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Evolution of humans
A special issue Proc Natl Acad Sci 106 (38) is dedicated to this problem. The table of content is copied here.
Out of Africa: Modern Human Origins Special Feature
Perspective
*Ian Tattersall Human origins: Out of Africa 16018-16021 Perspective
*T imothy D. Weaver The meaning of Neandertal skeletal morphology 16028-16033 Research Articles
*J. J. Hublin The origin of Neandertals 16022-16027
Michael P. Richards and Erik Trinkaus Isotopic evidence for the diets of European Neanderthals and early modern humans 16034-16039
* John F. Hoffecker The spread of modern humans in Europe 16040-16045
* G. Philip Rightmire Middle and later Pleistocene hominins in Africa and Southwest Asia 16046-16050 * d'Errico, Marian Vanhaeren, Nick Barton, Abdeljalil Bouzouggar, Henk Mienis, Daniel Richter, Jean-Jacques Hublin, Shannon P. McPherron, and Pierre Lozouet Additional evidence on the use of personal ornaments in the Middle Paleolithic of North Africa 16051-16056 * Michael DeGiorgio, Mattias Jakobsson, and Noah A. Rosenberg Explaining worldwide patterns of human genetic variation using a coalescent-based serial founder model of migration outward from Africa 16057-16062
Humans had spread across Asia by 50,000 years ago. Everything else about our original exodus from Africa is up for debate.
Nature 485 23, 24 (2012).
For decades, scientists thought that the Clovis hunters were the first to cross the Arctic to America. They were wrong and now they need a better theory
There is no doubt about our direct (and `main’) ancestors were from Africa. Even we have the following related fact:
Helicobacter pyrori is from Africa
Linz An African origin for the intimate association between humans and Helicobacter pylori
Nature 445 915 (2007)
* H. pylori seems to have spread from east Africa around 58,000 yr ago.
*Anatomically modern humans were already infected by H. pylori before their migrations from Africa and demonstrate that H. pylori has remained intimately associated with their human host populations ever since.
We still do not know how many waves came out of Africa:
Gunz et al., Early modern human diversity suggests subdivided population structure and a complex out-of-Africa scenario
PNAS 106 6094 (2009)
*Phenotype of neurocranial geometry to compare the variation in early modern human (200-160 kaBP) fossils with that in other groups of fossil Homo and recent modern humans.
*The early modern group has more shape variation than any other group in our sample, which covers 1.8 million years.
*Rather than a single out-of-Africa dispersal scenario, we suggest that early modern humans were already divided into different populations in Pleistocene Africa, after which there followed a complex migration pattern.
However, this is a morphological paper, so hardly conclusive.
Human phylo according to haplotype hetrozygosity
Li et al., Worldwide Human Relationships Inferred from Genome-Wide Patterns of Variation
Science 319, 1100 (2008).
*938 unrelated individuals from 51 populations of the Human Genome Diversity Panel at 650,000 common single-nucleotide polymorphism loci.
*Individual ancestry and population substructure were detectable with very high resolution.
*The relationship between haplotype heterozygosity and distance from Addis Ababa was consistent with the hypothesis of a serial founder effect with a single origin in sub-Saharan Africa.
It is generally accepted that there were at least two waves.
Mellars et al., Why did modern human populations disperse from Africa ca. 60,000 years ago ? A new model
Proc Natl Acad Soc 103 9381 (2006)
110-90kBP: temporary dispersal to southeast Asia (eg Qafze) associated with clear symbolic expression (their cultural level was not sufficient to withstand competition from the long-established Neanderthal); 80-70kBP rapid climatic and environmental changes in Africa (the transition from oxygen isotope stage 5 to stage 4), major social and tech change (induced by mutation?); 70-60kBP Major population expansion in Africa from a small source area. 60kBP Out of Africa.
The distribution spread rapidly along the seashore of Asia.
Macaulay et al., Single, Rapid Coastal Settlement of Asia Revealed by Analysis of Complete Mitochondrial Genomes
Science 308 1034 (2005)
Only a single dispersal from Africa, most likely via a southern coastal route, through India and onward into southeast Asia and Australasia occurred 65,000 years ago, most likely taking only a few thousand years.
It is a surprise that there still remain the people who support almost insane theory that we evolved almost simultaneously and spontaneously from Homo erectus at various places in Eurasia. However, this is due to the difference in the views of human. If one adopts the view that human beings are incorrigibly aggressive creatures, uniform evolution is an unthinkable foolish idea.
