Question

The eye of octopus and eye of cat show different patterns of structure, yet they perform similar functions. This is an example of
a. Homologous organs that have evolved due to convergent evolution.
b. Homologous organs that have evolved due to divergent evolution.
c. Analogous organs that have evolved due to convergent evolution.
d. Analogous organs that have evolved due to divergent evolution.

Answer 1

Hint: Although the eye of octopus and that of a cat have evolved completely independent of each other, both of them have a retina, cornea, iris and a lens with a fluid filled in the interior of the eye. They also have the same primary function to see the objects around them.

Complete answer:
When two or more organs have similar function but their origin is different, then they are called analogous organs. Organisms use these organs for the same purpose but those organisms must not have a common evolutionary background. The eye of octopus and that of cat perform similar functions i.e. to see, thus the eye of octopus and the eye of cat can be called analogous organs.

An evolution is said to be convergent, when the organisms are not related to each other yet they evolve similar functions with respect to any organ. These similarities in the functioning are the result of adaptations to a similar environment.
In the case of the eye of an octopus and of a cat, their ancestral origin is totally different but the function of the eye is the same, which is a result of convergent evolution.

Hence, the correct answer is option (C).

Additional information:
Examples of analogous structures can be the wings of an insect and that of a bird. Both the insect and the bird have wings that are used by them to fly, but their wings developed from different ancestral origins.

Note: Two organs are said to be homologous, when they have relation in their evolutionary history, for example, the forelimbs of vertebrates. In birds, the forelimbs are modified as wings to fly whereas in humans they perform the function of holding/handling.
In divergent evolution, two species that have similar evolutionary backgrounds have organs modified to perform different functions.