Answer to Question #119646 in Evolution for Délïss Whyte

Question

a. What are the structural differences between the hind foot of a dog, a goat and human?
b. How does the adaptations in the hind feet structure of these animals affect their movement?

Answer 1

 What are the structural differences between the hind foot of a dog, a goat and human?

The hind foot of a dog exhibit a digitigrade alignment whereby the articulation of both distal and proximal bones of the limbs leads into a quasi diverticular column alignment with a hock joint. In humans, the hind foot exhibit a unique plantigrade alignment whereby the tarsal is modified to be more robust to take up more load. Lastly, the unique structure of goat hind legs is the reduction in the number of toes where it has a total of three toes.

       b. How does the adaptations in the hind feet structure of these animals affect their movement?

             Dogs.

1)     Their movement is quadrupedal. They walk on four limbs.

2)     Hind legs determine momentum this makes the hind limbs to be motors of locomotion.

3)     The bones of the hind limb are the femur (articulates with the acetabulum of the pelvis), the tibia and fibula, the tarsals and metatarsals, and (primitively) five digits, each made up of two or more phalanges.

4)     The dog's muscles helps it to jump and leap. The muscles of the hind limbs are stronger than those of the rear limbs.

5)     The hind limbs of a dog helps it to stand and even walk.

                    Goats

1)      The hind limbs help in locomotion.

2)     Their movement is quadrupedal. They walk on four limbs.

3)     To facilitate standing, the stifle joint can be locked to preclude its collapse under body. This mechanism allows a goat to rest one hind limb at a time.

4)     They have a pair of cloven hooves that aids in its movement.

                   Humans

1)     Movement in human beings is called bipedal. This is because they only move with two limbs which are called legs. This allows the mobility and stability of humans.

2)   Muscles involved in movement include the following deltoids, biceps brachii, brachio-radialis,flexor-carpi-radialis and palmaris longus.