People get around by various means. While preferring to ride to reduce fatigue, we humans are meant to walk or run when necessary. While infants are unable to do this, toddlers gradually master these skills as their skeletal frame calcifies and their muscular coordination improves with practice and growth. Perhaps most of us take our pedes locomotion for granted, but we shouldn’t. After all the apostle Paul advised “… The head can’t say to the feet, ‘I don’t need you!’... God… has put the body together, giving greater honor to the parts that lacked it.” (1 Cor 12:21, 24).
This month marks the fifteenth anniversary of one of the most important paleontological announcements in recent history concerning the history of human development. This article is an account regarding one of the key parts of our wonderfully made body.
Human Uniqueness
What makes humans unique among all the other creatures – i.e., multi-cellular animals? Our unique creation by God? Our intellect? A few moments of watching “Libs of TikTok” or our Vice President’s pontificating should disabuse anyone of that notion. What about our brains that house that intellect, despite its grotesque misuse? Implausible, as its principal function merely facilitates congregating in larger groups when compared to other great apes, but commonly not much else. (Technological innovation is a potential answer, but that seems reserved only for ostracized introverts.) Besides, fossil evidence suggests that our Paleolithic forbearers had larger craniums than what we have today. Perhaps this is because human brains shrank at some point during our current Holocene period after we offloaded our memorization faculties in order to script in baked clay, stone, parchment (or cellphones).
What about our hairless bodies, which differs from other mammals? Recall that we share this trait with moles on land and cetaceans at sea. Our upright posture? Note that both bears and prairie dogs can stand intermittently. Bipedal travel? Kangaroos jump about, and ostriches can chase trucks – both on two legs with their toes on the ground. Opposable thumbs? Most other primates possess that feature on their hands. Our social structure? Buffalo and horses graze and gallop in herds, starlings flock in morphing swarms, sardines swim in tight schools, and ants nest in colonies. What about our propensity to erect structures? Beavers build dams, and bees and wasps construct elaborate honeycomb hives.
Well then, let us return to our peculiar stature. It is true that our skulls perch on our spines from underneath rather than cantilevered on the rear – the brain and spinal cord connect through an opening called the foramen magnum. Now we’re getting somewhere. But what change in our anatomy led to that development?
The answer: our feet.
Biblical Allusions
We tread the dusty ground with our feet them– and our species has migrated all across the globe on them. Their cleanliness marks domestic comfort (Songs 5:3). Abraham greets visitors offering to wash their feet before bringing them food (Genesis 18:4). Upon David’s marriage proposal, the widow Abigail rhetorically replies with her willingness to engage in foot washing (1 Samuel 25:41). When Jesus was invited to a town, a local woman bathed and anointed his feet with her hair (Luke 7:38). Jesus also washed the feet of his disciples at the Last Supper (John 13:5) – but only their feet – as they had all ritually bathed in a mikveh before entering Jerusalem to celebrate the Passover.
In some sense, humans recognize the symbolic importance of our principal means of locomotion, as is reflected in scripture. God’s word guides mankind as illumination at one’s feet (Psalm 119:105) which is repeated in the Canticle of Mary (Luke 1:79). Greetings to a beloved guest is symbolized by falling at one’s feet, as in the case of when Mary of Bethany met Jesus (John 11:32). The itinerate Paul exclaimed the beauty of feet in spreading the Gospel overland (Romans 10:15, echoing Isaiah 52:7).
Genetic Divergence
Genetic tracing and fossil remains point to our divergence from our closest living pan-cousins – chimpanzees and bonobos – out of a common ancestor many years ago. Fossilized bones are comparatively rare and difficult to find. Such fragments can be gathered and then analyzed by teams of paleontologists. Most recent discoveries have originated from the Great Rift Valley in western Africa. The Homogenus emerged with H. habilus and H. erectus about two million years ago (mya) and dispersed. Eventually our species H. sapiens supplanted them in successive migrations.
But earlier hominids revealed smaller precursors than their five-foot tall heirs. In 1974, one specimen of Austrlopithecus africanus, dated about 3.2 mya, became the most famous fossil. It was found by Donald Johnson and was named “Lucy” after a Beetles song. The “Taung child” skull fragment found in 1924 was our first encounter with this species. Fossil assemblages of A. afarensis indicated adult male height at four feet with cranial vaults slightly larger than chimpanzees in volume. Over the eons, heads became more bulbous to house swelling brains. However, locomotive accoutrement of spine, hips, knees and feet remains similar across the latter part of the Pliocene and the subsequent Pleistocene that ended with the last glacial maximum.
