Whether or not you believe in evolution, it does exist in some form or another. It may seem like a slow process but it is happening right now, in this very moment. We as humans have changed over the centuries, maybe not so much in our appearance but in our actions and ways of life. Here are just a few of the evolutionary traits that seem perfectly normal now, but wasn’t thought of many years ago.
Drinking Milk as an Adult
Drinking milk is a defining trait of all mammals. But did you know that humans are the only mammals that choose to drink it after infancy? Even though more than 75 percent of the population is lactose intolerant.
After weaning, all other mammals and most humans no longer produce lactase, which is the enzyme that breaks down lactose milk sugar. But there was a mutation that showed up in Hungary around 7,500 years ago that allowed humans to digest milk well into adulthood. The trait probably started with consuming cheeses such as cheddar or feta which contains less lactose that fresh milk or soft cheese. The new ability for humans to digest the calorie-dense dairy product was very useful for those who had to endure the cold winters in Europe. It provided them with a great amount of nourishment and today is milk is considered to be a healthy part of a well-balanced diet, unless you are lactose intolerant that is.
Resistance to Diseases
The key to evolution is survival of the fittest. And a big part of evolution is for the species to not die out before they are able to reproduce. That is why we have been provided with some traits that give our immune systems a boost against common diseases.
One of the most researched diseases that we have evolved to prevent is malaria. You may have heard that there is a connection with malaria and sickle-cell anemia. That is because there is specific gene present that, if you have one copy, will protect your red blood cells from being invaded by the malaria parasite. However, having two copies will distort the red blood cells and block their passage through blood vessels.
Another evolutionary trick that has the power to fight off malaria is that there are more than one hundred slightly different genes that may cause a shortage of protein which is involved in the breaking down of red blood cells. This process makes it harder for a person to become infected with malaria. Another mutation that has been found is one that blocks malaria parasites from invading placenta.
And malaria is not the only disease that our bodies are starting to fight off on their own. There are evolutionary adaptations that can help protect us against everything from tuberculosis to leprosy.
Scientists have determined that all people with blue eyes have come from a single ancestor that lived anywhere from 6,000 to 10,000 years ago. The color of the eyes is a mutation that affects the OCA2 gene which codes the protein necessary for producing melanin. This provides our skin, hair and eyes with their natural color. The mutation can turn off the person’s ability to have brown eyes by putting a limit on the melanin that is produced in the iris, and then dilating the eye color from brown to blue.
While having blue eyes does not provide us humans with any type of survival advantages, the gene for blue eyes does operate similar to a recessive trait, which in earlier times meant that blue-eyed fathers could be reassured that their children were in fact, their own.
Missing Wisdom Teeth
It seems that evolutions is doing some lucky people a favor by not supplying them with their wisdom teeth, which would eventually have to be removed with a painful oral surgery. It is believed that as we evolved as humans our brains crowded our skulls and caused our jaws to become narrow. This made it difficult for the third row of molars (or wisdom teeth) to grow out from the gums. After we started cooking the food that we eat, our food became much easier to chew, which meant that our jaw muscles didn’t grow as strong as they once did. That kept our wisdom teeth beneath the gums and increased the risk of having a painful and sometimes deadly infection.
Around one thousand years ago, a mutation came around that prevented wisdom teeth from growing at all. These days one in four people are missing at least one wisdom tooth. Oddly enough, the people who are most likely to be missing those teeth live in the northernmost region of Greenland, Canada and Alaska.