human evolution

“There are very naive peoples and men who believe that the ‘good man’ is something desirable, and that the course of human evolution is directed toward the survival of the ‘good man’ only. From a superior viewpoint one desires the contrary: the ever-increasing dominion of evil, the growing emancipation of man from the narrow and fear-ridden bonds of morality, and the increase of force to press the mightiest natural powers into service.”

—F. Nietzsche, The Will to Power, §386 (edited excerpt).

The Science of Skin Color

When ultraviolet sunlight hits our skin, it affects each of us a little differently. Depending on skin color, it will take only minutes of exposure to turn one person beetroot-pink, while another requires hours to experience the slightest change. So what’s to account for that difference and how did our skin come to take on so many different hues to begin with? Whatever the color, our skin tells an epic tale of human intrepidness and adaptability, revealing its variance to be a function of biology. It all centers around melanin, the pigment that gives skin and hair its color.

The type and amount of melanin in your skin determines whether you’ll be more or less protected from the sun. This comes down to the skin’s response as sunlight strikes it. Over the course of generations, humans living at the Sun-saturated latitudes in Africa adapted to have a higher melanin production threshold and more eumelanin, giving skin a darker tone. This built-in sun shield helped protect them from melanoma, likely making them evolutionarily fitter and capable of passing this useful trait on to new generations. 

But soon, some of our Sun-adapted ancestors migrated northward out of the tropical zone, spreading far and wide across the Earth. The further north they traveled, the less direct sunshine they saw. This was a problem because although UV light can damage skin, it also has an important parallel benefit. UV helps our bodies produce vitamin D, an ingredient that strengthens bones and lets us absorb vital minerals, like calcium, iron, magnesium, phosphate, and zinc. Without it, humans experience serious fatigue and weakened bones that can cause a condition known as rickets. For humans whose dark skin effectively blocked whatever sunlight there was, vitamin D deficiency would have posed a serious threat in the north. But some of them happened to produce less melanin. They were exposed to small enough amounts of light that melanoma was less likely, and their lighter skin better absorbed the UV light. So they benefited from vitamin D, developed strong bones, and survived well enough to produce healthy offspring.

Over many generations of selection, skin color in those regions gradually lightened. As a result of our ancestor’s adaptability, today the planet is full of people with a vast palate of skin colors, typically, darker eumelanin-rich skin in the hot, sunny band around the Equator, and increasingly lighter pheomelanin-rich skin shades fanning outwards as the sunshine dwindles. Therefore, skin color is little more than an adaptive trait for living on a rock that orbits the Sun. It may absorb light, but it certainly does not reflect character.

From the TED-Ed Lesson The science of skin color - Angela Koine Flynn

Animation by Tomás Pichardo-Espaillat

Humans are weird

So, Ive been reading a ton of humans are weird and earth is space australia posts, and I started thinking; what if what makes us so different and weird for aliens is our possibility to evolve? Like, we are able to train and become stronger, we willingly go through pain and feeling like shit in order to do amazing things? We can learn, we can get better. We can get so flexible, we actually fit in a little box if we put our mind to it. Our body and mind have so much potential, even to other humans it is frightening. What if aliens just don’t have that?

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Human face evolution in the last 6 million years