Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs or legs. An animal or machine that moves in a bipedal manner is known as a biped, meaning "two feet". Types of bipedal movement include running, or hopping. Few modern species are habitual bipeds. Within mammals, habitual bipedalism has evolved multiple times, with the macropods, kangaroo rats and mice, hopping mice and hominin apes as well as various other extinct groups evolving the trait independently. In the Triassic period some groups of archosaurs developed bipedalism. A larger number of modern species intermittently or use a bipedal gait. Several lizard species move bipedally when running to escape from threats. Many primate and bear species will adopt a bipedal gait in order to reach food or explore their environment, though there are a few cases where they walk on their hindlimbs only. Several arboreal primate species, such as gibbons and indriids walk on two legs during the brief periods they spend on the ground.
Many animals rear up on their hind legs whilst copulating. Some animals stand on their hind legs, in order to reach food, to keep watch, to threaten a competitor or predator, or to pose in courtship, but do not move bipedally; the word is derived from the Latin words bi'two' and ped-'foot', as contrasted with quadruped'four feet'. Limited and exclusive bipedalism can offer a species several advantages. Bipedalism raises the head. While upright, non-locomotory limbs become free for other uses, including manipulation, digging, combat or camouflage; the maximum bipedal speed appears less fast than the maximum speed of quadrupedal movement with a flexible backbone – both the ostrich and the red kangaroo can reach speeds of 70 km/h, while the cheetah can exceed 100 km/h. Though bipedalism is slower at first, over long distances, it has allowed humans to outrun most other animals according to the endurance running hypothesis. Bipedality in kangaroo rats has been hypothesized to improve locomotor performance, which could aid in escaping from predators.
Zoologists label behaviors, including bipedalism, as "facultative" or "obligate". This distinction is not clear-cut — for example, humans other than infants walk and run in biped fashion, but all can crawl on hands and knees when necessary. There are reports of humans who walk on all fours with their feet but not their knees on the ground, but these cases are a result of conditions such as Uner Tan syndrome — rare genetic neurological disorders rather than normal behavior. If one ignores exceptions caused by some kind of injury or illness, there are many unclear cases, including the fact that "normal" humans can crawl on hands and knees; this article therefore avoids the terms "facultative" and "obligate", focuses on the range of styles of locomotion used by various groups of animals. Normal humans may be considered "obligate" bipeds because the alternatives are uncomfortable and only resorted to when walking is impossible. There are a number of states of movement associated with bipedalism.
Standing. Staying still on both legs. In most bipeds this is an active process. Walking. One foot in front of another, with at least one foot on the ground at any time. Running. One foot with periods where both feet are off the ground. Jumping/hopping. Moving by a series of jumps with both feet moving together; the great majority of living terrestrial vertebrates are quadrupeds, with bipedalism exhibited by only a handful of living groups. Humans and large birds walk by raising one foot at a time. On the other hand, most macropods, smaller birds and bipedal rodents move by hopping on both legs simultaneously. Tree kangaroos are able to walk or hop, most alternating feet when moving arboreally and hopping on both feet when on the ground. There are fossil bipedal amphibians. Many species of lizards become bipedal during high-speed, sprint locomotion, including the world's fastest lizard, the spiny-tailed iguana; the first known biped is the bolosaurid Eudibamus. Its long hindlegs, short forelegs, distinctive joints all suggest bipedalism.
The species became extinct in the early Permian. All birds are bipeds. Bipedalism evolved more than once in archosaurs, the group that includes both dinosaurs and crocodilians. All dinosaurs are thought to be descended from a bipedal ancestor similar to Eoraptor. Bipedal movement re-evolved in a number of other dinosaur lineages such as the iguanodons; some extinct members of the crocodilian line, a sister group to the dinosaurs and birds evolved bipedal forms - a crocodile relative from the triassic, Effigia okeeffeae, is thought to be
In biology, mating is the pairing of either opposite-sex or hermaphroditic organisms for the purposes of sexual reproduction. Some definitions limit the term to pairing between animals, while other definitions extend the term to mating in plants and fungi. Fertilization is the fusion of both sex gamete. Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization. Mating may lead to external fertilization, as seen in amphibians and plants. For the majority of species, mating is between two individuals of opposite sexes. However, for some hermaphroditic species, copulation is not required because the parent organism is capable of self-fertilization; the term mating is applied to related processes in bacteria and viruses. Mating in these cases involves the pairing of individuals, accompanied by the pairing of their homologous chromosomes and exchange of genomic information leading to formation of recombinant progeny. For animals, mating strategies include random mating, disassortative mating, assortative mating, or a mating pool.
