Douglas Harper's Etymology Dictionary
Wiktionary
n. The habit of standing and walking on two feet; the state of being bipedal
WordNet
n. the bodily attribute of being bipedal; having two feet; "bipedalism made the human form of birth possible"
Wikipedia
Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning "two feet" (from the Latin bis for "double" and pes for "foot"). Types of bipedal movement include walking, running, or hopping.
Few modern species are habitual bipeds whose normal method of locomotion is two-legged. Within mammals, habitual bipedalism has evolved multiple times, with the macropods, kangaroo rats and mice, springhare, hopping mice, pangolins and homininan apes, as well as various other extinct groups evolving the trait independently. In the Triassic period some groups of archosaurs (a group that includes the ancestors of crocodiles) developed bipedalism; among their descendants the dinosaurs, all the early forms and many later groups were habitual or exclusive bipeds; the birds descended from one group of exclusively bipedal dinosaurs.
A larger number of modern species intermittently or briefly use a bipedal gait. Several non-archosaurian lizard species move bipedally when running, usually to escape from threats. Many primate and bear species will adopt a bipedal gait in order to reach food or explore their environment. Several arboreal primate species, such as gibbons and indriids, exclusively walk on two legs during the brief periods they spend on the ground. Many animals rear up on their hind legs whilst fighting or copulating. Some animals commonly stand on their hind legs, in order to reach food, to keep watch, to threaten a competitor or predator, or to pose in courtship, but do not move bipedally.
Usage examples of "bipedalism".
Charles Darwin in 1871, the matter of bipedalism was felt to be a non-issue.
It was bipedalism which also freed the hands to make stone tools, which helped early man change his diet to a carnivorous one which, in providing much more calorie-rich food, enabled further brain growth.
In addition, bipedalism also changed the pattern of breathing, which improved the quality of sound.
Second, modern experiments have shown that bipedalism does not increase energy efficiency, and as more fossils have been found we now recognise that early bipedal apes lived in environments where trees were plentiful.
We have seen that one consequence of bipedalism was an increase in the division of labour between males and females, leading to the nuclear family.
On the savannah, he suggested, bipedalism was a more suitable mode of locomotion.
Corballis speculates that bipedalism enabled early man to develop hand and facial gestures first and that speech only developed after the rules had been laid down in the brain for grammar, syntax etc.
They used their fingers to strain blue-green algae from the water and gobbled it down: a way of feeding that was another little gift of bipedalism.
Their bipedalism had helped: the repositioning of their larynxes and changes in the pattern of breathing improved the quality of the sounds they could make.