Explanation

Convergent evolution. Convergent evolution describes the acquisition of the same biological trait in an unrelated lineages. The wings are the classic example of convergent evolution in action. Flying insects, birds and bats have all evolved the capacity of flight independently. They have ‘convergent’ on this useful trait. The ancestors of both bats and birds were terrestrial quadrupeds, and each of them had independently evolved powered flight via adaptations are superficially ‘wing-shaped’, they are substantially dissimilar in construction. The bat wing is a membrane stretched across four extremely elongated fingers, while the airfoil of the bird wing is made of feathers, which are strongly attached to the forearm the ulna and the highly fused bones of the wrist and hand the carpometacarpus, with only tiny remnants of two fingers remaining, each anchoring a single feather. Both bats and birds have retained the thumb for specialized functions. So, while the wings of bats and birds are functionally convergent, they are not anatomically convergent