Archaic homo sapiens tools

OK, and what about ash below the Omo bones, which would help us narrow the range in time? How old is that? The bottom line is that the new dating for Omo Person fits with new models of modern human evolution that suggest our species diverged from our closest hominin ancestors around , to , years ago, Mounier says.

Meanwhile, completely unrelated work suggests that modern human populations in Africa diverged around , years ago — which makes sense if you think about the geography, vagaries of climate, and so on. And it bears keeping in mind that our divergence within our species may have begun then, but we Homo line persons have incredible wanderlust and we can assume that even populations who separated hundreds of thousands of years ago subsequently met anew, and mixed.

Ruth Schuster Jan. Get email notification for articles from Ruth Schuster Follow. Open gallery view. The Misliya jawbone: Early sapiens? Credit: Israel Hershkovitz. The Omo Kibish formation in Ethiopia. Credit: Christine Lane. The team sampling ash deposits that redate the oldest fossil remains at the Omo Kibish formation by 36, years. Credit: Alan Deino. Credit: Celine Vidal. Click the alert icon to follow topics: Evolution Paleontology Africa.

What if God Doesn't Forgive? Here's Why They Will Fail. Jewish Establishment. Homo erectus postcranial fossils are not frequently reported, but studies do suggest that in terms of overall size, the H. The primary distinctions between the two species appear to be morphological variation found in the crania. A wide range of Middle Pleistocene hominin fossils from different regions of the Old World that do not fit comfortably within either H.

The primary Chinese archaic H. The locations of these hominin fossil localities can be found in Figure 1 and representative samples of the hominin fossils are presented in Figures 2 and 3. Figure 2 Frontal top and lateral bottom views of typical Homo heidelbergensis crania from Europe and Africa left: Petralona; right: Kabwe. All rights reserved. Figure 3 Frontal top and lateral bottom views of typical archaic Homo sapiens crania from China left: Maba; right: Dali.

The primary morphological characteristics of archaic H. Relatively few studies have been conducted on postcranial remains. One of the more recent studies was an analysis of the postcranial remains from Jinniushan, China Rosenberg et al. The Rosenberg et al.

Over the past several decades, there has been a push by a number of paleoanthropologists e. The Mauer mandible is best known for being very robust, has a pronounced anteroposterior mandibular ramus length, and lacks a mental eminence i. Although the holotype of H. In turn, associated crania e. Overall similarities in general cranial bauplan between many of the European e. Besides Early Pleistocene occupations in higher latitudes by Homo erectus in Georgia and possibly the Nihewan Basin, northern China , for the most part Middle Pleistocene archaic Homo sapiens were the most wide and northerly ranging hominin group prior to the arrival of modern H.

They occupied most regions of the Old World from southern Africa e. Archaic H. In all likelihood, however, occupation of these higher latitudes was probably restricted to interglacial stages. Current data indicate that archaic H. This was a period when only modern H. Evidence of adaptation to a colder climate include Middle Pleistocene open-air sites that display evidence of structures e. The latter postdate such famous H.

In order to colonize Eurasia, early hominins probably had to have controlled fire. However, evidence for fire only appears sporadically in the Early Pleistocene record, with the earliest generally accepted evidence appearing at the Middle Pleistocene site of Gesher Benot Ya'aqov in Israel Goren Inbar et al.

The paucity of evidence of fire at sites older than the Late Pleistocene is probably related to the likelihood that occupations by H. The stone toolkits of archaic Homo sapiens did not differ much from earlier H. In eastern Asia, the stone tools most commonly associated with archaic H. It was originally noted that handaxes were absent in eastern Asia Movius This pattern in the archaeological data came to be known as the Movius Line.

The line was drawn between South Asia and eastern Asia with handaxes to the west of the line and traditional Oldowan core and flake tools to the east of the line Norton and Lycett Although handaxes have been found in eastern Asia Norton et al.

I thank Holly Dunsworth for the kind invitation to contribute this paper. I appreciate the thoughtful comments from Holly Dunsworth and two anonymous reviewers. I take full responsibility for any errors that may be present. Bae, C. The late Middle Pleistocene hominin fossil record of Eastern Asia: synthesis and review. Yearbook of Physical Anthropology 53 , Berna, F. Binford, L. Human ancestors: changing views of their behavior.

Journal of Anthropological Archaeology 4 , Brauer, G. The origin of modern anatomy: by speciation or intraspecific evolution? Evolutionary Anthropology 17 , Cultural evolution in France in its paleoecological setting during the Middle Pleistocene. In: After the Australopithecines , ed.

