Shave a gorilla and they have black skin:
Shave a chimp (or, in this case, the chimp had a medical condition that made it hairless) and they have a sort of "tan" olive skin:
As with humans, this skin colouring is caused by melanin. Our fellow primates - including lemurs - all have the melanin genes.
The melanin genes that we all carry, are extremely ancient. They're way older than the shared common ancestor of all primates, from whom all primates inherit these genes.
Modern humans emerged around 300,000 years ago. Melanin genes - through the fossil record - can be traced to being at least 300 million years old.
And that's why black and white and brown and yellow and red human beings can't be different species or subspecies.
We can't be divided along a line that all humans - all primates and heck a lot of the animal kingdom - all shared as a common ancient inheritance.
It doesn't logically make any sense, unless you're contending that the "white race" and "black race" are 300 million years old and have somehow impossibly evolved independently, yet exactly 1:1 mapped each other's evolutionary development gene-by-gene ever since.
We can't be divided by a thing that's far, far, far more ancient than all primates, let alone all hominids, let alone all Homo Sapiens. Or the division would have happened 300 million years ago, and there'd be absolutely no genetic nor evolutionary connection between white and black people of any kind ever since then.
I would appreciate if you could repeat back to me what I've just said, so that I can be sure that you intellectually understand
THE COMPLETE LOGICAL IMPOSSIBILITY of there being black and white "species" or "subspecies" or other racial divisions of that kind, and do understand why, as tufty absolutely 100% correctly states, that "race" does not exist in biology and it is NOT a biological term.
Because anyone who studies this subject, in even "interested amateur" depth, is immediately confronted with this logical impossibility. The melanin genes - that makes animals "black" and "white" (and various shades in-between) - are ancient to the tune of at least 300 million years, and therefore if this was a "species" or "subspecies" separate, then the division between "the white race" and "the black race" occurred 300 million years ago. It occurred long before mammals even came into existence. Reptiles and such. Land animals had only been a thing for around 100 million years at that point.
And if the division occurred that long ago, then how could black and white humans be otherwise genetically identical and able to cross-breed?
It doesn't make sense, because it's not true.
Melanin has a big visual impact, because it colours the skin of the animal - by sight, you could hardly not notice it. But, in terms of genes, vastly more genes are involved in determining your unique face, many more involved in determining your biological sex (and I don't think you'd propose that "women are a different species", other than maybe in a poetic sense) or the epigenetics that determines your fingerprints (because let us remember that our genes are far from the be-all and end-all that define us anyway).
Speaking of epigenetics, on my left forearm, I've got a couple of freckles. Whilst I'm white, I have the melanin genes. We all do. As mentioned, they are an ancient genetic legacy shared by all primates and vast tracts of the Animal Kingdom.
We all have the genes within us to produce melanin, but these genes are "turned off" in white people.
Except not within those freckles I've got; This is epigenetics. Whilst my DNA "blueprint" says that my melanin genes should be turned off, making me a white person, some skin cells within my left forearm didn't get the memo - didn't follow the DNA instructions correctly - and that's what those freckles are. A couple of spots on my skin, where the cells actually turned on the melanin production. Within that freckle, I am black.
And, well, cells reproduce. So the "black" skin cells in my forearm have copied themselves - complete with the melanin production genes turned on - ever since. All the cells in your body (minus a few in the brain stem) replenish themselves, but they do so by copying themselves. Therefore, this epigenetic "copying mistake" will be with me, almost certainly, until the day I die.
It's also not a static trait either. Go on your hols to sunny Spain and lie on the beach, catching a tan - or if you have less time and money, perhaps go to a tanning salon to use one of their tanning beds.
You've got a tan because, in response to the UVB radiation, your body actually turns on the melanin production. Because that's melanin is - natural "sunblock". The body's built-in "sun cream".
You don't want too much UVB radiation from the Sun. Because it causes damage and depletes folic acid. If you've ever been involved in a pregnancy, then you know that folic acid is important during pregnancy - women are prescribed folic acid, if they have a deficiency. Because it's vital to the whole process.
But, equally, your mother was right. When you wanted to stay indoors and play Nintendo, but she told you kids to go outside and play. Catch some sunlight.
