Biology 9700 · AS & A Level · Natural and artificial selection

Natural and artificial selection — practice question

Hippocampus, the seahorse, is a small and unusual fish. It produces live young, and the male rather than the female is the one that becomes pregnant. Fig. 1.1 shows a seahorse.
(a(i))[2]

Sketch a graph on the axes below to show how the size distribution of seahorses is affected by disruptive selection.

(a(ii))[3]

Explain why disruptive selection has continued to be maintained in this species of seahorse.

(a(iii))[1]

State the name of the type of selection in which variation in a characteristic is kept in its existing form over time.

(b)[2]

Suggest how these two different Hippocampus species may have arisen.

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