Have you ever wondered why the average human body temperature we always hear about is 98.6 F? How did they get so specific? Did they conduct a bunch of studies and actually come to that exact average?
It’s simple, actually: The rest of the world uses the metric system, so we tend to list the average human body temperature at 37 degrees Celsius. That isn’t to say that’s the exact number. It isn’t; human body temperature naturally fluctuates slightly throughout the day, so there really is no exact number. It just so happens that the average temperature is around 37 degrees Celsius, which, you guessed it, is equivalent to 98.6 degrees Fahrenheit.
Take a quick look around a world map and you may just figure out the location of a magma hot spot. The island chain of Hawaii, for example, was born via this way. As the Pacific plate moves, hot magma beneath the Earth’s crust pushes through, forming new land over millions of years. This process has given us the 4 main Hawaiian land masses in addition to well over a hundred tiny islands. Other areas of the world where we see this include the Galapagos islands and the peaks of Kilimanjaro.
As the Earth rotates, the Sun appears to rise over the horizon. As its rays become more and more directly overhead, there is less distance for them to travel through the atmosphere in order to reach us. (This longer travel is what creates wonderful sunrises and sunsets; light is refracted at a greater rate, allowing us to see a variety of frequencies and thus colors.) Keep this in mind if you like to tan. It’s best (i.e., healthiest) to catch your rays in the morning and evening since less ultraviolet light can reach you.
And, as always, don’t believe the quacks who say sunscreen is bad for you. If you’re tanning in the middle of the day, wear it. Cancer is bad, ya know?
The term “junk DNA” is a misnomer. It refers to DNA that does not code for proteins – only about 2% of genes do that – but it unfortunately implies a uselessness of certain DNA. That really isn’t what biologists mean when they use the phrase (or, rather, when others use the phrase; it has been out of vogue amongst professionals for some time now). All they mean is that we have DNA which appears to have no function. This makes sense in the light of evolution since natural selection wouldn’t necessarily be expected to select against useless DNA. After all, why not just leave it there? Unless it constitutes a substantial energy drain, it doesn’t matter. (Note: I am not referencing conserved DNA.)
However, new research is showing that much of our noncoding DNA does serve important functions. Namely, it regulates the genes that do produce proteins. There is still a substantial portion of the genome that appears to have no function, of course. Moreover, there is useless DNA out there that doesn’t code or regulate anything (microsatellites come to mind). However, we’ll all have to wait for further research before we really know the full nature of the human genome.