*adaptation

5

With a tail that can be long as its body, the Thresher Shark attacks its prey with violent whip like motions.

This behaviour has been suspected by researchers, but only recently has it been caught on film. The tail is used to stun, maim or even kill the prey, with the shock-wave created by the momentum also stunning surrounding fish.

It is thought to be an evolutionary adaptation as these sharks hunt mainly smaller fish such as sardines. This makes the whip mechanism much more efficient at catching multiple fish with a single blow, as opposed to one fish at a time the shark would tend to catch with its jaws.

The tail was caught moving at up to 80 km/h, spontaneously heating and even boiling small areas of water near the very tip of the tail due to the extreme forces involved. 

3

It’s Official: A ‘Pluto’ Anime is On Its Way!

The top pic – taken at the Annecy International Animation Film Festival – shows the teaser poster for an anime adaptation of Naoki Urasawa’s BEAUTIFUL manga series, Pluto. Pluto is itself an adaptation of another work, Osamu Tezuka’s brilliant Astro Boy storyline, “The Greatest Robot on Earth,“ the first novel-length Astro Boy story.

Amazon info page for Plutohttp://amzn.to/2skxM9d

Amazon shortlink for The Greatest Robot on Earthhttp://amzn.to/2sxnZwF

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