Sunday, March 15, 2009

Blogging the Origin

Darwin 200 / by Edit Staff / January 28, 2009

Charles Darwin's On the Origin of Species, chapter by chapter

John Whitfield has a confession. As an evolutionary biologist and science writer, he has frequently documented the role that evolutionary principles play in biology, literary criticism, language, and antiterror policy, but — 

like so many today who study and write about evolution — he had never actually read the landmark work that started it all: Darwin’s On the Origin of Species.

“It’s possible to have a professional relationship with evolution while remaining ignorant of its foundations,” Whitfield says. Because Darwin lacked the specialist knowledge of genetics and mathematical analysis that dominates the study of evolution today, many of his techniques are of little use to modern biologists.

So Seed set Whitfield to the task of parsing The Origin’s introduction and 14 chapters, examining them from the perspective of a 21st-century evolutionary biologist and blogging the experience.

Should The Origin be filed away as just another yellow-paged Victorian artifact, or do Darwin’s ideas still stand up in light of what genetics, ecology, and paleontology have taught us about evolution? Whitfield spent the past month teasing out this question. The result is an edifying and often amusing analysis of one of the most influential scientific works of our time. Read along.

Coming Out
“Let’s use part of our brains to try and ignore all that we now know about Darwin’s biography and legacy, pretend that this is our first encounter with his theory, and that evolution must stand or fall on the quality of the science and writing in The Origin.

“[T]he route into his theory begins, not with something obviously ‘extreme,’ like an elephant or a giant squid, but a bird that you would be pretty much guaranteed to see on a stroll in the woods around Down House.”

Chapter 1: Variation Under Domestication
“If it was down to you to invent biology, where would you begin? Darwin takes the time-honoured path of sacrificing realism for tractability, and studies a simplified and controlled version of nature: farming. He recognized that animal breeders were the biotechnologists of his day, and possessed the nearest thing to a body of experimental biological knowledge.”

Chapter 2: Variation Under Nature
“I felt like I’d gone from 1859 to 1959 in the turn of a page. Besides staking out the ground for population genetics, Darwin, in half-a-dozen dense pages at the end of the chapter, outlines many of the patterns in the diversity, abundance, and distribution of living things that ecologists are still trying to understand.”

Chapter 3: Struggle for Existence
“If I were running an undergraduate ecology course (which, for everyone’s sake, we can be glad that I am not), I would make this chapter the first thing on the reading list. It’s a capsule textbook, and about twenty-eight times more exciting than any of the required reading I encountered as a student.”

Chapter 4: Natural Selection
“Mathematicians and physicists speak of a result ‘falling out of the equations,’ implying that if you set things up properly, the rest takes care of itself. Chapter 4 of The Origin, ‘Natural Selection,’ is where evolution falls out of the machinery that Darwin has spent the three previous chapters assembling.”

Chapter 5: Laws of Variation
“To a man with a hammer, said Mark Twain, everything looks like a nail. The better your hammer, I would add, the more nail-like everything looks. In natural selection, Darwin had crafted one of the best hammers of all time. And in chapter 5 of The Origin, ‘Laws of Variation’,,’ you can hear him umming and aahing about various alternative mechanisms of evolutionary change before deciding that, actually, you know what this needs…hold ‘er steady…Thwack!”

Chapter 6: Difficulties with Theory
“Up until now, our route into the theory of evolution by natural selection has been all downhill. One thing has led effortlessly to another, with Darwin giving the occasional nudge to steer things in the right direction. Not any more.”

Chapter 7: Instinct
“If, like Darwin, you didn’t know about genetics, and thought that inheritance was a process of blending, it’s difficult to see how you could have made any more progress along this line of thought than he does here.”

Chapter 8: Hybridism
“What I think Darwin is doing in this chapter — and in other parts of the book where he seems to get bogged down in data, such as the second half of chapter 5 — is testing the limits of generalization in his science.”

Chapter 9: On the Imperfection of the Geological Record
“‘Paradigm’ is an overused word, but it’s a measure of the paradigm-shifting nature of The Origin that in much of it, such as in chapter 9 ‘On the imperfection of the geological record’, Darwin flies blind.”

Chapter 10: On the Geological Succession of Organic Beings
“Whether palaeontology gives Darwin quite as much support as he thought is an open question. The fact that many organisms remain recognizable across massive stretches of geological time suggests that stabilizing, or purifying, selection is also an important force, selecting against the extremes.”

Chapter 11: Geographical Distribution
“In the way it brings together Darwin the explorer and observer, Darwin the experimenter and Darwin the theorist, this chapter contains some of the most thoroughly convincing parts of the entire book.”

Chapter 12: Geographical Distribution, continued
“It’s been said that all European philosophy is a series of footnotes to Plato. Well, all ecology is a series of footnotes to Darwin.”

Chapter 13: Mutual Affinities of Organic Beings: Morphology: Embryology: Rudimentary Organs
“In [chapter 13], Darwin tackles the science of classification — perhaps more than in any other part of the book, I sensed that he was addressing his fellow pros (or gentlemen amateurs).”

Chapter 14: Recapitulation and Conclusion
“This relentless piling, sorting and re-arranging of evidence can make Darwin seem a little OCD, like an intellectual version of Wall-E. But he also knows that beneath all the case studies, there’s a logical core to evolution by natural selection, even if he can’t put it in an equation.”

“Biology doesn’t erase its past. It just forgets to cite it. The Origin is biology’s hub — all the routes that the science has taken since seem to pass through it.”

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