The author believes as a species H omo sapiens is an aggressive species (not meek in the Bible sense). This does not necessarily imply that they wish to confront and to kill each other or other species, but use of environmental resources, attitudes toward other animals, etc. are generally ‘aggressive.’ Recall that the worst cause of death of adult males of hunter-gatherers is murder. `Tendency as a species’ is not a mere prejudice; think of the difference between chimpanzees and bonobos; we are almost in the same genus [Incidentally, phylogenetically pure bonobos are nested within Chimps genetically: A Fischer et al., Bonobos Fall within the Genomic Variation of Chimpanzees. PLoS ONE 6 e21605 (2011). Bonobos consistently cluster together but fall as a group within the variation of chimpanzees for many of the regions. Thus, while chimpanzees retain genomic variation that predates bonobo-chimpanzee speciation, extensive lineage sorting has occurred within bonobos such that much of their genome traces its ancestry back to a single common ancestor that postdates their origin as a group separate from chimpanzees. ].
Those who disagree with the above opinion asserts mixing between Neandertal and us, but the idea was largely rejected. For example,
Hodgson et al., No evidence of a Neanderthal contribution to modern human diversity Genome Biol 9 206 (2008).
However, mixing with old type hominids has been established:
Who is Homo sapiens?
Liang M, Nielsen R, Q&A: Who is H. sapiens really, and how do we know?
BMC Biology 9 20 (2011).
Even before the publication of the Neanderthal genome, analyses of modern human DNA from different geographic sources by Jeffrey Wall and others had suggested that, contrary to the earlier consensus, anatomically modern humans evolved in Africa recently, but admixed with endemic archaic hominids---Neanderthals, Denisovans, or even Homo erectus---as they spread throughout the world, and that ancestral admixture may be much more. [see Wall J, Hammer M: Archaic admixture in the human genome. Curr Opinin Genet Dev 16 , 606-610 (2006); Plagnol V, Wall J: Possible ancestral structure in human populations. PLoS Genet 2
972-979 (2006).]
As to Denisovans, see
Krause et al., The complete mitochondrial DNA genome of an unknown hominin from southern Siberia
Nature 464 894 (2010)
*A complete mtDNA sequence retrieved from a bone excavated in 2008 in Denisova
Cave in the Altai Mountains in southern Siberia.
*It represents a hitherto unknown type of hominin mtDNA that shares a common ancestor with anatomically modern human and Neanderthal mtDNAs about 1.0 million years ago.
*It derives from a hominin migration out of Africa distinct from that of the ancestors of Neanderthals and of modern humans.
Notice that admixing evidence come from mtDNA, so these findings are consistent with the aggressive nature of human beings. cf
Half the native American Y is dominated by European males.
Smith et al., Asymmetric Male and Female Genetic Histories among Native Americans from Eastern North America
Mol Biol Evol 23 2161 (2006)
The vast majority of non–Native American Y chromosomes appear to be European in origin.
A recent big news is that H. floresiensis split from earlier than H. erectus
H floresiensis from H sp more archaic than H erectus ?
Jungers et al. The foot of Homo floresiensis Nature 459 81 (2009)
*LB1's foot is exceptionally long relative to the femur and tibia, proportions never before documented in hominins but seen in some African apes. Although the metatarsal robusticity sequence
*It is possible that the ancestor of H. floresiensis was not Homo erectus but instead some other, more primitive, hominin whose dispersal into southeast Asia is still undocumented.
*In PBS program NOVA it was compared with Lucy.
Whether megafaunal demise is human-caused or not is hotly debated:
Brantingham et al., Global archaeological evidence for proboscidean overkill
Proc Natl Acad Sci 102 6231 (2005)
Prehistoric human range expansion resulted in localized extinction events. In the present and the past, proboscideans have survived in refugia that are largely inaccessible to human populations.
However, the following theory also appeared:
Megafaunal extinctions, YD cooling, and termination of Clovis culture are due to an extraterrestrial impact
Firestone et al., Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling
Proc Nat Acad Sci 104 16016 (2007)
(BG) A carbon-rich black layer, dating to ca 12.9 ka, has been previously identified at ca50 Clovis-age sites across North America, contemporaneous with the abrupt onset of Younger Dryas (YD) cooling. The in situ bones of extinct Pleistocene megafauna, along with Clovis tool assemblages, occur below this black layer but not within or above it.
*An extraterrestrial (ET) impact event at ca 12.9 ka found: (i) magnetic grains with iridium, (ii) magnetic microspherules, (iii) charcoal, (iv) soot, (v) carbon spherules, (vi) glass-like carbon containing nanodiamonds, and (vii) fullerenes with ET helium.
