Homologous and Analogous Structures

Homologous Structures

Analogous Structures

Inherited from the same ancestor Not inherited from the same ancestor
Similar in morphology, anatomy, embryology and genetics Different in morphology, anatomy, embryology and genetics
Perform dissimilar functions Perform similar functions
Result from divergent evolution Result from convergent evolution

What are Homologous Structures?

These are the structures which have similar morphology, embryology and anatomy etc. but are dissimilar in their functions. They are inherited from a common ancestor. Their developmental patterns are also the same. They have similar kind of blood vessels, nerves, and bones etc. but they function differently. The relationship between such structures is called homology.

Examples of homologous structures include the arm of a human, the leg of a dog, the wing of a bird or a bat, and the flipper of a dolphin or whale.

What are Analogous Structures?

Analogous structures are those structures in different species which perform the same function, have similar appearance and structure but are not evolved together; therefore do not share a common ancestor. Analogous structures show how different species have evolved to become similar to each other. The analogy is not just limited to appearance but it can be behavioral as well.

One analogous structure may have evolved centuries ago while its analogous match may have evolved in the recent past, which means they are genetically unrelated regardless of the fact that they have evolved similar structures.

Examples of analogous structures are wings of a butterfly and wings of a bird which perform the same function but are genetically different.

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