Evolution of Homo Erectus to Homo Sapien
...s longer than arms, noticeable whites in the eyes, smaller hairs resulting in naked appearance and exposed skins, ect. Many scientists think Rudolfensis to be more ape like despite their large brains and bipedal locomotion. Homo georgicus is a species that was suggested to 2002 to describe fossil hominid skulls and jaws found in Dmanisi, Georgia in 1999 and 2001, which seem intermediate between Homo habilis and H. erectus. A partial skeleton was discovered in 2001. The fossils are about 1.8 million years old. At first, scientists thought they had found thirty or so skulls belonging to Homo ergaster, but size differences led them to consider erecting a new species, Homo georgicus, which would be the descendant of Homo habilis and ancestor of Asian Homo erectus. At around 600 cc, the skull D2700 is the smallest and most primitive hominid skull ever discovered outside of Africa. There is a strong sexual dimorphism, with males being significantly larger than females. Homo georgicus is the first hominid to settle in Europe, 800,000 years before Homo ergaster. Homo floresiensis ("Man of Flores") is a species in the genus Homo, remarkable for its small body, small brain, and survival until relatively recent times. It is thought to have been contemporaneous with modern humans (Homo sapiens) on the remote Indonesian island of Flores. One sub-fossil skeleton, dated at 18,000 years old, is largely complete except for arm bones which may yet be found. It was discovered in deposits in Liang Bua Cave on Flores in 2003. Also here, parts of six other individuals, all diminutive, have been recovered as well as similarly small stone tools from horizons ranging from 94,000 to 13,000 years ago. The first of these fossils were unearthed in 2003; the publication date of the original description is October, 2004; and confirmation of species status will probably appear soon with publication of recent revelations about the brain of Flores Man. Flores has been described (in the journal Nature) as "a kind of Lost World", where archaic animals, elsewhere long extinct, had evolved into giant and dwarf forms through allopatric speciation. The island had dwarf elephants (a species of Stegodon, a prehistoric elephant) and giant monitor lizards akin to the Komodo dragon, as well as H. floresiensis, which can be considered a species of diminutive human. The discoverers have called members of the diminutive species "hobbits", after J.R.R. Tolkien's fictional race of roughly the same height. In the island's mythology there were common references to Ebu Gogo, a small furry man, even into the 19th century. The Neanderthal or Neandertal was a species of genus Homo (Homo neanderthalensis) that inhabited Europe and parts of western Asia from about 230,000 to 29,000 years ago (in the Middle Palaeolithic, early Stone Age). Neanderthals were adapted to cold, as shown by their larger brains, short but robust builds and large nose. These traits are promoted by natural selection in cold climates, and are also observed in modern sub-arctic populations. Their brains were roughly 10 percent larger than those of modern humans. On average, Neanderthals stood about 1.65m tall (just under 5' 6") and were very muscular, comparable to modern weight-lifters. Their characteristic style of stone tools is called the Mousterian Culture, after a prominent archaeological site where the tools were first found. The first Neanderthal fossils were found in August, 1856, three years before Charles Darwin's Origin of Species was published. The fossils were found in a limestone quarry near Düsseldorf in the Neanderthal, Germany. The type specimen, dubbed Neanderthal 1, consisted of a skull cap. Other material found were two femora, the three right arm bones, two of the left arm bones, part of the left ilium, and fragments of a scapula and ribs. They were originally thought to be bear remains by the workers who recovered it. The workers gave the material to amateur naturalist Johann Karl Fuhlrott. Fuhlrott turned the fossils over to anatomist Hermann Schaafhausen and in 1857 the discovery was jointly announced. That discovery is now considered the beginning of paleoanthropology. These and other discoveries ultimately led to the idea that these remains were from ancient Europeans who had played an important role in modern human origins. Over 400 Neanderthals have been found since. Name and classification The term "Neanderthal Man" was coined in 1863 by Irish anatomist William King. Neanderthal is now spelled two ways: The spelling of the German word Thal, meaning "valley", was changed to Tal in the early twentieth century, but the former spelling is retained in English and in scientific names, while the modern spelling is used in German. For many years, there was a vigorous professional debate about whether Neanderthals should be classified as Homo neanderthalensis or Homo sapiens neanderthalensis. The latter places Neanderthals as a