In some birds, it includes behaviors such as feeding offspring. The human practice of mating and artificially inseminating domesticated animals is part of animal husbandry. In some terrestrial arthropods, including insects representing basal phylogenetic clades, the male deposits spermatozoa on the substrate, sometimes stored within a special structure. Courtship involves inducing the female to take up the sperm package into her genital opening without actual copulation. In groups such as dragonflies and many spiders, males extrude sperm into secondary copulatory structures removed from their genital opening, which are used to inseminate the female. In advanced groups of insects, the male uses its aedeagus, a structure formed from the terminal segments of the abdomen, to deposit sperm directly into the female's reproductive tract. Other animals reproduce sexually including many basal vertebrates. Vertebrates reproduce with internal fertilization through cloacal copulation, while mammals copulate vaginally.
Like in animals, mating in other Eukaryotes, such as plants and fungi, denotes sexual conjugation. However, in vascular plants this is achieved without physical contact between mating individuals, in some cases, e.g. in fungi no distinguishable male or female organs exist. Yeasts are eukaryotic microorganisms classified in the kingdom Fungi, with 1,500 species described. In general, under high stress conditions like nutrient starvation, haploid cells will die. Protists are a large group of diverse eukaryotic microorganisms unicellular animals and plants, that do not form tissues. Eukaryotes emerged in evolution more than 1.5 billion years ago. The earliest eukaryotes were protists. Mating and sexual reproduction are widespread among extant eukaryotes including protists such as Paramecium and Chlamydomonas. In many eukaryotic species, mating is promoted by sex pheromones including the protist Blepharisma japonicum. Based on a phylogenetic analysis and Roger proposed that facultative sex was present in the common ancestor of all eukaryotes.
However, to many biologists it seemed unlikely until that mating and sex could be a primordial and fundamental characteristic of eukaryotes. A principal reason for this view was that mating and sex appeared to be lacking in certain pathogenic protists whose ancestors branched off early from the eukaryotic family tree. However, several of these protists are now known to be capable of, or to have had, the capability for meiosis and hence mating. To cite one example, the common intestinal parasite Giardia intestinalis was once considered to be a descendant of a protist lineage that predated the emergence of meiosis and sex. However, G. intestinalis was found to have a core set of genes that function in meiosis and that are present among sexual eukaryotes. These results suggested that G. intestinalis is capable of meiosis and thus mating and sexual reproduction. Furthermore, direct evidence for meiotic recombination, indicative of mating and sexual reproduction, was found in G. intestinalis. Other protists for which evidence of mating and sexual reproduction has been described are parasitic protozoa of the genus Leishmania, Trichomonas vaginalis, acanthamoeba.
Protists reproduce asexually under favorable environmental conditions, but tend to reproduce sexually under stressful conditions, such as starvation or heat shock. Animal husbandry Breeding in the wild Breeding season Evolution of sex Lordosis behavior Mate choice copying Mating system Reproduction Sex determination system Sexual conflict Sexual intercourse Introduction to Animal Reproduction Advantages of Sexual Reproduction
Homo erectus is a species of archaic humans that lived throughout most of the Pleistocene geological epoch. Its earliest fossil evidence dates to 1.8 million years ago. A debate regarding the classification and progeny of H. erectus in relation to Homo ergaster, is ongoing, with two major positions: 1) H. erectus is the same species as H. ergaster, thereby H. erectus is a direct ancestor of the hominins including Homo heidelbergensis, Homo antecessor, Homo neanderthalensis, Homo Denisova, Homo sapiens. Some paleoanthropologists consider H. ergaster to be a variety, that is, the "African" variety, of H. erectus. H. Erectus became extinct throughout its range in Africa and Asia, but developed into derived species, notably Homo heidelbergensis; as a chronospecies, the time of its disappearance is thus a matter of contention. The species name proposed in 1950 defines Java Man as the type specimen. Since there has been a trend in palaeoanthropology of reducing the number of proposed species of Homo, to the point where H. erectus includes all early forms of Homo sufficiently derived from H. habilis and distinct from early H. heidelbergensis.
