Category Archives: Science

The Neanderthal Problem: Contemporary Theories of the Fate of Neanderthals

Well, I had intended to write a new post each week, but I have been busier this past month then I expected, and have been unable to find the time to write. I had at least planned to post the paper I wrote for my second assignment in my archeology class, but I lost my original document the day it was due (stupid Word), and the replacement I hastily wrote was so poor I would have been embarrassed to post it. So instead I am posting assignment number three… it is nothing special either, but I hope you enjoy it anyway.

Introduction

The discovery of the first Neanderthal specimen in a cave in Germany in 1856 marked the beginning of the field of palaeoanthropology, but it also planted the seed of one of the longest-lasting controversies in the field of palaeontology. The French palaeontologist Marcellin Boule characterized the fossil as that of a brutish, bent-kneed biped who did not walk fully erect. According to descriptions and illustrations by Boule, the Neanderthal was a hairy, gorilla-like figure with opposable toes. It wasn’t until later that anthropologists determined that the specimen was that of a crippled individual plagued by an extreme case of arthritis, giving him the deformed and hunched-over appearance that resulted in the earlier misrepresentations of the species. Unfortunately this mistake has stuck with the general perception of Neanderthals even to this day.

Neanderthals lived in Europe and parts of the Middle East, between about 400,000 and 30,000 years ago. While anatomically modern homo sapiens had lived throughout most of the old world since about 250,000 years ago, it wasn’t until about 40,000 years ago that they migrated into Europe. After a few thousand years during which both populations seem to have co-existed in Europe, all traces of the Neanderthals disappeared. However there is a lack of sufficient evidence to be certain of what happened to the Neanderthals at that time, or even if they were a species distinct from modern humans. This is the basis of the Neanderthal Problem.

The Neanderthal Problem

The ultimate fate of Neanderthals is still not really known, although many different theories prevail on this topic. These theories generally fall into two categories – those that hypothesize that Neanderthals were totally distinct from modern homo sapiens and went completely extinct with no living descendents, and those that instead theorize that there was some degree of interbreeding and that Neanderthals are direct descendents of at least some of the modern humans. However there has so far been insufficient evidence to bolster any particular theory on the fate of the Neanderthals.

Extinction Theories

There are several ways that the Neanderthals may have been driven to extinction, with theories ranging from gradual extinction due to competition, to rapid extinction due to violent conflict or disease.

Gradual Extinction

Neanderthals may have been out-competed by the more technologically advanced anatomically modern humans. These modern humans may have been more effective at hunting and gathering, and the Neanderthals would have had difficulty competing for food. The situation may have been exacerbated by global climate change. They may not have been able to adapt their hunting methods to the colder weather during the most recent Ice Age, while the better equipped modern humans were able to thrive compared to the Neanderthals[1]. Consequently they would have been poorly nourished, and would have become more frequent victims of starvation and disease.

Rapid Extinction

Another possible consequence of the spread of modern humans into Europe is genocide[2]. Neanderthals and modern humans may have become violent in their competition for resources, and the Neanderthals could have been vanquished by the modern humans with their more advanced weapons and tools.

Alternatively, the Neanderthals may have succumbed to infectious diseases introduced by the modern humans. Much like the Native Americans during the European conquest of the Americas, they would not have had adequate immunity to these diseases and would have been devastated by them.

A potential problem with rapid extinction theories such as genocide and disease is that the fossil evidence suggests a more gradual extinction, over the course of 10,000 to 20,000 years.

Interbreeding Theories

Another set of theories states that Neanderthals were not a completely different species, but instead interbred with modern humans to some extent. This theory therefore implies that the Neanderthals were not a distinct species from humans, as the extinction theories would imply, but rather a subspecies of humans that could interbreed with modern humans. There is evidence that Neanderthal and modern homo sapiens inhabited the same regions of Europe for thousands of years. Artifacts found at Neanderthal sites suggest that they may have traded with modern homo sapiens, rather than simply borrowing their technology.

Some late Neanderthal specimens suggest a transition from previous Neanderthals to modern humans. One skull in particular lacks a facial projection found on other Neanderthal skulls, which some anthropologists claim is evidence of a gradual transition between the two populations. Other fossils have also been found throughout Europe, which have been described as hybrids. This evidence would support the theory that Neanderthals did not simply go extinct, but were gradually blended in with the modern homo sapiens. To date, no evidence of Neanderthal lineage has been found in the DNA of modern Europeans. While this lack of evidence does not support the interbreeding theory, it also does not rule out the possibility that all such lineages died out more recently.

Conclusion

The current confusion and controversy about the nature and history of the Neanderthals may have initially been the result of bad timing and circumstance. The first widely-recognized Neanderthal fossil was found in 1856, three years before the publication of Darwin’s On the Origin of Species, so scientists of the time could not appreciate the significance of the find with regards to human evolution. Also, this first specimen also happened to be an atypical sample of the species, since it was of an individual suffering from advanced arthritis. However, much of the confusion perpetuates to this day due not only to these early misrepresentations of the species, but also due to a lack of sufficient evidence of any one theory regarding the fate of the Neanderthals.

