crowning achievement of the totemic system, which was instituted by the women.

The kinship system in its mature form grew up out of the totem-kinship system. The difference in development lies in the fact that the totem-kin included certain animals along with humans, whereas the mature system was restricted to humans alone. Lewis Morgan called this system the "classificatory" kinship system to distinguish it from the kinship system which exists today.

Classificatory kinship was a system of social kinship embracing all the members of the community. In other words, all the members of the clans and affiliated clans were social mothers, sisters, and brothers, their biological relationships being unknown or irrelevant. Like its predecessor the totem-kinship system, the classificatory system was also matrilineal. However, the male line of kinship and descent in the matriarchal period was traced through the "fraternal" line, i.e., the mothers' brothers.

In the course of time, patrilineal kinship also became recognised when the man who married the mother became the father of her child. About eight thousand years ago, what Morgan called the "pairing family" (the father living under the same roof with the mother and her child) came into existence. Gradually the father and patrilineal kinship crowded out the mother's brother and fratrilineal kinship. However, it was not until the fully developed patriarchal family displaced the pairing family that the classificatory system of kinship was overturned and replaced by the family system of kinship.

Patrilineal kinship in the period of the matriarchy was no more than a paternal relationship between two matrilineal clans in which the mother-brother relationship remained pre-eminent and decisive. In other words, every so-called patrilineal clan was also and more fundamentally a matrilineal clan with the mothers' brothers occupying a more important and permanent status than the newly emerging husbands and fathers.

As the anthropological record shows, the mothers' brothers were the guardians and tutors of their sisters' sons - and the male line of descent, succession, and inheritance accordingly passed from maternal uncle to nephew. This line of descent prevailed throughout the entire epoch of the matrilineal clan system, even after patrilineal kinship was recognised. However, while it was possible to assimilate patrilineal kinship into the mother-brother clan without altering its basic structure, the same was not true of patrilineal descent. Changing the line of male descent from mother's brother to father shattered the fratriarchy - and that, in turn, brought down the matriarchy. Both were replaced by the patriarchy.

In my book I explain that the matri-family (my term for Morgan's "pairing family") was the last stage in the evolution of the matri-clan system. Because it recognised the father and patrilineal kinship, it was a "divided family.' It was torn between two functional fathers - the mother's brother and her husband. However, the mother's brother held the fixed, permanent, and traditional ties to his sister's son, while the father had only ephemeral kinship ties to his wife's child. The "divided family" and was a serious obstacle in the path of the full development of a unified one-father family.

To us, in hindsight, it may seem like the easiest, most logical concession in the world for the mother's brother to resign his place in his sister's family, give up his matrilineal fathership of his sister's son, and move on to become the patrilineal father of his wife's son. But that is not the way it worked out at that historical turning point in the transition from the divided family to the one-father family.

The chains of tradition and custom bound the participants of that period. They did not know how or why they had inherited their one-sided matrilineal kinship system, nor did they know how to liberate themselves from it once it became outworn and obsolete.
The result was a protracted and bloody struggle between the contending categories of men - the matrilineal and the patrilineal fathers. I describe this transition in Woman's Evolution, which details the extremely painful process by which the divided family finally was replaced by the patriarchal one-father family. In the same process the family system of kinship replaced the former classificatory, or social, system of kinship.

My book ends with a fresh analysis of three great Greek tragedies about the myth-histories of Medea, Oedipus, and Orestes. All reflect in dramatic terms the terrible cost paid to achieve the victory of the patriarchal family.