Mad rantings about politics, evolution, and microbiology. Comment policy: say what you want, but back it up with an email address. I don't like anonymous trolls.
ScienceBlogling Mike Dunford reminds us that Michael Egnor's creationist stupidity, like Camus' plague, never disappears, but only wanes. Egnor has unleashed his formidable stupidity on the concepts of artificial and natural selection.
So many fucking morons, so little Mad Biologist. Fortunately, I've written about this before:
The difference between artificial selection and natural selection isn't that the selective agent (e.g., pesticides) is a result of human activity. The difference is in what determines what is the 'fittest': a person's decision as to what traits are preferable, or differential survival and reproduction. Artificial selection occurs when organisms with a certain trait or traits, such as looking like a Pomeranian, are chosen and allowed to survive and to reproduce. The 'fitness criterion' involved isn't survival and reproduction: it's the judgement of the human running the experiment that defines what is the most fit (I don't think Pomeranians in the wild would be very fit, but rather, a yummy snack for some nasty carnivore).
In the case that Egnor discusses, the researchers exposed bacteria to antibiotics; however, they did not select which types of mutations would allowed to propagate. There are all sorts of mutations that can give rise to resistance (e.g., over-expression of gene products, production of mucus, up-regulation of efflux pumps). The selective regime used was not specifically designed to enrich (select) mutants with an enzyme with increased stability, so this is an example of natural, not artificial, selection. Whether or not humans are involved has nothing to do with the type of selection, it has to do with the selection criterion.
Of course, in the midst of all of this, it's worth keeping in mind that the larger creationist strategy is to highlight any work that does not explicitly discuss evolution, and thereby proclaim TEH DARWINISMZ ARE DOOOMMED!!
Politics
Life Science
Comments
"I smell dead people."
Hj
Posted by: Bing McGhandi | March 10, 2008 2:13 PM
Posted by: brtkrbzhnv | March 10, 2008 2:28 PM
To expand and clarify brtkrbzhnv's comment, the difference lies in the role of an "end in view" in the processes of selection. In cases of natural selection, there is no end in view; i.e. selection is not directed toward any goal. In the case of artificial selection, the process is obviously goal directed. To use traditional terminology, artificial selection is teleological, while natural selection is not.
Posted by: bob koepp | March 10, 2008 6:32 PM
brtkrbzhnv,
Stop nitpicking. It was clear what I meant. In artificial selection, we often choose traits that if, having the best differential survival and reproduction in the absence of human decision, would be less fit.
Posted by: Mike the Mad Biologist | March 15, 2008 12:31 PM
Looks like we have a lot of Mikes here: Mike the Mad Biologist, Mike Dunford, and Michael Egnor. So I'll just call you the "Mad Biologist."
Mad Biologist:
IMO name-calling is uncalled-for.
Michael Egnor has a new article on Evolution News & Views, and I disagree with many of his statements:
http://www.evolutionnews.org/2008/03/mr_dunfords_knot.html#more
IMO Egnor's article has a lot of specious reasoning that is based just on his definitions of terms (definitions that I disagree with).
My definition of "artificial selection" is close to yours, a big difference being the ways in which we use the word "fitness." To me, "artificial selection" is selective breeding, where humans handpick animals and plants for breeding, e.g., the breeding of short-legged sheep because of their poor ability to jump fences. This poor ability to jump fences is "fitter" for human purposes but is not necessarily "fitter" (or "less fit") for the sheep. And sheep that can jump high fences are not necessarily "fitter" -- they could be more exposed to predators if they jump the fences.
Also, the term "natural selection" could falsely imply that the entire evolutionary process is natural, but the evolutionary process could include artificial elements that cannot occur in nature, e.g., man-made pesticides, non-native species that can only be introduced by humans, synthetic and semi-synthetic antibiotics, and mutations induced by massive doses of radiation. Maybe there should be a term called "pseudo-natural selection," "quasi-natural selection," or "semi-natural selection" to describe situations where the environment selects the organisms that propagate but the situation is one that cannot occur in nature.
IMO we should be somewhat flexible in the ways that we define and use terms.
I don't get the point of your picture.
Posted by: Larry Fafarman | March 23, 2008 5:31 PM