In this wider sense, H. erectus had been replaced by H. heidelbergensis by about 300,000 years ago, with possible late survival in Java as late as 70,000 years ago. The discovery of the morphologically divergent Dmanisi skull 5 in 2013 has reinforced the trend of subsuming fossils given separate species names under H. erectus considered as a wide-ranging, polymorphous species. Thus, H. ergaster is now well within the accepted morphological range of H. erectus, it has been suggested that H. rudolfensis and H. habilis should be considered early varieties of H. erectus. The Dutch anatomist Eugène Dubois, inspired by Darwin's theory of evolution as it applied to humanity, set out in 1886 for Asia to find a human ancestor. In 1891–92, his team discovered first a tooth a skullcap, a femur of a human fossil on the island of Java, Dutch East Indies. Excavated from the bank of the Solo River at Trinil, in East Java, he first allocated the material to a genus of fossil chimpanzees as Anthropopithecus erectus the following year assigned his species to a new genus as Pithecanthropus erectus —from the Greek πίθηκος and ἄνθρωπος —based on the proposal that the femur suggested that the creature had been bipedal, like Homo sapiens.
Dubois' 1891 find was the first fossil of a Homo-species found as result of a directed expedition and search. The Java fossil from Indonesia aroused much public interest, it was dubbed by the popular press as Java Man. Most of the spectacular discoveries of H. erectus next took place at the Zhoukoudian Project, now known as the Peking Man site, in Zhoukoudian, China. This site was first discovered by Johan Gunnar Andersson in 1921 and was first excavated in 1921, produced two human teeth. Davidson Black's initial description of a lower molar as belonging to a unknown species prompted publicized interest. Extensive excavations followed, which altogether uncovered 200 human fossils from more than 40 individuals including five nearly complete skullcaps. Franz Weidenreich provided much of the detailed description of this material in several monographs published in the journal Palaeontologica Sinica. Nearly all of the original specimens were lost during World War II. Similarities between Java Man and Peking Man led Ernst Mayr to rename both Homo erectus in 1950.
Throughout much of the 20th century, anthropologists debated the role of H. erectus in human evolution. Early in the century, due in part to the discoveries at Java and Zhoukoudian, the belief that modern humans first evolved in Asia was accepted. A few naturalists—Charles Darwin most prominent among them—theorized that humans' earliest ancestors were African: Darwin pointed out that chimpanzees and gorillas, humans' closest relatives and exist only in Africa; the derivation of the genus Homo from Australopithecina took place in East Africa after 3 million years ago. The inclusion of species dated to just before 2 million years ago, Homo habilis and Homo rudolfensis, into Homo is somewhat contentious; as H. habilis appears to have coexisted with H. ergaster/erectus for a substantial period after 2 Mya, it has been proposed that ergaster may not be directly derived from habilis. Homo erectus emerged about 2 million years ago. Fossils dated close to 1.8 million years ago have been found both in
The Aka or Bayaka are a nomadic Mbenga pygmy people. They live in northern Republic of the Congo. An ecologically diverse people, they occupy 11 different ecological zones of the Western Congo Basin, they are related to the Baka people of Cameroon, northern Congo, southwestern Central African Republic. Unlike the Mbuti pygmies of the eastern Congo, the Aka speak their own language along with whichever of the 15 Bantu peoples they are affiliated. In 2003, the oral traditions of the Aka were proclaimed one of the Masterpieces of the Oral and Intangible Heritage of Humanity by UNESCO, they were featured in the July 1995 National Geographic article "Ndoki: the Last Place on Earth". A traditional hunter-gatherer society, the Aka have a varied diet that includes sixty-three plants, twenty-eight species of game and twenty species of insect, in addition to nuts, honey and roots; some Aka have taken up the practice of planting their own small seasonal crops, but agricultural produce is more obtained by trading with neighboring villages, whom the Aka collectively term as Ngandu.
