Neanderthal fossils are not commonly found but a few have been found and analyzed. These fossils were most likely found in arid climates or an isolated caves where their preservation greatly depended on the local environment in which they died. The majority of Neanderthal were not buried which further limits the fossil record. Also, the areas of the world that have been researched are generally near population centers, there has been a great deal of bias in the fossil record resulting from the fact that paleontologists have not equally searched all areas of the globe. As we saw in the Denisova Cave Video. Due to the inaccessibility of some regions, such as Central Asia and much of Africa, their fossil records are poorly understood compared to those of Europe and North America. We are left with a hazy picture of the past, especially the early past. Despite these problems, we have been able to piece together a better understanding of the evolution of Neanderthals on earth through fossil evidence.
When paleontologists trace the evolution of a species line, like Neanderthals, they often find that there are gaps of time in the fossil record, these periods are known as missing links in evolution. These gaps are often the result of the changing preservation conditions or climate in the past. The climate has dramatically changed many times in the past. When that occurred, Neanderthals often died out in one region but flourished in others. Larger gaps in the fossil record are usually filled through intensive worldwide research as we saw in this week’s lecture and videos. This results in an ever more accurate picture of how Neanderthals lived in the past.
The more massive build of Neanderthals, and other features such as flatter noses, has been interpreted as an adaptation to the harsh glacial climates of Ice Age Europe. The more limited Neanderthal technology, compared to that of modern humans, combined with the Neanderthal’s stockier build are thought by some to indicate a very physical method of hunting, involving running down and spearing prey, which consisted of large mammals. Not all bones survive equally well, lightweight bones deteriorate more quickly and are less often fossilized, small bones are delicate and are likely to be crushed or carried away. Neanderthal bones are, in general, more massive than modern human bones. Neanderthals had large ridges over their brows and other protrusions of the skull not generally seen in modern humans. They were more muscular than modern humans. They had receding chins. And, their brains were somewhat larger than those of modern humans. Since Neanderthal bones were thick and massive, they are more likely to survive for a longer period of time, where paleontologists can study their fossils today.
By looking at Neanderthal growth patterns, their fossilized teeth show that they matured at a faster rate than modern humans, reaching full adulthood by their mid-teens. If Neanderthals had physically stressful lives, their higher mortality rates and a shorter life span than humans, earlier maturation would have provided an advantage for them, especially for faster maturity and quicker reproduction rates. Some of the fossils show interbreeding between modern humans and Neanderthal characteristics in the skull. These mixtures included an occipital bun, a swelling at the back of the skull, a muscle attachment at the back of the skull, and certain muscle attachments in the jaw. These characteristics are rarely or never seen in modern humans. By comparing the fossil records of the Neanderthal to a modern human, paleontologists can learn more about human evolution.
Paleontologist’s study fossils through Mitochondrial DNA, as we learned in the video, “The Great Human Migration” that DNA is transferred from mother to daughter, generation after generation. In the mitochondria, the DNA is not recombined as it passes generation to generation linking it to past generations. Mutations also are passed on through the Mitochondria, scientists can see in the fossil record when they appeared. Scientists can also use archeological evidence by the way the humans lived or their migration patterns of past generations. And, of course, through fossil evidence if the Neanderthal or other species remains were properly preserved, in the proper environment.
My opinion as the largest contributor to human diversity is isolating population groups regionally. The isolation of a group of people is the best way to create variances among the same species. If humans were still largely isolated there would be an even larger gap in diversity. The lectures and videos pointed out regional differences as the most obvious reason for species variance.