Isaac, pp. The Hague: Mouton Etler, D. The fossil evidence for human evolution in Asia. Annual Review of Anthropology 25 , Goren-Inbar, N. Evidence of hominin control of fire at Gesher Benot Ya'aqov, Israel. Science , Groves, C. A bush not a ladder: speciation and replacement in human evolution. Perspectives in Human Biology 4 , Klein, R. Lycett, S. World Archaeology 42 , A demographic model for Palaeolithic technological evolution: the case of East Asia and the Movius Line.

Quaternary International , Mayr, E. Taxonomic categories in fossil hominids. Mounier, A. Is Homo heidelbergensis a distinct species?

New insight on the Mauer mandible. Journal of Human Evolution 56 , Movius, H. The projecting occipital bone present in other archaic Homo sapiens is also more prominent in Neanderthals, extending the trend found in archaics. Among Neanderthals, this projection of bone is easily identified by its bun shape on the back of the skull and is known as an occipital bun. This projection appears quite similar to a dinner roll in size and shape.

Its purpose, if any, remains unknown. Continuing the archaic Homo sapiens trend, Neanderthal brow ridges are prominent but somewhat smaller in size than those of Homo erectus and earlier archaic Homo sapiens. In Neanderthals, the brow ridges are also often slightly less arched than those of other archaic Homo sapiens. In addition to extending traits present in archaic Homo sapiens, Neanderthals possess several distinct traits.

Neanderthal infraorbital foramina , the holes in the maxillae or cheek bones through which blood vessels pass, are notably enlarged compared to other hominins. The Neanderthal postcrania are also unique in that they demonstrate increased robusticity in terms of the thickness of bones and body proportions that show a barrel-shaped chest and short, stocky limbs, as well as increased musculature.

These body portions are seen across the spectrum of Neanderthals—in men, women, and children. Many of the unique traits that Neanderthals possess can be attributed to adaptation to the extreme cold environments in which they often lived. Together explained as cold adaptations, these traits are thought to be a response to the cold, dry environments in which Neanderthals lived and which certainly exerted strong selective forces.

In addition, the Neanderthal skull also exhibits adaptations to the cold. The midfacial prognathism present in Neanderthals indicates that Neanderthals would have had a large nose. This enlarged nose may also have been beneficial to have in cold weather due to longer nasal passages and mucus membranes for cold air to travel through before reaching the lungs. It is very uncomfortable and challenging to breathe and exert oneself in exceptionally cold, dry air.

The more time the air spends in the mucus membranes, the warmer and more moist the air will be before it reaches the lungs. Distinct Neanderthal Anatomical Features. Brain Size. Brow Ridge Size. Nose Size. Large, with midfacial prognathism. Reduced, but large jaw size, creating retromolar gap. Occipital Region. Enlarged occipital region, occipital bun. Other Unique Cranial Features. Large infraorbital foramina.

Short and stocky body, increased musculature, barrel-shaped chest. This table outlines key features associated with Neanderthals. In summary, Neanderthal characteristics are a distinct cluster of features, some of which were apparent in previous hominins and others that were unique. Additionally, it is clear that Neanderthals were specially adapted to a particular environment—a very cold one.

A classic example of a Neanderthal with all of the characteristics mentioned above is the La Ferrassie 1 Neanderthal, from France. The skeleton is near complete, which is not necessarily unique among Neanderthal fossils as many partially complete remains have been found, but it does provide us with a lot of information.

The La Ferrassie 1 Neanderthal, who was male, had a brain size of around cc and had an extremely large nose and infraorbital foramina. Additionally, the brow ridges are marked in size, and the overall skeleton is robust Figure What are the benefits or the potential challenges Neanderthals could have faced for being highly specialized to one particular environment, when we know their environment and climate were in flux? One key Neanderthal adaptation was their cultural innovations. Cultural innovation is a key way that hominins adapt to their environment.

As you recall, the culture of Homo erectus was marked by the development of a bifacial tool, the Acheulean handaxe, which allowed them differential access to meat on animal carcasses when compared to their predecessors. For Homo erectus , the Acheulean handaxe allowed more efficient removal of meat and possibly calculated scavenging. The increase in their body and brain size, along with their more effective tools, allowed them to track predators and snatch their kills sometimes even before the predators themselves had even fed.

Acheulean tools represent a significant increase in complexity over Oldowan tools, as they required more time, effort, and skill to shape. Acheulean handaxes were not only worked on two sides, they shared a common shape, which required forethought and advanced planning by their makers. Homo erectus would have had a mental template for the desired outcome and, with practice, these tools were likely made quite quickly and could have been made by most individuals.

