Explain with examples how the following are evidences in favour of evolution in organisms:

(i) Homologous organs

(ii) Analogous organs

(iii) Fossils

The following are evidences in favour of evolution in organisms:

1. Homologous Organs:

• Definition: Organs in different organisms that share a similar basic structural design and developmental origin but perform different functions.
• Evidence: They indicate that these organisms have evolved from a common ancestor and adapted to different ecological niches over time.
• Example: The forelimbs of a human, a frog, and a lizard have the same basic bone structure (humerus, radius, ulna, carpals, metacarpals) but are modified for grasping, leaping, and running respectively.

1. Analogous Organs:

• Definition: Organs in different organisms that have different basic structural designs and origins but perform similar functions.
• Evidence: They show that different organisms can adapt to similar environments independently (convergent evolution), rather than inheriting the trait from a common ancestor.
• Example: The wings of a bird (supported by bones) and the wings of an insect (supported by chitinous membranes) both serve the purpose of flight but have completely different structures.

1. Fossils:

• Definition: Fossils are the preserved remains or traces of organisms that lived in the past.
• Evidence: They provide direct historical evidence of evolutionary changes, showing transitional forms and the progression from simple to complex life forms over geological time.
• Example: Fossils of Archaeopteryx exhibit features of both reptiles (teeth, long tail) and birds (feathers, wings), acting as a connecting link.