The transversal arch, absent in modern-day gorillas and chimpanzees, developed in humans around 3.4 million year ago
Humans got the arch-shaped foot some 3.4 million years ago, for a reason In the kingdom of animals, there are only a handful of species that can walk on two feet. Humans are obviously the first species that comes to mind but they are not the only bipedal species, meaning those that mostly rely on two feet for walking, in the world. Birds, apes, kangaroos and rodents are known to walk on two feet.
But thanks to evolution, walking and running is easier for humans than their bipedal counterparts. And the reason for this is that arch-like structure of our foot. The arch on the inside of the foot, called the longitudinal arch, makes the foot more rigid. This is the curved area we see running between our toes and heel.
Beneath the layer of skin are bones called metatarsals that are arranged in a curve across the foot’s width. This bend, called the transverse tarsal arch, stiffens the foot length-wise. The transversal arch is absent in modern-day gorillas and chimpanzees, which have flat and flexible feet. Only the genus Homo developed the transversal arch around 3.4 million years ago, according to a report published in the Nature journal.
To understand how the arch’s curvelends stiffness to the foot, you will have grab Rs 50 note. Lay the money flat and slightly curl its long edges so the middle bends up—as if forming a tube or highway tunnel. This creates an arch, running lengthwise down the note. Push a finger on the middle of the note’s arch, and you’ll notice some resistance or stiffness.
If it were not for these curves/arches on our feet, our movement would have been slow and sluggish like our primates.During the experiment, the researchers found that the tissue, acting together with the bones, accounted for more than 40% of the stiffness of the whole foot.
However, this is not the only anatomical change that has made walking on two feet easy for humans. For example, the curve of your lower back absorbs shock when you walk. This is a unique feature of humans. Similarly, long thigh bones enable us to take long strides, key to walking faster and further than our predecessors.
We are a voice to you; you have been a support to us. Together we build journalism that is independent, credible and fearless. You can further help us by making a donation. This will mean a lot for our ability to bring you news, perspectives and analysis from the ground so that we can make change together.
Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.