erectus was the direct ancestor of later species, including Homo sapiens. Louis Leakey argued energetically that H. erectus populations, particularly per Africa, overlap per time with more advanced Homo sapiens and therefore cannot be ancestral onesto the latter. Some support for Leakey’s point of view has che razza di from analysis of anatomic characteristics exhibited by the fossils. By emphasizing a distinction between “primitive” and “derived” traits per the reconstruction of relationships between species, several paleontologists have attempted preciso esibizione that H. erectus does not make per suitable morphological ancestor for Homo sapiens. Because the braincase is long, low, and thick-walled and presents a strong browridge, they claim that H. erectus shows derived (or specialized) characteristics not shared with more modern humans. At the same time, it is noted, Homo sapiens does share some features, including a rounded, lightly built cranium, with earlier hominins such as H. habilis. For these reasons, some paleontologists (including Leakey) consider the more slender, or “magro,” H. habilis and H. rudolfensis puro be more closely related to Homo sapiens than is H. erectus. These findings are not widely accepted, however. Instead, studies of size mediante human evolution indicate that representatives of Homo can be grouped into per reasonable ancestor-to-descendant sequence showing increases durante body size. Despite having verso heavier, more flattened braincase, H. erectus, most particularly the African representatives of the species sometimes called H. ergaster, is not out of place sopra this sequence.
If this much is agreed, there is still uncertainty as sicuro how and where H. erectus eventually gave rise sicuro Homo sapiens. This is a major question mediante the study of human evolution and one that resists resolution even when hominin fossils from throughout the Old World are surveyed per detail. Several general hypotheses have been advanced, but there is still in nessun caso firm consensus regarding models of gradual change as opposed sicuro scenarios of rapid evolution durante which change in one region is followed by migration of the new populations into other areas.
Theories of gradual change
A traditional view held by some paleontologists is that verso species may be transformed gradually into per succeeding species. Such successive species in the evolutionary sequence are called chronospecies. The boundaries between chronospecies are almost impossible sicuro determine by means of any objective anatomic or functional criteria; thus, all that is left is the guesswork of drawing per boundary at a moment sopra time. Such verso chronological boundary may have esatto be drawn arbitrarily between the last survivors of H. erectus and the earliest members of a succeeding species (anche.g., Homo sapiens). The problem of defining the limits of chronospecies is not peculiar to H. erectus; it is one of the most vexing questions sopra paleontology.
Such gradual change with continuity between successive forms has been postulated particularly for North Africa, where H. erectus at Tighenif is seen as ancestral to later populations at Rabat, Temara, Jebel Irhoud, and elsewhere. Gradualism has also been postulated for Southeast Asia, where H. erectus at Sangiran may have progressed toward populations such as those at Ngandong (Solo) and at Kow Swamp durante Australia. Some researchers have suggested that similar developments could have occurred con other parts of the world.
The supposed interrelation of cultural achievement and the shape and size of teeth, jaws, and brain is per theorized state of affairs with which some paleoanthropologists disagree. Throughout the human fossil superiorita there are examples of dissociation between skull shape and size on the one hand and cultural achievement on the other. For example, a smaller-brained H. erectus anche fire, but much bigger-brained people durante other regions of the world living later per time have left no evidence that they knew how puro handle it. Gradualism is at the core of the so-called “ multiregional” hypothesis (see human evolution), per which it is theorized that H. erectus evolved into Homo sapiens not once but several times as each subspecies of H. erectus, living durante its own territory, passed some postulated critical threshold. This theory depends on accepting per supposed erectus-sapiens threshold as correct. It is opposed by supporters of the “ out of Africa” hypothesis, who find the threshold concept at variance with the modern genetic theory of evolutionary change.
Theories of punctuated change
Per gradual transition from H. erectus sicuro Homo sapiens is one interpretation of the fossil primato, but the evidence also can be read differently. Many researchers have come esatto accept what can be termed a punctuated view of human evolution. This view suggests that species such as H. erectus may have exhibited little or niente affatto morphological change over long periods of time (evolutionary stasis) and that the transition from one species puro a descendant form may have occurred relatively rapidly and sopra a restricted geographic dipartimento rather than on http://www.datingranking.net/it/xcheaters-review per worldwide basis. Whether any Homo species, including our own, evolved gradually or rapidly has not been settled.
The continuation of such arguments underlines the need for more fossils preciso establish the range of physical variation of H. erectus and also for more discoveries con good archaeological contexts onesto permit more precise dating. Additions preciso these two bodies of scadenza may settle remaining questions and bring the problems surrounding the evolution of H. erectus nearer puro resolution.
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