While green eyes are also part of this, the development of blue eyes is important to science. Mostly because they are really the first color eyes went to when they shifted only from the brown we knew them for. Funny enough, eye color changed for the same reason skin color changed among many humans. Those who stayed in the Middle East or African regions kept their brown, olive, or black skin as well as their brown eyes. But those who moved further north slowly began to see lighter skin colors. That is directly due to covering up more throughout the year.
Roughly 6,000 to 10,000 years ago, in the heart of the Holocene, blue eyes sprang up. Initially, it was a gene mutation that developed in the OCA2 gene. Likely happening through a family line adapting or evolving to their environment. Then, the eye color was passed on. While some believe it comes from one ancestor, it is likely others evolved to do the same. Basically, the proteins in the OCA2 gene affect melanin within the eyes to change color from the default brown. This could happen to any family line evolving or adapting to an environment potentially.
It is likely that you’ve had a drink of alcohol in your life, even if it was a small amount. However, it used to be that pretty much everyone drank alcoholic drinks, even children. Beer was invented between 3500 to 3100 BCE while Wine was invented as early as 7,000 BCE in China. Both were critical to human survival because, unlike water, they went through distilling and essentially a purifying process overall. This made them far safer to drink than water.
However, while wine and beer might have been safer, they have alcohol that could make someone impaired. Moreover, while they could affect your brain they could also affect the heart and liver. At one point, our bodies could not handle them very much but that all changed. Our bodies evolved to handle them by developing the ADH1B enzyme. Most of the human population has this, but there are some who do not.
You might not know what the Plica Semilunaris is off the top of your head. But you certainly know it if you saw it. If you look at your eyes or heck, someone else’s, you’ll notice a small pink-looking thing in the corner. That is your Plica Semilunaris, and it happens to be critical to human eyes. In our human evolution, it came from a nictitating membrane we used to have that covered the entire eye. It acted sort of like a third eyelid that was translucent, allowing us to see through it.
Naturally, this allowed us to see underwater as well as during strong winds. Obviously, the area no longer does this, so what happened? It might have stopped its previous job, but the role then changed. It now has a much more important role than before. the Plica Semilunaris acts as a barrier from anything getting inside our eyes and into any of the orbital cavities. This became critical in the Holocene when people were around a lot of smoke, sand, and other elements that could tear through an eyelid but cannot tear through this without a mighty force.
Before you look at this as a potential push for vegetarian diets, we must reference a few key things. People have the right to have the diet they choose, but completely plant-based diets will miss key vitamins and proteins that meat will provide. Which can, at times, cause them to need to eat more specific foods and need to take vitamin pills to give them what they need. Yet there are times human evolution adapts to this diet, as long as it is done through generations. It all involves the FADS2 gene.
In 2016, it was even found that a population within Pune, India showed a higher frequency of mutation to the FADS2 gene. Due to eating a mostly plant-based diet for generations, the people here needed this mutation to take place. It allowed them to process omega-3 and omega-6 fatty acids from non-meat sources. They could then convert those compounds into nutrients needed for brain health. But those who eat meat regularly would not have this gene, meaning humans could adapt to this diet.
Like the appendix initially, most have been pretty confused as to why men have nipples. We know why women have them, as they help to feed children until they reach the age to stop. But if men are not feeding kids, why have they kept their nipples for thousands of years until now in human evolution? To be honest, what you might assume about male nipples is a lie. Not only can they feed babies, it still happens in some parts of the world. While it is a bit harder to do, as men do not have the large mammary glands women have… they can still do it.
While in their mother’s womb, nipples will form before the child is set to become a male or female. However, once the Y chromosome kicks in, male genes begin to form. That stops as much estrogen production and thus the lack of female breast production. Yet some men randomly lactate due to mammary glands forming similar to women. Other men, even the men reading this, can breastfeed a child. It will take time and some priming, but it can be done. During the Holocene, men stopped doing this with children and we evolved where women mostly did it. But it is still done in tribes in various places worldwide.
