Understanding Evolution

Homology: Legs and Limbs

Frogs, birds, rabbits and lizards all have differently shaped forelimbs, reflecting their different lifestyles. But those different forelimbs all share the same set of homologous bones — the humerus, the radius, and the ulna. These same bones can even be seen in fossils of the extinct lobe-finned fish, Eusthenopteron. Such homologies reveal the common ancestry of all these animals.

Limb homology

 

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Understanding Evolution © 2015 by The University of California Museum of Paleontology, Berkeley, and the Regents of the University of California