It may seem as if the evolutionary process ended years ago, but the human body is still evolving. It was only about four million years ago when the first members of the Homo genus walked the earth. And there are still so many commonalities between humans and chimpanzees. Humans matured as a species, but there are still signs of evolution in the human body. Even our chins are remnants from the evolutionary process.
Many ancestors of the human species died out, but they left their descendants with a few unmistakable physical heirlooms. In fact, vestigial limbs are still very present on the human body; some of them don't even have a purpose.
You may have a hard time grasping the concept of evolution, but you won't be able to deny the physical proof of it that's occurring on your own body.
If you don't have the palmaris longus, the tendon that protrudes from your wrist, you are an exception; only about 14% of the population doesn't have it. This tendon helped ancient monkeys swing through trees, giving their wrists high levels of mobility. Modern-day apes and humans still have the palmaris longus, but it is much shorter and less strong.
Many surgeons use this tendon for cosmetic skin grafts now because it no longer serves any purpose.
Many birds, reptiles, and amphibians have a third eyelid - a semi-transparent membrane that moves across the eye. Only one primate, the Calabar angwantibo ape, has this membrane in present times. However, many scientists believe that early hominids and primates had the membrane as well. The semi-transparent membrane gave those early mammals better vision while hunting.
Humans have a pink plica semilunaris on the corner of the eye that's likely a remnant from the third eyelid. We no longer have muscles to control the membrane, however, and no one knows when those muscles were lost. Some evolutionists believe that humans lost the need for the eyelid because they began to live and hunt in groups. The additional vision that the eyelid provided wasn't necessary when someone else could watch your back.
Humans don't typically climb around in trees or grab branches with their feet anymore, but some people still have extremely flexible feet. Researchers suggest that 8% of people have flexible feet because of a midtarsal break in the middle of their respective feet.
Much like chimpanzees, people with this break can easily grasp things with their feet. This difference is nearly indistinguishable if the individuals wear shoes, however. And they don't have trouble walking though doctors say they should.
The Sherpa, native Nepali people who help guide Everest climbers up the mountain, have evolved to live in such high altitudes. When average people climb Everest, it takes them a few days and a consistent supply of oxygen. But a Sherpa person can climb Everest in about 20 hours without any additional oxygen.
The Sherpa people can even live in these high altitudes, though the lack of oxygen might kill others. Research shows that the Sherpa process oxygen more efficiently than the rest of us. They also burn fat at lower rates than we do; burning fat requires more oxygen than burning sugar.
Other people can learn to breathe a little easier in higher altitudes, but they will never reach the Nepali people's level of oxygen efficiency. After all, it took the Sherpa about 9,000 years to evolve to this point.