By means of comparative anatomy, homologous and analogous organs are found and differentiated in different organisms by contrasting them.
These have a similarity with the internal structure but they fulfill different functions depending on the species. In general, the homology in the bodies comes because they come from a common ancestral organ.
These functions become totally unequal because the species adapt to the peculiarities of the environment where they develop.
The evolution of homologous organs occurs thanks to divergent evolution, where two related species change a common ancestral line during their development to survive by performing different functions.
Organs are homologous when they have the same evolutionary origin, that is, a common ancestor, even though they have developed to fulfill functions for different purposes.
Example: the forelimbs of vertebrates, such as the arms, the wings of birds and the fins of a dolphin are homologous organs because they arise from the same ancestor at the same time and fulfill totally different functions.
They are those that are morphologically similar or perform similar functions despite having a different genetic origin. The origin and embryonic development of the analogous organs is not the same, but their structure is similar.
Generally, the analogy occurs with species that have evolved separately but have had to adapt to the same type of environment.
This development process is thanks to convergent evolution, there are organisms that have developed literally separately, they develop similar characteristics because the environmental conditions where they evolve are very similar. Sharks and dolphins are two species that have developed convergingly.
Example: the wings of birds and those of insects are morphologically different, but both fulfill the same function because both species can fly.
Homologous and Analogous Organs
|homologous organs||analogous organs|
|Definition||Organs similar in their structure with different functions.||Those organs with a different origin that perform the same function.|
|Presence||It can be observed in species that inhabit different environments.||They are found in species that inhabit similar environments.|
|examples||Bat wings and chimpanzee arms are homologous organs.||Bat wings and bird wings are analogous organs.|