Is the Thumb the Top Contributor to Human Evolution? [Reading Science]

The human thumb is a "thumb that opposes." It is a form that has evolved for survival.
[Photo by YouTube screenshot]

[Asia Economy Reporter Kim Jonghwa] What is the most important organ in the human body? Since all organs are important, it is difficult to say that any one organ is especially more important. However, among the most frequently used organs, shouldn't the 'hand' definitely be included?

There are 206 bones in an adult human body, and about a quarter of them, 54 bones, are in the hand. In terms of the number of bones, this means the hand ranks in the 'top 4' among body organs. The hand is necessary for using tools, and the role of the fingers, which are part of the hand, is especially important.

So, among the five fingers of a human hand, which finger is the most important? Scientists unanimously point to the 'eomji sonkkarak (thumb)'. The thumb is the shortest and thickest finger on the human hand. However, it is also the finger with the most remarkable functions.

Professor Nigel Spivey of the University of Cambridge in the UK, in his book Opposable Thumb, argued, "The thumb made humans artists. Only humans who can move their thumbs relatively freely can engage in artistic activities." Why do scientists value the thumb so highly?

When you extend your fingers and fold them one by one, only the thumb folds in a different direction. Because of this, the thumb can touch the other four fingers. This characteristic of the thumb is called the 'opposable thumb'.

Primates similar to humans, such as apes and koalas, also have opposable thumbs, but the human thumb bends better than those of these animals. In the case of apes, when holding objects, they grip with their fingers but cannot grasp tightly, so they rely only on grip strength.

Humans needed to grip objects tightly to hold tools or throw stones, and for that, the thumb had to bend freely in a different direction. As a result, through 'natural selection'?where some individuals adapted to the environment and survived to leave offspring?about 2.6 million years ago, the human thumb evolved differently from other animals.

Can you see the long fingers of the chimpanzee? On the other hand, the proportion of the thumb is much smaller compared to the human thumb.
[Photo by YouTube screen capture]

Humans learned that the strength of the grip, which involves curling the fingers to hold tools or throw stones, varies depending on the grip type, and evolved accordingly. The grip can change through the movement of the thumb; when precise directionality is required, like throwing a baseball, a 'precision grip' is used, and when swinging strongly or performing power tasks, a 'power grip' is used.

The animal whose hand is most similar to the human hand is the chimpanzee's hand. Since chimpanzees need to move across trees, their thumbs are small, and the other four fingers have evolved to be long. The human thumb is shorter than the other four fingers but much longer than the thumbs of chimpanzees and other animals.

Since these evolved according to their respective survival environments, it cannot be said that the human fingers are more evolved than chimpanzee fingers. Recently, scientists making robotic hands have been focusing most on the thumb. The performance of robotic hands reportedly varies depending on the role the thumb plays.