PURPLE BUTTERFLIES EVOLVED BY SCIENTISTS,
according to Biology News Net 5 August 2014 and PNAS doi:
10.1073/pnas.1402770111. Scientists at Yale university have “produced the first
structural colour change in an animal by influencing evolution”. Biology News
Net quotes Antónia Monteiro, one of the researchers, described the experiment:
“What we did was to imagine a new target colour for the wings of a butterfly,
without any knowledge of whether this colour was achievable, and selected for it
gradually using populations of live butterflies”. In the PNAS summary the
research team described their experiment: “We used artificial selection on a
laboratory model butterfly, B. anynana, to evolve violet scales from UV
brown scales and compared the mechanism of violet colour production with that of
two other Bicyclus species, Bicyclus sambulos and Bicyclus
medontias, which have evolved violet/blue scales independently via natural
selection”. The colour of these butterfly wings is produced by reflected light
from the scales on their wings, rather than from pigment. The purple colour is
produced by the scales reflecting light at a wavelength of 400nm. Starting with
brown butterflies, the scientists chose butterflies whose scales reflected light
closest to 400nm and bred them together, repeating the process for successive
generations until they got butterflies with a purple stripe on their wings. The
scientists examined the scales of the newly bred purple butterflies and found
the purple coloured regions had thicker scales than the original brown
butterflies. They also examined the scales of a closely related butterfly
species that was naturally purple, and found they also had thicker scales than
brown ones. The research team concluded: “This work shows that populations
harbour large amounts of standing genetic variation that can lead to rapid
evolution of scales’ structural colour via slight modifications to the scales’
physical dimensions”. Link:
Biology
News Net, PNAS
ED.
COM. In spite of the boastful statement quoted by Biology News Net which
included the word ‘evolution’ and implying the scientists got something
completely new to evolve, their conclusion in the PNAS article is an admission
that they did not produce anything new. Furthermore, in spite of the claim they
were able to “to evolve violet scales from UV brown scales” the process had
nothing to do with evolution. What they actually did was select from the
variation already present until they got what they wanted and which was a result
they already knew was a possibility because closely related species of this
butterfly already had purple coloured scales. This experiment is a good reminder
that selection, whether artificial or natural, is a real process in biology, but
it never produces the evolution of one kind of creature into another. Different
coloured butterflies with different thicknesses of scales on their wings already
existed before anyone did this experiment. Selection simply brought out the
built-in variation that already existed within this kind of butterfly – exactly
what you would expect to get if they were created as fully functioning creatures
according to their kinds, just as Genesis says. Don’t forget these experiments
also show nothing about how light reflecting scales came into being in the first
place. (Ref. Lepidoptera, structural colour)
Creation Research.
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