Question

A butterfly collector is studying a species of butterfly that has expanded its range into a new area over the last thirty years. The butterflies in the new area feed on a species of flower that has a deeper throat than the flowers exploited by the butterfly species in its original range. The average length of the proboscis that is used to suck nectar from flowers is also greater in butterflies that inhabit the new area.

The collector hypothesizes that individual butterflies that moved into the area and exploited the flower in the new area grew longer proboscises during their lifetimes in order to reach the nectar. The gene for the longer proboscis was then inherited by the offspring of these individuals until the entire population consisted of butterflies with longer proboscises than butterflies in the original population.

Helpful Hints: The researcher’s hypothesis is invalid according to accepted evolutionary theory.

Using your knowledge of evolutionary theory:

• discuss why the researcher's explanation for the increase in average proboscis length in butterflies inhabiting the new area is invalid; and

• provide an alternative explanation that is consistent with accepted evolutionary theory for the change in proboscis length in butterflies inhabiting the new area.

(YOU ARE LIMITED TO 150-300 WORDS)

Answer 1

Although Darwin’s theory of natural selection and sexual selection is still valid, the field of psychology has adopted and formed the evolutionary theory as follows. Evolutionary process is not only physical but also psychological involving the brain which constantly adapts to new situations by providing solutions to survive and reproduce. I would also like to point out Darwin’s ‘survival of the fittest theory’, where the one that adapts to the new environment survives. Evolutionary theory also suggests that the physical genetic make-up takes many successive generations.

Based on this theory, the genetic make-up must not have happened in a single generation but the psychological adaptation which suggests that the butterfly found a new way to suck the nectar, probably the way it sits on the flower, probably it tore the flower a bit. So, this basic instinct for survival has made it find another way to suck the nectar in.

So the alternative hypothesis would be that Butterflies that inhabited the new area extend their proboscis as much as possible to get to the nectar.