A Truly crucial leap in the gradual hominin evolutionary transformation into common Homo

sapiens sapiens was the move from quadripedalism to bipedalism. A complete change would take

place with regards to the locomotion method of some members of the Hominin family. Along with this

switch in hominin locomotor evolution came costs and advantages: changes in anatomy and an increased

tax on the systems of these newly bipedal organisms. The switch from quadrapedalismto bipedalism did

not only manifest changes in hominin morphology, it naturally manifested changes in the evolution of

human behavior. The evolution of hominin culture is directly tied to the moment bipedalism first took

early hominins out of their arboreal habitat and forced them to use the terrestrial style of locomotion

used by current extant hominins. By comparing and contrasting two recent academic journal articles:The

Metabolic Cost of Walking in Humans, Chimpanzees, and Early Hominins and Locomotion and Posture

from the Common Hominoid Ancestor to Fully Modern Hominins, with Special Reference to the Last Common

Panin/Hominin Ancestor, one can attain a significant amount of knowledge regarding the evolution of

terrestrial bipedalism and the costs that this mode of locomotion had on hominin life forms physically,

behaviorally, and culturally. While the two articles differ on distinct issues regarding the evolutionary

processes leading to bipedalism, both clearly detail that the selection of hominin bipedalism may possibly

have been the most significant item in the evolution of hominins both physically and behaviorally.

                Initially, the two journal articles have similarities in some areas of their analysis. Both Pontzer et al and

Crompton et al agree that terrestrial bipedalism is a more energy efficient mode of locomotion

(Pontzer et al, 2009; 45) (Crompton et al, 2008; 511). Therefore, it is only natural that human bipedalism

became the selected evolutionary trait. This transformation of locomotion techniques would free up the use

of the fore limbs which could then be used towards aspects other than transportation. This key advantage of

bipedalism significantly affected the behavior and culture of early hominins. This is due to the fact that the

forelimbs could now be used to carry items long distances, create and use tools, transport the young, and

whatever else these early hominins could imagine. Behavior patterns and culture would have to evolve to allow

for the transmission of these new traits to future generations. Pontzer et al and Crompton et al additionally

both agree that the evolutionary move to bipedalism coincided with a gradual move away from an arboreal way

of living and towards a more terrestrial form of habitation(Pontzer, 2009; 44) (Crompton et al, 2008; 510-511).

This move in habitation, from arboreal to terrestrial, would change hominin behavior; the first bipedal hominins

would naturally begin to travel farther distances in search of food sources and develop varied subsistence

strategies which would eventually evolve towards the more nomadic lifestyles of later hominins like Homo

neanderthalensis. Logically, a change to orthograde bipedalism would require changes to the physical anatomy

of early hominini. Pontzer et al and Crompton et al mutually agree that morphological changes would have to

have taken place to provide for bipedalism and notably they both often refer to BHBK or bent hip bent knee a

defining factor in bipedal hominins(Pontzer et al, 2009; 56)(Crompton et al, 2008; 508). Additionally Crompton

et al goes into great detail regarding morphological changes to the femur, metatarsals, pelvis, etc

(Crompton et al, 2008; 507-510,533-535). Data from extant Hominidae is used by both studies to support their

particular theories regarding bipedal evolution, particularly with regards to that of orangutans and chimpanzees

(Pontzer et al, 2009)(Crompton et al, 2008).

                The main contrast found between the two articles, regarding bipedal hominin evolution, is the question of what

form of locomotion was the most recent predecessor to common hominin bipedalism. Crompton et al stressed that

current hominin bipedalism was derived from the branch suspended bipedalism of early hominins with locomotion

traits similar to orangutans and chimpanzees of today (Crompton et al, 2008; 509,511). Basically, Crompton asserts

that early hominin’s need to reach the food sources that were located in the tree canopy translated into arboreal

bipedalism which, in turn, translated to terrestrial bipedalism. However, Pontzer et al disagrees with Crompton and

believes the preceding locomotion method to terrestrial bipedalism was in fact quadrapedal knucklewalking like that

of the common great ape the Gorilla. Pontzer cites taxonomic similarities between humans and extant quadrapedal

knucklewalkers along with post cranial similarities to support his team’s hypotheses (Pontzer et al, 2009, 45).

Crompton, on the other hand, states quadrapedal knucklewalking was likely the predecessor to arboreal bipedalism

(Crompton, 2008; 533). His reasoning is that displacement from natural deforestation forced knucklewalkers into the

tree canopy to find additional sources of food which in turn led to flex hip flex knee habits from vertical

climbing(Crompton, 2008;533). These “flex hip flex knee” skeletal differences lead to a body more equipped for

arboreal bipedalism. Although these ideas on bipedal evolution are highly differing, both articles clearly show

the advantages that terrestrial bipedalism had on the cultural and physical evolution of hominins.

                Both studies do an exceptional job of detailing the evolution and the costs and advantages that bipedalism had on

the physical and behavioral aspects of hominin evolution. The extensive use of empirical data for support of their

hypotheses does much to strengthen their arguments, but, one may wonder how accurate can it actually be if both

articles use data from extant primates to supplement data for extinct hominin species. Unfortunately, with subjects

such as these the only option is to use the closest living relative to produce the best approximate data regarding

these extinct hominins. Regardless, it is vital to notice that hominin development evolved a highly advantageous form

of locomotion that enabled tool use, carrying of items, and the dispersal of hominin populations, as well as being a

more cost efficient method of transportation. The importance of hominin bipedalism is not in what it evolved from,

but in what it enabled later hominins to evolve into. You little bitch.