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Q40 - Sensory Drive Speciation in Lake Victoria Cichlids

Theoretical 1 Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license
Speciation & Reproductive Isolation

Pundamilia pundalilia and P. nyererei are a closely related sister species pair of cichlids in Lake Victoria. These two species are distinct in male nuptial body colors, in that the former and latter are blue and red, respectively. By contrast, the females of the two species are not distinct, both possessing cryptic body coloration. P. pundamilia and P. nyererei inhabit shallow and deep environments, respectively. The light component in Lake Victoria is oriented to be blue (short wavelength) in shallow and red (long wavelength) in deep environments. The opsin protein of the two species are shifted to the same wavelength of their habitat light components. In addition, inter-species hybridization occurs under the specific light condition, where red and blue lights cannot be distinguished.

Using the information and data, determine which of the statements are true or which are false.

A. The speciation of the two species is considered to have been caused by mating preference of males to females.
B. During evolution, each of the two species is considered to have adapted their visual cues to their habitat light environment.
C. The consistency between the male nuptial colorations and the light components of their habitats are explained by natural selection for camouflage.
D. The sequences of the opsin gene differ between males and females in each species.
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Question reproduced from IBO 2020, Theoretical Exam 1, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)