Homology

Homology is the relationship between parts derived from their corresponding embryonic development, whether among different beings, as is the case of the arm of humans, the front foot of quadrupeds and the wing of birds; or within the same individual, as is the case of the front and back legs of quadrupeds, the segments or rings and their appendices that compose the body of worms or centipedes. The latter form of homology is called serial homology. Parts related to each other in this way are called homologous, and such a part or organ is said to be homologous to the other. Among different plants, parts of the flower are homologous and, in general, these parts are seen as homologous with the leaves.