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Physical World

Question
CBSEENPH11020055

The shells of crabs found around a particular coastal location in Japan seem mostly to resemble the legendary face of a Samurai. Given below are two explanations of this observed fact. Which of these strikes you as a scientific explanation ?

(a) A tragic sea accident several centuries ago drowned a young Samurai. As a tribute
to his bravery, nature through its inscrutable ways immortalised his face by imprinting it on the crab shells in that area.

(b) After the sea tragedy, fishermen in that area, in a gesture of honour to their dead hero, let free any crab shell caught by them which accidentally had a shape resembling the face of a Samurai. Consequently, the particular shape of the crab shell survived longer and therefore in course of time the shape was genetically
propagated. This is an example of evolution by artificial selection.

[Note : This interesting illustration taken from Carl Sagan’s ‘The Cosmos’ highlights
the fact that often strange and inexplicable facts which on the first sight appear  ‘supernatural’ actually turn out to have simple scientific explanations. Try to think
out other examples of this kind].



Solution

Explanation (b) is the correct scientific explanation of the given fact.