This is a part of human evolution that is pretty negative for us. Antibiotics as we know them have been around for nearly 100 years now. While Alexander Fleming did accidentally discover the penicillin mold was capable of eliminating specific bacteria in 1928, the Penicillin antibiotic took time to reach the market. It was not seen there until around 1945, which ended up helping him win the Nobel Prize alongside his colleagues. But sadly, many bacterias slowly began to develop a resistance to Penicillin. That sparked new antibiotics to form until we saw the versions we have today.
Yet some bacteria are even able to stand up to newer antibiotics too. Also, people have taken them too often, causing some to have antibiotic resistance. As in, their bodies fight off the aid the antibiotics offer, and thus they do not help them with their infection. While the antibiotics only assist with symptoms of infections and do not rid you of infection, the symptoms are often the worst part. Those can even kill a person, especially when fevers are involved. This is why doctors try to avoid giving antibiotics out as much as possible today unless they feel a person must have them to get better.
If you are born in an environment high above sea level, specifically in a mountain range, there is a good shot you will develop the ability to have impressive breathing skills. Specifically when it comes to breathing in higher altitudes. This is a big reality for the Sherpa, a group of people famous for being Mount Everest guides. The Himalayan mountains, even outside Everest itself, can be tough areas to live in. One must be able to breathe well in this environment if they are to live there obviously.
Scientists were amazed at how they could live and work up here with lower oxygen levels compared to lower elevations. Thus, several Tibetan people were tested, including some Sherpa. They found that they produce more oxygen-transporting hemoglobin protein than an average person. This mutation began about 3,000 years ago when groups of people began living in the Himalayans. Since they possess such impressive breathing, the Sherpa’s main source of income is in guiding tourists.
Most of the world is lactose intolerant. Yet in spite of that, this does not mean you cannot drink milk or have any milk or dairy products. Ultimately, it would only cause some gastrointestinal issues, if anything at all. This intolerance began several thousands of years ago. That caused people to be unable to drink milk without getting sick once they became adults. Yet this enzyme along with other gene mutations took place in humans at some point between 2,000 to 15,000 years ago.
That mutation changed humans, allowing us to drink milk without sickness taking place. While we might still get some small GI problems, most people are not allergic to milk nowadays. Why did this change happen? Ultimately, scientists believe farming had a lot to do with it. In East Africa, researchers believe genetic changes happened about 3,000 years ago once people there began raising cattle. This meant more milk and milk products would be used, thus the need to develop a mutation.
For the longest time, having wisdom teeth was important to humans. They came about during human evolution due to the fact that early humans had to eat relatively tough food. Of course, this was an annoyance so eventually humans managed to soften their foods or simply find softer sources. That diet change was critical, and our jaw muscles no longer had to grow to be as large or as strong. That meant we developed smaller jaws that caused wisdom teeth to stay behind the gums.
That meant that when they came in, pain could be caused and infections could also occur from them. Nowadays, dentists offer to pull them out even before they become an issue. However, many are no longer developing wisdom teeth at all. In fact, 1 in 4 people is born missing at least one or all of their wisdom teeth. As weird as it sounds, Inuit people in Greenland and Canada are more likely to be missing them, in spite of a diet traditionally rougher than what we’d consider “the norm.”
We sort of just referenced this, but jaws used to be much larger than they are today. However, a change happened nearly 20,000 years ago once we switched up food options. Specifically, when humans began to eat fruits, vegetables, and even insects more. On top of this, the invention of tools helped as well. We were now able to use them to cut and mash up foods rather than use our teeth. Teeth used to be large, flat surfaces that with our sizable jaw, could mash up food easily.
