THE NEANDERTHALS

=''Homo neanderthalensis''= [image:http://i.imgur.com/qbc57m5.png?1] Neanderthal man existed around 400,000 – 28,000 years ago, a period which overlaps significantly with that of anatomically modern humans. The DNA of Neanderthals and ''Homo sapiens'' suggests that they diverged from a common ancestor between 350,000 and 400,000 years ago. This ancestor was probably ''Homo heidelbergensis''. It is thought ''Homo heidelbergensis'' populations in Africa evolve into modern human (''Homo sapiens'') while those in Europe and Asia evolved into the neanderthals. Modern humans (''Homo sapiens'') and Neanderthals are anatomically very similar and their DNA differs by just 0.12%. Some people believe that Neanderthals interbred with modern humans and are actually a subspecies of ''Homo sapiens''. DNA evidence suggest that there was some, albeit limited, interbreeding with anatomically modern humans (''Homo Sapiens'') as they left Africa. Non-African populations may have inherited as much as 5% of their genome from the Neanderthals. However, no evidence has been found of cultural interaction and the evidence from mitochondrial DNA studies has been interpreted as evidence that the Neanderthals were a distinct species. [image:http://i.imgur.com/UNO4oWD.png?1] ==Anatomy== [image:http://i.imgur.com/U3hlboel.png?1] '''General Features:''' Neanderthals’ body proportions are similar to those of modern '''cold-adapted''' people: short and solid, with short limbs. They had a more robust build with a wider, barrel-shaped rib cage. They were slightly shorter, but comparable in height to modern humans. Their bones are thick and heavy, and show signs of powerful muscle attachments. Neanderthals would have been extraordinarily strong by modern standards, and their skeletons show that they endured brutally hard lives. Skeletal evidence suggests that few individuals lived past 35 years of age. '''Skull:''' The average cranial capacity of Neanderthals was 1600 cm3, slightly larger than that of modern humans (essentially just proportionate to their larger body size). Neanderthals had a larger nose that started somewhat higher on the face. The Neanderthal nasal cavity is longer and wider -an adaption to the cold which allows more time for inhaled air to be warmed. Neanderthals had very strong jaws that protruded forward slightly, a reduced chin, and larger incisors than modern humans. Their eyesight may have been better than that of modern humans, owing to larger eye sockets and larger areas of the brain devoted to vision (occipital bun). [image:http://i.imgur.com/eDTUW0U.png] ==Distribution== [image:http://i.imgur.com/2Yz1Pqo.png] The Neanderthals occupied a cultural period known as the Middle Palaeolithic (Stone Age). This period included the end of the last ice age, so their survival demanded considerable toughness. Neanderthals were adapted biologically to cold weather and were predominantly confined to '''Europe and Western Asia''', while modern Humans remained in Africa until approximately 60,000 years ago. The Neanderthals at times displaced modern humans in parts of the Middle East when the climate got cold enough. Neanderthals are not known to have ever lived south-west of present-day Israel. When climate change caused warmer temperatures, the Neanderthal range likewise retreated to the north, along with the cold-adapted species of mammals. ==Disappearance== The Neanderthals disappeared around 40,000 years ago which roughly coincides with the arrival of ''Homo sapiens'' who had started to move out of Africa. The two different human populations shared Europe for up to 5,000 years, but the exact nature of biological and cultural interaction between Neanderthals and other human groups is still heavily debated. Possible reasons for the disappearance of the Neanderthals include: '''Competition with modern humans''' Neanderthals were less energy efficient. The sheer size and robust nature of the Neanderthals meant that they had much higher energy requirement than H. sapiens. When food became scarce, this difference may have played a major role in the Neanderthals' extinction. There is also evidence that modern humans were able to use larger, more complex social networks to source materials and food whereas the Neanderthals were restricted to local resources. Modern humans (''Homo sapiens'') used more sophisticated tools and may have been more intelligent. Despite having a larger brain, a much greater portion of the Neanderthal brain was devoted to vision and movement. Modern human actually had a greater brain volume dedicated to other cognitive function. It's though that this enabled them to form more complex social interactions and that this gave them a competitive advantage over the Neanderthals. A violent conflict resulting in the displacement and eventual extinction of the Neanderthals has also been suggested. '''Climate''' About 55,000 years ago, the weather began to fluctuate wildly from extreme cold conditions to mild cold and back in a matter of a few decades. Neanderthal bodies were well suited for survival in a cold climate—their barrel chests and stocky limbs stored body heat better than the modern humans. However, the rapid fluctuations of weather caused ecological changes to which the Neanderthals could not adapt; familiar plants and animals would be replaced by completely different ones within a lifetime. The disappearance of the Neanderthals about 40,000 years ago coincides with the start of a very cold period in Europe. There is some evidence that neanderthal numbers were already in drastic decline before human arrived on the scene. '''Interbreeding Theory''' This theory is essentially based upon the idea that the Neanderthals were simply a European subspecies of ''Homo sapiens''. In this scenario, the Neanderthals interbred with the other ''Homo sapiens'' and contributed at least in part to the formation of modern humans. Genetic evidence actually supports the idea that there was some interbreeding, but it appears to be very limited and wouldn't account for the disappearance of the Neanderthals. '''Disease''' H. sapiens may have introduced a disease that contributed to the extinction of Neanderthals. More recent historical events in Europe, Asia and the Americas show a similar pattern. The unintentional introduction of viral, or bacterial pathogens to unprepared populations has often led to mass mortality and local population extinction.