Presence of gills in the tadpole of frog indicates that :-
A
Fishes evolved from frog like ancestors
B
Frogs will have gills in future
C
Frogs evolved from gilled ancestors
D
Fishes were amphibious in the past
The answer is C.
Solution
The tadpole larva of a frog lives in water, breathes through gills and has a tail and a two-chambered fish-like heart, like a fish. During metamorphosis it loses the gills and develops lungs. According to the recapitulation theory (biogenetic law of Haeckel), the development of an individual briefly repeats stages of its evolutionary history. So the gilled tadpole stage indicates that frogs (amphibians) evolved from gilled, fish-like ancestors. It does not mean that fishes evolved from frogs or that frogs will have gills in future. So the presence of gills in the tadpole indicates that frogs evolved from gilled ancestors.
ConceptRecapitulation in tadpole
Evolution in past papers
143 questions from this chapter have appeared across 27 exam years.
