Let’s Learn About Evolution!

Looks like from now through the 2016 elections, the default question for idiot reporters who want to want to play “Gotcha!” with Republican candidates is going to be something like, “Blah blah blah EVOLUTION! Huh?! What do you say about that, huh?!?!”

Never mind that most reporters couldn’t define the word “evolution” if you put a gun to their heads. Those who would find themselves on the business end of those questions (Maybe you, dear reader, are thinking about running for president. Have you seen the current crop of candidates? You couldn’t help but be an improvement.) would do well to know more about the subject than the questioner. It won’t be hard. Just review a few paragraphs on the meaning of evolution helpfully provided by our friend Justin Taylor. For instance:

1. Evolution as Change Over Time

Nature has a history; it is not static. Natural sciences deal with evolution in its first sense—change over time in the natural world—when they seek to reconstruct series of past events to tell the story of nature’s history. Astronomers study the life cycles of stars; geologists ponder the changes in the earth’s surface; paleontologists note changes in the types of life that have existed over time, as represented in the sedimentary rock record (fossil succession); biologists note ecological succession within recorded human history, which may have, for example, transformed a barren island into a mature forested island community. Although the last example has little to do with neoDarwinian evolutionary theory, it still fits within the first general sense of evolution as natural historical progression or sequence of events.

2. Evolution as Gene Frequency Change

Population geneticists study changes in the frequencies of alleles in gene pools. This very specific sense of evolution, though not without theoretical significance, is closely tied to a large collection of precise observations. The melanism studies of peppered moths, though currently contested, are among the most celebrated examples of such studies in microevolution. For the geneticist, gene frequency change is “evolution in action.”

3. Evolution as Limited Common Descent

Virtually all scientists (even many creationists) would agree that Darwin’s dozen or more famed Galapagos Island finch species are probably descended from a single continental South American finch species. Although such “evolution” did not occur during the brief time scale of the lives of scientists since Darwin (as in the case of the peppered moth), the pattern of biogeographical distribution of these birds strongly suggests to most scientists that all of these birds share a common ancestor. Evolution defined as “limited common descent” designates the scientifically uncontroversial idea that many different varieties of similar organisms within different species, genera, or even families are related by common ancestry. Note that it is possible for some scientists to accept evolution when defined in this sense without necessarily accepting evolution defined as universal common descent— that is, the idea that all organisms are related by common ancestry.

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