Because, in the other direction, UVB radiation is involved in the body's natural production of vitamin D. If you don't catch enough rays, then you could end up with a vitamin D deficiency, and you need that vitamin for strong bones. A severe vitamin D deficiency causes bone problems, like rickets.
So, to summarise, you don't want too much UVB or it causes physical damage (think sunburn or even skin cancers at the extreme) and depletes folic acid, vital for pregnancy. But you also don't want too little UVB, as it's needed for natural vitamin D production, vital for strong and straight bones.
Not too little. Not too much.
But when you live up North on planet Earth, the angle of incidence between Earth's surface and the Sun's rays is more spread out and, therefore, less intense. When you live in Scandinavia, there's really no danger of you getting too much UVB from the Sun. But there absolutely is a danger of you getting too little and suffering rickets.
Therefore, the body reacts appropriately and the melanin production is turned off. Melanin is the body's natural "sunblock" and you absolutely do not need any, when you're living up North in Europe. Dial that melanin right down to zero. Hence white people.
But if you live at the Equator, the Sun's rays are (more or less) raining straight down on your head and are much more intense. It's boiling hot and the Sun's scorching. You are really in no danger whatsoever of not getting enough UVB. On the contrary, the worry is that you're going to get much too much, and it's going to start depleting that folic acid and causing skin cancers.
Therefore, the body reacts appropriately and the melanin production is turned up to 11. It blocks most of the UVB - but enough gets through for that vital vitamin D production for your bones. Hence black people.
And for latitudes in-between? Well, what we see are olive-skinned and brown people. There is melanin production but it's not cranked up to full.
And that's it. That's why Africans - living near the Equator - are black, and Nordics are white as the driven snow. And, at more mid latitudes, you've got olive-skinned Greeks and Arabs and Egyptians.
We live on a ball. The intensity of sunlight - the intensity of the UVB radiation in that sunlight - varies by the Cosine Rule.
Look where the white and the black people originate from and - oh, look - it varies by latitude, exactly as predicted and expected.
And we even have our "exception that proves the rule" as well. The Inuit Eskimoes live far North, so surely they should be as white as the driven snow? But, wait, they're more olive-skinned than your typical European. Is this breaking the rule? No, it's exception that proves it. Because up where they live in North America, there's near permanent snow cover. And the sunlight's being reflected back up by the snow - and you have to watch out for "snow blindness" from indirect sunlight from the snow. They are the exception that proves the rule, because thought the direct sunlight up there is less intense, you're getting a lot of indirect reflected sunlight from the snow.
(This, by the way, is really what "the exception proved the rule" really means. People often illogically think it means that you need an exception to your rule to prove the rule. But, no, an exception that contradicts the rule disproves it. What it really means is that you've got an exceptional circumstance but the rule still holds. If the Inuit Eskimoes live where, due to the environment, there's more sunlight but they remained white as a sheet, then our rule would have problems. But it doesn't, so this exception has just proven the rule.)
And that's what's really going on here. When a population has lived in sunny / not sunny conditions for thousands of years, then natural selection favours the local conditions. Near the Equator, folks with black skin aren't getting skin cancers and their pregnancies - bringing the next generations - have enough folic acid for healthy births. Rinse and repeat for 300,000 years or so, and the population is black skinned.
Meanwhile, if your ancestors wandered up North to Europe and Scandinavia, then natural selection favours low to no melanin production, as conditions like rickets get in the way of your survival (whilst there's no chance of folic acid depletion, at least from sunlight alone).
But the crucial thing here is that this is natural selection, but there's no mutation involved. Natural selection is shuffling the deck, but the cards in the deck were decided long, long ago. Again, we return full circle to the fact that the melanin genes are ancient. An inheritance 300 million years in the making. We
ALL have the melanin genes, all that's being selected for by natural selection is whether they do or don't produce melanin. And, again, if you're a white person and you get a sun tan, that's the body dynamically reacted to the amount of UVB and turning on the melanin production.
You see, there's, in fact, absolutely nothing to be scared of with black skin. It's just the body's natural "sun cream", and the distribution of white and black people can be perfectly explained by the fact that the Earth is not flat. And it has nothing to do with mutation or "species" / "subspecies", as we're talking about ancient, ancient genes that all of us possess.
No need to panic. No need to mass-deport anyone. Just keep calm and carry on.
"Words ought to be a little wild - for they are assaults of thought on the unthinking."
- John Maynard Keynes
