Thank Goodness the NCSE Is Wrong: Fitness Costs Are Important to Evolutionary Microbiology

The evolution of antibiotic resistance is typically the result of small changes allowing for survival in a microbe or other organism under special circumstances where the organism faces extremely strong selection pressure due to the presence of some antibiotic drug. In other cases, it is the result of the transfer of pre-existing antibiotic resistance genes from one microbe to another, and the selection of such microbes in an environment containing antibiotics. Even in the first example, evolution does not produce a truly new function. In fact the change produced often makes the microbe less fit when the antibiotic is removed–it reproduces slower than it did before it was changed. This effect is widely recognized, and is called the fitness cost Read More ›

Testing the Orchard Model and the NCSE’s Claims of “Nested Patterns” Supporting a “Tree of Life”

In my previous post responding to the National Center for Science Education’s (NCSE) attacks on Explore Evolution‘s treatment of biogeography, I explained that there are many examples where there is inconsistency between evolutionary expectations of biogeography and plate tectonics. The NCSE is thus wrong to have claimed that “The consistency of these sorts of nested patterns cannot be explained without reference to common descent. The creationist ‘orchard’ is scientifically meaningless, since it makes no predictions.” * The classical “universal common descent” view is contrasted with the orchard model at below: The NCSE’s claim is perplexing because, as noted, the NCSE also claimed that “continuity [between biogeographic and evolutionary patterns] is what would be expected of a pattern of common descent, Read More ›