Patterns of Middle Pleistocene hominin evolution in Africa and the emergence of modern humans

2012 ◽  
pp. 394-422 ◽  
Author(s):  
Emma Mbua ◽  
Günter Bräuer
Keyword(s):  
Middle Pleistocene ◽  
Modern Humans ◽  
Hominin Evolution

scholarly journals Homoplasy in the evolution of modern human-like joint proportions in Australopithecus afarensis

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Anjali M Prabhat ◽  
Catherine K Miller ◽  
Thomas Cody Prang ◽  
Jeffrey Spear ◽  
Scott A Williams ◽  
...  
Keyword(s):  
Upper Limb ◽  
Lower Limb ◽  
Modern Human ◽  
Homo Erectus ◽  
Australopithecus Afarensis ◽  
Modern Humans ◽  
Homo Habilis ◽  
Hominin Evolution ◽  
Parsimonious Explanation ◽  
Phylogenetic Hypotheses

The evolution of bipedalism and reduced reliance on arboreality in hominins resulted in larger lower limb joints relative to the joints of the upper limb. The pattern and timing of this transition, however, remains unresolved. Here, we find the limb joint proportions of Australopithecus afarensis, Homo erectus, and Homo naledi to resemble those of modern humans, whereas those of A. africanus, Australopithecus sediba, Paranthropus robustus, Paranthropus boisei, Homo habilis, and Homo floresiensis are more ape-like. The homology of limb joint proportions in A. afarensis and modern humans can only be explained by a series of evolutionary reversals irrespective of differing phylogenetic hypotheses. Thus, the independent evolution of modern human-like limb joint proportions in A. afarensis is a more parsimonious explanation. Overall, these results support an emerging perspective in hominin paleobiology that A. afarensis was the most terrestrially adapted australopith despite the importance of arboreality throughout much of early hominin evolution.

scholarly journals Dental evolutionary rates and its implications for the Neanderthal–modern human divergence

2019 ◽  
Vol 5 (5) ◽  
pp. eaaw1268 ◽  
Author(s):  
Aida Gómez-Robles
Keyword(s):  
Divergence Time ◽  
Modern Human ◽  
Evolutionary Rates ◽  
Middle Pleistocene ◽  
Last Common Ancestor ◽  
Modern Humans ◽  
Bayesian Analyses ◽  
Sima De Los Huesos ◽  
Dental Evolution ◽  
Quantitative Analyses

The origin of Neanderthal and modern human lineages is a matter of intense debate. DNA analyses have generally indicated that both lineages diverged during the middle period of the Middle Pleistocene, an inferred time that has strongly influenced interpretations of the hominin fossil record. This divergence time, however, is not compatible with the anatomical and genetic Neanderthal affinities observed in Middle Pleistocene hominins from Sima de los Huesos (Spain), which are dated to 430 thousand years (ka) ago. Drawing on quantitative analyses of dental evolutionary rates and Bayesian analyses of hominin phylogenetic relationships, I show that any divergence time between Neanderthals and modern humans younger than 800 ka ago would have entailed unexpectedly rapid dental evolution in early Neanderthals from Sima de los Huesos. These results support a pre–800 ka last common ancestor for Neanderthals and modern humans unless hitherto unexplained mechanisms sped up dental evolution in early Neanderthals.

scholarly journals Brain enlargement and dental reduction were not linked in hominin evolution

2017 ◽  
Vol 114 (3) ◽  
pp. 468-473 ◽  
Author(s):  
Aida Gómez-Robles ◽  
Jeroen B. Smaers ◽  
Ralph L. Holloway ◽  
P. David Polly ◽  
Bernard A. Wood
Keyword(s):  
Brain Size ◽  
Behavioral Changes ◽  
Modern Humans ◽  
Distinctive Features ◽  
Hominin Evolution ◽  
Large Brain ◽  
Dental Reduction ◽  
Selection For ◽  
Brain Reorganization ◽  
Evolutionary Simulations