subspecies of Homo sapiens; however, recent evidence from mitochondrial DNA studies indicates that Neanderthals were not a subspecies of Homo sapiens. It is generally accepted that both Neanderthals and Homo sapiens evolved from earlier "archaic" Homo sapiens, but the classification of Neanderthals depends on when in the timeline these modern humans are considered a separate species from the "archaic" forms. This complication is introduced because the "archaic" forms are a chronospecies. Physical traits Reconstruction of a Neanderthal man shown in the Neandertal museum in Mettmann Compared to modern humans, Neanderthals were larger in size and had different cranial features. Much of their size is understood to be an adaptation to the cold climate of Europe during the Pleistocene epoch. The following is a list of physical traits that distinguish Neanderthals from modern humans; however, not all of them can be used to distinguish Neanderthals from other extinct populations. Also, many of these traits can occasionally occur in modern humans. Nothing is known about the skin color, the hair, or the shape of soft parts such as eyes, ears, and lips of Neanderthals. · Cranial o Suprainiac fossa, a groove above the inion o Occipital bun, a protuberance of the occipital bone that looks like a hair knot o Projecting mid-face o Globe-shaped skull (from rear) o Low, flat, elongated skull o Supraorbital torus, a browridge o 1200-1700 cm³ skull capacity (slightly greater than that of modern humans) o No chin o Crest on the mastoid process behind the ear opening o No groove on canine teeth o A space behind the last molars o A broad, projecting nose o Bony projections on the side of the nose opening o Different shape of the bony labyrinth in the ear · Post-Cranial o Considerably more muscular o Large round finger tips o Barrel-shaped rib cage o Different shape of the pelvis o Large kneecaps o Long collar bones o Short, bowed shoulder blades o Thick, bowed shaft of the thigh bones o Short shinbones and calf bones Language The theory that Neanderthals lacked complex language was widespread until 1983, when a Neanderthal hyoid bone was found at the Kebara Cave in Israel. The bone that was found is virtually identical to that of modern humans. The hyoid is a small bone that holds the root of the tongue in place, and its presence seems to imply some ability to speak. Many people believe that even without the hyoid bone evidence, it is obvious that tools as advanced as those of the Mousterian Era, attributed to Neanderthals, could not have been developed without cognitive skills encompassing some form of spoken language. A recent study conducted on the Neanderthal hyoid found that due to the physical characteristics of Neanderthals and the fact that their Larynx would have been stouter than that of modern man, the average note emmited by Neanderthals would have been high pitched and sharper than that of modern man. Tools Neanderthal (Middle Paleolithic) archeological sites show both a smaller and a less flexible toolkit than in the Upper Paleolithic sites, occupied by modern humans that replaced them. There is little evidence that Neanderthals used antlers, shell, or other bone materials to make tools: their bone industry was at most incipient and crude. However, there is good evidence that they routinely constructed a variety of stone implements. The Neanderthal (Mousterian) tool case consisted of sophisticated stone-flakes, task-specific hand axes, and spears. Many of these tools were very sharp. Also, while they had weapons, they were not used as projectile weapons. They had spears in the sense of a long wooden shaft with an arrow head firmly attached to it, but spears were first used as projectiles by Homo sapiens. Although much has been made of the Neanderthal's burial of their dead, their burials were less elaborate than those of anatomically modern humans. The interpretation of the Shandiar IV burials as including flowers, and therefore being a form of ritual burial (Solecki 1975), has been questioned (Sommer 1999). In some cases Neanderthal burials include grave goods such as bison and aurochs bones, tools, and the pigment ochre. Neanderthals performed a sophisticated set of tasks normally associated with humans alone. For example, they constructed complex shelters, controlled fire, and skinned animals. Particularly intriguing is a hollowed-out bear femur with four holes in the diatonic scale deliberately bored into it. This flute was found in western Slovenia in 1995 near a Mousterian Era fireplace used by Neanderthals, but its significance is still a matter of dispute. Homo sapiens sapiens - Human beings define themselves in biological, social, and spiritual terms. Biologically, humans are classified as the species Homo sapiens (Latin for "knowing man"): a bipedal primate belonging to the superfamily of Hominoidea, with all of the apes: chimpanzees, gorillas, orangutans, and gibbons. Humans have an erect body carriage that frees