While these tools were a significant step forward in tool production, they were not intended to be kept. Homo erectus discarded the tools after use and treated them as a disposable item. In contrast, Neanderthal tools mark a significant innovation both in tool-making technique and their use. Mousterian tools were significantly smaller, thinner, and lighter than Acheulean handaxes and formed a true toolkit. The materials used for Mousterian tools were of higher quality, which allowed for both more precise toolmaking and tool reworking when the tools broke or dulled after frequent reuse.

The use of higher-quality materials is also indicative of required forethought and planning to acquire them for tool manufacture. It is noteworthy that the Neanderthals, unlike Homo erectus , saved and reused their tools, rather than making new ones each time a tool was needed. Mousterian tools are constructed in a very unique manner, utilizing the Levallois technique Figure The Levallois technique is a multistep process that requires preparing the core, or raw material, in a specific way that will yield flakes that are roughly uniform in dimension.

The flakes are then turned into individual tools. The preparation of the core is akin to peeling a potato or carrot with a vegetable peeler—when peeling vegetables, you want to remove the skin in long, regular strokes, so that you are taking off the same amount of the vegetable all the way around.

In the same way, the Levallois technique requires removing all edges of the cortex , or outside surface of the raw material, in a circle before removing the lid. The flakes, which will eventually be turned into the individual tools, can then be removed from the core. The potential yield of tools from one core would be many, as seen in Figure Neanderthal tools were used for a variety of purposes.

They would have constructed a tool for each specific task they needed to complete, such as cutting, butchering, woodworking or antler working, and hide working. Additionally, because the Mousterian tools were lighter than previous stone tools, Neanderthals could haft , or attach the tool onto a handle, as the stone would not have been too heavy.

Neanderthals attached small stone blades onto short wood or antler handles to make knives or other small weapons, as well as attached larger blades onto longer shafts to make spears. New research examining tar-covered stones and black lumps at several Neanderthal sites in Europe suggests that Neanderthals may have been making tar by distilling it from birch tree bark, which could have been used to glue the stone tool onto its handle.

If Neanderthals were, in fact, manufacturing tar to act as glue, this would predate modern humans in Africa making tree resin or similar adhesives by nearly , years! While research on specific applications continues, from just this brief discussion, it should be clear that Neanderthal tool manufacturing was much more complex than previous tool-making efforts, requiring skill and patience to carry out.

With their more sophisticated suite of tools, Neanderthals were better armed for hunting than previous hominins and had very robust bodies with larger muscles. The animal remains in Neanderthal sites show that unlike earlier archaic Homo sapiens , Neanderthals were very effective hunters who were able to kill their own prey, rather than relying on scavenging.

Oftentimes, this included very large animals like deer, horses, and bovids relatives of the cow. In fact, isotopes from Neanderthal bones show that meat was a primary and significant component of their diet, similar to that seen in carnivores like wolves Bocherens et al.

Though more sophisticated than the tools of earlier hominins, the Neanderthal spear was not the kind of weapon that would have been thrown; rather, it would have been used in a jabbing fashion Churchill ; Kortlandt This may have required Neanderthals to hunt in groups rather than individually, and it almost certainly meant that they would have had to approach their prey quite closely. Remember, the animals living with Neanderthals were very large-bodied due to their adaptations to cold weather.

In addition to large bovids, prey included ibex, seals, rabbits, and pigeons. Though red meat was a critical component of the Neanderthal diet, evidence shows that at times they also ate limpets, mussels, and pine nuts. Tartar examined from Neanderthal teeth in Iraq and Belgium reveal that plant material including wheat, barley, date palms, and tubers were also eaten by Neanderthals and were cooked to make them palatable.

While the new, close-range style of hunting used by Neanderthals was effective, it also had some major consequences. Many Neanderthal skeletons have been found with significant injuries, which could have caused paralysis or severely limited their mobility.

Many of the injuries are to the head, neck, or upper-body. What do Neanderthals and rodeo workers have in common?

They were both getting very close to large, strong animals, and at times their encounters might have gone awry. The extensive injuries sustained by Neanderthals are evident in many fossil remains. Shanidar 1 Figure Shanidar 1 sustained—and healed from—an injury to his face that would have likely caused blindness. His lower right arm was missing and his right humerus shows severe atrophy, likely due to disuse. This pattern has been interpreted to indicate a substantial injury that required or otherwise resulted in amputation or wasting away of the lower arm.

