Thesis on human evolution

But the find left no doubts that she walked erect. The shape of her pelvis showed clearly that she was bipedal. A few years would pass, however, before the full importance of Lucy would become clear. Significantly, she dated to a period before hominids split into the brand that led to us and the one that led to extinction. Second, because Lucy is basically so primitive, man may have split from his ape ancestors much later than 15 million years ago, as is commonly supposed.

Write to Lily Rothman at lily. L3 is about 70, years old, while haplogroups M and N are about , years old.

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Of all the lineages present in Africa, only the female descendants of one lineage, mtDNA haplogroup L3 , are found outside Africa. If there had been several migrations, one would expect descendants of more than one lineage to be found. L3's female descendants, the M and N haplogroup lineages, are found in very low frequencies in Africa although haplogroup M1 populations are very ancient and diversified in North and North-east Africa and appear to be more recent arrivals. A possible explanation is that these mutations occurred in East Africa shortly before the exodus and became the dominant haplogroups thereafter by means of the founder effect.

Alternatively, the mutations may have arisen shortly afterwards. Results from mtDNA collected from aboriginal Malaysians called Orang Asli indicate that the hapologroups M and N share characteristics with original African groups from approximately 85, years ago, and share characteristics with sub-haplogroups found in coastal south-east Asian regions, such as Australasia, the Indian subcontinent and throughout continental Asia, which had dispersed and separated from their African progenitor approximately 65, years ago.

This southern coastal dispersal would have occurred before the dispersal through the Levant approximately 45, years ago. Evidence of the coastal migration is thought to have been destroyed by the rise in sea levels during the Holocene epoch. The group that crossed the Red Sea travelled along the coastal route around Arabia and Persia until reaching India. The indigenous people of the Andaman Islands also belong to the M lineage. The Andamanese are thought to be offshoots of some of the earliest inhabitants in Asia because of their long isolation from the mainland.


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They are evidence of the coastal route of early settlers that extends from India to Thailand and Indonesia all the way to Papua New Guinea. The proportion of haplogroup M increases eastwards from Arabia to India; in eastern India, M outnumbers N by a ratio of Crossing into Southeast Asia, haplogroup N mostly in the form of derivatives of its R subclade reappears as the predominant lineage.

A study of African, European and Asian populations, found greater genetic diversity among Africans than among Eurasians, and that genetic diversity among Eurasians is largely a subset of that among Africans, supporting the out of Africa model.

Aquatic ape hypothesis

Based on this evidence, the study concluded that human populations encountered novel selective pressures as they expanded out of Africa. According to this study, Papua New Guineans continued to be exposed to selection for dark skin color so that, although these groups are distinct from Africans in other places, the allele for dark skin color shared by contemporary Africans, Andamanese and New Guineans is an archaism.

Endicott et al. A study by Gurdasani et al. Another promising route towards reconstructing human genetic genealogy is via the JC virus JCV , a type of human polyomavirus which is carried by 70—90 percent of humans and which is usually transmitted vertically, from parents to offspring, suggesting codivergence with human populations.

For this reason, JCV has been used as a genetic marker for human evolution and migration. From this Shackelton et al. Evidence for archaic human species descended from Homo heidelbergensis having interbred with modern humans outside of Africa, was discovered in the s. This concerns primarily Neanderthal admixture in all modern populations except for Sub-Saharan Africans but evidence has also been presented for Denisova hominin admixture in Australasia i.

Archaic admixture in some Sub-Saharan African populations hunter-gatherer groups Biaka Pygmies and San , derived from archaic hominins that broke away from the modern human lineage around , years, was discovered in In addition to genetic analysis, Petraglia et al.


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  • He proposed that the stone tools could be dated to 35 ka in South Asia, and the new technology might be influenced by environmental change and population pressure. The cladistic relationship of humans with the African apes was suggested by Charles Darwin after studying the behaviour of African apes , one of which was displayed at the London Zoo.

    Haeckel argued that humans were more closely related to the primates of South-east Asia and rejected Darwin's African hypothesis. In the Descent of Man , Darwin speculated that humans had descended from apes, which still had small brains but walked upright, freeing their hands for uses which favoured intelligence; he thought such apes were African:. In each great region of the world the living mammals are closely related to the extinct species of the same region.