the upper limbs for manipulating objects, and a highly developed brain and consequent capacity for abstract reasoning, speech, language, and introspection. Behaviorally, human beings are defined by their use of language; their organization into complex social structures composed of many cooperating and competing groups, nations, states, and institutions, distinguished by their different aims and ritual practices; and their development of complex technology. These behavioral differences have given rise to myriad cultures incorporating many forms of beliefs, myths, rituals, values, and social norms. The self-consciousness of human beings, their resultant curious and introspective nature, and their dominance over other animals have given rise to attempts to explain the development and nature of the species, in both materialist and spiritual terms. The latter emphasizes a spiritual or non-physical dimension to life, and may include belief in God, gods or other supernatural entities, and reference to the concept of the soul. Such self-reflection is the basis of philosophy and is present in the earliest historical records. Terminology In English, juvenile males are called boys, adult males men, juvenile females girls, and adult females women. Humans are commonly referred to as persons or people and collectively as man, mankind, humanity, or the human race. Until the 20th century, human was only used adjectivally ("pertaining to mankind"). Nominal use of human (plural humans) is short for human being, and used not to be considered good style in traditional English grammar. As an adjective, human is used neutrally (as in human race), but human and especially humane may also emphasize positive aspects of human nature, and can be synonymous with benevolent. A distinction is maintained in philosophy and law between the notions "human being," or "man," and "person". The former refers to the species, while the latter refers to a rational agent: see, for example, John Locke's Essay concerning Human Understanding II 27 and Immanuel Kant's Introduction to the Metaphysic of Morals. The term "person" is thus used of non-human animals, and could be used of a mythical being, an artificial intelligence, or an extraterrestrial. An important question in theology and the philosophy of religion concerns whether God is a person. In Latin, humanus is the adjectival form of the noun homo, translated as "man" (to include males and females). The Old English word man could also have this generic meaning, as demonstrated by such compounds as wifman (“female person”) wiman woman. Biology Birth and death The life of the individual begins at conception. An egg is usually fertilized inside the female by the male through sexual intercourse, though in vitro fertilization methods are also used. The developing individual is first called a zygote; as it grows through successive stages inside the female's uterus over a period of 38 weeks, it is called an embryo, then a fetus. At birth, the fully grown fetus, now called a baby, is expelled from the female's body and breathes independently for the first time, at which point the baby is recognized as a person entitled to the full protection of the law, though some jurisdictions extend personhood to human fetuses while they remain in the uterus. Human life ends with the individual's death. Compared with that in other species, human childbirth is relatively complicated. Painful labors lasting up to twenty-four hours or more are not uncommon, and may result in injury to the child or the death of the mother, although the chances of a successful labor increased significantly during the twentieth century in wealthier countries. It remains an arguably more dangerous ordeal in remote, underdeveloped regions of the world, though the women who live in these regions have argued that their natural childbirth methods are safer and less traumatic for mother and child. The prospect of death may cause unease or fear. Burial ceremonies are characteristic of human societies, often inspired by beliefs in an afterlife. Institutions of inheritance or ancestor worship may extend an individual's presence beyond his physical lifespan. Physiology Biologically, humans are defined as hominids of the species Homo sapiens, of which the only extant subspecies is Homo sapiens sapiens. They are usually considered the only surviving species in the genus Homo, although some argue that the two species of chimpanzees should be reclassified from Pan troglodytes and Pan paniscus to Homo troglodytes and Homo paniscus, given their sharing a recent ancestor with man. Humans exhibit fully bipedal locomotion. This leaves the forelimbs available for manipulating objects using opposable thumbs. Humans vary substantially around the mean height and mean weight, which vary depending on locality and historical factors. Although body size is largely determined by genes, it is also significantly influenced by diet and exercise. The mean height of a North