Solar radiation can have positive and negative effects on the climate, ecosystem and living organisms on earth. Solar radiation which presents through the visible light helps us see clearly during the day time, and the infrared solar radiation or infrared light provides us heat. Ultraviolet radiation, also known as black light, is a source used for medical equipment sterilization and natural skin tanning. These are the more common positive effects that we get from the sun's radiation. Overexposure to the sun's rays leads to life threatening conditions, such as skin cancer. Too much UV radiation may cause skin cancer and alter your immune system, and make you vulnerable to infectious diseases. It may also cause a person to have cataracts and other eye diseases, and excessive infrared radiation may lead to heat stroke. High levels of solar radiation also impacts the survival of humans by disturbing homeostasis. UVA rays are more dangerous to humans as they have the ability to penetrate through the epidermis (top layer of skin) to the dermis (second layer of skin). UVB rays only have the ability to penetrate the epidermis layer. There is one benefit humans receive from UV radiation and that is the production of vitamin D from UVB rays. If humans get sunburned the UVA and UVB rays can cause the immune system to be suppressed for a short time. UVB rays are the most harmful towards humans, because it can damage our DNA cells and potentially cause genetic problems, and lead to skin cancer. This type of damage can disturb homeostasis and can be life threatening to the human species.

Short term adaption does not pertain to high levels of solar radiation. If a person becomes overexposed to UVA and UVB rays they could become sunburned. If a person has a sunburn then this is a sign that the human has failed to adapt to the high level of radiation. A sunburn simply lets us know we have been overexposed, and can be dangerous as mentioned before. A fair skin person is more likely to get a sunburn when compared to a person of darker skin. A person with high skin pigmentation also known as melanin is less likely to a get sunburn, because melanin helps to protect us from UV rays. Fair skin people do not produce as much melanin causing them to burn easier and may have to use other products to help avoid sunburn. 

A type of facultative adaptation that helps to protect our skin from the harmful UV rays would be tanning. Tanning occurs when exposure to sunlight triggers a protective mechanism through increased melanin on the epidermis layer. Melanin can also act as a natural sunscreen produced by our bodies, and the epidermis layer will remain tanned until no longer being overexposed to UV rays. When people spend more time in the sun during the summer season, it is common to see fair skin people and dark skin people have a darker pigmentation. People who are albino have a genetic mutation preventing their bodies from producing melanin. When people lack the ability to tan they are more likely unable to protect their skin from UV rays. 

A developmental change can be found in populations which have a higher amount of people with darker skin pigmentation. People with darker skin pigmentation again, have higher melanin levels which acts as a natural sunscreen protecting our skin. Populations that have the most exposure to the sun's harmful rays for example, can be in parts of Africa such as the Savannah or plains. There seems to be a direct correlation geographically in those regions that shows a higher density of people with darker skin pigmentation. Too much exposure to UV rays can result in skin cancer, but if there isn't enough exposure a person can become vitamin D deficient which can have negative effects on the body. Populations that lack sun exposure can be prone to developing diseases such as rickets. Populations with lighter skin pigmentation do not produce as much melanin which can be due to less sunlight. 

A cultural adaptation to the harmful UV rays is clothing, shelter and sunscreen lotions. The invention of shelter and clothing made it possible for early homo sapiens to avoid high levels of melanin production. Migration to other environments also contributed to the reduction of high levels of UV exposure. Geographically we can see that populations with lighter skin are in northern regions and populations with darker skin pigmentation are in the southern and central regions near the equator. People that take part in outdoor activities or  play sports are also at risk for high levels of UV ray exposure. The invention of sun screen helps people in certain regions to protect their skin from UV ray exposure. However, it is not considered a solution that completely protects you from skin cancer regardless if you are a dark or light skinned person. 

The benefits of studying human variation is that by studying the changes within a population we can evaluate and see the environmental stressors that can affect that population. We can take a population with certain traits and move them to a new environment other than were they currently live, and eventually we will see an evolutionary adaptation to the new environment. For example, studying rickets in fair skinned populations can help us understand how we need some sunlight exposure in order to avoid the disease. The study might help scientist come up with a solution for populations at risk for rickets in certain regions whether it is a lack of just vitamin D or a lack of sunlight or both, they would be able to narrow it down.

The only time race should be used is when classifying geographic populations of people that have  a similar set of adaptations to an environment. This will allow us to see how our ancestors developed and changed over time, and we can have a better understanding of the origins of that population. I think we will also see what type of changes might occur in that population given the different type of environmental stressors. For example, if we had moved a group of light skin people to Africa in the Savannah, we could see how well the group will adapt compared to dark skin populations that already populate the area. Scientists could see more people with sunburn and higher levels of melanin, and we would see a change in skin color in the group of lighter skin people. I think by studying the environmental influences of a population overtime, there will be changes that occur as the group adapts to those stressors. Some adaptations can become permanent and others can remain until the stressor is removed. For example, being born light or dark skin can be permanent, and people that tan in the sun during summer will remain darker until the increased sun exposure is removed or lessened. The ability to adapt to a new environment has been passed down from previous generations, and connects humans more closely on a genetic level compared to any of the outward differences we may see. By studying the human species we can use this as a tool to help people overcome racism, and help people see how we are in many ways very similar and less different from each other.  

