If "jumbo shrimp" is an oxymoron, what is "medium shrimp?"
Just Joe
Friday, June 29, 2012
Monday, June 25, 2012
UEFA EURO 2012
Back on June 8, the countries of Europe began competing for the Union of European Football Associations (UEFA) Championship. That's "soccer" to us ignorant Americans. Just yesterday Italy beat England in penalty kicks to advance on to the semi final match against Germany, which is being played in Poland.
Soooo... Italy and Germany are meeting up... in Poland! I wonder if the Pols are as nervous as I am for them?
Just Joe
Soooo... Italy and Germany are meeting up... in Poland! I wonder if the Pols are as nervous as I am for them?
Just Joe
Monday, June 18, 2012
Evolution (of Skin Color)
Human beings are so remarkable that it's difficult to put into words. I could go 1000 different ways with a statement like that, but this time I'm referring to the complexity of our physiology and how it came about.
Dr. Nina Jablonski is an anthropologist who teaches at Penn State University. She wanted to delve into the evolution of skin color. The prevailing convention at the time she started was that dark skin occurred in areas with lots of sun exposure in order to prevent skin cancer. Although the cause of dark skin seemed right, the reasoning didn't. Skin cancer is normally found in people who are beyond ideal reproduction ages, so in a sense, the body isn't even aware of skin cancer before it passes its DNA onto the next generation. Since evolution occurs through the passing down of helpful gene traits, whichever traits seem beneficial up until reproduction are passed along while traits that develop after reproduction aren't really taken into consideration for passing along. (Example: Let's say longer limbs are beneficial to the aged but a hindrance to the young. Because the young'ns are the ones reproducing, limbs will be shorter. Over simplified, yes. But you get the point.)
Dr. Jablonski dug a little deeper and found that there are 2 types of radiation in sunlight, UVA and UVB. Turns out that UVA radiation is what causes melanomas. But Dr. Jablonski figured it had to effect something up to or during the time of pregnancy otherwise cancer-causing UVA exposure would not affect reproduction. Further tests and evaluations proved her correct as UVA penetrates through skin and destroys folates in the bloodstream. The big deal here is that folates are key in maintaining healthy reproductive cells. Therefore, too much UVA exposure before reproducing could mean reproducing either won't happen or could happen with birth defects. So how did the human body adapt to ensure future generations? Yep, by darkening the skin and filtering out more of the sun's light.
Not fascinating enough? Well, the story continues. If keeping out as much UVA as possible is good, why doesn't everyone just have dark skin? The answer turns out to be UVB!
UVB radiation is actually a good thing (in moderation) because, get this, it reacts with a cholesterol in human skin to create vitamin D! And vitamin D is important because it aids in the absorption of calcium into bones and such. Apparently back in 1900s England there was an epidemic of rickets which was eventually determined to be a result of vitamin D deficiencies and led to laws being created mandating that bread be fortified with vitamin D. Back to the story now, as darker skinned humans began migrating to northerly climates with less sun exposure, too much of the UVB radiation was kept out of the bloodstream (likely leading to skeletal problems) so the human body adapted once again by lightening skin color.
There you have it, an incomplete, tip of the iceberg, generalization on the evolution of skin color.
Just Joe
Dr. Nina Jablonski is an anthropologist who teaches at Penn State University. She wanted to delve into the evolution of skin color. The prevailing convention at the time she started was that dark skin occurred in areas with lots of sun exposure in order to prevent skin cancer. Although the cause of dark skin seemed right, the reasoning didn't. Skin cancer is normally found in people who are beyond ideal reproduction ages, so in a sense, the body isn't even aware of skin cancer before it passes its DNA onto the next generation. Since evolution occurs through the passing down of helpful gene traits, whichever traits seem beneficial up until reproduction are passed along while traits that develop after reproduction aren't really taken into consideration for passing along. (Example: Let's say longer limbs are beneficial to the aged but a hindrance to the young. Because the young'ns are the ones reproducing, limbs will be shorter. Over simplified, yes. But you get the point.)
Dr. Jablonski dug a little deeper and found that there are 2 types of radiation in sunlight, UVA and UVB. Turns out that UVA radiation is what causes melanomas. But Dr. Jablonski figured it had to effect something up to or during the time of pregnancy otherwise cancer-causing UVA exposure would not affect reproduction. Further tests and evaluations proved her correct as UVA penetrates through skin and destroys folates in the bloodstream. The big deal here is that folates are key in maintaining healthy reproductive cells. Therefore, too much UVA exposure before reproducing could mean reproducing either won't happen or could happen with birth defects. So how did the human body adapt to ensure future generations? Yep, by darkening the skin and filtering out more of the sun's light.
Not fascinating enough? Well, the story continues. If keeping out as much UVA as possible is good, why doesn't everyone just have dark skin? The answer turns out to be UVB!
UVB radiation is actually a good thing (in moderation) because, get this, it reacts with a cholesterol in human skin to create vitamin D! And vitamin D is important because it aids in the absorption of calcium into bones and such. Apparently back in 1900s England there was an epidemic of rickets which was eventually determined to be a result of vitamin D deficiencies and led to laws being created mandating that bread be fortified with vitamin D. Back to the story now, as darker skinned humans began migrating to northerly climates with less sun exposure, too much of the UVB radiation was kept out of the bloodstream (likely leading to skeletal problems) so the human body adapted once again by lightening skin color.
There you have it, an incomplete, tip of the iceberg, generalization on the evolution of skin color.
Just Joe
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