The large brain and small postcanine teeth of modern humans are among our most distinctive features, and trends in their evolution are well studied within the hominin clade. Classic accounts hypothesize that larger brains and smaller teeth coevolved because behavioral changes associated with increased brain size allowed a subsequent dental reduction. However, recent studies have found mismatches between trends in brain enlargement and posterior tooth size reduction in some hominin species. We use a multiple-variance Brownian motion approach in association with evolutionary simulations to measure the tempo and mode of the evolution of endocranial and dental size and shape within the hominin clade. We show that hominin postcanine teeth have evolved at a relatively consistent neutral rate, whereas brain size evolved at comparatively more heterogeneous rates that cannot be explained by a neutral model, with rapid pulses in the branches leading to later Homo species. Brain reorganization shows evidence of elevated rates only much later in hominin evolution, suggesting that fast-evolving traits such as the acquisition of a globular shape may be the result of direct or indirect selection for functional or structural traits typical of modern humans.

scholarly journals Homo naledi and Pleistocene hominin evolution in subequatorial Africa

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Lee R Berger ◽  
John Hawks ◽  
Paul HGM Dirks ◽  
Marina Elliott ◽  
Eric M Roberts
Keyword(s):  
Middle Stone Age ◽  
Present Knowledge ◽  
Middle Pleistocene ◽  
Late Time ◽  
Stone Age ◽  
Star System ◽  
Cave System ◽  
Hominin Evolution ◽  
Cradle Of Humankind ◽  
Close Relatives

New discoveries and dating of fossil remains from the Rising Star cave system, Cradle of Humankind, South Africa, have strong implications for our understanding of Pleistocene human evolution in Africa. Direct dating of Homo naledi fossils from the Dinaledi Chamber (<xref ref-type="bibr" rid="bib10">Berger et al., 2015</xref>) shows that they were deposited between about 236 ka and 335 ka (<xref ref-type="bibr" rid="bib36">Dirks et al., 2017</xref>), placing H. naledi in the later Middle Pleistocene. Hawks and colleagues (<xref ref-type="bibr" rid="bib55">Hawks et al., 2017</xref>) report the discovery of a second chamber within the Rising Star system (<xref ref-type="bibr" rid="bib34">Dirks et al., 2015</xref>) that contains H. naledi remains. Previously, only large-brained modern humans or their close relatives had been demonstrated to exist at this late time in Africa, but the fossil evidence for any hominins in subequatorial Africa was very sparse. It is now evident that a diversity of hominin lineages existed in this region, with some divergent lineages contributing DNA to living humans and at least H. naledi representing a survivor from the earliest stages of diversification within Homo. The existence of a diverse array of hominins in subequatorial comports with our present knowledge of diversity across other savanna-adapted species, as well as with palaeoclimate and paleoenvironmental data. H. naledi casts the fossil and archaeological records into a new light, as we cannot exclude that this lineage was responsible for the production of Acheulean or Middle Stone Age tool industries.

scholarly journals Divergence, demography and gene loss along the human lineage

2010 ◽  
Vol 365 (1552) ◽  
pp. 2451-2457 ◽  
Author(s):  
Hie Lim Kim ◽  
Takeshi Igawa ◽  
Ayaka Kawashima ◽  
Yoko Satta ◽  
Naoyuki Takahata
Keyword(s):  
Dna Sequences ◽  
Sequence Data ◽  
Homo Sapiens ◽  
Divergence Time ◽  
Cell Receptor ◽  
Middle Pleistocene ◽  
Human Lineage ◽  
Modern Humans ◽  
Olfactory Receptor Genes ◽  
Living Organisms

Genomic DNA sequences are an irreplaceable source for reconstructing the vanished past of living organisms. Based on updated sequence data, this paper summarizes our studies on species divergence time, ancient population size and functional loss of genes in the primate lineage leading to modern humans ( Homo sapiens sapiens ). The inter- and intraspecific comparisons of DNA sequences suggest that the human lineage experienced a rather severe bottleneck in the Middle Pleistocene, throughout which period the subdivided African population played a predominant role in shaping the genetic architecture of modern humans. Also, published and newly identified human-specific pseudogenes (HSPs) are enumerated in order to infer their significance for human evolution. Of the 121 candidate genes obtained, authentic HSPs turn out to comprise only 25 olfactory receptor genes, four T cell receptor genes and nine other genes. The fixation of HSPs has been too rare over the past 6–7 Myr to account for species differences between humans and chimpanzees.

scholarly journals Neanderthal-Denisovan ancestors interbred with a distantly-related hominin

2019 ◽  
Author(s):  
Alan R. Rogers ◽  
Nathan S. Harris ◽  
Alan A. Achenbach
Keyword(s):  
Population Size ◽  
Effective Size ◽  
Middle Pleistocene ◽  
Human Populations ◽  
Modern Humans ◽  
Out Of Africa