Unexpected Discovery
Later, Tim White at University of California, Berkeley meticulously collected and reassembled a skeleton of Ardipithecus ramidus from the Middle Awash area ofEthiopia. The remains of the specimen named “Ardi” were gathered in 1992-94, and the several authors contributed to the discoveries published fifteen years ago in October of 2009 in Science. The topics included habitat, teeth, hands and pelvis. Professor White’s subsequent research as well as video put out by Science magazine provided additional anatomical comparison of the cranial base and an a summary of the discovery.
Ardi lived about 5.6 mya – about 1.4 million years earlier than the earliest Austrlopithecus example and possessed markedly smaller brains. However, what made Ardi special was her feet. Humans have phalanges that fan out slightly from the heel with roughly equal angular spacing, the largest of these being the metatarsals. Ardi’s big toe stuck out like a sore thumb. This fact and other evidence indicate that Ardi lived at the edge of a forest and was able to climb trees as well as perambulate on the ground. Based on this, one can postulate that the physiology of arboreal pan-apes altered as much or more than that of hominids in the shape of their hips and spine.
Science as Story-Telling
The 2020 book Fossil Men by Kermit Pattison provides insights related to recent discoveries of rare skeletal remains from long ago. The author devotes his narrative to White’s discovery of Ardi and the controversies surrounding the investigation. Science is a human endeavor and, as such, draws ambitious and competitive persons that can engender fierce rivalries and contentious arguments. Pattison illuminates this obscure, uncomfortable and often hazardous field of study, and portrays Professor White as the hero of his book. At the same time he gives public recognition to his Ethiopian colleagues and other examples of his professionalism. (One local tribesman who was hired as a reconnaissance guide extended his appreciation by giving White an African wildcat as a pet, which he named Lubaka.)
Tim White had joined prior expeditions with the flamboyant Don Johnson and the world-renown Leakey family. Johnson’s publicity-derived fame greatly facilitates the funding of such research projects, while White’s diligence and keen observation enabled him to examine logistically difficult terrain, as well as reassemble anatomical clues from fossilized fragments.
However, he didn’t suffer fools lightly, rudely dismissing shoddy research with his acerbic humor. At a 1983 conference, the White shark explained that a clavicle found in Libya ostensibly from a primitive ape, had actually been a rib belonging to an ancient dolphin he derisively labeled “flipperpithecus.” Although not biographical in tone, Pattison’s description of the human dimension involved in such dry field work and laboratory analysis presents a window into a world few readers will have explored.
Fossils as History of our Species
Hominid erect locomotion separated our distant ancestors from other mammals long before our craniums began to enlarge. The act of walking involves several interrelated skeletal and muscular motions, none of which are with us when we first enter the world.
During the development of our bodies as children, our compact straight spines curve into a sinusoid to balance weight, balancing on our hips to which our elongating legs hinge. Our knees and ankles flex as we perambulate. When motivated, chimpanzees walk in a waddling fashion, but in crouch with bent knees while doing so – their hips and feet are better suited for negotiating through jungle trees, but not for traversing savannas.
Over eons, human precursors rotated their feet’s “thumbs” into forward-facing stabilizing toes transforming our leg appendages from distal grasping hands into effective shock absorbers against the ground. That shift gradually transformed skeletal and muscular frames to being fit for standing and climbing and later to upright walking. By freeing our hands, hominids could gather more food and grasp weapons for combat or hunting, and thereby acquire nourishment to expand the craniums relative to their bodies. Once our ancestors tamed fire and could cook meat, gullets could further shrink, improving nimbleness in a dangerous environment by the use of one’s feet adapted for steady locomotion. It’s amazing to appreciate these symbiotic and iterative anatomical features.
Scientific inquiry is ultimately a human endeavor brought about by our desire to better understand the world that God created. The participants of Ardi’s discovery, with their meticulous efforts under arduous conditions that they refused to deter in spite of obstacles, both natural and personal, have expanded public knowledge of insights into our earliest ancestry.
Photo Credit- Wiley Online Library