frozen-heart
11-21-2010, 04:43 AM
In the name of Allah
كنت اناقش مؤمنا بالانتخاب الطبيعي من امريكا فسالته كيف تطور الانسان المنتصب القامة فكانت هذه اجابته
Your question answers itself. HOW did humans become bipedal? As your question itself states, THROUGH NATURAL SELECTION. If you want to know how natural selection works, then it could be understood through several other examples rather than this single case. Therefore, your real question probably is WHY did humans become bipedal. The most fundamental answer is that being bipedal provided humans with an evolutionary advantage, but why in turn it provided them with an evolutionary advantage is still being debated.
The ancestors of humans originally moved about by swinging from tree to tree and hanging from branches. (Even today you can see remnants of this capability in the uninterrupted 360 degree rotational ability of our shoulder joints and hands that are very good at grasping things.) This type of movement is called BRACHIATION. Over time, we began to move more and more around and between trees, which is how we developed BIPEDALISM through spines, legs, and feet capable of supporting our entire body weight for greater and greater distances. (More evidence that humans were not always bipedal include the common problems of back pain and arthritis due to the pressures placed on our skeleton because of walking, problems which can be traced back to the switch to bipedalism four million years ago. If God/Jesus/Santa had intelligently designed humans, simply walking around would not result in chronic skeletal problems.)
There are at least half a dozen more specific explanations for why humans became bipedal, which are not necessarily mutually exclusive. One of the more likely ones is thermal regulation, where standing up allowed us to distance most of our body from the hot ground and take advantage of breezes. Another funny one is that it might have been a mating display (men wanted to show off their penises, which are easier to see when they are standing upright). If women consequently thought they were hot and had a lot of sex with them, eventually all of them would stand up all the time.
لقد اندهشت لهذا المنطق ... يقبلون اي خرافة الا وجود مصمم ... حتى الام الظهر يفهمونها بشكل تطوري.
كنت اناقش مؤمنا بالانتخاب الطبيعي من امريكا فسالته كيف تطور الانسان المنتصب القامة فكانت هذه اجابته
Your question answers itself. HOW did humans become bipedal? As your question itself states, THROUGH NATURAL SELECTION. If you want to know how natural selection works, then it could be understood through several other examples rather than this single case. Therefore, your real question probably is WHY did humans become bipedal. The most fundamental answer is that being bipedal provided humans with an evolutionary advantage, but why in turn it provided them with an evolutionary advantage is still being debated.
The ancestors of humans originally moved about by swinging from tree to tree and hanging from branches. (Even today you can see remnants of this capability in the uninterrupted 360 degree rotational ability of our shoulder joints and hands that are very good at grasping things.) This type of movement is called BRACHIATION. Over time, we began to move more and more around and between trees, which is how we developed BIPEDALISM through spines, legs, and feet capable of supporting our entire body weight for greater and greater distances. (More evidence that humans were not always bipedal include the common problems of back pain and arthritis due to the pressures placed on our skeleton because of walking, problems which can be traced back to the switch to bipedalism four million years ago. If God/Jesus/Santa had intelligently designed humans, simply walking around would not result in chronic skeletal problems.)
There are at least half a dozen more specific explanations for why humans became bipedal, which are not necessarily mutually exclusive. One of the more likely ones is thermal regulation, where standing up allowed us to distance most of our body from the hot ground and take advantage of breezes. Another funny one is that it might have been a mating display (men wanted to show off their penises, which are easier to see when they are standing upright). If women consequently thought they were hot and had a lot of sex with them, eventually all of them would stand up all the time.
لقد اندهشت لهذا المنطق ... يقبلون اي خرافة الا وجود مصمم ... حتى الام الظهر يفهمونها بشكل تطوري.