Human Variation

Solar radiation impacts the survival of humans if the level of exposure is too high or too low.  Of course, solar radiation is needed as a source of Vitamin D. Having inadequate amounts of Vitamin D can contribute to weakened protection from UV rays, high blood pressure, and developmental factors such as skeletal deformities. Overexposure of UV radiation can cause damage to the DNA. UV radiation is directly absorbed into the cells by the DNA which can cause skin cancer.  Also, UV radiation depletes folate - a B vitamin - which can disturb developmental processes in pregnant women and result in the defect spina bifida.  This damage at the genetic level disturbs homeostasis and is life threatening to the species.

   

Unfortunately, humans do not have a short term adaptation to over exposure to solar radiation.  However, humans have adapted to higher levels of solar radiation in many ways, and there are many factors of the adaptation.

A facultative adaptation humans have adapted to combat excessive solar radiation is by tanning, and temporarily producing more melanin.  

A developmental adaptation that protects humans from UV radiation is skin color.  Melanin is one of three factors that alter skin color and assists with protection from UV exposure by absorbing the UV radiation that causes genetic mutations.  Individuals that have had a greater exposure to solar radiation would tend to have a darker complexion due to increased melanin production.  Whereas individuals located in areas where they have less exposure to UV radiation, or limited exposure due to other conditions (more clothing due to colder climates), would have a lesser amount or lack of melanin, resulting in a lighter or fairer skin tone. 

Cultural adaptations to high levels of UV radiation can be the use of shelter and shade, clothing, and of course the use of sun screen. Sun screen is a modern tool used to provide supplementary protection from the sun.  Although, sunscreen isn’t complete protection, it does allow for longer UV exposure without damage.   

The benefit of studying across environmental clines is to see how different people have adapted to different environmental influences. If we only studied one environment, we wouldn’t see the whole spectrum of solar radiations impact.  By studying the effects of UV radiation on varying populations we understand how much radiation is necessary and how much is harmful for differently pigmented skins.  This information is useful for preserving health and can be used to preemptively avoid harm, such as sunburns, cancer, or folate deficiency.

As we learned in the lessons this week, there is no real race (other than the human race), so we have to look at the adaptations of those in a given environment.  In terms of solar radiation, this is the measurement of pigment in an individual’s skin.  Therefore, if you must use the term race, it would be defined as a population with similar adapted traits (in this case level of skin pigmentation).
Using the study of adaptations to environmental influences is a better way to understand human variation, because as we have learned, adaptation to environmental influences and mutation are the causes of the variation.

Australopithecus deyiremeda

Here is a link to an article that may be of interest to some.

http://phys.org/news/2015-05-human-ancestor-species-ethiopia-lucy.html

Enjoy.

Language Blog

Part 1: You were asked to engage in a conversation for 15 minutes where you were not allowed to use any version of a symbolic language (no speaking, writing, or ASL).

Holding a conversation with someone when you are unable to speak or use any other form of symbolic language (writing, sign language, texting) makes the conversation very difficult. In my efforts to communicate without speech, I turned to a form of charades and hand gestures.  This was hilarious to my family, who had never experienced this with me before.  However, to me it was extremely aggravating as I had difficulty in conveying my message.  I have to say my family was very patient and paid very close attention. This project turned more into a game than a conversation.  The various members of my family had complete control of the conversation as my input was limited.  They controlled the topic of discussion and I did my best to contribute.  The conversation turned superficial as it was almost impossible to discuss anything to difficult.  By the end of the 15 minutes, the only thing accomplished was a good laugh at my expense. I’m sure, if for some reason one of us could no longer communicate via speech, writing or sign language, we would work out a system that would allow us to communicate.

In a scenario where two separate cultures, one using speech and the other that doesn’t, the culture that could speak would definitely have the advantage in explaining complex ideas. The speaking culture would become impatient with the other culture because speaking is a much more efficient way of conveying ideas, where other means of communication take more time and effort.  Deaf Individuals in our culture have difficulty with spoken language.  In my previous profession I had a great many experiences attempting to communicate with deaf individuals.  At first, it can be very difficult to communicate, however necessity prevails, and through greater adaptability on their part than mine, we eventually would be able to communicate with one another. They were very patient with me and both of us would put forth the effort to adapt.  The most important aspect was understanding and patience. If patience is shown, and the effort is mutual, the language barrier can be overcome.

Part 2: You were asked to spend 15 minutes communicating without any physical embellishments, i.e., no hand signals, not vocal intonation, not head, facial, or body movements. 

Holding a conversation with someone when you are unable to show any type of physical embellishments (facial expression, hand signals or body movements) or emotion (vocal intonation) is very difficult, but not quite as difficult as the first experiment (no speech, writing, symbolic language or sign language). The conversation was easier than the first because we could still understand each other, but monitoring and trying to curb my facial expression was daunting. Immediately, I failed this experiment by raising my eyebrows when communicating.  I never really considered how much I embellish my speech with facial cues and vocal intonation.  Communicating without vocal intonation does not really provide the proper message intended.  Vocal intonation is common to several of the languages that I have studied. It is necessary to distinguish a statement from a question, to convey exclamation or alarm.  It is necessary for survival, ex., “There is something big over there,” in comparison to, “THERE IS SOMETHING BIG OVER THERE!”

My partners in this experiment weren’t affected by my lack of intonation or expression during our conversation because they knew it was a project, however, had this been a real life conversation, there would be the great potential of them feeling annoyed, or that I was annoyed with them, they might feel unappreciated or under-valued.  I feel without the ability to use facial expression or vocal intonation in particular I felt very impersonal and robotic.

