Kaksinivelinen

Kaksinivelinen is a Finnish term that translates to "bipedal" in English. It refers to any organism that walks on two legs. This form of locomotion is primarily associated with humans and certain other primates, but some birds, like ostriches and emus, are also bipedal. The evolutionary development of bipedalism in hominins is a significant topic in anthropology, with various theories explaining its advantages, such as freeing up the hands for tool use, improved efficiency in long-distance travel, and better thermoregulation.

The skeletal structure of bipedal animals is adapted for upright posture and locomotion. This typically includes a pelvis that is broader and more bowl-shaped to support the weight of the torso, legs that are longer than the arms, and feet that are adapted for weight-bearing and propulsion. The spine develops an S-shaped curve to absorb shock and maintain balance. The development of bipedalism is considered a defining characteristic of the human lineage. While other animals may occasionally adopt a bipedal stance, habitual bipedalism, as seen in humans, is a unique adaptation with profound implications for their biology and behavior.