Darwin was forgetful

Darwin was heavily criticized for not acknowledging some of the work he drew inspiration from that preceded Origin of Species. He was even accused of plagiarism. Well it turns out that he simply forgot to include the preface of his book when he sent it to the publisher.

As a side note, He also forgot to adequately explain the evolution of permanent large breast in humans by sexual selection. I always thought it was selected by man as a predictor of good maternal lactation, but the story is a lot more interesting : "Another false “bigger is better” argument is that which says that a man will find big breasts sexy because he knows that any children he fathers by the breasts’ owner will not go hungry. In fact, the breasts on a nullipara contain mainly fat, not milk-producing tissue. They are almost no indication at all of the amount of milk a woman might produce in the future. Breasts typically increase in size for the first eight months of lactation. Besides, an ability to produce more milk than is needed is no advantage. Once a woman has produced enough to feed her baby well, any excess production is expensive waste. Almost all women can produce enough to feed a child. Milk production increases to meet demand, so a woman bearing twins will produce more (2)."

On a related topic (and author)" check out this guy's explanation of the evolution of fat thighs: "There was a definite cost of a paunch. Paunches are not sexy. The reason a paunch on a woman is not sexy is simple. A woman with a paunch looks pregnant, and pregnant women are in no state to be impregnated by a man, and so men’s instincts will evolve to find big prominent bellies unsexy. In order to avoid appearing pregnant, women evolved to deposit fat stores away from the belly, and the next nearest place was the backside and thighs. Here, the cost of encumbrance was that women could not run quite as fast as otherwise they might, but the benefit of looking more fertile was greater than that cost."