Question

6. In a hypothetical species of butterfly, wing spots are controlled by a single locus where BB individuals have blue spots, YY individuals have yellow spots, and BY individuals have green spots. Ten years ago, a previous collector randomly collected 1000 butterflies and reported finding 90 blues, 420 greens, and 490 yellows. You collect 40 blues, 320 greens, and 640 yellows. Has there been evolution in this population? If yes, is natural selection involved? Explain and justify your answers.

Answer 1

As the proportion of Blue, Green and Yellow winged butterflies with respect to each other has changed, there is a chance of evolution coming into picture. Contrary to normal belief, recent research shows that evolution can happen even in a time period smaller than 10 years. However, If natural selection had been involved, assuming green to be the dominant colour in the environment of the butterflies, green winged butterflies should have been dominant in the population, but that isn't the case. Thus, natural selection might not be a reason behind it. Stonger linkage of the yellow-colouring genes can be one of the reasons.