    It is, therefore, probable that Africa was formerly inhabited by extinct apes closely allied to the gorilla and chimpanzee ; and as these two species are now man's nearest allies, it is somewhat more probable that our early progenitors lived on the African continent than elsewhere.

    How Lucy the Australopithecus Changed the Way We Understand Human Evolution

    But it is useless to speculate on this subject, for an ape nearly as large as a man, namely the Dryopithecus of Lartet, which was closely allied to the anthropomorphous Hylobates , existed in Europe during the Upper Miocene period; and since so remote a period the earth has certainly undergone many great revolutions, and there has been ample time for migration on the largest scale. In there were hardly any human fossils of ancient hominins available.

    Almost fifty years later, Darwin's speculation was supported when anthropologists began finding fossils of ancient small-brained hominins in several areas of Africa list of hominina fossils. The hypothesis of recent as opposed to archaic African origin developed in the 20th century. The "Recent African origin" of modern humans means "single origin" monogenism and has been used in various contexts as an antonym to polygenism.

    The debate in anthropology had swung in favour of monogenism by the midth century. Isolated proponents of polygenism held forth in the midth century, such as Carleton Coon , who thought as late as that H. The historical alternative to the recent origin model is the multiregional origin of modern humans , initially proposed by Milford Wolpoff in the s. This view proposes that the derivation of anatomically modern human populations from H. The hypothesis necessarily rejects the assumption of an infertility barrier between ancient Eurasian and African populations of Homo.

    The hypothesis was controversially debated during the late s and the s. In the s, Allan Wilson together with Rebecca L. Cann and Mark Stoneking worked on genetic dating of the matrilineal most recent common ancestor of modern human populations dubbed " Mitochondrial Eve ". To identify informative genetic markers for tracking human evolutionary history, Wilson concentrated on mitochondrial DNA mtDNA , passed from mother to child. This DNA material mutates quickly, making it easy to plot changes over relatively short times.


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    • With his discovery that human mtDNA is genetically much less diverse than chimpanzee mtDNA, Wilson concluded that modern human populations had diverged recently from a single population while older human species such as Neanderthals and Homo erectus had become extinct. By , estimates ranged around , years for the mt-MRCA and 60, to 70, years for the migration out of Africa. From —, there was controversy about the mitochondrial DNA of " Mungo Man 3 " LM3 and its possible bearing on the multiregional hypothesis.

      A reanalysis on LM3 and other ancient specimens from the area published in , showed it to be akin to modern Aboriginal Australian sequences, inconsistent with the results of the earlier study. From Wikipedia, the free encyclopedia. This article is about modern humans. For migrations of early humans, see Early hominin expansions out of Africa.

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      See also: Early human migrations. Further information: Skhul and Qafzeh hominins.

      Main article: Great Coastal Migration. Further information: List of first human settlements. See also: Toba catastrophe theory. Further information: Human genetic variation and Human genetic clustering. Main article: Interbreeding between archaic and modern humans. Further information: Aterian , Baradostian , and Microlith. Main article: Multiregional origin of modern humans. Essentials of Physical Anthropology. Cengage Learning. Retrieved 14 June Each genetic marker represents a single-point mutation SNP at a specific place in the genome.

      First, genetic evidence suggests that a small band with the marker M migrated out of Africa along the coasts of the Arabian Peninsula and India, through Indonesia, and reached Australia very early, between 60, and 50, years ago.

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      Second, a group bearing the marker M89 moved out of northeastern Africa into the Middle East 45, years ago. From there, the M89 group split into two groups. One group that developed the marker M9 went into Asia about 40, years ago. Samples from the megadrought times had little pollen or charcoal, suggesting sparse vegetation with little to burn. The area around Lake Malawi , today heavily forested, was a desert approximately , to 90, years ago. However, this is where the consensus on human settlement history ends, and considerable uncertainty clouds any more detailed aspect of human colonization history.

      Bibcode : Natur. Henry Holt and Company. American Journal of Physical Anthropology. Retrieved 23 March March Scientific Reports. Bibcode : NatSR It hints that humans began leaving Africa far earlier than once thought". The New York Times. Retrieved 11 July Retrieved 10 July July Bibcode : Sci American Journal of Human Genetics.