scholarly journals Comment on "Ongoing Adaptive Evolution of ASPM, a Brain Size Determinant in Homo sapiens" and "Microcephalin, a Gene Regulating Brain Size, Continues to Evolve Adaptively in Humans"

Science ◽  
2006 ◽  
Vol 313 (5784) ◽  
pp. 172a-172a ◽  
Author(s):  
M. Currat
Keyword(s):  
Adaptive Evolution ◽  
Homo Sapiens ◽  
Brain Size

Comment on "Ongoing Adaptive Evolution of ASPM, a Brain Size Determinant in Homo sapiens"

Science ◽  
2007 ◽  
Vol 316 (5823) ◽  
pp. 370b-370b ◽  
Author(s):  
F. Yu ◽  
R. S. Hill ◽  
S. F. Schaffner ◽  
P. C. Sabeti ◽  
E. T. Wang ◽  
...  
Keyword(s):  
Adaptive Evolution ◽  
Homo Sapiens ◽  
Brain Size

Ongoing Adaptive Evolution of ASPM, a Brain Size Determinant in Homo sapiens

Science ◽  
2005 ◽  
Vol 309 (5741) ◽  
pp. 1720-1722 ◽  
Author(s):  
N. Mekel-Bobrov
Keyword(s):  
Adaptive Evolution ◽  
Homo Sapiens ◽  
Brain Size

Seven Steps in the Evolution of the Human Imagination

2007 ◽  
Author(s):  
STEVEN MITHEN
Keyword(s):  
Cultural Change ◽  
Homo Sapiens ◽  
Brain Size ◽  
Modern Human ◽  
Clear Picture ◽  
Modern Humans ◽  
Creative Imagination ◽  
African Apes ◽  
Ways Of Thinking ◽  
Forms Of Knowledge

The modern human is a product of six million years of evolution wherein it is assumed that the ancestor of man resembles that of a chimpanzee. This assumption is based on the similarities of the ape-like brain size and post-cranial characteristics of the earliest hominid species to chimpanzees. Whilst it is unclear whether chimpanzees share the same foresight and contemplation of alternatives as with humans, it is nevertheless clear that chimpanzees lack creative imagination — an aspect of modern human imagination that sets humanity apart from its hominid ancestors. Creative imagination pertains to the ability to combine different forms of knowledge and ways of thinking to form creative and novel ideas. This chapter discusses seven critical steps in the evolution of the human imagination. These steps provide a clear picture of the gradual emergence of creative imagination in humans from their primitive origins as Homo sapiens some 200,000 years ago. This chronological evolution of the imaginative mind of humans involves both biological and cultural change that began soon after the divergence of the two lineages that led to modern humans and African apes.

scholarly journals Midsagittal Brain Variation among Non-Human Primates: Insights into Evolutionary Expansion of the Human Precuneus

2017 ◽  
Vol 90 (3) ◽  
pp. 255-263 ◽  
Author(s):  
Ana Sofia Pereira-Pedro ◽  
James K. Rilling ◽  
Xu Chen ◽  
Todd M. Preuss ◽  
Emiliano Bruner
Keyword(s):  
Homo Sapiens ◽  
Brain Size ◽  
Anatomical Variation ◽  
General Pattern ◽  
Dorsal Surface ◽  
Modern Human ◽  
Brain Morphology ◽  
Functional Region ◽  
Medial Side ◽  
Species Specific

The precuneus is a major element of the superior parietal lobule, positioned on the medial side of the hemisphere and reaching the dorsal surface of the brain. It is a crucial functional region for visuospatial integration, visual imagery, and body coordination. Previously, we argued that the precuneus expanded in recent human evolution, based on a combination of paleontological, comparative, and intraspecific evidence from fossil and modern human endocasts as well as from human and chimpanzee brains. The longitudinal proportions of this region are a major source of anatomical variation among adult humans and, being much larger in Homo sapiens, is the main characteristic differentiating human midsagittal brain morphology from that of our closest living primate relative, the chimpanzee. In the current shape analysis, we examine precuneus variation in non-human primates through landmark-based models, to evaluate the general pattern of variability in non-human primates, and to test whether precuneus proportions are influenced by allometric effects of brain size. Results show that precuneus proportions do not covary with brain size, and that the main difference between monkeys and apes involves a vertical expansion of the frontal and occipital regions in apes. Such differences might reflect differences in brain proportions or differences in cranial architecture. In this sample, precuneus variation is apparently not influenced by phylogenetic or allometric factors, but does vary consistently within species, at least in chimpanzees and macaques. This result further supports the hypothesis that precuneus expansion in modern humans is not merely a consequence of increasing brain size or of allometric scaling, but rather represents a species-specific morphological change in our lineage.

scholarly journals The evolution of the human pelvis: changing adaptations to bipedalism, obstetrics and thermoregulation

2015 ◽  
Vol 370 (1663) ◽  
pp. 20140063 ◽  
Author(s):  
Laura Tobias Gruss ◽  
Daniel Schmitt
Keyword(s):  
Evolutionary History ◽  
Heat Dissipation ◽  
Homo Sapiens ◽  
Brain Size ◽  
Major Change ◽  
Habitat Diversity ◽  
Bipedal Walking ◽  
Birth Canal ◽  
Selective Pressures ◽  
Hominin Evolution

The fossil record of the human pelvis reveals the selective priorities acting on hominin anatomy at different points in our evolutionary history, during which mechanical requirements for locomotion, childbirth and thermoregulation often conflicted. In our earliest upright ancestors, fundamental alterations of the pelvis compared with non-human primates facilitated bipedal walking. Further changes early in hominin evolution produced a platypelloid birth canal in a pelvis that was wide overall, with flaring ilia. This pelvic form was maintained over 3–4 Myr with only moderate changes in response to greater habitat diversity, changes in locomotor behaviour and increases in brain size. It was not until Homo sapiens evolved in Africa and the Middle East 200 000 years ago that the narrow anatomically modern pelvis with a more circular birth canal emerged. This major change appears to reflect selective pressures for further increases in neonatal brain size and for a narrow body shape associated with heat dissipation in warm environments. The advent of the modern birth canal, the shape and alignment of which require fetal rotation during birth, allowed the earliest members of our species to deal obstetrically with increases in encephalization while maintaining a narrow body to meet thermoregulatory demands and enhance locomotor performance.

scholarly journals Cerebral blood flow rates in recent great apes are greater than in Australopithecus species that had equal or larger brains

2019 ◽  
Vol 286 (1915) ◽  
pp. 20192208 ◽  
Author(s):  
Roger S. Seymour ◽  
Vanya Bosiocic ◽  
Edward P. Snelling ◽  
Prince C. Chikezie ◽  
Qiaohui Hu ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Homo Sapiens ◽  
Brain Size ◽  
Blood Flow Rate ◽  
Brain Perfusion ◽  
Synaptic Activity ◽  
Evolutionary Trajectory ◽  
Metabolic Intensity ◽  
The Cost

Brain metabolic rate (MR) is linked mainly to the cost of synaptic activity, so may be a better correlate of cognitive ability than brain size alone. Among primates, the sizes of arterial foramina in recent and fossil skulls can be used to evaluate brain blood flow rate, which is proportional to brain MR. We use this approach to calculate flow rate in the internal carotid arteries ( Q ˙ ICA ) , which supply most of the primate cerebrum. Q ˙ ICA is up to two times higher in recent gorillas, chimpanzees and orangutans compared with 3-million-year-old australopithecine human relatives, which had equal or larger brains. The scaling relationships between Q ˙ ICA and brain volume ( V br ) show exponents of 1.03 across 44 species of living haplorhine primates and 1.41 across 12 species of fossil hominins. Thus, the evolutionary trajectory for brain perfusion is much steeper among ancestral hominins than would be predicted from living primates. Between 4.4-million-year-old Ardipithecus and Homo sapiens , V br increased 4.7-fold, but Q ˙ ICA increased 9.3-fold, indicating an approximate doubling of metabolic intensity of brain tissue. By contrast, Q ˙ ICA is proportional to V br among haplorhine primates, suggesting a constant volume-specific brain MR.

Mental attention, not language, may explain evolutionary growth of human intelligence and brain size

2006 ◽  
Vol 29 (1) ◽  
pp. 19-20 ◽  
Author(s):  
Juan Pascual-Leone
Keyword(s):  
Homo Sapiens ◽  
Brain Size ◽  
Great Apes ◽  
Homo Erectus ◽  
Human Intelligence ◽  
Heuristic Model ◽  
Growth Data ◽  
Mental Attention ◽  
Size Growth ◽  
Evolutionary Growth

Using neoPiagetian theory of mental attention (or working memory), I task-analyze two complex performances of great apes and one symbolic performance (funeral burials) of early Homo sapiens. Relating results to brain size growth data, I derive estimates of mental attention for great apes, Homo erectus, Neanderthals, and modern Homo sapiens, and use children's cognitive development as reference. This heuristic model seems consistent with research.

Human Paleoneurology and the Evolution of the Parietal Cortex

2018 ◽  
Vol 91 (3) ◽  
pp. 136-147 ◽  
Author(s):  
Emiliano Bruner
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Parietal Lobe ◽  
Homo Sapiens ◽  
Brain Size ◽  
Morphological Changes ◽  
Spatial Models ◽  
Brain Anatomy ◽  
Modern Humans ◽  
Fossil Species

Paleoneurology deals with the study of brain anatomy in fossil species, as inferred from the morphology of their endocranial features. When compared with other living and extinct hominids, Homo sapiens is characterized by larger parietal bones and, according to the paleoneurological evidence, also by larger parietal lobes. The dorsal elements of the posterior parietal cortex (superior parietal lobules, precuneus, and intraparietal sulcus) may be involved in these morphological changes. This parietal expansion was also associated with an increase in the corresponding vascular networks, and possibly with increased heat loads. Only H. sapiens has a specific early ontogenetic stage in which brain form achieves such globular appearance. In adult modern humans, the precuneus displays remarkable variation, being largely responsible for the longitudinal parietal size. The precuneus is also much more expanded in modern humans than in chimpanzees. Parietal expansion is not influenced by brain size in fossil hominids or living primates. Therefore, our larger parietal cortex must be interpreted as a derived feature. Spatial models suggest that the dorsal and anterior areas of the precuneus might be involved in these derived morphological variations. These areas are crucial for visuospatial integration, and are sensitive to both genetic and environmental influences. This article reviews almost 20 years of my collaborations on human parietal lobe evolution, integrating functional craniology, paleoneurology, and evolutionary neuroanatomy.

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