I know not everyone reads the comments on blogs, so I'm repeating here something I added in response to a question after the last posting.
The quote 'I care more about Drosera than the origin of all the species' does need a little context... It was a temporary state of mind. Darwin was trying to finish a paper on insect-eating plants, so at that time Drosera was indeed more important to him than all the other big questions in the world.
The quote is from a letter to Charles Lyell (24 November 1860). It's worth quoting a bit more of the letter because it shows that even after publishing The Origin of Species, Darwin continued to be astonished, and shocked, by what he discovered about life on earth.
He says to Lyell:
"But I will & must finish my Drosera M.S. which will take me a week, for at this present moment I care more about Drosera than the origin of all the species in the world. But I will not publish on Drosera till next year, for I am frightened & astounded at my results.
I declare it is a certain fact, that one organ is so sensitive to touch that a weight of 1/78,000 of a grain (ie seventy-eight times less weight than that, viz 1⁄1000 of a grain, which will move the best chemical balance) suffices to cause conspicuous movement.
Is it not curious that a plant shd be far more sensitive to a touch than any nerve in the human body! Yet I am perfectly sure that this is true.
When I am on my hobby-horse, I never can resist telling my friends, how well my hobby goes, so you must forgive the rider."
If you have an interest in Darwin's correspondence see the wonderful Darwin Project website - it's where I found the quote.