Explain with examples how the following are evidences in favour of evolution in organisms.
(i) Homologous organs
(ii) Analogous organs
(iii) Fossils
(i) Homologous Organs: They have same basic structural design and development origin but have different functions and appearance. These organs follow the same basic plan of organisation during their development but has been modified to perform different functions. Example: The forelimb of a frog, lizard, a bird and a man.
(ii) Analogous organs: They have different basic structure but have similar appearance and perform similar functions. Example is wings of an insect and a bird, they have different structures but they perform same function of flying. They provide evidence for evolution that organisms from different ancestors perform similar functions to survive, flourish as well as keep on evolving in prevailing environment.
(iii) Fossils: They are remains of dead organisms which lived in remote past. Fossils provide evidence for evolution for example; fossils of man. Example: A fossil bird is Archaeopteryx. It looks like a bird but it has many other features found in reptiles. So Archaeopteryx is a connecting link between reptiles and birds and so it suggests that “birds have evolved from the reptiles”.