Question

Sweet potato is homologous to
A. Potato.
B. Colocasia.
C. Ginger.
D. Turnip.

Answer 1

Hint: Homologous organs structures do not have to look precisely the same, or have the same function. The most important part, as hinted by their name, is that they are structurally similar. They developed as a result of the adaptation to a different environment.

Complete answer:
Homologous structures are those structures that have the same origin but can perform the same or different functions in different organisms. They contain different nutrients and have different functions.
Homologous structures inherited from a common ancestor as a result of divergent evolution.
A tuberous root or storage root, is a modified lateral root, enlarged to function as a storage organ. Examples of plants with tuberous roots include the sweet potato, cassava, and dahlia.

Now let us match this with given options :-
Potato :- it is a type of modified stem and root like sweet potato. Sweet potato is a modified root which stores food but potato is a modified stem. So they are not homologous.
Colocasia :- it is a type of modified stem that stores food but sweet potato. Sweet potato is a modified root which stores food. So they do not have the same structure and hence they are not homologous.
Ginger :- ginger just like potato and Colocasia is an underground stem which stores food but sweet potato is a root that stores food. Hence they are not homologous.
Turnip :- it has tap roots that store food just like sweet potatoes have tuberous roots that stores food in it. So they both are homologous.

Our required answer is D. turnip.

Note: Rudimentary organs such as the human tailbone, how much reduced from their functional state, are readily understood as signs of evolution, the explanation being that they were cut down by natural selection from functioning organs when these organs were no longer in use and they become vestigial but make no sense at all if species are considered to be fixed. The tailbone is homologous, that is they have the same structure to the tails of other primates.