Origin Ch.1: Just So 1

This post is part of a series on The Origin Of Species.  It was originally posted on the old blog in feb 2009, during the Darwin 200 celebrations.

In Chapter one of the Origin, Darwin discusses inheritance and variation. It’s an interesting choice for a starting point, because as everyone knows, while Darwin could win Mastermind with a specialist topic of variation, he knew next to nothing about how inheritance works, and that which he did know was almost entirely wrong. Every important discovery about inheritance — its particulate nature, the segregation of the germ-line from the somatic line, chromosomes, DNA, meiosis, and the rest — were after Darwin’s time. So Darwin made do with some speculative hypotheses which turned out to be embarrassingly wrong, such as Lamarck’s idea that characteristics acquired by effort during one’s lifetime could be passed on to offspring.

In blogging this chapter though, I don’t want to just repeat an effort that has already been done, and better. If you want to read more about these issues, go over to Blogging the Origin. What I noted was one particular thing that Darwin says in this chapter:

Not one of our domestic animals can be named which has not in some country drooping ears; and the view which has been suggested that the drooping is due to the disuse of the muscles of the ear, from the animals being seldom much alarmed, seems probable.

Hey, look! It’s Darwin telling an evolutionary “just-so story”! A Lamarckian just-so story no less. Darwin is repeating a hypothesis designed to explain the origin of a characteristic based on no evidence but mere thinking about the trait and the processes believed to have produced it. It’s pure speculation, but the result is attractive, and so Darwin ignores its weak foundation to give it a glowing endorsement.

This is exactly the sort of story that these days is so dearly loved by popular media, and so vehemently hated by biologists. The sort of story that it is rarely possible even to put to the test, but which the Daily Telegraph will report as fact: “scientists said, today, …”.

I guess making up just-so stories is just too damn fun. I bet they’re every biologist’s guilty secret hobby, really.