Biology / Unit 8 Bio 1659 short lesson, about 20 seconds
Homologous Structures
Captions available
The idea
Homologous structures are anatomically similar features inherited from a shared ancestor, even where present-day size, shape, or function has diverged.
In practice
The same bone arrangement appears in a human arm, a bat wing, and a whale flipper, inherited from one ancestor's forelimb.
Where people slip
Homology is judged by shared structure and origin — not by whether the structures currently serve the same function.
Your place on the trail
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