A regular letter contributor to this page recently argued that evolutionary theory is wrong because, among other things, “No one has ever seen or documented macro-evolution such as a dog giving birth to a cat or a reptile to a bird” (Daily News, Feb. 17). I agree with this statement. If we did observe such an event, evolutionary biologists would need to go back to the drawing board. Further, this statement tells us that the writer simply does not understand evolutionary theory and given the long history of similar statements from this individual, we can only assume that willful ignorance is his modus operandi in such matters (including the topic of climate change).

Macroevolution concerns differences that distinguish higher levels of taxonomic division (e.g., genus, family, order, etc.). In the example given by the reader, cats and dogs share a common ancestor from the time that the kingdom Animalia emerged, through the separation of the phylum Chordata from others to the class Mammalia, and to the order Carnivora. But the shared common ancestry for cats and dogs separated at the level of family (Felidae and Canidae, respectively).

Consequently, even in your wildest nightmare, the idea that a dog would beget a cat is completely absurd. In the fullness of time, and given sufficient genetic variation, selection pressure, genetic isolation, etc., a descendent lineage of dogs might come to resemble domestic cats in shape and size, but it would not be a member of Felidae. That boat left the harbor a long time ago.

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