Now, we no longer needed this so throughout human evolution, we began seeing our jaws and mandible shrink along with our teeth. However, Stanford University researchers dispute this. They claim the size change is a lifestyle disease connected to the epidemic of human practices. Such as today’s obesity, type 2 diabetes, and heart disease issues. In spite of this, even if it’s a lifestyle change or disease, one still has to adapt. Thus, the change is something that “evolves” over a period of time.
While this is often referred to as the “Asian Flush” at times, it’s really a response one’s body makes to alcohol. About 36% of East Asians, including portions of Chinese, Japanese, and Koreans, have facial flushing and severe nausea when they drink alcohol. The reason for this is that the enzyme ALDH2 became mutated in their bodies and caused a deficiency. It seems odd that this would happen to them, as things like beer have a heavy connection to China alone dating back thousands of years.
If there was going to be any group of people who would be immune to such issues, it should be them. This type of flushing can also be a key way to notice if a person has a health problem too. In fact, those with a deficiency in ALDH2 have a greater risk of developing esophageal cancer from drinking alcohol than an average person. Human evolution apparently has made these people adapt to a society that no longer needs alcohol. East Asia is also known for its many teas and wines, which are said to have a great health benefit. Those wines also have a far lower rate of alcohol than in previous generations too.
Malaria is often not a problem in the developed world. In fact, most developed nations rarely even see insects that carry malaria at all. But in places like Africa and parts of Asia, malaria is a huge problem. Yet the problem could reduce sooner rather than later thanks to human evolution. Back in the 1940s and 1950s, scientists J.B.S. Haldane and A.C. Allison found a sickle-cell mutation known as Glu6Val in the beta hemoglobin gene known as HBB. This mutation proved to be resistant to malaria.
More mutations have occurred in the HBB area as well. On top of this, the Duffy antigen gene or FY has also mutated for some people. FY is a membrane protein used by the Plasmodium Vivax malaria parasite to access human red blood cells. Mutation to this FY system stopped malaria right at the access point, preventing it from starting at all. In fact, this specific trait has now been seen in 100% of cases for people in Sub-Saharan Africa, but nowhere else as of yet.
We often assume those with big brains are smarter while those with smaller brains are less intelligent. But that has proven to not be true. In fact, our ancestors had brains far larger than us. Yet many scientists believe the Neanderthals were relatively dumb creatures in our human evolution cycle. In the last 20,000 years, brains have been shrinking and our heads/skulls have shrunk along with them. Obviously, our skull protects our brain, so if the brain is not massive then the skull shouldn’t be either.
The change over this 20,000 period, our brains have shrunk enough to compare the total change to a tennis ball. Basically, this is the amount of brain we no longer need. Likely, due to our brain smartly adjusting and evolving to do its job with less room needed to do it. However, it is not just humans that see this change. Dogs and cats also have smaller heads and smaller brains today versus what they were thousands of years ago.
It used to be that our bones needed to be relatively large. This was due to having to take down animals for food as well as fight among ourselves for food too. We now know that compared to other hominins in our history, our bones are now weaker and less dense. This changed roughly 12,000 years ago when humans began to get into farming and agriculture. Diets changed due to this, as well as the physical activity we took part in.
Now, our skeletons are lighter and more fragile than before. Dating back to 2015, a study on the trabecular bone tissue proved there was a decrease in thickness and volume. Due to no longer hunting and the adjustment to farming, we did not need heavier and more durable bones any longer. While researchers and scientists disagree on whether or not a diet or physical activity is more to blame, they all agree this change happened due to the rise of agriculture.
The HIV/AIDS epidemic began mostly back in the 1980s. It is said that it began originally in chimpanzees somewhere in Western Africa. While some assume that someone might have had to “get it on” with the chimp, that was not how it crossed over. Rather, since HIV can be passed via blood too, a person likely ate a chimp and caught the virus. This slowly increased and began to affect humans. While many assumed only gay men could catch and spread it, this all changed in the 1990s.
