Wednesday 30 November 2016

Speciation Observed in a Laboratory

Ecological speciation of bacteriophage lambda in allopatry and sympatry | Science

Two central article of faith in creationist circles are that speciation has never been observed and that evolution can't be replicated in a laboratory.

So essential are these dogmas to creationism that nothing will shake their faith in them, not even the evidence of evolution being replicated in a laboratory and speciation being observed in the process. You can rarely make any progress with a creationist without these 'killer' assertions being thrown into the debate. They are almost the motto or battle-cry of creationism. So we can be sure the best available dismissal techniques will be brought to bear on the paper published in Nature a few days ago showing exactly that.

That's right, creationists, scientists have observed evolution, including speciation, in the laboratory. And their experiment is reproducible.

The team who did this was from the University of California San Diego and Michigan State University.

Understanding the conditions that allow speciation to occur is difficult because most research has focused on either long-lived organisms or asexual microorganisms. We propagated bacteriophage λ, a virus with rapid generations and frequent recombination, on two Escherichia coli host genotypes that expressed either the LamB or OmpF receptor. When supplied with either single host (allopatry), λ improved its binding to the available receptor while losing its ability to use the alternative. When evolving on both hosts together (sympatry), the viruses split into two lineages with divergent receptor preferences. Although the level of divergence varied among replicates, some lineages evolved reproductive isolation via genetic incompatibilities. This outcome indicates that, under suitable conditions, allopatric and sympatric speciation can occur with similar ease.

With these experiments, no one can doubt whether speciation occurs. More importantly, we now have an experimental system to test many previously untestable ideas about the process...

The virus we started the experiment with, the one with the nondiscriminatory appetite, went extinct. During the process of speciation, it was replaced by its more evolved descendants with a more refined palette.

Justin R. Meyer,
assistant professor of biology at UC San Diego.
Lead author. Quoted in ScienceDaily
The experiment was elegantly simple. A phage virus, which normally replicates by entering an E. coli bacterium, can only gain entry by locking on two receptor molecules on the cell surface. By varying these receptor molecules the researchers were able to supply the virus with a medium containing a choice of two different populations of E. coli. Initially, the virus was indiscriminate but the population quickly diversified into two specialist types, each of which could only infect its own E. coli variant. Meanwhile, the 'primitive' non-discriminatory virus went extinct. The virus had quickly speciated, eve becoming genetically isolated.

In short, the founder population of viruses was not only observed to evolve to utilise the new opportunities but it was also seen to speciate into two genetically distinct populations or species. The only surprise was that it occurred so quickly.

Even though we set out to study speciation in the lab, I was surprised it happened so fast, yet the deeper Justin [Meyer] dug into things -- from how the viruses infected different hosts to their DNA sequences -- the stronger the evidence became that we really were seeing the early stages of speciation.

Richard Lenski,
professor of microbial ecology at Michigan State University,
Co-author. Quoted in ScienceDaily
The same series of experiments also demonstrated the two major types of evolution - sympatric and allopatric evolution. When the primitive form of the virus was supplied with only one E. coli variant (allopatry) it quickly evolved to specialise in that receptor and the primitive form became extinct. When supplied with both variants simultaneously (sympatry) diversification and speciation occurred as described above.

So now, whenever someone like Ken Ham, Kent Hovind, Ray Comfort or one of the many other frauds making money by telling the lies they think you want to hear, tell you that speciation has never been observed or that evolution can't be replicated in a laboratory, you know they are lying to you. Whenever you tell someone this piece of false creationist dogma, you know you are lying to them and, if they have any interest in the subject, there is a good chance they will know you are lying to them.

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