Question

Forelimbs of humans and wings of birds are
A. Analogous organs
B. Homologous organs
C. Parallel organs
D. Vestigial organs

Answer 1

Structural features of organisms provide evolutionary relationships among them in the form of- homology, analogy, vestigial organs and atavism.

Complete step by step answer:
-Analogous organs
These are the organs of different origin but similar form and function.
For example- Wings of insect, bat and birds are of different origin but similar function.
Analogous organs are examples of convergent evolution.
Homologous organs
These are the organs in different organisms that have the same origin but different structure and function.
Homology existing between different species is called phylogenetic homology while homology between the sexes of the same species is called sexual homology.
For example- heart and brain of vertebrates, forelimbs of humans and wings of birds, in all plants leaves are homologous organs, leaves modified as thorns in Bougainvillea and tendrils in Cucurbita.
Homologous organs are examples of divergent evolution.
-Parallel organs
Parallelism is the phenomenon in which the closely related organisms have changed in the same direction.
-Vestigial organs
These are the organs that were once functional in the ancestral form but later become non-functional.
Presence of structure in an animal indicates its origin from the stock where it was functional.
For example- vestiges of the hind limb and pelvic girdle in python, splint bones in the horse.
Man has more than a hundred vestigial organs like a wisdom tooth, vermiform appendix, coccyx, body hair, pinna muscle, nictitating membrane, etc.
So the Correct option is B, Homologous organs.

Note: So, homologous, analogous, parallel and vestigial organs, are evidence indicating that modern diverse forms of organisms have arisen by evolution from more ancient forms.