Tuesday, November 20, 2012

Questions Follow Answers

[Johnathan Clayborn]
Most people wish that they had answers for certain things. Many of us sit around and accept the likelihood that those answers will never come. This is certainly true with me in my attempts to uncover my genetic family roots. But, some scientists are lucky enough to find the answers that they seek. Ironically, those answers are only bittersweet as they almost immediately yield more questions, particularly when discussing the ancient world.
In my next article I’ll discuss some of the mind-boggling, scientific quandaries that make us question our very understanding of the ancient world. In the meantime I want to summarize a fascinating show that I was watching on TV last night about why Egypt fell.
The show started out by following two different scientists working independently in different parts of Egypt; one studying ancient ruins and pyramids, and the other studying the migration and habitation pattern of the Nile delta.  Both came to the same independent conclusions; when Pharaoh Pepi  II of Egypt died (2184 BC) and was buried Egypt was at the height of its power building pyramids and other large structures. Then, rather suddenly, Egypt was gone without reason or explanation. In terms of historical accounting “suddenly” means within one generation. By 2150 BC, 34 years later, Egypt had fallen.

Knowing that the fall of Egypt was a rather sudden and cataclysmic event both scientists set out in search of answers. Within a rather short time, both scientists came to the exact same conclusion; a drought.  The scientist studying the ruins and the pyramids saw evidence of a sudden stoppage in construction. Since most of the materials were borne to the job sites via waterways the foregone conclusion was that there may not have been enough water to get the supplies there. But, this was after Pepi II died because there was still enough water to transport his sarcophagus, the largest ever built.  The scientist studying habitation patterns in the delta used satellites to locate ancient settlements without having to dig up the entire area. What she found was that people rapidly abandoned those settlements to migrate towards the larger cities where they could pool their resources.  Since most of these smaller villages were along the tributaries of the Nile, she concluded that they abandoned them because of a lack of food and that they lacked food because the water had dried up.
Of course, all of this was only a theory that needed proof. So, they set out to find it. One of the scientists was also an archeologist and took core samples near the areas where there were known to have been deep lakes. What he found was a layer of wind-blown, arid sand. This meant that no water reached that site whatsoever. Not only did he find the sand he looking for, the thickness of the layer indicated that this area suffered a drought that lasted for roughly four decades.  In fact, conditions of the drought were so bad that some reports indicate that they may have resorted to eating their own children to survive.

After publishing their findings researchers in Turkey, Iran, Mesopotamia and Greece have all uncovered the same drought conditions in those regions at the exact same time. Not only was Egypt affected, but the entire Mediterranean Sea area was affected as well. Besides Egypt, this drought, which is now called the 4.2 Kiloyear Event, was also responsible for the fall of the Akkadian Empire. Although not wiped out to the point of extinction there is some evidence to suggest that the drought at least influenced the development of the Persian Empire and several cultures that inhabited China.
So, they answered the question of what happened to Ancient Egypt, and in the process they uncovered a much more important discovery. But, this answer begot another question; what caused this drought to begin with? The current theories center on the concept that the Atlantic Current stopped moving. This current sends warm air into the atmosphere and helps regulate the temperature around the world. If this current stops flowing, then the Mediterranean region undergoes a severe drought while the continental US will undergo a small Ice Age. According to the fossil record in North America, there was an Ice Age in 2200, B.C., which is exactly what they expected to find.

Now they’ve answered the question about what caused the drought, which is exciting, but a more disturbing question looms; what caused that current to stop flowing? Evidence suggests that it has stopped several times throughout the Earth’s history. But no one knows why.




Tuesday, November 6, 2012

Are We Evolving?

[Johnathan Clayborn]
This question was posed to me earlier today and it got me thinking. I don't think that most people I know would argue against the notion that evolution has infact happened. Assuming that evolution is true, I think the more obvious questions with regards to evolution should be: are we still evolving, and if so, how much?

From a purely biological perspective with regards to physical characteristics, I would argue that the answer would be "not really", and I'll explain that in a minute.

