منابع مشابه
The origin of man.
Five characters separate man from other hominoids-a large neocortex, bipedality, reduced anterior dentition with molar dominance, material culture, and unique sexual and reproductive behavior. Evidence provided by the fossil record, primate behavior, and demographic analysis shows that the traditional view that early human evolution was a direct consequence of brain expansion and material cultu...
متن کاملThe origin of life
Ž 9 . Microfossil finds have been firmly established at about 3.5 Ga giga annees10 years , but no rocks older than about 4.0 Ga have been demonstrated, leaving the history of the first 0.6 Ga missing. This gap has been filled by models of the solar system. The origin of the ocean, atmosphere, and much crustal material apparently lies in a heavy rain of comets, subsequent to the catastrophic Moo...
متن کاملThe Origin of Life
The origin of life is in a sense a genetic problem, for, as H. J. Muller pointed out many ears ago, the essential attribute that identifies living matter is its capacity to replicate itself and its variants (1). Because this uniquely biological property has its physical basis in proteins and nucleic acids, the goal of modem work on the origin of life is to discover the manner of origin of these...
متن کاملThe Origin of Life
living beings were constantly arising out of dead matter. Maggots were suposed to be generated spontaneously in decaying meat. In 1668 Redi showed that this did not happen provided insects were carefully excluded. And in 1860 Pasteur extended the proof to the bacteria which he had shown were the cause of putrefaction. It seemed fairly clear that all the living beings known to us originate from ...
متن کاملOrigin of sex chromosome monosomy in man.
There are striking contrasts when the apparent origin of the 45,X anomaly is compared with most trisomic conditions, and recent work gives interesting clues to the causes of sex-chromosome monosomy. Except for a small proportion of cases arising from secondary non-disjunction of primary trisomic subjects-or cells-and a further group of segregational examples arising from centric fusion heterozy...
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ژورنال
عنوان ژورنال: Nature
سال: 2009
ISSN: 0028-0836,1476-4687
DOI: 10.1038/459316a