Question

Part of the research by Sinervo and Lively on side-blotched lizard (Uta stansburiana) dealt with proportions of males of the orange, blue, and yellow morphs in a population of this species. What did they find?

1) Individuals of the large, aggressive orange morph were always most numerous.
2) Individuals of the smaller, vigilant blue morph were always most numerous.
3) Individuals of the female-mimic yellow morph were always most numerous.
4) There was a predictable cycling in frequencies of the three morphs.

Answer 1

The study by Sinervo and Lively on side-blotched lizards found a predictable cycling in the frequencies of the three morphs (orange, blue, yellow), due to varying selection pressures in a rock-paper-scissors competition dynamic for mating.

Step-by-step explanation:

The research by Sinervo and Lively on side-blotched lizard morphs found that there is a predictable cycling in frequencies of the three morphs (orange, blue, and yellow) in the population. This cycle resembles a game of rock-paper-scissors, where orange morph males beat blue, blue morphs beat yellow, and yellow morphs beat orange in the competition for mates.

The orange morphs are larger and more aggressive, thus can outcompete blue morphs for mates. Blue morphs, on the other hand, are able to guard against yellow morphs effectively. The smallest, yellow morphs can mimic females and sneak copulations when orange morphs are preeminent. Each morph is favored under different conditions, encouraging a dynamic frequency shift in the population.