The forelimbs of all vertebrates are built upon the same pattern as they all have the same bones namely humerus, radius, ulna carpels. These bones differ in different animals because they are modified and specialized according to different modes of life, such as swimming, walking, jumping, flying, climbing, digging, etc. Such structures are said to be homologous organs. They show that once all different vertebrates shared a common ancestor which diverged into different species as per requirement of adaptation with different geographical conditions and lifestyles. Hence, it supports evolution.