However,
Paleoindian demography does not support the extraterrestrial impact hypothesis
Buchanan et al., Paleoindian demography and the extraterrestrial impact hypothesis
Proc Natl Acad Sci 105 11651 (2008)
*The results of the analyses were not consistent with the predictions of extraterrestrial impact hypothesis.
Again however, the impact theory of YD seems on the way to be established:
Bunch et al., Very high-temperature impact melt products as evidence for cosmic airbursts and impacts 12,900 years ago
Proc Natl Acad Sci 109 E1903 (2012)
Younger Dryas cooling episode is due to multiple impactor. Abundance peaks in SLO (= siliceous scoria-like objects )s were observed in the YDB layer at three dated sites at the onset of the YD cooling episode (12.9 ka). Thermal radiation from air shocks sufficient to
melt surface sediments at temperatures up to or greater than the boiling point of quartz (2,200 $¥deg$C) was concluded. Of the 18 investigated sites, only Abu Hureyra (Syria), Blackville, and Melrose display large melt masses of SLOs, so the authors propose that
there were three or more major impact/airburst epicenters for the YDB impact event. If so, the much higher concentration of SLOs at Abu Hureyra suggests that the effects on that settlement and its inhabitants would have been severe.
An i nteresting related paper is:
Leonard et al., Megafaunal Extinctions and the Disappearance of a Specialized Wolf Ecomorph
Curr Biol 17 1146 (2007)
Megafauna-adapted genetically distinct from the modern wolves
A similar story goes on in Australia:
Miller et al., Ecosystem Collapse in Pleistocene Australia and a Human Role in Megafaunal Extinction
Science 309 287 (2005)
Brantingham et al., Global archaeological evidence for proboscidean overkill
Proc Natl Acad Sci 102 6231 (2005)
Prehistoric human range expansion resulted in localized extinction events. In the present and the past, proboscideans have survived in refugia that are largely inaccessible to human populations.
Wroe et al., Prolonged coexistence of humans and megafauna in Pleistocene Australia
Proc Natl Acad Sci 102 8381 (2005)
Recent claims for continent wide disappearance of megafauna at 46.5 thousand calendar years ago (ka) to support a ‘‘blitzkrieg’’ model, must be reconsidered 36-30 ka unequivocal coexistence at Cuddie Springs
On Mesolithic revolution
The following may be an appropriate introductory article:
Bar-Yosef, THE UPPER PALEOLITHIC REVOLUTION
Ann Rev Anthropology 31 363 (2002)
It is thought that the modern language was born around this era. As to the origin of arts see
Bouzougga et al., 82,000-year-old shell bead s from North Africa and implications for the origins of modern human behavior
Proc Natl Acad Sci 104 9964 (2007)
Nassarius gibbosulus shell beads of 82,000 years ago confirmed.
*These findings imply an early distribution of bead-making in Africa and southwest Asia at least 40 millennia before the appearance of similar cultural manifestations in Europe.
Technological innovations such as invention of missiles (an introductory article is Science 308 491 (2005)) are also thought to be contemporary:
Origin of projectile launcher : lightweight points associated with projectile launchers originated in Africa (40-50 ky). Modern humans had a technological advantage when they left Africa and spread around the globe. ``These lightweight points show up more than 50,000 years ago in Africa,'' says Stan Ambrose (UIUC). ``They may have helped modern humans get out of Africa.''
Animal intelligence: not ordinary examples
Recently two papers appeared as to the intelligence of birds:
C. Schloegl et al.,
Grey parrots use inferential reasoning based on acoustic cues alone
PRS 279 4135 (2012)
Inference of contents by shaking the container: Apes can solve this. Surprisingly, the performance of African grey parrots was sensitive to the shaking movement: they were successful with containers shaken horizontally, but not with vertical shaking resembling parrot head-bobbing. Thus, grey parrots seem to possess ape-like cross-modal reasoning skills, but their reliance on these abilities is influenced by low-level interferences.
Rachael Miller and Russell D. Gray
New Caledonian crows reason about hidden causal agents
PNAS 109 16389 (2012)
Tool-making New Caledonian crows react differently to an observable event when it is caused by a hidden causal agent. Eight crows watched two series of events in which a stick moved. In the first set of events, the crows observed a human enter a hide, a stick move, and the human then leave the hide. In the second, the stick moved without a human entering or exiting the hide. The crows inspected the hide and abandoned probing with a tool for food more often after the second, unexplained series of events. This difference shows that the crows can reason about a hidden causal agent.
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