From the Ngandu, they obtain manioc, yams, maize, squash, papaya, pineapple, palm oil, rice in exchange for the bushmeat and other forest products the Aka collect. There are over 15 different village tribes with whom the 30,000 Aka associate; as a result of their hunter-gatherer lifestyle, which exposes them to the blood of jungle fauna, they have among the highest rates of seropositivity for Ebola virus in the world. Fathers of the Aka tribe spend more time in close contact to their babies than in any other known society. Aka fathers have their infant within arms' reach 47% of the time and make physical contact with them five times as per day as fathers in some other societies; the men help the women, by feeding their children. It is believed that this is related to the strong bond between Aka wife. Throughout the day, couples share hunting, food preparation, social and leisure activities; the lifestyle of the Aka has been shifted from their traditional customs by European colonialism. The slave trade of the 18th century caused the migration of several tribes into Aka lands.
These tribes subsequently became affiliated with the Aka. By the end of the 19th century, the Aka were the major elephant hunters providing tusks for the ivory trade. Affiliated tribes acted as middlemen in these transactions. From 1910 to 1940, the Aka lands were part of French Equatorial Africa, nearby affiliated tribes were forced into rubber production by the colonialists; these laborers escaped into forests inhabited by the Aka, increasing the demand for bushmeat. To meet this demand, the Aka developed the more efficient method of net hunting to replace traditional spear hunting; this caused a change in the social structure of the Aka: net hunting was seen as less physically challenging than using spears to kill game, so women were encouraged take part in hunting activities. In the 1930s, the French pressed the Aka to move into roadside villages. However, like the Efé of the Ituri rainforest, most Aka disobeyed and retreated into the jungle, with few joining the new settlements. Today, economic pressures have forced the Aka to further deviate from their traditional customs.
Many Aka now work in the coffee plantations of neighbouring tribes during the dry season instead of hunting as they would have done, others have found employment in the ivory and lumber trade. The World Wildlife Fund of Washington, DC, has worked with the Aka since the 1980s to protect gorilla habitats, minimize logging of forest, promote other conservation efforts while empowering the Aka and other indigenous peoples, their complex polyphonic music has been studied by various ethnomusicologists. Simha Arom has made historical field recordings of some of their repertoire. Michelle Kisliuk has written a detailed performance ethnography. Mauro Campagnoli studied their musical instruments in depth, comparing them to neighbouring pygmy groups such as the Baka Pygmies. Aka musicians appear on African Rhythms, Echoes of the Forest: Music of the Central African Pygmies, BOYOBI: Ritual Music of the Rainforest Pygmies, Bayaka: The Extraordinary Music of the BaBenzele Pygmies. Song from the Forest by German director Michael Obert tells the story of American Louis Sarno who has lived among the Bayaka pygmies in the central African rainforest for 25 years and travels with his son, 13-year-old pygmy boy Samedi, to New York City.
The film premiered at the International Documentary Film Festival Amsterdam 2013 where it was honored with the Award for Best Feature-Length Documentary. Other Pygmy groups Efé Baka Twa peoplesAnthropologists studying the Aka Barry Hewlett Michelle Kisliuk Seize the Dance! BaAka Musical the Ethnography of Performance by Michelle Kisliuk. Song from the Forest -- My Life Among the Ba-Benjellé Pygmies by Louis Sarno. Article: "Are the men of the African Aka tribe the best fathers in the world?" Fieldwork about Baka and other pygmy groups African Pygmies with photos and ethnographic notes www.songfromtheforest.com Countries and Their Cultures: Aka
Sahelanthropus tchadensis is an extinct species of the Hominini and is the ancestor to Orrorin, dated to about 7 million years ago, during the Miocene epoch very close to the time of the chimpanzee–human divergence. Few specimens other than the partial skull, nicknamed Toumaï, are known. Existing fossils include a small cranium named Toumaï, five pieces of jaw, some teeth, making up a head that has a mixture of derived and primitive features; the braincase, being only 320 cm3 to 380 cm3 in volume, is similar to that of extant chimpanzees and is notably less than the approximate human volume of 1350 cm3. The teeth, brow ridges, facial structure differ markedly from those found in Homo sapiens. Cranial features show a flatter face, u-shaped dental arcade, small canines, an anterior foramen magnum, heavy brow ridges. No postcranial remains have been recovered; the only known skull suffered a large amount of distortion during the time of fossilisation and discovery, as the cranium is dorsoventrally flattened, the right side is depressed.
Sahelanthropus tchadensis may have walked on two legs. However, because no postcranial remains have been discovered, it is not known definitively whether Sahelanthropus was indeed bipedal, although claims for an anteriorly placed foramen magnum suggests that this may have been the case. Upon examination of the foramen magnum in the primary study, the lead author speculated that a bipedal gait "would not be unreasonable" based on basicranial morphology similar to more recent hominins; some palaeontologists have disputed this interpretation, stating that the basicranium, as well as dentition and facial features, do not represent adaptations unique to the hominin clade, nor indicative of bipedalism. Further, according to recent information, what might be a femur of a hominid was discovered near the cranium—but which has not been published nor accounted for. Fifteen years after the discovery of the fossil, the anthropologist Roberto Macchiarelli—professor at the University of Poitiers and the Museum of Natural History of Paris—suspects Michel Brunet and his laboratory in Poitiers of blocking information about a femur found close to the skull.
That the laboratory would have delayed identification may question the bipedalism of Toumaï. The fossils were discovered in the Djurab Desert of Chad by a team of four led by a Frenchman, Alain Beauvilain, three Chadians, Adoum Mahamat, Djimdoumalbaye Ahounta, Gongdibé Fanoné, members of the Mission paleoanthropologique Franco-tchadienne led by Michel Brunet. All known material of Sahelanthropus was found between July 2001 and March 2002 at three sites: TM 247, TM 266, which yielded most of the material, including a cranium and a femur, TM 292; the discoverers claimed that S. tchadensis is the oldest-known human ancestor after the split of the human line from that of chimpanzees. The bones were found far from most previous hominin fossil finds, which are from Eastern and Southern Africa. However, an Australopithecus bahrelghazali mandible was found in Chad by Mamelbaye Tomalta and Alain Beauvilain, Michel Brunet and Aladji H. E. Moutaye as early as 1995. With the sexual dimorphism known to have existed in early hominins, the difference between Ardipithecus and Sahelanthropus may not be large enough to warrant a separate species for the latter.
Sahelanthropus may represent a common ancestor of humans and chimpanzees, though no consensus has been reached yet by the scientific community. The original placement of this species as a human ancestor but not a chimpanzee ancestor would complicate the picture of human phylogeny. In particular, if Toumaï is indeed a direct human ancestor its facial features bring into doubt the status of Australopithecus whose thickened brow ridges were reported to be similar to those of some fossil hominins, where the brow ridge morphology of Sahelanthropus differs from that observed in all australopithecines, most fossil hominins and extant humans. Another possibility is that Toumaï is related to both humans and chimpanzees, but is the ancestor of neither. Brigitte Senut and Martin Pickford, the discoverers of Orrorin tugenensis, suggested that the features of S. tchadensis are consistent with a female proto-gorilla. If this claim is upheld the find would lose none of its significance, because at present few chimpanzee or gorilla ancestors have been found anywhere in Africa.
