Friday, May 23, 2014

Is Evolution Predictable?

Source: news report 5/15/14

This report highlights something that anti-evolutionists need to recognize: scientists no longer debate whether evolution happens or not; they instead are interested in how evolution works.  Furthermore, the science has developed to the point where experiments can shed light on whether or not evolution is predictable.  The report describes research into the mechanism of evolution using an insect that evolved to resemble a leaf on a plant. 
So Patrik Nosil, an evolutionary biologist at the University of Sheffield in the United Kingdom, turned to a stick insect called Timema cristinae. In many places in California, this species has split into two forms, or ecotypes, on a hillside. One form is wide and lives on a wide-leaf plant; the other is narrow, with a stripe down its back, and lives on a plant with narrow leaves. Nosil and his colleagues sequenced the genomes of dozens of individuals of each ecotype from multiple hillsides to assess the genetic differences that arose to make them specialized for their particular host plant.
The report goes on to describe the following experiment:
Nosil’s team transplanted hundreds of individual stick insects onto the plant they weren’t adapted to and collected the offspring a year later. They checked the offspring’s DNA to see how the frequency of different versions of their genes shifted compared with those frequencies in the parents. Such shifts represent places where one version provides a better survival advantage than another, enabling the insects with that version to reproduce. Dozens of those shifts coincided with the DNA differences between the ecotypes, signaling that those differences were due to selection, not chance.
Experiments such as this are common in biology today.  They contradict the commonly repeated assertion by anti-evolutionists that evolution cannot be tested.  In fact, thousands of experiments have been conducted which, like this one, show the process of evolution in experiments.  The ability to sequence DNA adds another layer to the understanding of evolution, since the DNA is the physical link that makes evolution possible. 


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