(C) Daily Kos
This story was originally published by Daily Kos and is unaltered.
. . . . . . . . . .



Human Origins 201: The Human Hand [1]

['This Content Is Not Subject To Review Daily Kos Staff Prior To Publication.']

Date: 2025-03-08

One of the important characteristics of humans is the ability to make and use tools. One of the anatomical human features that makes this possible is the human hand. In his book Evolving: The Human Effect and Why it Matters, Daniel Fairbanks writes:

“If there is any one part of the human body that most directly reflects our dependency on tools, it is the hand.”

Our starting point in understanding the hand and its importance to human evolution is to compare it with that of our closest relative, the chimpanzee (Pan troglodytes). It should be stressed in looking at the anatomical differences between human hands and chimpanzee hands, that modern humans are not descendants of chimpanzees, but the relationship is more like distant cousins as we share a common ancestor in the distant past (about 7 million years ago).

Chimpanzee fingers are curved with narrow tips, while human fingers are straight with broad tips. Chimpanzees have short thumbs, while human thumbs are larger and stouter. The hand structure of chimpanzees is designed for a power grip that is important in climbing and grasping tree limbs. While both humans and chimpanzees have hands that are capable of grasping and holding things, only humans have opposable thumbs.

Shown above is a Human Hand Mold and a Bonobo Hand Life Cast. This exhibit was in the North American Bigfoot Center Museum in Boring, Oregon.

According to the North American Bigfoot Center Museum:

“Bonobos, also known as pygmy chimpanzees, are a distinct species of chimpanzee with many shared physical traits. Their hands are characterized by four long curved fingers and a thumb with is opposable, meaning that it moves independently from the rest of the digits.”

Daniel Fairbanks compares human and ape hands this way:

“Ape fingers are long and curved, adaptations well suited to tree climbing, swinging from branches, and knuckle-walking. Our fingers are shorter, and our thumb is positioned in such a way that we can easily touch the tips of each finger with it, giving us highly advanced dexterity.”

In his book Human Bones: A Scientific and Pictorial Investigation, McNeill Alexander describes the human hand this way:

“Our hands are better built than ape hands for precision grips, in two ways. First, we have longer thumbs, better able to reach the tip of the index finger. Second, the structure of the joints of the hand enables us (unlike apes) to rotate the thumb as it approaches the index finger, so that they meet fingertip to fingertip.”

In his book Thumbs, Toes, and Tears and Other Traits that Make Us Human, Chip Walter explains:

“What is different is that we can effortlessly swing our thumbs across the palms of our hands to meet our small and ring fingers, the fourth and fifth digits. Nothing like this exists elsewhere in nature. It’s called the ulnar opposition.”

Opposition makes possible the precision grip which is a key element in our ability to make and use a variety of tools. In their book The Dawn of Human Culture, Richard Klein with Blake Edgar write:

“The human hand promotes a precision grip that is well suited for opening a jar, writing with a pencil, or flaking stone.”

In her chapter in The Story of Us, Kate Wong reports:

“The modern human hand, with its short, straight fingers and long, opposable thumb, is purpose-built for power, precision and dexterity—traits we exploit every time we swing a hammer, turn a key or send a text.”

In his book The Body: A Guide for Occupants, Bill Bryson provides a more detailed description of the thumb:

“What we do have in our thumbs are three small but resplendently named muscles not found in other animals, including chimps: the extensor pollicis brevis, the flexor pollicis longus, and the first volar interosseous of Henle. Working together, they allow us to grasp and manipulate tools with sureness and delicacy.”

With regard to human fingers, Chip Walter reports:

“The fingers of our hands actually have no muscles. They operate by remote control, like marionettes. A web of tendons, anchored in the palm, midforearm, and as far north as the shoulder are the strings that make your digits dance.”

Writing about the importance of the hand in human evolution, Desmond Morris, in his book The Naked Woman: A Study of the Female Body, says:

“Freed from the task of locomotion, both on the ground and in the trees, the design of the hands could for the first time become solely manipulatory. This was one of the most important steps in the whole evolution of our species.”

In his book The Gap: The Science of What Separates Us from Other Animals, Thomas Suddendorf writes:

“A human hand is capable of power and precision grip that allow effective clubbing and throwing.”

The hand set the stage for tool-making and tool-using and with tools, humans moved out of Africa and colonized the rest of the world.

With regard to the evolution of the hand, Mary Marzke, in her report on the hand in the Handbook of Human Symbolic Evolution, writes:

“The concurrent appearance, in the earliest fossil hominids, of morphological features in both the hand and the locomotor apparatus that are essential to the distinctively human facility in tool-use is consistent in the divergence of hominids from the pongid line.”

With regard to time period in which human ancestors evolved the human hand, Chip Walter writes:

“Based on the garbled messages the fossil record has so far provided, science’s best guess is that they reached something like their current, thumb-opposable state a little more than two million years ago.”

With regard to genetics , the evolution of the human hand is associated with the HAR2 gene which drives gene activity in the wrist and thumb during fetal development. Katherine Pollard, in her chapter in Becoming Human: Our Past, Present and Future, writes:

“This finding is particularly provocative because it could underpin morphological changes in the human hand that permitted the dexterity needed to manufacture and use complex tools.”

With regard to evolution, the development of our complex hand with precision grip came about only after humans had become bipedal. Daniel Fairbanks writes:

“Bipedalism freed the arms and hands from constraints imposed by quadrupedal locomotion. Adaptations that favor advanced tool use could best evolve only after bipedalism was habitual and had fully freed the arms and hands for other functions.”

In her book Written in Bone: Hidden Stories in What We Leave Behind, British forensic anthropologist Sue Black sums it up this way:

“The human hand is a miracle of evolution working in harmony.”

More Human Origins

Note: The designation 201 indicates a revision of an earlier essay.

Human Origins: Feet, Legs, Buttocks

Human Origins: Sexual Dimorphism

Human Origins: Eyes

Human Origins: Humans as naked apes

Human Origins: Sex

Human Origins: Menopause

Human Origins: Bipedalism

Human Origins: The Large Brain

[END]
---
[1] Url: https://www.dailykos.com/stories/2025/3/8/2308120/-Human-Origins-201-The-Human-Hand?pm_campaign=front_page&pm_source=more_community&pm_medium=web

Published and (C) by Daily Kos
Content appears here under this condition or license: Site content may be used for any purpose without permission unless otherwise specified.

via Magical.Fish Gopher News Feeds:
gopher://magical.fish/1/feeds/news/dailykos/

You are viewing proxied material from magical.fish. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.