American adult female is 162 cm (64 in) and the mean weight is 62 kg (137 lb). North American adult males are typically larger: 175 cm (69 in) and 78 kilograms (172 lb). Human children are born after a nine-month gestation period, with typically 3-4 kilograms (6-9 pounds) in weight and 50-60 centimetres (20-24 inches) in height. Helpless at birth, they continue to grow for some years, typically reaching sexual maturity at 12-15 years of age. Boys continue growing for some time after this, reaching their maximum height around the age of 18. These values vary too, depending on genes and environment. Human skin color can range from very dark brown to very pale pink in different people. In general, people with ancestors from sunny regions have darker skin than people with ancestors from regions with less sunlight. However, this is complicated by the fact that there are people whose ancestors come from both sunny and less sunny regions; and these people may have skin colors across the spectrum. On average, women have slightly lighter skin than men. Two young female humans The human lifespan can be split into a number of stages: infancy, childhood, adolescence, maturity and old age, though the lengths of these stages, especially the later ones, are not fixed. There are striking differences in life expectancy around the world. The developed world is quickly getting older, with the median age around 40 years (highest in Monaco at 45.1 years), while in the developing world, the median age is 15-20 years (the lowest in Uganda at 14.8 years). Life expectancy at birth is 77.2 years in the U.S. as of 2001. The expected life span at birth in Singapore is 84.29 years for a female and 78.96 years for a male, while in Botswana, due largely to AIDS, it is 30.99 years for a male and 30.53 years for a female. One in five Europeans, but one in twenty Africans, is 60 years or older, according to The World Factbook. (http://www.cia.gov/cia/publications/factbook) The number of centenarians in the world was estimated by the United Nations (http://www.un.org/ageing/note5713.doc.htm) at 210,000 in 2002. The maximum human life span is thought to be over 120 years. Worldwide, there are 81 men aged 60 or over for every 100 women, and among the oldest, there are 53 men for every 100 women. Because humans are bipedal, the pelvic region and spinal column tend to get worn, creating locomotion difficulties in old age. Humans are also more likely than other primates to suffer from obesity because of poor diet and lack of exercise. Genetics Humans are a eukaryotic species. A human has 46 chromosomes: (22 pairs of autosomes, and 2 sex chromosomes). At present estimate, humans have approximately 20,000-25,000 genes and share 98.5% of their DNA with their closest living evolutionary relatives, the common chimpanzee and the bonobo, or pygmy chimpanzee. Humans have an XY sex determination system, so that females have the sex chromosomes XX and males have XY. The X chromosome is longer and carries many genes not on the Y chromosome, which means that defects of X-linked recessive genes affect men more often than women. For example, genes that control the clotting of blood reside on the X chromosome. Women have a blood-clotting gene on each X chromosome so that one normal blood-clotting gene can compensate for a flaw in the gene on the other X chromosome. But men are hemizygous for the blood-clotting gene since there is no gene on the Y chromosome to control blood clotting. As a result, men will suffer from hemophilia more often than women. Intelligence Leonardo da Vinci's Vitruvian Man Many humans consider themselves as the most intelligent species in the animal kingdom. Certainly, humans are the only technologically advanced animal. Along with neural complexity, the brain-to-body-mass ratio is generally assumed to be a good indicator of relative intelligence. Humans have the second highest brain-to-body-mass ratio or encephalization quotient (EQ) of all animals, with the tree shrew having the highest and the bottlenose dolphin very similar to humans. The human ability to abstract may be unparalleled in the animal kingdom. Human beings are one of four species to pass the mirror test — which tests whether an animal recognizes its reflection as an image of itself — along with chimpanzees or bonobos, orangutans, and dolphins. Human beings under the age of four usually fail the test. Emotion Human emotion has a significant influence on, or can even be said to control, human behaviour. Emotional experiences perceived as pleasant, like love or joy, contrast with those perceived as unpleasant, like hate, envy, or jealousy. In Pensées, Blaise Pascal wrote of the emotions: Weariness — Nothing is so insufferable to man as to be completely at rest, without passions, without business, without diversion, without study. He then feels his nothingness, his forlornness, his insufficiency, his dependence, his weakness, his emptiness. There will immediately arise from the...