The topic continues to be controversial, since the truth about what happened to this population of hominids has so much bearing on the understanding of the origins and history of our own species. Are we descended from Neanderthals, or is our species responsible for their demise? Or is it perhaps a combination of these factors, or even something entirely different? Surely we will someday find enough evidence to determine which of these theories best describes the ultimate fate of the Neanderthals.


Bibliography

Diamond, Jared. The Third Chimpanzee: The Evolution and Future of the Human Animal. Harper Perennial, 1992.

National Geographic News, “Climate Change Killed Neandertals, Study Says”. http://news.nationalgeographic.com/news/2004/02/0209_040209_neandertals.html

Neandertals: A Cyber Perspective. http://web.archive.org/web/20060409170743/sapphire.indstate.edu/~ramanank/


[1] National Geographic News, “Climate Change Killed Neandertals, Study Says”, http://news.nationalgeographic.com/news/2004/02/0209_040209_neandertals.html

[2] Jared Diamond, The Third Chimpanzee: The Evolution and Future of the Human Animal (Harper Perennial, 1992).

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Recent Discoveries in Evolution and Their Impact on the Future of Evolutionary Studies

As I mentioned in my introductory post, this is a paper I wrote recently for my archaeology class. It was written hastily but I hope you find it interesting.

Introduction

When Charles Darwin published On the Origin of Species in 1859, he presented his idea of speciation by natural selection of random mutations without any way of knowing the mechanism for how traits were inherited. It wasn’t until Mendelian genetics were rediscovered at the turn of the 20th century that biologists had a valid model to understand how traits were passed on to subsequent generations. Despite this missing piece of information, the impact of Darwin’s book on the scientific community – although not a new idea, nor uniquely his own – was profound. In fact it is considered to be the foundation of the field of evolutionary biology.

In the century and a half since the publication of Darwin’s seminal work, while the basic theory he presented has survived basically intact, many developments and discoveries (such as Mendel’s laws of genetic inheritance) have provided new insight into the study of human evolution. Fossil evidence has demonstrated the ancestry of many modern species, including humans from Homo Erectus and Homo Habilis. The development of molecular biology, the discovery of the structure of DNA, and improvements in genetic sequencing methods has given insight into the mechanisms of how new traits are created through mutations, and has provided the means of determining the common ancestry of many species. Modern developments in socio-biology have helped to explain the evolutionary origin of certain human behaviours such as a sense of morality and altruism. Advances in computer hardware and software have allowed the development of more detailed and elaborate evolutionary models. Discoveries in biotechnology have led to the ability to modify entire genomes, and may eventually lead to the synthesis of new artificial organisms. The new field of evolutionary developmental biology promises to provide further evidence and insight into the ancestry of all forms of life, including humans. In this paper I will discuss some of the more recent of these developments and their impact on the future study of human evolution.

Recent Fossil Discoveries

Even after Darwin’s Theory of Evolution was gaining support in the scientific community, there was still some doubt and even skepticism about the evolutionary origins of humans[1]. Very few fossils of ancestral humans had been discovered in the 19th century – only a handful of Neanderthal skulls had been found, and at the time there was no clear indication that Neanderthals were even related to humans. However beginning in the 20th century, fossil sites in central Africa and China began to turn up remains of hominids that were clear indications of human ancestry. Fossils of ape-like human ancestors such as Homo erectus and Homo habilis began to shed light on the common ancestry of humans and other apes. They also helped to develop theories of the origins of modern origins such as the Out-of-Africa model, which suggests that modern humans first developed in Africa and then spread outwards to all currently settled continents in one or more waves of migration.

Other fossil discoveries have revealed the evolutionary origins of many other living species from extinct ancestors as well. Over the past century or more, fossils have been found that demonstrate the evolutionary progression of horses from smaller, five-toed ancestors; of whales from land-walking mammalian ancestors; and even of land-walking animals from water-swimming ancestors.

The discovery of tiktaalik in 2004 was an especially important discovery. This extinct tetrapod, which lived about 380 million years ago, is of particular interest because it represents the evolution of water-based fishlike animals which evolved the ability to move on the land, eventually leading to tetrapod descendants that lived entirely on land[2]. This find was also quite remarkable because of how it was found. Using information from other disciplines such as geology and geomorphology, the paleontologists who found tiktaalik determined the most likely location to find an ancestral link between fish and tetrapods. Based on what they knew about such a species (that it would have lived in a swampy area between 350-400 million years ago), they knew exactly what type of rock formation in which they would find such a fossil. By consulting geological maps of the earth, they determined that the best place to search for this fossil would be on Ellesmere Island in northern Canada. After 3 summers of searching, they finally found exactly what they had been looking for.

This example illustrates perfectly how combining scientific knowledge from many different fields of study will continue to aid paleontologists with future discoveries. These fossil findings continue to flesh out the evolutionary tree, and in the process we will learn more and more about the processes of evolution and speciation that have resulted in the diversity of life forms we see on earth today.

