When our distant ancestors left the trees to walk in the savannah, physical changes occurred that are still visible today. Some are vestigial and no longer needed, while others hold up as efficiently as ever.
In fact, modern humans can thank many ancient advantages for their survival, including laughter and eyebrows. Human evolution is far from finished. Here are 10 fascinating facts about human evolution, from changing female voices to genes ruining drinking games!
The nails are much older than we expected.
Up until 58 million years ago, primates were introduced to nails. It provided various benefits for the creatures living in the tree. The main goal was to make them better for navigating trees where they were basically limited. The nails strengthened the fingers, allowing them to grip better. Also, relative to other tree animals, primates became superior to picking fruit from the ends of branches.
At one point, humans stopped nesting in trees any more because an ancestor realized that the land was more suitable for living. As the lineage evolved, humans ventured into caves and flatter lands. During a radical habitat change and physical changes that have been going on for thousands of years, humans have kept their claws down. The woodworking skill of nails has evolved into productive crafting and the endless tasks the human hand can perform today.
What is the main purpose of laughing?
The act of laughing seems simple at first. People laugh when they find something funny or pretend it’s something funny. No one wants to meet someone with a killer gaze or an argumentative nature. Research has shown that laughter is a powerful social glue.
The habit of laughing probably evolved in the past as a way to strengthen alliances and reject violence. While our fake laughter seems to remove the same barriers as a real giggle, it may not deceive the people around us.
Unexpected effect of female friend voice
In one study, men and women were brought together for 30 appointments that would happen quickly. The men moved to other tables every six minutes, while the women stayed at the same table. Each of them had to mark a card indicating whether they liked the other person or not.
When the researchers then listened to the recorded conversations, it turned out that both sexes lowered their tones when talking to a loved one. It contradicted previous studies that showed men were attracted to louder women because they looked younger and more feminine. However, many find that a quieter conversation is more sincere. When flirting in a room full of people, a woman might lower her voice just for privacy.
Interestingly, it showed that female voice recordings from 1945 were lowered when compared to those taken in the 1990s. This may be because women are trying to convey maturity and dominance in a more equal opportunity world.
Why don’t people have fur?
Compared to other animals, humans do not have a dense bristle and fur. Fur kept our earliest ancestors warm, protected their skin and provided camouflage. But a circumstance in evolution pressed to delete it.
The strongest theory for the extinction of our fur was that after leaving the trees to live in open savannas, a body covered in fur made it impossible to live and hunt in the heat of the sun, as the new environment was warmer. It is also thought that people’s sweat glands become quite active as the fur becomes thinner. In fact, modern humans are the sweatiest primates on the planet.
Why did the big toe change so slowly?
In one study, the big toe was identified as one of the last foot bones to develop after the transition from tree-swinging ancestors to land-dwelling ancestors. It required major overhaul of the feet to walk upright. The big toe was instrumental in this change because it allowed traction during walking.
Despite its importance, the fingers were attached for a long time in primate origin. In the beginning it was almost like a single finger, holding branches and working like a tool. For this extremely useful feature to be even more effective, the fingers had to harden, and this happened very slowly over millions of years. But later research proved that the big toe doesn’t really affect the ability to walk efficiently.
Do men’s nipples produce milk?
Male mammals cannot feed their young, but they still have the means to suckle. Some men even give off lactic acid, known as lactic acid, but this is usually due to a hormonal problem. Male nipples are not an evolutionary oddity. They are the result of a biological process that prevents evolution from deleting a useless trait.
A mammalian embryo has the potential to be either sex. Somehow, when the time comes, the chromosome set decides the sex. If there is a male XY couple, a gene called SRY activates and starts everything the embryo needs to develop into a male child.
However, there is another process that takes place before the male genetic switch can be reversed. Mammary glands in mammals begin to develop extremely early, and these glands do not care for any old set of chromosomes. They lay the groundwork for breast tissue and nipples and there is nothing SRY or evolution can do about it.
A pretty useless tendon
One of the most useless things nature has left in the human body is the palmaris longus tendon. It appears quite prominently on the wrist. Most people can see this when they touch their thumb and little finger together and tilt the hand slightly towards them. A raised line will appear in the middle of the wrist. If it does not appear, it is between 10-15% of people born without it.
The tendon attaches to the palmaris longus muscle but does not make it stronger. The only time it serves a purpose is when surgeons remove and use it elsewhere in the body during plastic and reconstructive surgery. It remains unclear why people have useless tendons. It is a relic from a time when the forearms as well as the legs were used to move it, according to a not very valid guess.
Is the function of eyebrows just to protect the eyes?
Eyebrows serve an obvious purpose today: They act as a protective barrier for the eyes. Without eyebrows, humans might have gone extinct like Neanderthals, according to a surprising study. Neanderthals and apes had prominent bony prominences above the eyes, much like modern primates. Research has shown that this non-human protrusion has no real purpose other than to look wild.
Returning bone: Fabella
The human kneecap was once accompanied by a small bone called the fabella. Millions of years ago, it had the same function for monkeys as the modern kneecap. As humans evolved, the fabella disappeared and got smaller. However, it only takes a few kneecap surgeries and scans to realize that fabella is still present in some people.
In 2019, researchers conducted an extensive study. They reviewed medical records from 27 countries involving more than 21,000 knees. The results were pretty clear. The tiny bone fabella was returning. Records spanned almost a century, with the earliest showing that in 1875 about 18% of the population had it. In 1918 only 11.2 percent had it. But it’s estimated that about 39 percent of people today have returned remains.
Could your genes be at play if you are prone to hangovers?
One of the weirdest ways humans still evolve is with the alcohol dehydrogenase (ADH) gene cluster. Normally, when a person drinks one or fifty beers, the body breaks down the alcohol into poisonous acetaldehyde. When these things accumulate, the drinker no longer feels so cheerful. The face becomes red and the person experiences nausea and rapid heartbeat. Typically, acetaldehyde is rapidly metabolized to a less irritating acetate that is easily excreted from the body.
Some individuals of East Asian and West African descent showed an evolved cluster of ADHs that bothered very quickly when drinking. This makes it harder to process alcohol, and so such people are hit with super hangovers faster. It is not clear how quickly the adaptation spread to other populations or whether the genes were changed to protect people from drunkenness.
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