Additionally, Shanidar 1 suffered from severe arthritis in his feet and bony growths in his inner ear that would have significantly impaired his hearing. He also exhibited extensive anterior tooth wear, matching the pattern of wear found among modern populations who use their teeth as a tool.

Rather than an anomaly, the type of injuries evident in Shanidar 1 are similar to those found in many other Neanderthal fossils, revealing injuries likely sustained from hunting large mammals as well as demonstrating a long life of physical activity. The pattern of injuries is as significant as the fact that Shanidar 1 and other injured Neanderthals often show evidence of having survived their severe injuries. One of the earliest known Neanderthal discoveries—the one on whom misinformed analysis shaped the stereotype of the species for nearly a century—is the La Chapelle-aux-Saints Neanderthal.

The La Chapelle Neanderthal had a damaged eye orbit that likely caused blindness and suffered arthritis of the spine. He had also lost of most of his teeth, many of which he had lived without for so long that the mandibular and maxillary bones were partially reabsorbed due to lack of use. Such caretaking behavior is also evident in the survival of other seriously injured Neanderthals, such as Shanidar 1.

Long thought to be a hallmark human characteristic, taking care of the injured and elderly, to the extent of even preparing or pre-chewing food for those without teeth, indicates strong social ties among Neanderthals. The care expressed in taking care of the sick or injured may have been expressed upon death as well. Full Neanderthal skeletons are not uncommon in the fossil record, and many of these skeletons were so well preserved due to having been placed in deliberate burials.

These burials appear intentional, as the graves are dug down a bit, and the bodies found in the graves are in specific positions quite distinct from the natural position the body automatically goes into after death during rigor mortis.

Neanderthal burials are often in a flexed position , or fetal position. Discoveries of pollen in a grave at the Shanidar site in the s led scientists to think that perhaps Neanderthals had deliberately placed flowering plants in the grave, an indication of ritual ceremony or spirituality so common in modern humans.

But future investigations have raised some doubt about this conclusion. The pollen may have been brought in by burrowing rodents. Claims of grave goods or other ornamentation in burials are similarly debated, although possible. Some tantalizing evidence for symbolism, and debatably, ritual, is the frequent occurrence of natural pigments, such as ochre red and manganese dioxide black in Neanderthal sites.

Such pigments could have been used for art, like some of the spectacular cave paintings produced by modern humans who lived in this area after the Neanderthals.

However, how these pigments were actually used by Neanderthals themselves is unclear, as there is very little evidence of art or paintings in Mousterian sites. One exception may be the recent discovery in Spain of a perforated shell that appears to be painted with an orange pigment, which may be some of the best evidence of Neanderthal art and jewelry.

However, many pigments also have properties that make them good emulsifiers in adhesive like for attaching a stone tool to a wooden handle or useful in tanning hides. So the presence of pigment may or may not be associated with symbolic thought, but it at the very least shows a technological sophistication beyond that exhibited by earlier archaic hominins and clearly counters the old stereotypes of Neanderthals as dumb, thoughtless brutes.

The more recent time period in which Neanderthals lived and extensive excavations completed across Europe allow for a much more complete archaeological record from this time period. Additionally, the increased cultural complexity such as complex tools and ritual behaviors expressed by Neanderthals left a more detailed record than previous hominins. Intentional burials enhanced preservation of the dead and potentially associated ritual behaviors.

Such evidence allows for a more complete and nuanced picture of this species. Additional analyses are possible on many Neanderthal finds, due to increased preservation of bone, the amount of specimens that have been uncovered, and the recency in which Neanderthals lived. These additional studies include the examination of dental calculus and even DNA analysis.

While limited, some samples of Neanderthal DNA have been successfully extracted and analyzed. Studies thus far have identified specific genetic markers that show some Neanderthals were light-skinned and probably red-haired with light eyes.

Genetic analyses, different than the typical hominin reconstruction done with earlier species, allow scientists to further investigate soft tissue markers of Neanderthals and other more recent hominin species. Evidence shows that raw materials used by Neanderthals came from distances as far away as km. This could indicate a variety of things regarding Neanderthal behavior, including a limited trade network with other Neanderthal groups, or simply a large area scoured by Neanderthals when collecting raw materials.

Additionally, we know that Neanderthals lived in groups and may have relied on their group members for survival. In other nonhuman primates like chimpanzees and earlier hominins, injured individuals would have been left on their own, to either survive or perish. The impressive cultural innovations and behavioral expansions seen in the Neanderthals would have required at least a basic form of communication in order to function, which suggests to many researchers that Neanderthals spoke.

The challenge with this line of research is that speech, itself, of course is not preserved, so indirect evidence must be used to support this conclusion. It is thought that Neanderthals would have possessed some basic speech, as evidenced from a variety of sources, including throat anatomy and genetic evidence.

There is only one bone in the human body that could demonstrate if a hominin was able to speak, or produce clear vocalizations like modern humans, and that is the hyoid, a U-shaped bone that is found in the throat and is associated with the ability to precisely control the vocal cords.

Very few hyoid bones have been found in the archaeological record; however, a few have been uncovered in Neanderthal burials. The shape of the Neanderthal hyoid is nearly identical to that of modern humans, pointing to the likelihood that they had the same vocal capabilities as modern humans. Genetic evidence has been debated concerning the likelihood of speech. Geneticists have uncovered a possible mutation, the FOXP2 gene, that has been linked to the ability to speak and that both modern humans and Neanderthals possess.

Finally, scientists have also pointed to the increasingly complex cultural behavior of Neanderthals as a sign that symbolic communication, likely through speech, would have been the only way to pass down the skills needed to make, for example, a Levallois blade or to position a body correctly for intentional burial. One of the enduring questions about Neanderthals centers on their intelligence, specifically in comparison to modern humans. Brain volume indicates that Neanderthals certainly had a large brain, but it continues to be debated if Neanderthals were of equal intelligence to modern humans.

Brain volume, cultural complexity, tool use, and compassion toward their kind all point to an increase in intellect among Neanderthals when compared to previous hominins. However, there have been several studies that seem to indicate that while Neanderthals did have a large brain volume and were far more advanced than their previous relatives, they may not have been nearly as intelligent as or may have even lacked the intellectual abilities possessed by modern humans. Euluned Pearce and colleagues, from the University of Oxford, noted that based on cranial endocasts, the frontal lobe of Neanderthals and modern humans are almost identical.

However, Neanderthal faces and other cranial features were larger. Neanderthals possessed larger eye sockets, and the larger eyes they held would have helped Neanderthals see in the low light levels common for the latitudes at which they lived. Because of the larger eye sockets, the visual cortex—the portion of the brain involved in processing visual information—would have had to have been enlarged, as well.

This would have left Neanderthals with less neural tissue for other components of the brain, including those that would have aided them in dealing with expansive social networks, one of the differences that it has been suggested existed between Neanderthals and modern humans.

New research is suggesting additional differences between Neanderthal brains and our own. Research being conducted by geneticist John Blangero and his team from the Texas Biomedical Research Institute are examining genes involved in certain diseases among modern populations. His team has also looked at brain structure and function.

Comparing data from the Neanderthal genome against MRI data from his modern study participants, Blangero and his team discovered that some Neanderthal brain components were very different, and smaller, than those in the modern sample. These areas include decreased gray matter surface area, a smaller amygdala, and less white matter.

These three regions are important in the processing of information and controlling emotion and motivation, as well as overall brain connectivity.

Finally, scientists are fairly certain that Neanderthal brain development after birth was not the same as that of modern humans. After birth, anatomically modern Homo sapiens babies go through a critical period of brain expansion and cognitive development. This could also be related to the length of the period of childhood. Modern humans enjoy an extended period of childhood, which, among many things, allows children to engage in imaginative play and develop creativity.

Child development studies indicate that children who have extended, undirected play opportunities will be better off academically and socially later in life than their peers who had less play opportunities. Based on their anatomical developments, it appears that Neanderthals had a limited childhood.

It has been suggested that this limited time for play and developing a creative mind might have limited adult creativity and how successful they were as a species, in the long run. The exact nature of Neanderthal intelligence remains under investigation, however. Some studies disagree with the idea that Neanderthal intelligence had limitations compared to our own, noting that there is extensive evidence showing that Neanderthals displayed limb asymmetry.

Their tools also have wear marks indicating that they were hand-dominant. It has been established that favoring the right hand is one key marker between modern humans and chimpanzees, and that handedness is likely also related to language development, in the form of bilateral brain development. That Neanderthals likely were hand-dominant as well suggests that they at least had many of the preconditions for human speech and likely experienced similar bilateral brain development to our own.

In addition to cut marks on animal bones, there are marks on Neanderthal teeth that demonstrate hand dominance. Neanderthal upper incisors, or front teeth, show not only wear from using their teeth when preparing hides or cordage but also cut marks that were created by using their teeth as a third limb when eating.

When looking at 17 Neanderthals and their tooth wear, only two do not show markings made by a right-hand dominant individual.

This research suggests another similarity between Neanderthal and modern human brains and their associated intelligence. While Neanderthals made their home on and adapted to the European and Asian continents, evidence of fossil humans in Africa show they were also adapting to their local environments.

These populations in Africa exhibit many more similarities to modern humans than Neanderthals, as well as overall evolutionary success. While the African fossil sample size is smaller and more fragmentary than the number of Neanderthal specimens across Europe and Asia, the African sample is interesting in that it represents a longer time period and larger geographical area.

As with archaic Homo sapiens , there is much variability seen in this African set of fossils. There are also a few key consistent elements: none of them exhibit Neanderthal skeletal features; instead, they demonstrate features that are increasingly consistent with anatomically modern Homo sapiens. Similarities to Neanderthals and MSA contemporaries in Africa are seen, however, in their behavioral adaptations, including stone tools and other cultural elements.

The tools associated with the specimens living in Africa during this time period are, like their physical features, varied. In some parts of Africa, namely Northern Africa, stone tools from this time so closely resemble Neanderthal tools that they are classified as Mousterian. Some scholars argue that these could also be a type of Mousterian tools, but they are still typically subdivided based on geographical location.

Recall that Mousterian tools were much more advanced than their Acheulean predecessors in terms of how the stone tools were manufactured, the quality of the stones used, and the ultimate use of the stone tools that were made. In addition, recent evidence suggests that MSA tools may also have been heat treated—to improve the quality of the stone tool produced. Evidence for heat treating is seen not only through advanced analysis of the tool itself but also through the residue of fires from this time period.

Fire residues show a shift over time from small, short fires fueled by grasses probably intended for cooking to larger, more intensive fires that required the exploitation of dry wood, exactly the type of fire that would have been needed for heat treating stone tools.

Other cultural elements seen with specimens dating to the MSA include use of marine sea-based resources for their diet, manufacture of bone tools, use of adhesive and compound tools e. While many of these cultural elements are also seen to a limited extent among Neanderthals, many of the developments at MSA sites are far more complex than what is demonstrated with Neanderthal sites. Several explanations have been posited to explain this expansion of cultural complexity.

It has been suggested that MSA cultural expansion was a response to climate change. It has also been suggested that perhaps the MSA cultural expansion was due to an increased use of language, which triggered increased symbolic thought. Others have suggested that the cultural expansion of the MSA was due to the increase of marine resources in their diet, which included more fatty acids and may have aided their cognitive development. Still others have suggested that the increased cultural complexity was due to an increase in competition and interaction among groups, which spurred competition to innovate with increased cultural complexity.

Recent studies suggest that perhaps the best explanation for the marked cultural complexity and diversity demonstrated by MSA cultural artifacts is best explained by the simple fact that they lived in diverse habitats. This would have necessitated a unique set of cultural adaptations for each habitat type for example, specialized marine tools would have been needed along coastal sites but not at inland locations.

Simply put, the most useful adaptation of MSA was their flexibility of behavior and adaptability to their local environment. As noted previously in this chapter, flexibility of behavior and physical traits, rather than specialization, seems to be a feature that was favored in hominin evolution at this time.

While MSA were increasingly successful and ultimately transitioned into modern Homo sapiens , Neanderthals disappear from the fossil record by around 35, years ago. The main question that lingers, however, is what happened to them. We know, based on genetics, that modern humans come largely from the modern people who occupied Africa around , to , years ago, at the same time that Neanderthals were living in the icy portions of northern Europe and Asia. Modern humans expanded out of Africa around 60, to 40, years ago, rapidly entering areas of Europe and Asia inhabited by Neanderthals and likely other populations of archaic hominins.

Despite intense interest and speculation in fictional works about possible interactions between these two groups, there is very little direct evidence of either peaceful coexistence or aggressive encounters. It is clear, though, that these two closely related hominins shared Europe for thousands of years, and recent DNA evidence suggests that they at least occasionally interbred. This is generally interpreted as indicating limited regional interbreeding with Neanderthals. Interestingly, while some studies suggest interbreeding was often problematic for their offspring, gene flow from Neanderthals may have benefited modern Homo sapiens.

David Enard and Dmitri Petrov compared sequenced Neanderthal and modern human DNA, observing that the portions of Neanderthal DNA in modern humans of European descent seem to confer defense against viral pathogens that they would have been exposed to as they moved out of Africa. While some interbreeding likely occurred, as a whole, Neanderthals did not survive. What is the cause for their extinction? This question has fascinated many researchers and several possibilities have been suggested that deserve some exploration.

Possibilities include the following:. As Neanderthal populations were fairly small to begin with estimated between 5, and 70, individuals Bocquet-Appel and Degioanni , one or a combination of these factors could have easily led to their demise. As more research is conducted, we will likely get a better picture of exactly what led to Neanderthal extinction. While Neanderthals represent one regionally adapted branch of the archaic Homo sapiens family tree, recent discoveries in Siberia and the Tibetan Plateau have surprised paleoanthropologists by revealing yet another population that was contemporary with archaic Homo sapiens , Neanderthals, and modern Homo sapiens.

Additional studies have suggested two separate instances of interbreeding between humans and Denisovans, whom researchers have yet to classify as a separate species, pending additional information. Genetic analysis reveals that Denisovans potentially had at least three populations and had genetic adaptations for life at high altitudes, preventing them from developing altitude sickness and hypoxia. Recent publications also suggest that Denisovans shared these genetic adaptations with modern Tibetans through interbreeding 30, to 40, years ago.

Research continues on this population and other archaic populations in the hopes of discovering more DNA evidence that can confirm current hypotheses and clarify our understanding of the complex interactions of archaic groups.

There has been much debate in anthropological circles concerning the origin of modern humans and their relationship with other hominin populations. Three competing models have been developed and seek to explain the fossil evidence and what it indicates for modeling human origins. The first model, the Out-of-Africa Hypothesis, states that modern humans originated in Africa, replacing archaic populations found elsewhere in the Old World.

Theorists including Christopher Stringer argue that each archaic population comprised a separate species, making interbreeding between populations impossible. Admixture resulting from gene flow would not have been possible according to this model. The second, called the Multiregional Continuity Hypothesis, states that modern Homo sapiens are directly derived from Homo erectus and evolved in place after Homo erectus left Africa and populated areas in Asia and Europe.

Milford Wolpoff argues that interbreeding between regions and across regional boundaries contributed to gene flow that maintained Homo sapiens as a single species throughout the Old World, despite regional variation. The third model, dubbed the Assimilation Hypothesis, draws from the strengths of both previous models, attempting to recognize some of the evidence that was not previously addressed and blending the fossil and DNA evidence together into one cohesive view.

In this model, modern humans originated in Africa, spreading outward into Asia and Europe and interbreeding with more archaic forms they encountered along the way. For example, while the Out-of-Africa model argues that interbreeding would have been impossible, many fossils have been found with what appear to be a mixture of archaic and more modern traits, suggesting interbreeding between populations, such as Neanderthals and modern humans.

DNA evidence increasingly also suggests that, while limited, interbreeding between modern Homo sapiens and Neanderthals or modern Homo sapiens and Denisovans occured in at least three instances. While this is more interbreeding than allowed under the Out-of-Africa Hypothesis, it is considerably less than modeled in the Multiregional Continuity Hypothesis. The Assimilation Hypothesis, argued by Eric Trinkaus , and others, represents an attempt to incorporate all lines of evidence, although new research will tell whether it can capture the full complexity revealed in the next generation of hominin studies, such as that revealed by ancient DNA.

Ancient DNA has provided us with new insights into our evolutionary history that cannot be garnered from the fossil record. It has also assisted with the discovery of the new hominin species the Denisovans, for which little fossil evidence is available.

It has helped us better understand the evolution of Neanderthals, Denisovans, and modern humans. Through genomic data and the use of population genetics, we have been able to make some inferences about Neanderthal and Denisovan population structure and relationships within these populations as well as between different groups of hominins.

Two theories dominated the debate regarding the evolution of modern humans: the multiregional theory and the Out-of-Africa theory. Though it was clear—based on a plethora of evidence—that modern humans evolved in Africa, what happened when our ancestors migrated out of Africa was still questioned.

Ancient DNA aDNA helped answer this question, indicating that modern humans interacted with other archaic hominins such as Neanderthals and Denisovans. We will discuss all the above in this section. Sequencing of a portion of the mitochondrial genome provided molecular evidence that Neanderthals belonged in a clade separate from modern humans and that they were four times more different from modern humans than modern humans were from each other based on mtDNA data. Sequencing of nuclear DNA would not occur until more than ten years later.

The first nuclear genomic sequence representing Neanderthals was produced by sequencing three individuals and using their sequences to create a composite draft Neanderthal genome in The first high-coverage sequence of a single Neanderthal was that of a female Neanderthal who lived in Siberia, which was published in , followed by another high-coverage sequence from a female Neanderthal whose remains were found in the Vidja cave in Croatia, which was published in High-coverage sequences are produced when the genome has been sequenced multiple times.

This is to ensure that the sequences obtained are a true reflection of the genomic sequence and not due to errors that occur during the process of sequencing.

