Human Being Biological Classification

Kingdom: Animalia
Phylum: Chordata
Class: Mamalia
Order: primates
Family: Hominidaea
Tribe: Hominini
Genus: Home
Species: sapiens
Human being is called Homo sapiens and it is the only surviving species of Genus Homo. The modern man is the Homo Sapiens Sapiens which is different from their argued fiirect ancestor, Homo Sapien Idaltu, which is now extinct. The earliest man is known to be Herecctus and said to have evolved 200,000 years ago.the other two sub species are said to have gone into extinction 500,00 years ago i.e homo neanderthalensis and Homo rhodesiensis but this claim is not widely accepted.
There is abundant evidence for common ancestry of human and apes despite the large gap that separates them. Human beings are products of evolution. A man like ape named Ramapithecus. It probably lived on the fringe of the forest and savannah in Africa nearly 20 million years ago. They are the genus of extinct primates and their fossils are found in northern india and East Africa beginning in 1932, through it was generally an apelike creature, Ramapithecus was considered a possible human ancestor on the basis of reconstructed jaw of dental characteristics of fragmental fossils. A complete jaw discovery in 1976 was clearly non-hominid, however, the Ramapithecus is now regarded by many as a member of Sivapithecus a genus considered to be an ancestor of Orangutan.

Human Evolution
Theory of the origins of human species (Homo sapiens).
Modern understanding of human origins is derived largely from the findings of paleontology, anthropology, and genetics, and involves the process of natural selection (see Darwinism). Although gaps in the fossil record due to differential preservation prevent the complete specification of the line of human descent, H. sapiens share clear anatomical, genetic, and historic relationships to other primates. Of all primates, humans bear particularly close affinity to other members of a group known as hominoids, or apes, which includes orangutans, gibbons, gorillas, chimpanzees, and humans. Humans and their immediate ancestors, known as hominids, are notable among hominoids for their bipedal locomotion, slow rate of maturation, large brain size, and, at least among the more recent hominids, the development of a relatively sophisticated capacity for language, tool use, and social activity.

Evolutionary tree
Humans are mammals of the Primate order. The earliest primates evolved about 65 million years ago in the geological period known as the Paleocene epoch. They were small-brained, arboreal fruit eaters, similar to modern tree shrews. Primates of the Eocene epoch (55 to 38 million years ago) were similar and ancestral to contemporary tarsiers, lemurs, and tree shrews, and are classified as lower primates or prosimians. During the late Eocene, the higher primates, or anthropoids, developed from prosimian ancestors and, aided by continental drift, diverged into New World (or platyrrhine) and Old World (or catarrhine) monkeys. The branching of Old World monkeys and hominoids apparently occurred in the late Oligocene (38 to 25 million years ago) or early Miocene (25 to 8 million years ago) a time period poorly represented in the fossil record. The lesser apes (gibbons and siamangs) and other hominoid lines diverged about 20 million years ago, while the Asian great apes (the orangutan being the only surviving form) diverged from the African hominoids about 15 to 10 million years ago.
Genetic evidence suggests that the ancestral lines of gorillas diverged about 8 million years ago and that chimpanzees and hominids diverged about 5 million years ago.
Hominid Evolution which date to more than 4 million years ago is unlike other primates. But like all hominids, australopithecines were bipedal. Their crania, however, were small and apelike, with an average cranial capacity of about 450 cc in the gracile species and 600 cc in the robust forms. Australopithecines that have been considered ancestral in the lineage leading to the human genus Homo include A. afarensis (an important skeleton of which is popularly known as Lucy) and A. africanus. The exact position of these and other early species on the hominid family tree continues to be disputed.

The first member of the genus Homo, a small gracile species known as H. habilis, was present in east Africa at least 2 million years ago. H. habilis was the first hominid to exhibit the marked expansion of the brain (with an average cranial capacity of about 750 cc) that would become a hallmark of subsequent hominid evolutionary history. By about 1.6 million years ago, H. habilis had evolved into a larger, more robust, and larger-brained species known as Homo erectus. Cranial capacities ranged from about 900 cc in early specimens to 1050 cc in later ones. H. erectus persisted for well over a million years and migrated off the African continent into Asia, Indonesia, and Europe.

Between 500,000 and 250,000 years ago, H. erectus evolved into H. sapiens. Transitional forms between H. erectus and H. sapiens are referred to as archaic H. sapiens. With the exception of H. sapiens neandertalensis (see Neanderthal man), no additional subspecies are recognized. Indeed, some scientists consider Neanderthal a separate species. Archaic H. sapiens changed gradually, becoming somewhat larger, more gracile and larger-brained through time. Cranial capacity, for example, increased from about 1150 cc in early transitional forms to the current world average of just over 1350 cc. By 150,000 years ago in Africa and Asia and 28,000 years ago in Europe (see Cro-Magnon man), the transition to H. sapiens was complete, and fully modern humans became the single surviving hominid species (with the possible exception of the humans represented by the remains found on Flores, Indonesia, which may represent a dwarf hominid species that survived until 13,000 years ago).

Evolution of Culture
Among hominids, a parallel evolutionary process involving increased intelligence and cultural complexity is apparent in the material record. Evidence of greater behavioral flexibility and adaptability presumably reflects the decreased influence of genetically encoded behaviors and the increased importance of learning and social interaction in transmitting and maintaining behavioral adaptations (see culture). Because the organization of neural circuitry is more significant than overall cranial capacity in establishing mental capabilities, direct inferences from the fossil record are likely to be misleading. Contemporary humans, for example, exhibit considerable variability in cranial capacity (1150 cc to 1600 cc), none of which is related to intelligence.

Tool use was once thought to be the hallmark of members of the genus Homo, beginning with H. habilis, but is now known to be common among chimpanzees. The earliest stone tools of the lower Paleolithic, known as Oldowan tools and dating to about 2 to 2.5 million years ago, were once thought to have been manufactured by H. habilis. Recent finds suggest that Oldowan tools may also have been made by robust australopithecines. The simultaneous emergence of H. erectus and the more complex Achuelian tool tradition may indicate shifting adaptations as much as increased intelligence.

While it is clear that H. erectus was much more versatile than any of its predecessors, adapting its technologies and behaviors to diverse environmental conditions, the extent and limitations of its intellectual endowment remain a subject of heated debate. This is also the case for both archaic H. sapiens and Neanderthals, the latter associated with the more sophisticated technologies of the middle Paleolithic. However impressive the achievements of H. erectus and early H. sapiens, most material remains predating 40,000 years ago reflect utilitarian concerns. Nonetheless, there is now scattered African archaeological evidence from before that time (in one case as early as 90,000 years ago) of the production by H. sapiens of beads and other decorative work, perhaps indicating a gradual development of the aesthetic concerns and other symbolic thinking characteristic of later human societies. Whether the emergence of modern H. sapiens corresponds to the explosion of technological innovations and artistic activities associated with Cro-Magnon culture or was a more prolonged process of development is a subject of archaeological debate.
Man, Homosapien (including me and you) is the only animal that walks upright. He has an erect posture, lighter jaws with smaller front teeth, shorter arms arched foot and large pollex. There is a general lack of body hair (though some variants exists) and his hallux is not opposed to any other toe. Although he has ceased to be arboreal, his aboreal ancestry promoted binocular vision, a fine visiotactile discrimination and manipulative skills in the use of his hands , his extraordinarily developed brain is responsible for giving him. The preeminent position among living organisms. The species can be divided into four primary races that are genetically distinguished from others: the Caucasoid, the Mongoloid, the Negroid and the Australoid

Olabode Aderemi Temitayo
B.SC.ED (Biology)


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