Thus if S. tchadensis is an ancestral relative of the chimpanzees or gorillas it represents the earliest known member of their lineage. And S. tchadensis does indicate that the last common ancestor of humans and chimpanzees is unlikely to resemble extant chimpanzees, as had been supposed by some paleontologists. A further possibility, highlighted by research published in 2012, is that the human–chimpanzee split is earlier than thought, with a possible range of 7 to 13 million years ago, based on slower than thought changes between generations in human DNA. Indeed, some researchers consider suggestions that Sahelanthropus is too early to be a human ancestor to have evaporated. Sediment isotope analysis of cosmogenic atoms in the fossil yielded an age of about 7 million years. In this case, the fossils were found exposed in loose sand. In fact, Toumaï may have been reburied in the r
Hunting is the practice of killing or trapping animals, or pursuing or tracking them with the intent of doing so. Hunting wildlife or feral animals is most done by humans for food, recreation, to remove predators that can be dangerous to humans or domestic animals, or for trade. Lawful hunting is distinguished from poaching, the illegal killing, trapping or capture of the hunted species; the species that are hunted are referred to as game or prey and are mammals and birds. Hunting has long been a practice used to procure meat for human consumption; the meat from a healthy wild animal that has lived its life and on a natural diet of plants has a higher nutritional quality than that of a domestic animal, raised in an unnatural way. Hunting an animal for its meat can be seen as a more natural way to obtain animal protein since regulated hunting does not cause the same environmental issues as raising domestic animals for meat on factory farms. Hunting can be a means of pest control. Hunting advocates state that hunting can be a necessary component of modern wildlife management, for example, to help maintain a population of healthy animals within an environment's ecological carrying capacity when natural checks such as predators are absent or rare.
However, excessive hunting has heavily contributed to the endangerment and extinction of many animals. The pursuit and release, or capture for food of fish is called fishing, not categorised as a form of hunting, it is not considered hunting to pursue animals without intent to kill them, as in wildlife photography, birdwatching, or scientific research activities which involve tranquilizing or tagging of animals or birds. The practice of foraging or gathering materials from plants and mushrooms is considered separate from hunting. Skillful tracking and acquisition of an elusive target has caused the word hunt to be used in the vernacular as a metaphor, as in treasure hunting, "bargain hunting", "hunting down" corruption and waste. Animal rights activists argue that hunting is cruel and unethical; the word hunt serves as a verb. The noun has been dated to the early 12th century, "act of chasing game," from the verb hunt. Old English had huntung, huntoþ; the meaning of "a body of persons associated for the purpose of hunting with a pack of hounds" is first recorded in the 1570s.
Meaning "the act of searching for someone or something" is from about 1600. The verb, Old English huntian "to chase game" developed from hunta "hunter," is related to hentan "to seize," from Proto-Germanic huntojan, of uncertain origin; the general sense of "search diligently" is first recorded c. 1200. Hunting has a long history, it pre-dates the emergence of Homo sapiens and may predate genus Homo. The oldest undisputed evidence for hunting dates to the Early Pleistocene, consistent with the emergence and early dispersal of Homo erectus, about 1.7 million years ago. While it is undisputed that Homo erectus were hunters, the importance of this for the emergence of Homo erectus from its australopithecine ancestors, including the production of stone tools and the control of fire, is emphasised in the so-called "hunting hypothesis" and de-emphasised in scenarios that stress omnivory and social interaction. There is no direct evidence for hunting predating Homo erectus, in either Homo habilis or in Australopithecus.
The early hominid ancestors of humans were frugivores or omnivores, with a carnivore diet from scavenging rather than hunting. Evidence for australopithecine meat consumption was presented in the 1990s, it has often been assumed that at least occasional hunting behavior may have been present well before the emergence of Homo. This can be argued on the basis of comparison with chimpanzees, the closest extant relatives of humans, who engage in hunting, indicating that the behavioral trait may have been present in the Chimpanzee–human last common ancestor as early as 5 million years ago; the common chimpanzee engages in troop predation behaviour where bands of beta males are led by an alpha male. Bonobos have been observed to engage in group hunting, although more than Pan troglodytes subsisting on a frugivorous diet. Indirect evidence for Oldowan era hunting, by early Homo or late Australopithecus, has been presented in a 2009 study based on an Oldowan site in southwestern Kenya. Louis Binford criticised the idea that early humans were hunters.