If you have many sequences from the same region and there is one sequence that has a slight difference while the other copies are all the same, it is easier to identify the variant as an error. Ancient DNA can be collected from many different sources including soft tissue such as skin and muscle, hair, paleo feces, soils, and sediments.

However, in the case of ancient hominins, they are often collected from bone and teeth. When collecting aDNA, usually around mg to mg of bone powder needs to be collected. Because extraction of aDNA requires destruction of part of the bone, and the morphology of the skeletal element might be informative, care needs to be taken when deciding which part of the bone is sampled.

It is advised that multiple samples be taken so that sequencing is repeated to show reproducibility of results.

Contamination is an important consideration when it comes to sequencing aDNA; thus, it is best that samples that are used had minimal handling before extraction of DNA. It has taken a lot of time and much trial and error to sequence these ancient genomes because of the fragility of DNA. Endogenous aDNA is the DNA that comes from the bone and was present in the tissue before decomposition of the body and before the introduction of DNA from other sources, such as microbes or contamination from modern humans, which is known as exogenous DNA Figure There are also modifications that occur to aDNA that are a result of chemical reactions known as deamination.

Thus, there are sequence changes in aDNA that might not reflect the original hominin sequence. The environment in which the DNA is preserved also plays a significant role. DNA preserves well in cold conditions such as permafrost, which extends the lifespan of DNA significantly. Factors such as water percolation, salinity, pH, and microbial growth all affect the preservation of aDNA.

This changed with the advent of high throughput sequencing, which has revolutionized sequencing the genomes of ancient hominins. High throughput sequencing allows for the parallel sequencing of many fragments of DNA in one reaction.

Thus, we can sequence as much of the available aDNA as possible. Because the high throughput sequencing method does not discriminate between endogenous aDNA from hominins and contamination from modern humans and microbial DNA, it is important to either ensure that there is as little contamination as possible or create methods that allow for differentiation between modern human sequences and ancient hominin sequences.

Both methods have been used when sequencing hominin aDNA. The Denisovans are named after the cave in which they were discovered, the Denisovan Cave in the Altai Region of Siberia. Denisovans were initially identified as a distinct group based on analysis of mtDNA sequences indicating that they had haplotypes outside the range of variation of modern humans and Neanderthals.

A haplotype is a set of genetic variants located on a single stretch of the genome. This unique combination of variants on a stretch of the genome can be used to differentiate groups who will have different combinations of variants.

Some haplotypes may be more similar to one another. The more similar two haplotypes are, the more closely related they are. Dubbed lineage X, the mtDNA sequence showed that Denisovans diverged from modern humans and Neanderthals at around 1 million years ago mya.

The subsequent high-coverage sequence of a Denisovan 3 nuclear genome showed that Denisovans are a sister group to Neanderthals and thus more closely related than indicated by the mtDNA data. Because mtDNA and nuclear DNA have different patterns of inheritance, they can paint different pictures about the relationships between two groups when used to construct phylogenies. The Denisovans are thought to have a mtDNA sequence that is derived from an ancient hominin group that hybridized with Denisovans and introduced the mtDNA sequence.

Sequences are also available for three other Denisovans, Denisovan 2, 4, and 8. Using a combination of usual dating methods such as radio carbon dating and uranium dating as well as genetic data, it has been determined that Denisovans occupied the Denisovan cave from around kya to 52 kya to 76 kya. DNA can assist with dating because younger sequences will have accumulated more sequence changes from the putative common ancestral sequence than older samples.

This is because younger sequences would have had more time over which changes to the DNA sequence through mutation could occur. Thus, it is possible to conclude based on sequence data that Denisovan 2 is Molecular data indicates that Neanderthals and Denisovans separated between kya and kya and that the branch leading to Denisovans and modern humans diverged around kya.

Denisovans are also more closely related to another set of fossils found in the cave Sima de los Huesos dated to kya. Thus, the split between Neanderthals and Denisovans must have occurred before kya. Ancient DNA has helped us understand the demographics of Neanderthals and Denisovans and make inferences about population size and history. The genomic data from Neanderthals indicates that their population was small toward the end of their existence.

This is supported by three lines of evidence. The first is by using coalescent methods. This is the process used to determine which population dynamics in the past are most likely to give rise to the genetic sequences we have, allowing us to use genetic sequences to estimate population genetic parameters in the past. It can be used to understand recombination, population subdivision, and variable population size. The second indicator that Neanderthals and Denisovans had smaller population size is that these groups carried many deleterious genomic variants.