It is the replicating gene (not the species) which is 'selfish,’ and whose 'job’ is to duplicate itself. A mutated gene is just as 'selfish’ as the gene from which it mutated. Keep in mind, that most species go extinct and most mutations are thought to be neutral with regards to fitness with fitness defined as the average reproductive output of a class of genetic variants in a gene pool.

The process of evolution can be summarized in three sentences: Genes mutate. [gene: a hereditary unit] Individuals are selected. Populations evolve. In the decades-long Lenski experiment, individual bacteria were naturally selected because they flourished in their citrate-rich culture environment due to genetic mutation thus giving rise to an evolved population that were fit in the sense that their average (asexual in the case of bacteria) reproductive output of a class of genetic variants in a gene pool increased. Therefore, Lenski demonstrated evolution clearly and thrillingly in his laboratory research.

Though it is my understanding that Lenski’s evolved population of E. coli bacteria is a variant of the species, and not a new species, even if this particular evolution resulted in a different species, those species would share genes (so those selfish genes still are duplicating!) just as humans share genes with many other species (both plant and animal) with whom we can’t interbreed.

NOTE: Italicized quotes are taken from here

Posted: January 17th 2009

See all questions answered by logicel

For those who came in late, here’s the background. Professor Lenski’s team bred E.coli bacteria for years, separating populations and observing every significant mutation. One set of bacteria developed the ability to metabolise (eat) citrate in addition to glucose, making better use of its surroundings and directly contradicting the creationist claim that there are no beneficial mutations. It’s evolution in action.

They’re still bacteria, though whether they’re still true E.coli might be debatable.

Bacteria reproduce through asexual division, not sex. They can never interbreed. The mutation didn’t rob them of the ability.

Say the subjects were sea monkeys (brine shrimp), not bacteria, and the mutation had robbed groups of the ability to interbreed. (This usually takes many mutations over many generations, not just one.) The mutated monkeys could still breed within their own group, as could the unmutated monkeys, so no one is prevented from breeding.

The mutated creatures would be a new species of sea monkey, so the propagation of the original species is not affected except that it now has competition. If the citrate-eaters outbred the citrate-haters and become a majority, the propagation of the population as a whole would certainly benefit; it would have a brand new food source.

Posted: January 17th 2009

See all questions answered by SmartLX

You may have it slightly back-to-front here: the ability to interbreed is a major factor in deciding whether two organisms are the same species, though not the only one. So, it could be argued that you now have two species in the same genus.

I would not say that such a “fork” is inherently advantageous or disadvantageous, but that it depends on circumstances. For example, are they competing for resources? Maybe each species eventually evolves to fit a slightly different ecological niche. These kinds of questions and observations are what made Darwin’s trip to the Galapogos so valuable in the development of evolutionary theory.

I read that there has been a clumsy creationist attempt to discredt Lenski and his work – using such methods as accusing him of withholding information, when he had already published it in a peer-reviewed journal and for free on his website.

Posted: January 17th 2009

See all questions answered by brian thomson