Natural selection has led to a relationship between all living creatures – some being much more closely related than others. Humans and chimpanzees maintain an extremely close relationship, sharing many physical and skeletal features. Similarities do not stop there. Humans share close relationships with many small amphibians as well, including frogs.
The skeletal setup of the limbs of both frogs and humans clearly has an advantageous design – otherwise, natural selection would have stricken the frog from existence long ago. The frog’s larger back legs consist of a femur as the strong, upper leg support, just like in humans, albeit on a different-sized scale. The back legs also consist of a fibula, as well as tibia; however, on the frog these two bones are fused together into one.
Arms and Front Legs
The arms of humans have a much different skeletal setup compared with the legs. Like humans, a frog's front legs are also setup very differently from its hind legs, sharing more features in common with human arms than with its own hind legs. The frog’s leg bones consist of a humerus, which is also the strong part of human’s arms, connecting the shoulder to the elbow. The ulna and radius also exist in the frog’s arm, just as it does in humans.
Other similar structures to the human skeleton are the shoulder blades of frogs, which come in sets of two. Also called scapulae, the shoulder blades within both frogs and humans combine with clavicles (collarbones), providing additional support for the movement of the arms.
Toes and Fingers
Another feature of a frog’s skeletal makeup that holds similarities to humans (or at least some similarities) is the toes, which are akin to the toes and fingers on humans. Frog feet consist of five different toes, matching the number on human feet; although frog’s toes are much longer than those of humans. Frogs' front toes are also much longer and only consist of four toes.