Difference between homologous and analogous organs
The organs homologs are those that have a similar structure but work differently, the analogs they are the organs that fulfill similar functions despite having a different evolutionary origin.
Through comparative anatomy, homologous and analogous organs in different organisms can be found and differentiated by contrasting them.
| Homologous organs | Analogous organs | |
|---|---|---|
| Definition | Similar organs in their structure with different functioning. | Those organs with a different origin that perform the same function. |
| Characteristics |
|
|
| Type of evolution | Divergent. | Convergent. |
| Presence | It can be observed in species that inhabit different environments. | They are present in species that inhabit similar environments. |
| Examples | The wings of bats and the arms of a chimpanzee are homologous organs | The wings of bats and the wings of birds are analogous organs |
What are homologous organs?
Homologous organs are those that are
similar in their internal structure, but that they fulfill different functions depending on the species.Homology normally occurs in bodies because they come from a common ancestral organ.
The functions performed by homologous organs can become totally different because the species have adapted to the characteristics of the environment where they develop.
The development of homologous organs happens thanks to the divergent evolution, where two related species change a common ancestral structure during their evolution in order to survive performing different functions.
For this reason it is said that the organs are homologous when they have the same evolutionary origin, that is to say, a common ancestor, although they have developed fulfilling functions with different purposes.
Example: the forelimbs of vertebrates, such as the arms, wings of birds, and the fins of a dolphin are homologous organs because they come from the same common ancestor, while fulfilling functions totally different.
What are analogous organs?
Analogous organs are those that are morphologically similar or carry out similar functions despite having a different genetic origin.
This means that the origin and embryonic development of the analogous organs is not the same, although their structure is similar or they fulfill the same function.
Normally, the analogy occurs when the species have evolved separately but have had to adapt to the same type of environment.
This development process is possible thanks to the convergent evolution. Here, organisms that have had to evolve totally separate develop similar characteristics because the environmental conditions where they develop are quite similar.
Sharks and dolphins are two species that have had to evolve in a convergent way.
Example: the wings of birds and insects are morphologically different, but both serve the same function because they allow these species to fly.
Doctor in Biochemistry from the Venezuelan Institute of Scientific Research (IVIC), with a degree in Bioanalysis from the Central University of Venezuela.
