Question

Distinguish between homologous and analogous organs with example.

Answer 1

Hint: Animals and Human body have many organs inside their body. The different organs are classified into homologous and analogous organs. They are classified based on the theory of evolution. They provide morphological and anatomical evidence.

Complete Answer:

Sl.No	HOMOLOGOUS ORGANS	ANALOGOUS ORGANS
1.	They have morphological differences.	They have superficial resemblance.
2.	Organs have similar structure.	These organs have different structures.
3.	These organs perform different functions.	These organs perform the same function.
4.	They have similar developmental stages.	They have different developmental stages.
5.	These organs are developed in organisms that are related to each other.	These organs are developed in organisms that are unrelated to each other.
6.	The type of evolution is divergent.	The type of evolution is convergent.
7.	The pattern of development is similar.	The pattern of development is different.
8.	Example : Forelimbs of mammals,Wings of fish and sparrow and Invertebrate legs	Example: Wings of a small insect and wings of a bird.The wings of an insect is made up of membranes with folds that are associated with muscles , whereas the wings of a bird is made of flesh skeleton and has an outer covering called feather.They both have wings with different structures but they perform the same function which is flying.

Note: Homologous organ was found by Richard Owen.It is evident that species with homologous organs evolved from the common ancestors.That is why they are divergent in nature. Many species lived in a big crater a long time ago.Because of heavy rainfall the load of craters has increased making it an unsuitable place for the species to survive.So some of the species started developing wings so that they could fly and lead a life at a different place.This is how the analogous organs have evolved.They have one or more adaptive radiation in an isolated geographical area with different habit.This is the reason for their convergent nature.