Language

             I found the experiment of not using any verbal form of communication really difficult. I was able to make some sentences using my hands and pointing at certain items or parts of my body to explain what I was trying to say. I think most people take for granted the ability to talk and communicate with each other. Until this experiment, I never really thought about how hard it would be to communicate with another person if you didn't know ASL or another form of communication. This experiment was very similar to a game of charades, because in a sense sometimes I acted out what I was trying to say since I couldn't verbalize it. The partners I used in my experiment did not try to alter their way of communicating with me, instead they just took it as a fun game and kept trying to figure out what I was trying to say. I think the partners I used in my experiment found it to be very difficult to communicate with me since I was not verbalizing anything. I had the idea of learning Morse code and use a pen or pencil to tap it on a table to communicate with each other. It is a form of communication and does not require verbal communication, and is not a form of ASL.

            Unfortunately that would take time to learn because you would have to listen closely to each break in between and you would need to study a chart for the Morse code alphabet. I think the culture that would have to most success in a situation like this would be one that can use symbolic language, because they are able to simply speak and ask the other person a simple question. The other culture may have an easy way to communicate as well if you used some form of universal signs or symbols to communicate with the other culture. For example, if you wanted to know how much pain someone had you could use a scale of 1-10 and draw a face at number 1 which is smiling and as you go down the scale you could draw a really sad or upset face at number 10. If you want to asked a question, how much pain do you have?, you would have to get creative to symbolize the first part and then use your scale and drawings for the rest of the question. I think that could be very challenging to express for some people and it would make communication a lot more difficult. I think the culture that speaks would have that same impression as my partners, it was difficult to understand certain questions I was trying to ask. It took several minutes to understand some questions, but other questions or answers were very easy to express.

            The individuals that might have the hardest time are those who are deaf or non verbal. If you don't know ASL then I think it is very hard for that person and the verbal person to communicate with each other, and it is possible that some people who are deaf became deaf over time and can write on paper what they want to communicate. Others that are deaf over time may also have learned how to read lips and can communicate that way as well. For those who are born deaf, you will just need to find a translator unless you can get really creative with what you want to communicate to them and vice versa. People who are non verbal or born non verbal may have to same issue, either they can write it on paper or someone needs to know ASL. I notice that when people who aren't deaf want to communicate with a deaf person, for some reason they always seem to raise their voice which doesn't help at all. I think people like that are viewed as rude because yelling or raising your voice doesn't always help, and if they are partially deaf it might  work sometimes. It can also be offensive toward the family members of that person who may not be deaf. If an individual is able to speak and is communicating with someone who is not it will go two ways, either they are going to get their message across and have success with what they wanted to say or they will become really frustrated and give up on communicating with that person and have someone else try.

            To go 15 minutes without using physical movements, hand signals or vocal intonation, was not as easy as I thought. This experiment lasted a full 15 minutes, but my partners were just as frustrated as they were in the first 15 minutes. I was able to communicate much easier due to the fact that I was able to speak, but to stay in a consistent mono tone for 15 minutes was a little difficult. One of the difficult parts of the experiment was trying to give instructions and not having the ability to actually show them what I was trying to explain. For example, I was trying to show them how to play a couple guitar chords, but without physically showing them how to press on the chord  it became difficult. After about 6 minutes my partners finally were able to play two chords. I found that my partners were having trouble with understanding my instructions so I had to get creative with my instructions, and had to explain all my instructions in specific details instead of my normal routine. The  more common way to teach would be less specific and you would be able to use your hands to physically show the chords. I chose to use my guitar, because I felt it was going to be the most challenging to explain given our rules for this experiment. My partners found this easier compared to the first experiment and they were able to figure out what I was trying to say in a much shorter amount of time.

            These experiments have shown how hard it really is to communicate with another person if we were given these certain limitations. Communicating with our hands, nodding or smiling all help us when talking with other, because it lets the other person know when we agree or disagree with what is being said. Other signs such as a person's body language could also help in identifying what might be going on or what is being said. A person's body language could let you know when someone is angry, sad or happy. Whether we are non verbal or unable to use any physical movements, I think we could still communicate with each other, it would just take a little longer to get your message across to the other person. Some people can understand just verbal commands better than others, and some people are able to figure out body language better than others. I think the most common benefit to "not" reading body language would be when a person is being interrogated and is not showing signs of nervousness. The person maybe guilty but if he shows no signs or nervousness and there isn't much evidence to support that he or she is guilty, then they might just be released. Another example would be a parent who is being accused of child abuse. If the person is crying, we may think they are innocent when really they could be crying because they are scared and regret the decision they made. Body language can be used for many different reasons and without body language it may alter our interpretation about that person.