When LA Lakers star Magic Johnson caught HIV from unprotected relations with a woman, it was proven to be an issue for both sexes. Yet now we also know there are some with resistance to it. Studies found that a gene mutation known as CCR5-Delta 32 makes a person resistant to the human immunodeficiency virus. This also, by proxy, makes those with this mutation resistant to AIDS too. On top of this, scientists found this gene mutation could have also helped people survive the Black Plague. If that is the case, this is likely a gene mutation that has been happening in our human evolution for quite a while now.
While our bones are getting lighter, it seems this is freeing up our bodies to get taller. Yet there might also be a connection to higher education and even longevity. Both men and women are taller now than they ever wore in history. Evidence suggests the average male just 2,000 years ago was 5 foot, 5 inches. Anyone above this would be considered quite tall. Meanwhile, women 2,000 years ago had an average height between 5 feet to 5 feet, 2 inches.
Neanderthals seemed to lower our height during human evolution because previous ancestors were slightly taller. This could be why human height was so much shorter thousands of years ago. Today, the average male height is about 5 feet 9 inches or 5 feet, 10 inches. Yet women have an average height of 5 feet, 4 inches. Of course, there are anomalies to this for both sexes where people are well over 6 feet.
People do not really discuss this change in human evolution as much as they should. But many years ago, there was a big change for the Inuit people. Researchers found various, unique genetic mutations within the Inuit genome that allowed them to adapt to the severe cold much better than the average person. On top of this, they had a mutation that allowed them to have a high-fat diet.
The mutation allowed them to have a diet high in omega-4 fatty acids. While this often came with the side effect of being shorter, the Inuits still managed to live proper lives. Of course, this diet was high in seafood like fish and even seal or whale at times. The average human today could not handle such a diet without having some sort of health complication. But the Inuits, even those of today, have the ability to handle this diet.
It is stated that today, many kids are developing complications and sicknesses far more. However, the one community where this never happens is the Amish community. Why? Many people overprotect their children and do not allow them to get out and play in the dirt, with insects, and much more. However, the Amish community sees their children grow up around animals and agriculture, putting them outdoors and among potential viruses or infections often.
That slowly develops their immune system. A similar thing happens with doctors, and thanks to human evolution, healthcare workers often develop something known as Glutathione. It is an antioxidant and a protector of cells, which allows people like doctors and nurses to avoid getting sick from patients much easier. While things like their masks, uniforms, or classic coat also assist in protecting them from germs too, this antioxidant might be the prime reason they are so healthy.
During the human evolution process, we have often dropped things from our genetic makeup or altered them. Sometimes, things might develop or show in the womb but won’t be present when a baby is born. It used to be that we had an extra vein running down our forearm that formed temporarily in the womb. Yet this always vanished before birth. Now, many people are still being born with this according to researchers at Flinders University and the University of Adelaide.
Essentially, we are now seeing people born with what is basically an extra channel of vascular tissue that flows from under the wrist. The researchers found that the consistent nature of people being born more and more with this goes back to the 18th century. Roughly 10% were born with it in the mid-1880s but that popped up to 30% during the 20th century! Our median artery works just fine in humans, so anything extra is not exactly useful. Some assume that having this could offer some sort of extra aid like more dexterity or strength. Rather, it makes one more prone to carpal tunnel syndrome than anything else.
Human evolution can be a really cool thing. One would assume that we would not often see it in action among humans in such a major way. Since evolution is a slow process, we have to look at humans from an entire history, not just a few years. Yet the climate has only risen for the world. The massive rise is a direct result of human activity that is now out of control, along with the hole in our Ozone layer. As a result, humans are overheating.
Since the world also goes through a normal climate change, this has to happen along with what we are doing to it. Thus, making things happen quicker. This is thought to be why humans have dropped in temperature as a way to adapt. While the average temperature had been 98.6 Fahrenheit for most average, healthy humans. Today, we are seeing people more and more with temperatures of 97.3 to 97.9 degrees. As we know by climate, even one degree can be important.
Where do we find this stuff? Here are our sources: