* Astronomy

 Early humans in China 1 million years ago
Chronology and adaptability of early humans in different palaeoclimatic and palaeoenvironmental settings are important topics in the study of human evolution. China houses several early-human (Palaeolithic) archaeological sites along the Nihewan Basin near Mongolia, some with artefacts that date back about 1 million years ago. Deng et al. analyse one specific locality in the Nihewan Basin, called the Feiliang Palaeolithic Site, where several stone artefacts and mammalian bone fragments have been found buried in basin silts. By analysing remnant magnetizations of basin silt layers and comparing these data with charts of known magnetic reversals, the authors identify that the artefact layer was deposited about 1.2 million years ago, just prior to a major climate transition that occurred during the mid-Pleistocene. The transition brought increased climate variability to the region. This finding, coupled with other studies, indicates a prominent early human presence in the high northern latitudes of East Asia. The authors indicate that further studies on the artefacts themselves could reveal the manner in which humans weathered these climate shifts.

Title: Magnetochronology of the Feiliang Paleolithic site in the Nihewan Basin and implications for early human adaptability to high northern latitudes in East Asia
Authors: Chenglong Deng, Caicai Liu, Hong Ao, Yongxin Pan and Rixiang Zhu: Paleomagnetism and Geochronology Laboratory, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China;
Fei Xie: Hebei Province Institute of Cultural Relics, Shijiazhuang, China.

Source: Geophysical Research Letters (GRL) paper 10.1029/2007GL030335, 2007

In what appears to be a major discovery, archaeologists have found two over one million years old human footprints preserved on a sandstone at the Margalla Hills.
The Indusians Research Cell, which is working under the supervision of world renowned archaeologist and historian Dr Ahmad Hassan Dani of Taxila Institute of Asian Civilisations, Quaid-i-Azam University, Islamabad, has made the discovery, which is likely to add a new chapter to the archaeological history and heritage of the federal capital and attract visitors.
A footprint of 1 feet is in complete and well preserved form while another is broken from the finger side which is also of the same size in comparative manner. The notable marks of the feet are the clear veins and opposite folded appearance.

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Why do we humans walk on two legs?
Because it's easier than walking on four.
That's the basic finding of a study conducted by a team of researchers that included University of Arizona anthropologist David Raichlen. Its findings appear today in the Proceedings of the National Academy of Sciences.
The scientists studied the energy used by four humans walking upright on a treadmill and compared it with that expended by five chimpanzees walking both upright and in the four-limbed alignment known as quadrupedal knuckle-walking.
On average, the chimpanzees used four times the amount of energy expended by humans in both alignments, but there were wide differences in energy used by individual chimpanzees. The chimpanzee with the anatomy that allowed the longest stride used the least energy walking upright.

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Insights into Ape Locomotor Evolution and the Origins of Bipedalism

Source


Title: Acquisition of bipedalism: the Miocene hominoid record and modern analogues for bipedal protohominids
Author: Masato Nakatsukasa

The well-known fossil hominoid Proconsul from the Early Miocene of Kenya was a non-specialized arboreal quadruped with strong pollicial/hallucial assisted grasping capability. It lacked most of the suspensory specializations acquired in living hominoids. Nacholapithecus, however, from the Middle Miocene of Kenya, although in part sharing with Proconsul the common primitive anatomical body design, was more specialized for orthograde climbing, hoisting and bridging, with the glenoid fossae of the scapula probably being cranially orientated, the forelimbs proportionally large, and very long toes. Its tail loss suggests relatively slow movement, although tail loss may already have  occurred in Proconsul. Nacholapithecus-like positional behaviour might thus have been a basis for development of more suspensory specialized positional behaviour in later hominoids. Unfortunately, after 13 Ma, there is a gap in the hominoid postcranial record in Africa until 6 Ma. Due to this gap, a scenario for later locomotor evolution prior to the divergence of Homo and Pan cannot be determined with certainty. The time gap also causes difficulties when we seek to determine polarities of morphological traits in very early hominids. Interpretation of the formfunction relationships of postcranial features in incipient hominids will be difficult because it is predicted that they had incorporated bipedalism only moderately into their total positional repertoires. However, Japanese macaques, which are trained in traditional bipedal performance, may provide useful hints about bipedal adaptation in the protohominids. Kinematic analyses revealed that these macaques walked bipedally with a longer stride and lower stride frequency than used by ordinary macaques, owing to a more extended posture of the hindlimb joints. The body centre of gravity rises during the single-support phase of stance. Energetic studies of locomotion in these bipedal macaques revealed that energetic expenditure was 2030% higher in bipedalism than in quadrupedalism, regardless of walking velocity.

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Evidence that up to 10 percent of human genome may have changed very recently revealed by CU researchers
A Cornell study of genome sequences in African-Americans, European-Americans and Chinese suggests that natural selection has caused as much as 10 percent of the human genome to change in some populations in the last 15,000 to 100,000 years, when people began migrating from Africa.
The study, published in the June 1 issue of PLoS (Public Library of Science) Genetics, looked for areas where most members of a population showed the same genetic changes. For example, the researchers found evidence of recent selection on skin pigmentation genes, providing the genetic data to support theories proposed by anthropologists for decades that as anatomically modern humans migrated out of Africa and experienced different climates and sunlight levels, their skin colours adapted to the new environments.
However, the study found no evidence of differences in genes that control brain development among the various geographical groups, as some researchers have proposed in the past.

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