Discovery of the structure of DNA

In the first half of the 20th century, it was understood that the chromosomes played a major role in the manifestation of physical traits in living things, and were also crucial in the inheritance of these traits from generation to generation. However, it was not clearly understood how the chromosomes actually worked. When Watson and Crick discovered the molecular structure of the DNA molecule, biologists were finally able to unlock the mysteries of chromosomes. It was now possible to understand exactly how traits are inherited from previous generations, how mutations which produce new traits can occur, and even to understand how life may have originated. The discovery of the structure of DNA also made possible further discoveries such as the Human Genome Project.

Human Genome Project

In 2003, The Human Genome Project announced that the entire human genome had been sequenced, which consists of about 30,000 genes. Analysis of the human genome and how the genes express themselves will allow us to further understand how certain diseases occur, and will allow us to develop better ways of treating or curing these diseases.

One of the more interesting discoveries resulting from analysis of the human genome is that all humans are genetically 99.99% similar, and that most of the genetic variation occurs within the races and not between them[3]. This implies that there is little or no genetic basis for the separation of humans into the traditional racial groups. This also suggests that all living humans are descended from a single fairly recent common ancestor. Discoveries such as this should in the future provide common ground for better relations between all cultures, and thus allow people of all cultures to better understand themselves and others.

Further study of the human genome and comparison with our closest living ancestors, the non-human apes, will lead to a more detailed and accurate picture of how early humans evolved from ape-like ancestors.

Computers and Evolutionary Studies

Recent advances in computer technology are also leading to new discoveries in evolutionary studies, and should continue to do so in the future at an ever-increasing rate. Improvements in computer hardware and software allows for better and more sophisticated evolutionary models, which can lead to further understanding of the implications of evolutionary theory. Computers are also useful in assisting with the process of genome sequencing (Human Genome Project, for example), and with genetic analysis. Computers make it possible to do detailed analyses of genomes that would not otherwise be possible, due to the enormous amount of genetic information. The human genome, for example, contains just over 3 billion base pairs. Any attempt at identifying patterns in such a huge sample size would be an impossible task without computer algorithms. With the help of the vast processing power of modern computers, we will also be able to analyze and compare the genomes of various species, and by identifying when certain mutations occurred in certain shared genes, we will be able to reconstruct a large part of the evolutionary tree with a fair amount of accuracy[4].

Evolutionary Origins of Human Behavior

Recent research in the field of socio-biology has attempted to explain the origin of human behaviours such as morality and altruism. In particular, biologist Richard Dawkins has proposed the gene-centric perspective to explain how these cultural phenomena have come about due to evolutionary processes[5]. Future research into this field promises to provide much insight into the nature of human behaviour, and this may have an impact on many other fields as well, such as psychology, medicine and perhaps even sociology or cultural relations.

Conclusion

As demonstrated from the above examples, many discoveries have been made recently in the field of evolutionary studies, and the impact of these findings has been profound. Entirely new fields of study have been created to investigate the implications of these discoveries, and our understanding of ourselves and of humanity’s place in nature have been greatly enhanced. In the future, these studies promise to benefit us through new medical treatments, better international relations, and more fossil discoveries.

Bibliography

Dawkins, Richard. The Ancestor’s Tale: A Pilgrimage to the Dawn of Life. Boston: Houghton Mifflin, 2004.

Dawkins, Richard. The Selfish Gene. Oxford University Press, 1976.

Shubin, Neil. Your Inner Fish: A Journey Into the 3.5 Billion-Year History of the Human Body. Pantheon Books, 2008.

Social Science Research Council. “Is Race ‘Real’?” http://raceandgenomics.ssrc.org/Lewontin/

Wikipedia. “History of evolutionary thought.” http://en.wikipedia.org/wiki/History_of_evolutionary_thought.


[1] Wikipedia, “History of evolutionary thought”, http://en.wikipedia.org/wiki/History_of_evolutionary_thought.

[2] Neil Shubin, Your Inner Fish: A Journey Into the 3.5 Billion-Year History of the Human Body (Pantheon Books, 2008).

[3] Social Science Research Council. “Is Race ‘Real’?” http://raceandgenomics.ssrc.org/Lewontin/

[4] Richard Dawkins, The Ancestor’s Tale: A Pilgrimage to the Dawn of Life (Boston: Houghton Mifflin, 2004).

[5] Richard Dawkins, The Selfish Gene (Oxford University Press, 1976).

Welcome to my new (science) blog!

As you can probably guess from the title, this blog is about science, but is not for scientists. It is for people like me – those of you who have a passing to moderate interest in science, but not necessarily a formal education in any scientific discipline. It is my hope that I can impart upon you some of the passion and excitement that I have for science, or at least that you can find here some interesting tidbits of knowledge that you didn’t have before.

I would like to start things off by posting my submission for an assignment I had recently in my archaeology class. I am taking this class at the university where I work – one of the perks of my union is that I can get my tuition waived! I hope you enjoy it, and I promise my writing will improve without the rigid deadlines of academia. Thank you for visiting!