Question

How do homologous and analogous organs provide evidences in favour of evolution?

plz answer fast

Answer 1

This means that homology found in different animals or plants indicate their evolution from common ancestors. Therefore,this helps in the study of how different groups of species have evolved(modified)from an ancestor. And basically this is what evolutionary biologists study about!

For example:in all the insects the mouth parts comprise labrum,mandibles and maxilla (representing similar origin and structure) but they have different functions. Function of mouth in-

cockroaches -biting and chewingHoney bee -chewing and lappingMosquito -piercing and sucking

Evidently,the same structure is developed along different divergent evolution and these structures are Homologous. Divergent evolution is the process whereby groups from the same common ancestor evolve and accumulate differences, resulting in the formation of new species.

Now the term 'Adaptive Radiation' is worth mentioning here. Species which have diverged after origin from common ancestor giving rise to new species adapted to new habitats and ways of life is called Adaptive Radiation. Species with adaptive radiation exhibit large number of Homologous organs which makes it evident for divergent evolution. For example: adaptive radiation gave rise to a variety of marsupials in Australia.

Organs which have different origin and dissimilar fundamental structure but have similar functions are called Analogous organs.

This means that Analogous organs do not show common ancestor though they show convergent evolution. Development of similar adaptive functional structures in unrelated groups of organism is called convergent evolution or adaptive convergence. Further,more than one adaptive radiation in an isolated geographical area(representing different habits for different organisms),leads to convergent evolution. For example:some of the marsupials of Australia resemble like placental mammals that live in similar habitats of other continents.

I hope you are able to understand.