Bipedal locomotion is one of the hallmarks of our species.?

Question

Bipedal locomotion is one of the hallmarks of our species.

1. What parts of our anatomy reflect changes for bipedal locomotion? What are these changes?

2. How did the development of bipedal locomotion affect human culture and social behavior?

Help I just dont get my Anthropology class!!

Answer 1

The foramen magnum (where the spine and skull join) has been relocated from the back of the skull to the base of the skull, since the skull must be perpendicular to the spinal column. The upper and lower spine of bipedal creatures must be curved to absorb the shock of the bipedal gate. In contrast, the spine of apes is nearly straight. In addition, the rib cage of bipeds is barrel shaped, in contrast to the inverted V-shape of the apes. The muscles that attach to these bones must be restructured to accommodate the skeletal changes.

Longer legs and smaller toes, arched foot and a different transmission of weight when in motion (now heel to ball, instead of along the outside and to toes as in primates).

Modern human hip joints are larger than quadrupedal ancestral species to better support the greater amount of body weight passing through them, as well as a shorter, broader shape. This alteration in shape brought the vertebral column closer to the hip joint, providing a stable base for support of the trunk while walking upright. Also, because bipedal walking requires humans to balance on a relatively unstable ball and socket joint the placement of the vertebral column closer to the hip joint allows humans to invest less muscular effort to balance.The shape change of the hip may have led to the decrease in the degree of hip extension, an energy efficient adaptation.

The vertebral column of humans takes a forward bend in the lumbar (lower) region and a backward bend in the thoracic (upper) region. Without the lumbar curve, the vertebral column would always lean forward, a position that requires much more muscular effort for bipedal animals. With a forward bend, humans use less muscular effort to stand and walk upright. Together, the lumbar and thoracic curves bring the body's center of gravity directly over the feet. Also, the degree of body erection (the angle of body incline to a vertical line in a walking cycle) is significantly smaller to conserve energy.

Enlarged knee joints to support the weight.

The first answerer is correct about the b*****s changing into a sexual signal as a result of bipedalism, in primates they are usually long and dangly. The human face has also converted lips into a secondary sexual signal that mimics the 'lower lips'. If you get a good look at female chimps they have swollen red vulvas, but that's not part of the human anatomy you see when upright, so the focus has shifted to the lips you can see when upright.

It's not seen often in modern humans, but steatopygous buttocks are also a bipedal adaptation. You really only see it in Bushmen and the Negrito peoples now. It's the hugely fat buttocks that you see on ancient Venus figurines, it allows toddlers to ride on their mothers backs more safely when the mothers are moving.

http://olimu.com/Notes/Steatopygia.jpg

Standing upright allowed the hands to develop opposable thumbs, and that allowed advanced tool use, and opened out other food sources. Once we could run fast over long distance, humans began stamina hunting (running down over long distances) and started eating a lot more meat, improving the fat and protein in our diet and allowing for more brain growth. All our complex cultural behaviours are related to this increase in brain size.Things like writing, farming, construction, etc.

Socially, well we aren't really that much different to other primates. It means we've adapted to use our faces as the primary means of visual communication, instead of things like raising hairs on our backs, or flashing our buttocks like baboons (although you'll still see this throwback behaviour after alcohol). Our focus is on what is at eye level, the face.

You'll also notice that most forms of ornamentation center around the upper half of the body, the part most often seen up close. It also makes vertical height visually more significant than outright body mass.

Answer 2

This is not meant to sound sexist, but womens b*****s are a part of anatomy that changed because of bipedal locomotion.  When humans began walking upright, there needed to be something to sexually attract the males.  When we were bent over it was the rear end, upright, it is the b*****s.  Ever notice that pressed together b*****s resemble buttox.  Also, not too sure about this one, but opposable thumbs could be part of the result of bipedal motion.  Not walking on our hands meant they were freed up, and possibly adapted  to be able to be used, assuming you believe in evolution.

As far as what parts of culture and social behaviour were affected, not too sure, but i would say most things we do with our hands is a result of having them freed up, such as Art.  Wanted to say building, but beavers build dams and are not bipedal, and turtles dig nests not being bipedal, so i figure construction is out.

Answer 3

Well it wasn't aways a condition of our ancestors.

From what I read, bipedalism was forced upon our ancestors around 3.5 to 4 million years ago by geophysical uplifting in East Africa.

The trees were replaced by Savannah forcing our ancestors to walk upright, if for no other reason, safety.

Among the physical changes forced upon our skeletal system was the opportunity for the elongation of our laryngeal organ this elongation allowing for the production of more complex sounds and eventually leading to...speech.

Hello!

Answer 4

Hip structure and bone geometry are drastically different in humans compared to other primates. Also, the shape of the spine reflects more upright movement. While other primates show bipedal behavior (apes, chimps, etc.) there are no other primates that do it the way humans do (running, balance on one foot, etc.). It also allows us to travel much longer distances more efficiently (calorie-wise).

Answer 5

The guy above is right and we know where his mind wanders but being able to feed a baby while travelling allowed the group to find a more varied diet. It also allowed babies to be babies longer and that helped the brain to develop.  Travelling groups ran into new situations that stationary groups didn't experience creating a need for more signals.  The root of language.

Answer 6

-the structure of the pelvis changed to more of a bowl, rather than having the hips flared out like the early hominids we're derived from. the boney bowl like structure had to be able to support the compounded pressure of organs, upper body skeletal structure being completely vertical. hominids that move partially on all fours distribute their weight more evenly.

-the structure of the foot changed.  the big toe rearranged itself to be in line with the other toes, which aided habitual bipedal locomotion.  

-muscles changed, forgot how.

-the foramen magnum aligned directly at the base of the skull to allow for a fully erect posture.

- our body hair became less dense; cooling mechanism.

-biped. affected human culture in that it freed our hands to carry stuff, and was important in early semiosis leading to language. was necessary in the development of tool use, without which we wouldn't be able to adapt to so many different environments successfully.

- because we didn't require as much energy to cover a lot of ground as it had before...could move around a lot to exploit different resources without much difficulty.

i think we had opposable thumb before bipeds.  many of our real early ancestors that branched off were arboreal, needed the thumb.

ive never heard that one about the b*****s.

Answer 7

I believe none of the above answers are correct. Bipedal locomotion is not a hallmark of the species, as all primates are bipedal. If you only have two legs, then you are bipedal. We use our limbs as suits our lifestyle. Peep Peep