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evolution, frustration

I finished Richard Dawkins' "The Ancestor's Tale" recently. Well worth the read. A few things that are confusing to someone with my background:

  1. Family trees are not trees, because everyone has two parents. (Duh!)
  2. "X and Y are members of the same species" is not a transitive relationship. There are examples of species X0, X1, ..., Xn such that Xi and Xi+1 interbreed for all 0 ≤ i < n, but X0 and Xn do not.

Actually, "species" turns out to be a much more fuzzily-defined term than you'd think. There are species that probably could interbreed, but are considered separate just because they never do. Biologists also insist on putting individuals together in groups even when they never interbreed (because they reproduce asexually). Etc., etc.

I spent entirely too much of the morning trying to tweak my apache2/mod_php configuration to get drupal running again. (I have no idea how it stopped in the first place.) I couldn't find anything wrong except that whenever I asked for in firefox, it tried to give me the source of the php script.

Eventually I figured out what was happening: I'd fixed the problem long ago, and firefox was just caching the wrong result. I don't know how to force firefox to load the new thing in that case.