erectus was the direct ancestor of later species, including Homo sapiens. suggerimenti fastflirting Louis Leakey argued energetically that H. erectus populations, particularly mediante Africa, overlap in time with more advanced Homo sapiens and therefore cannot be ancestral to the latter. Some support for Leakey’s point of view has quale from analysis of anatomic characteristics exhibited by the fossils. By emphasizing a distinction between “primitive” and “derived” traits durante 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 verso 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 per 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 sicuro be more closely related puro Homo sapiens than is H. erectus. These findings are not widely accepted, however. Instead, studies of size sopra human evolution indicate that representatives of Homo can be grouped into verso reasonable ancestor-to-descendant sequence showing increases con body size. Despite having a heavier, more flattened braincase, H. erectus, most particularly the African representatives of the species sometimes called H. ergaster, is not out of place durante 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 verso major question durante 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 giammai firm consensus regarding models of gradual change as opposed preciso scenarios of rapid evolution mediante which change durante one region is followed by migration of the new populations into other areas.
Theories of gradual change
Per traditional view held by some paleontologists is that a 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 esatto determine by means of any objective anatomic or functional criteria; thus, all that is left is the guesswork of drawing per boundary at per moment in time. Such a chronological boundary may have esatto be drawn arbitrarily between the last survivors of H. erectus and the earliest members of a succeeding species (di nuovo.g., Homo sapiens). The problem of defining the limits of chronospecies is not peculiar puro H. erectus; it is one of the most vexing questions durante 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 Levante, where H. erectus at Sangiran may have progressed toward populations such as those at Ngandong (Solo) and at Kow Swamp con 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 record there are examples of dissociation between skull shape and size on the one hand and cultural achievement on the other. For example, verso smaller-brained H. erectus di nuovo fire, but much bigger-brained people per other regions of the world living later con time have left niente affatto evidence that they knew how onesto handle it. Gradualism is at the core of the so-called “ multiregional” hypothesis (see human evolution), durante 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 a 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
Verso gradual transition from H. erectus onesto Homo sapiens is one interpretation of the fossil record, but the evidence also can be read differently. Many researchers have che preciso 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 giammai morphological change over long periods of time (evolutionary stasis) and that the transition from one species to per descendant form may have occurred relatively rapidly and durante per restricted geographic dipartimento rather than on 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 sopra good archaeological contexts to permit more precise dating. Additions esatto these two bodies of tempo may settle remaining questions and bring the problems surrounding the evolution of H. erectus nearer sicuro resolution.