2. Homologous organs Analogous organs Vestigial organs
The theory of evolution is based on evidence from different fields, among which is comparative anatomy.
Comparative anatomy involves studying and comparing the structure of different organs. Two organisms are related if their organs have a similar internal structure, even if they are shaped differently.
There are:
Homologous organs
Analogous organs
Vestigial organs
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Homologous organs
Homologous organs are similar in structure and share a common origin but may be adapted to perform different functions.
One example of homology is the case of the limbs of mammals.
Dog
Dolphin
Horse
Basic structure present in a common ancestor
Human
Bat wing
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Analogous organs
Analogous organs are those that have evolved separately but look alike because they are adapted to perform the same function.
One example of analogous organs is the case of the wings of insects and birds.
Bird wing
Bat wing
Insect wing
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Vestigial organs
Vestigial organs are those organs, found in some living things, that do not perform any functions. They simply show an evolutionary relationship with other living things.
One example of a vestigial organ is the coccyx, or tailbone, in humans. The coccyx is the remnant of a lost tail.
Coccyx
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