LIFE SCIENCE

Detailed explanation-1: -Yes, It is necessary that homologous structures always have a common ancestor. As explained in the above example, the basic structure of arm of human and wing of bat is similar but they modified to perform different function in different vertebrates. Therefore, this shows that they have evolved from a common ancestor.

Detailed explanation-2: -Similar body parts may be homologies or analogies. Both provide evidence for evolution. Homologous structures are structures that are similar in related organisms because they were inherited from a common ancestor. These structures may or may not have the same function in the descendants.

Detailed explanation-3: -In evolutionary biology, analogous structures are defined as biological structures having similar or corresponding functions but not from the same evolutionary origin. In other words, species use these biological structures for the same purpose and yet these species are from unrelated evolutionary lines.