The sociocultural aspect of our collective societies is evolving; of that there seems to be little doubt. Humans have always evolved culturally. (A fascinating read on the overall topic of human civilizations and evolutionary behaviors is Guns, Germs and Steel by Prof. Jared Diamond). In our modern digital world it seems as though our current cultural evolutionary process is leading us to world that is more close-knit and united.

One of the interesting side-effects of becoming more multicultural as a species is that it invariably leads to interracial breeding on a scale not seen before. There have been several studies on the impacts of this. A quick survey of the census records in the US also show this to the be the case as more and more immigrants from other countries move here. Cultural behavior, and certainly multicultural behavior certainly shapes our genetic makeup as we trade and mix DNA with an ever-growing host of potential mates that was not readily available 100 years ago. The October 2011 issues of Psychology Today discusses this very issue citing a 2003 study conducted by Joan Chiao of Northwestern University. The study linked DNA to behavior in ways that were not so expected; such as China's idolization of Communism and the Western culture's adoration of independence. These behaviors are now understood to be driven by genetics. By that logic, changing our genetic makeup will certainly change our behavior. As other's pointed out, I'm not convinced that this would make us any less pliable or adaptable as a species.

Certainly having a genetic admixture will result in noticable physiological changes; skin tone, hair color and type, height, etc. But, from a biological standpoint the question that I find myself asking is: so what? Okay, so my descendants will one day have a skin tone that is more coppery than my fair Irish skin. Does that afford them any special advantages? No. Does having a different height or a different hair type help ensure their survival? Not really. In today's technological world medicine and medications have gone a long way in stamping out things which would have eradicated "weaker specimens" even just a hundred years ago. From that standpoint the introduction of "weak" genes into the genepool persists whence it would have been stamped out before.

From a fundamental standpoint the purpose of evolution is to provide those specimens with the strongest genes the best chance to reproduce and spread healthy offspring. From what I've seen none of the physiological changes that are occurring in our current admixtures of genes seem to be doing this. Sure, they change our physical appearances, but that's about it. This example dealing with shark Genetics (http://www.nbcnews.com/technology/futureoftech/australias-hybrid-shark-reveals-evolution-action-904726) reveals a more arguable demonstration of evolution in action; the sharks are adapting to endure different temperature climates than what they were otherwise used to. What primary advantages does the admixture of modern human genetics provide us? We have houses to shelter us from the elements, we have medicine to cure our illnesses. Even within the human species the sexual dimorphism of Homo Sapiens is already far less pronounced than in other species in our genus. The rest of our traits are spread across a wide array of polymorphic attributes.

From a Taxonomy viewpoint the consideration of the human species in general is rather fascinating. For every other species on the planet we break down their taxonomical classifications into distinct sub-groups based on geography and physical characteristics. For example; the Willow Warbler is divided into three distinct sub-species that are genetically identical and the only differences between them is the location of their habitat and the coloring of their plumage. Their skeletal structures are identical. Humans, Homo Sapiens Sapiens in particular, have a wide range of skin colors, hair colors, natural habitats, slightly genetic makeups that, although compatible, are slightly different. And yet, we are all lumped into the exact same genus and sub-species despite obvious polymorphic differences. Surely this muddles the question of evolution and genetic admixture. If you were to break human beings into separate sub-species based on their genetic haplogroups, then because the specific traits that are being analyzed are so narrow, it would certainly argue a stronger case for continuing evolution.

As you might have guessed I can relate to both sides of the debate that humans are and are not evolving. I personally don't have a strong opinion about it one way or the other. However, I do feel compelled to point out that in my own studies of evolution over a long period of time the driving factor in pushing major physiological changes within a species seems to be either radical climate change or natural disaster on an epic scale (like a giant meteor). Fossil records of human settlements show that our physiology has remained largely unchanged for the last 200,000 years. If this is true, then how much evolutionary process is truly going on now within the span of a few centuries?