The use of signs in our language is extremely important. Body language and especially facial expression is a large part in understanding one another. Facial expression, eye contact or avoiding eye contact, nervous gestures (constantly shifting one’s weight, wringing of one’s hands, looking around while talking) etc. are all very important in the interpretation of one’s message and intent. Some people don’t pick up on body language as easily as others, however I believe this is a crucial tool for properly interpreting one’s true message.  The benefit of reading body language is a key to our daily lives.  As children, I am sure most of us knew a certain look from our parent meant our current behavior had better cease.  If you see someone approaching you with a menacing look on their face and their body is tense, these could be cues that trouble is afoot.  It is important to be aware of one’s own body language as well.  You would not want to avoid eye contact and yawn while being interviewed for a wanted position.  You wouldn’t want to nervously fidget, cross your arms and look around constantly when being questioned by the authorities investigating a crime.  You wouldn’t want to convey an apathetic look or one of disinterest when approached by someone you have a romantic interest in.

People with alexithymia have difficulty or the inability to read and interpret body language.  They have difficulty in distinguishing and appreciating the emotions of others, which is thought to lead to empathic and ineffective emotional responding.  I personally have not had any contact with this difficulty.  Personally I cannot see a benefit in not being able read another’s body language as even those who intend to lie or provide inaccurate information often give off clue’s to their deceit.          

Piltdown Man Hoax

In early in 1912 workers at a gravel pit near the village of Piltdown, in East Sussex, uncovered a piece of fossil and gave it to an amateur archaeologist Charles Dawson.  Dawson then wrote a letter to Arthur Smith Woodward, Keeper of Geology at the Natural History Museum, in which he claimed to have found a piece of thick human-like skull in gravel beds at Piltdown in Sussex.  Dawson and Woodward joined forces and unearthed more skull fragments and a jawbone with 2 teeth.  Believing the pieces to be from the same individual Woodward made a reconstruction that suggested an early human with a large brain and the ape-like jawbone with human-looking teeth.  This reconstruction suggested it could be an early human relative who lived about 500,000 years ago and was given the name Eoanthropus dawsoni (Dawson’s Dawn Man). 

In December of 1912 Woodward announced the discovery of Piltdown Man to the world.  While scientists outside Briton were skeptical, later finds in Piltdown; a canine tooth in 1913, a tool carved from a piece of fossil elephant bone in 1914, as well as a claim by Dawson in 1915 that he had found a molar tooth and skull pieces closely matching those of Piltdown Man at a nearby site seemed to silence some of the doubts.  However since Dawson’s death in 1916, no other evidence had been discovered despite Woodward’s efforts.  

The Piltdown skull was a hoax, a hoax that lasted for 40 years and led science astray.  After Piltdown Man, increasing numbers of ancient human fossils were discovered in Africa, China, Indonesia, Asia and Europe.  However, none of these discoveries replicated or validated the Piltdown Man find.  The new findings suggested that the jaws and teeth became human-like before the evolution of a larger brain unlike the Piltdown Man.

Considering the discrepancies and with the advent of new dating technology, new investigation into the Piltdown Man began.  The Piltdown hoax was finally exposed in 1953 by Kenneth Oakley through fluorine absorption testing.  Fluorine absorption testing uses fluorine’s accumulation in calcium containing organic matter such as bones and teeth.  With this testing Oakley was able to estimate that the Piltdown fossils were probably less than 50,000 years old.  Based on Oakley’s findings biological anthropologist Joseph Weiner and human anatomist Wilfrid Clark also tested the Piltdown fossils and found that the skull was from a medieval human and the jaw was probably from an Orangutan.  Visible scratches on the surfaces of the teeth revealed that the teeth had been filed down to make them look human.  Lastly they discovered that the Piltdown fossils had been chemically aged.

Up until the Piltdown find fossils of early humans had been found in Germany, France and Asia, but nothing from the British Isles.  This hoax could have been perpetrated for self-interest or national pride.  It seems the scientist in Briton didn’t further analyze (or didn’t have the technology to do so) the Piltdown findings as critically as would seem prudent given its importance to the scientific community.  Perhaps this was in defense of national pride, however this hoax was a huge hit to their scientific prestige.  However, the perpetrator of the hoax has never been determined, though Dawson would appear the prime suspect and he could have been motivated by ambition.  Few suspect Woodward and most think that he had been duped all those years.  

Blind ambition, self-interest and even national pride could have come into play in this scenario.  Because some scientists chose not to (for whatever reason) do proper research and analysis of the evidence, science was led down the wrong path for 40 years.  Science and evolution also suffered the public doubt of their theories and their processes.

Thanks to science’s constant questioning of data and evidence this hoax was uncovered.  When additional finds produced conflicting evidence, scientists renewed their analysis of the Piltdown finds, and with the help of new technology (fluorine absorption testing) were able to falsify the Piltdown findings.

I don’t believe the “human” factor can be removed from science due to the fact that it is the “human” factor of curiosity that produces new theories and the challenging of those theories.  While pride, ambition and self-interest are “human” factors as well, the scientific method is set up to constantly question and analyze findings and data to root out claims and theories based upon those negative “human” factors.

A good life lesson to take from this scenario is to question everything.  Do not take statements or theories at face value, be prepared to put in the effort to always question and analyze, do your own research and determine the facts for yourself.