Human evolution no relation H. erectus
Human evolution is the evolutionary process within the history of primates that led to the emergence of Homo sapiens as a distinct species of the hominid family, which includes all the great apes. This process involved the gradual development of traits such as human bipedalism, dexterity and complex language, as well as interbreeding with other hominins (a tribe of the African hominid subfamily), indicating that human evolution was not linear but weblike. The study of human evolution involves several scientific disciplines, including physical and evolutionary anthropology, paleontology, and genetics.Primates diverged from other mammals about 85 million years ago (mya), in the Late Cretaceous period, with their earliest fossils appearing over 55 mya, during the Paleocene. Primates produced successive clades leading to the ape superfamily, which gave rise to the hominid and the gibbon families; these diverged some 15–20 mya. African and Asian hominids (including orangutans) diverged about 14 mya. Hominins (including the Australopithecine and Panina subtribes) parted from the Gorillini tribe (gorillas) between 8–9 mya; Australopithecine (including the extinct biped ancestors of humans) separated from the Pan genus (containing chimpanzees and bonobos) 4–7 mya. The Homo genus is evidenced by the appearance of H. habilis over 2 mya, while anatomically modern humans emerged in Africa approximately 300,000 years ago.Anatomical changes
Since Homo sapiens separated from its last common ancestor shared with chimpanzees, human evolution is characterized by a number of morphological, developmental, physiological, behavioral, and environmental changes. Environmental (cultural) evolution discovered much later during the Pleistocene played a significant role in human evolution observed via human transitions between subsistence systems. The most significant of these adaptations are bipedalism, increased brain size, lengthened ontogeny (gestation and infancy), and decreased sexual dimorphism. The relationship between these changes is the subject of ongoing debate. Other significant morphological changes included the evolution of a power and precision grip, a change first occurring in H. erectus.Evidence
The evidence on which scientific accounts of human evolution are based comes from many fields of natural science. The main source of knowledge about the evolutionary process has traditionally been the fossil record, but since the development of genetics beginning in the 1970s, DNA analysis has come to occupy a place of comparable importance. The studies of ontogeny, phylogeny and especially evolutionary developmental biology of both vertebrates and invertebrates offer considerable insight into the evolution of all life, including how humans evolved. The specific study of the origin and life of humans is anthropology, particularly paleoanthropology which focuses on the study of human prehistory.Evidence from genetics
The closest living relatives of humans are bonobos and chimpanzees (both genus Pan) and gorillas (genus Gorilla). With the sequencing of both the human and chimpanzee genome, as of 2012 estimates of the similarity between their DNA sequences range between 95% and 99%. By using the technique called the molecular clock which estimates the time required for the number of divergent mutations to accumulate between two lineages, the approximate date for the split between lineages can be calculated.
The gibbons (family Hylobatidae) and then the orangutans (genus Pongo) were the first groups to split from the line leading to the hominins, including humans—followed by gorillas (genus Gorilla), and, ultimately, by the chimpanzees (genus Pan). The splitting date between hominin and chimpanzee lineages is placed by some between 4 to 8 million years ago, that is, during the Late Miocene. Speciation, however, appears to have been unusually drawn out. Initial divergence occurred sometime between 7 to 13 million years ago, but ongoing hybridization blurred the separation and delayed complete separation during several millions of years. Patterson (2006) dated the final divergence at 5 to 6 million years ago.Genetic evidence has also been employed to compare species within the genus Homo, investigating gene flow between early modern humans and Neanderthals, and to enhance the understanding of the early human migration patterns and splitting dates. By comparing the parts of the genome that are not under natural selection and which therefore accumulate mutations at a fairly steady rate, it is possible to reconstruct a genetic tree incorporating the entire human species since the last shared ancestor.
Each time a certain mutation (single-nucleotide polymorphism) appears in an individual and is passed on to his or her descendants, a haplogroup is formed including all of the descendants of the individual who will also carry that mutation. By comparing mitochondrial DNA which is inherited only from the mother, geneticists have concluded that the last female common ancestor whose genetic marker is found in all modern humans, the so-called mitochondrial Eve, must have lived around 200,000 years ago.
Human evolutionary genetics studies how human genomes differ among individuals, the evolutionary past that gave rise to them, and their current effects. Differences between genomes have anthropological, medical and forensic implications and applications. Genetic data can provide important insight into human evolution.
no relation