Previous research has shown that modern Eurasians interbred with their Neanderthal and Denisovan predecessors. We show here that hundreds of thousands of years earlier, the ancestors of Neanderthals and Denisovans interbred with their own Eurasian predecessors—members of a “superarchaic” population that separated from other humans about 2 mya. The superarchaic population was large, with an effective size between 20 and 50 thousand individuals. We confirm previous findings that: (1) Denisovans also interbred with superarchaics, (2) Neanderthals and Denisovans separated early in the middle Pleistocene, (3) their ancestors endured a bottleneck of population size, and (4) the Neanderthal population was large at first but then declined in size. We provide qualified support for the view that (5) Neanderthals interbred with the ancestors of modern humans.One-sentence summaryWe document the earliest known interbreeding between ancient human populations and an expansion out of Africa early in the middle Pleistocene.

The Morphological and Behavioural Origins of Modern Humans

2004 ◽  
Author(s):  
Chris Stringer
Keyword(s):  
Homo Sapiens ◽  
Modern Human ◽  
Human Behaviour ◽  
Genetic Evidence ◽  
Middle Pleistocene ◽  
African Origin ◽  
Modern Humans ◽  
Speciation Event ◽  
Out Of Africa

This chapter provides an update on the speciation of modern Homo sapiens and the Out of Africa hypothesis. The majority of the fossil and genetic evidence favours an African origin for modern humans during the later part of the Middle Pleistocene (prior to 130,000 years ago), and one or more range expansions out of Africa after that date. However, a number of uncertainties remain. If there was a speciation event at the appearance of modern humans, what was its nature? Furthermore, did the evolution of modern human behaviour occur gradually or punctuationally? The discussion examines the difficulties faced in defining what is meant by ‘modern’ humans, and in reconstructing the morphological and behavioural origins of our species.

Carpals

2020 ◽  
pp. 99-105
Author(s):  
Matthew W. Tocheri ◽  
Job Kibii
Keyword(s):  
Functional Morphology ◽  
Southern Africa ◽  
Comparative Morphology ◽  
Carpal Bones ◽  
Geographical Region ◽  
Modern Humans ◽  
Extreme Caution ◽  
Australopithecus Africanus ◽  
Hominin Evolution ◽  
Fossil Hominin

A capitate and scaphoid are the only carpal bones known from Sterkfontein, and are described here. These bones lack the derived features that characterize the wrist of modern humans and Neandertals solely on the geological and paleontological context of where these specimens were recovered. These elements are attributed to Australopithecus africanus because of where they were recovered, but recent discoveries of A. sediba and Homo naledi from the same geographical region underscore the complexity and diversity of hominin evolution in southern Africa throughout the Pleistocene and suggest extreme caution is needed in attributing isolated hominin elements to particular taxa. Functional interpretations based on single fossil carpals also must be treated cautiously until more reasonably complete fossil hominin hand skeletons are recovered. That said, however, the comparative morphology of these bones suggests that they belonged to hominins in which hand functional morphology was likely broadly similar to that of other early hominins, such as australopiths and Homo floresiensis.

scholarly journals Neanderthal-Denisovan ancestors interbred with a distantly related hominin

2020 ◽  
Vol 6 (8) ◽  
pp. eaay5483 ◽  
Author(s):  
Alan R. Rogers ◽  
Nathan S. Harris ◽  
Alan A. Achenbach
Keyword(s):  
Population Size ◽  
Effective Size ◽  
Middle Pleistocene ◽  
Modern Humans

Previous research has shown that modern Eurasians interbred with their Neanderthal and Denisovan predecessors. We show here that hundreds of thousands of years earlier, the ancestors of Neanderthals and Denisovans interbred with their own Eurasian predecessors—members of a “superarchaic” population that separated from other humans about 2 million years ago. The superarchaic population was large, with an effective size between 20 and 50 thousand individuals. We confirm previous findings that (i) Denisovans also interbred with superarchaics, (ii) Neanderthals and Denisovans separated early in the middle Pleistocene, (iii) their ancestors endured a bottleneck of population size, and (iv) the Neanderthal population was large at first but then declined in size. We provide qualified support for the view that (v) Neanderthals interbred with the ancestors of modern humans.

Sign in / Sign up

Export Citation Format

Share Document