On the basis of the analysis of the skeletal remains of the consumed animals, he concluded that hominids and early humans were scavengers, not hunters, Blumenschine proposed the idea of confrontational scavenging, which involves challenging and scaring off other predators after they have made a kill, which he suggests could have been the leading method of obtaining protein-rich meat by early humans. Stone spearheads dated as early as 500,000 years ago were found in South Africa. Wood does not preserve well and Craig Stanford, a primatologist and professor of anthropology at the University of Southern California, has suggested that the discovery of spear use by chimpanzees means that early humans used wooden spears as well five million years ago; the earliest dated find of surviving wooden hunting spears dates to the end of the Lower Paleolithic, just before 300,000 years ago. The Schöningen spears, found in 1976 in Germany, are
Homo is the genus which emerged in the otherwise extinct Australopithecus genus that encompasses the extant species Homo sapiens, plus several extinct species classified as either ancestral to or related to modern humans, most notably Homo erectus and Homo neanderthalensis. The genus is taken to emerge with the appearance of Homo habilis, just over two million years ago. Genus Homo, together with the genus Paranthropus is sister to A. africanus in the genus Australopithecus, which itself had split from the lineage of Pan, the chimpanzees. Homo erectus appeared about two million years ago and, in several early migrations, it spread throughout Africa and Eurasia, it was the first human species to live in a hunter-gatherer society and to control fire. An adaptive and successful species, Homo erectus persisted for more than a million years, diverged into new species by around 500,000 years ago. Homo sapiens emerges close to 300,000 to 200,000 years ago, most in Africa, Homo neanderthalensis emerged at around the same time in Europe and Western Asia.
H. sapiens dispersed from Africa in several waves, from as early as 250,000 years ago, by 130,000 years ago, the so-called Southern Dispersal beginning about 70,000 years ago leading to the lasting colonisation of Eurasia and Oceania by 50,000 years ago. Both in Africa and Eurasia, H. sapiens interbred with archaic humans. Separate archaic human species are thought to have survived until around 40,000 years ago, with possible late survival of hybrid species as late as 12,000 years ago. See Homininae for an overview of taxonomy; the Latin noun homō means "human being" or "man" in the generic sense of "human being, mankind". The binomial name Homo sapiens was coined by Carl Linnaeus. Names for other species of the genus were introduced beginning in the second half of the 19th century. Today, the genus Homo has not been properly defined. Since the early human fossil record began to emerge from the earth, the boundaries and definitions of the genus Homo have been poorly defined and in flux; because there was no reason to think it would have any additional members, Carl Linnaeus did not bother to define Homo when he first created it for humans in the 18th century.
The discovery of Neanderthal brought the first addition. The genus Homo was given its taxonomic name to suggest that its member species can be classified as human. And, over the decades of the 20th century, fossil finds of pre-human and early human species from late Miocene and early Pliocene times produced a rich mix for debating classifications. There is continuing debate on delineating Homo from Australopithecus—or, delineating Homo from Pan, as one body of scientists argue that the two species of chimpanzee should be classed with genus Homo rather than Pan. So, classifying the fossils of Homo coincides with evidence of: 1) competent human bipedalism in Homo habilis inherited from the earlier Australopithecus of more than four million years ago, as demonstrated by the Laetoli footprints. From the late-19th to mid-20th centuries, a number of new taxonomic names including new generic names were proposed for early human fossils. Many such names are now dubbed as "synonyms" with Homo, including Pithecanthropus,Protanthropus,Sinanthropus,Cyphanthropus,Africanthropus,Telanthropus,Atlanthropus, Tchadanthropus.
Classifying the genus Homo into species and subspecies is subject to incomplete information and remains poorly done. This has led to using common names in scientific papers to avoid trinomial names or the ambiguity of classifying groups as incertae sedis —for example, H. neanderthalensis vs. H. sapiens neanderthalensis, or H. georgicus vs. H. erectus georgicus. Some extinct species in the genus Homo are only discovered and do not as yet have consensus binomial names. Since the beginning of the Holocene, it is that Homo sapiens has been the only extant species of Homo. John Edward Gray was an early advocate of classifying taxa by designating families. Wood and Richmond proposed that Hominini be designated as a tribe that comprised all species of early humans and pre-humans ancestral to humans back to after the chimpanzee-human last common ancestor. Designations alternative to Hominina existed, or were offered: Australopithecinae and Preanthropinae. See Hominini and Chimpanzee–human last common ancestor for the separation of Australopithecina and Panina.
Several species, including Australopithecus garhi, Australopithecus sediba, Australopithecus africanus, Australopithecus afarensis, have been proposed as the direct ancestor of the Homo lineage. These species have morphological features that align them with Homo