Tagged: Charles Darwin

Variation abound!

After four sessions of variation, I think we kinda got the hang of what Darwin is trying to say in Chapter 2. The crux hasn’t differed much from what we had gathered from our first discussion of the chapter. The difference is a tinge of light peeking through the haze of all that confusion. There’s one thing that struck me while I was reading the second chapter for the third or fourth time. Darwin was writing this manuscript at a time when the creationist point of view was dominant. It’s hard for us (ecologists/biologists) to think of something like that right now in this era when we’ve been schooled to think that evolution is the only explanation to life, the universe and everything (ok, I’m exaggerating). But let’s just step back into time and place ourselves in Darwin’s shoes…figuratively speaking. I have no clue what his shoe size was. That’s when you’ll realise why he’s being so cautious in his approach to asking the ultimate questions, “Why should there be so much variability in nature?” and “Why should some genera have more variability than others?” if there was a God/Almighty Creator who just decided to create and populate the Earth. Darwin must have realised it’s not because God just felt like it. There was too much of a pattern that emerged from analysing all his tables (by the way, I have no clue what tables he was talking about) for variation to be attributed to something as random as God creating species. Where there is pattern, there is process. And Darwin very cautiously introduces and speculates on the processes which he thinks are at work that gives rise to those observed patterns.

In this chapter he introduces (very slowly) his ideas on the slow “manufactory of species” that is “still in action”. And the action is through “natural selection accumulating… differences of structure in certain definite directions.” He doesn’t define what natural selection is yet, although he does mention that such action is not only because of the physical environment in which an individual organism resides, but because of other factors such as competition with other individuals. Of course, there’s an entire chapter dedicated to natural selection. I’m sure he goes into great detail there. But before that he’ll be dealing with another of his musings…about the Struggle for Existence. That’s chapter 3, and, thankfully, a very straight-forward one. Looking forward to discussing that one this Wednesday, February 20th, 5:30pm.

PS: There were some points that we were still not clear about while discussing this chapter. I’ll list those out here so that we can continue the discussion online:

1. Viraj had asked if natural selection is something that would act on a population or an individual. Navendu and I thought that it would act on individual traits, but Viraj and Vijay thought it would most likely act on a population. Now, considering that a population is a group of individuals, what do you think?

2. A trivial point, but Navendu and I were very confused on a distinction that Darwin had made with the distribution of a species, because he had used “wide-ranging” and “diffused” to mean two very different things. Well, at least he explicitly said so. So to help us out with that you’ll have to read the chapter. Good luck with that.

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Origin of domestic races

Charles_Darwin_by_G._Richmond 1830's

Charles Darwin in 1830’s after the expedition by G. Richmond

Year 1831. 27th December. H.M.S. Beagle set on an epic expedition to survey Patagonia and other parts of the Neotropical coast. The captain of the ship, Fitzroy, would have never even dreamt that the journey is going to rewrite the history of life on Earth. Nor would he have realized that a young guy, who shared a cabin with him, will be the reason behind this. No marks for guessing who it was: Mr. Charles Darwin, my second hero (had given the first place to Mr. Wallace a long while ago!). The idea that of the origin of species, has its origin traced back to his five-year long journey (Are you listening?! Bloody five years, braving the odds of sea and uncharted landscapes. Imagine five long years of field work for your PhD. I wouldn’t have seen the end). That spark generated in him, generated a fire that burnt in him for almost twenty long years before culminating in a book, “the book” that shook the world. That’s 24 years after that expedition. In Darwin’s view an abstract. Hmm…what took him so long? More than that, what is that he wrote demands an understanding among students like us, separated in time by almost 150 years. Thanks to our ESS secretaries for deciding to explore this. The first meeting happened last Thursday. Target: The Introduction and Chapter 1.

I can summarise Darwin’s introduction based on three aspects.

  1. Darwin’s emphasis on the role of biogeography towards his insights,
  2. The controversy behind Wallace and Darwin and
  3. Influence of “vestiges of creation” on him.
200px-Charles_Darwin_aged_51 Maull and Fox 1859

Charles Darwin during the publication of Origin of species by Maull and Fox 1859

 As a student of biogeography, the first statement from Darwin’s Origin that remained etched in my mindscape is this one by him in the opening paragraph:

When on board H.M.S. ‘Beagle,’ as naturalist, I was much struck with certain facts in the distribution of the inhabitants of South America, and in the geological relations of the present to the past inhabitants of that continent. These facts seemed to me to throw some light on the origin of species—that mystery of mysteries.” Darwin, 1859.

It was astronomer Sir John Herschel, in a letter to Charles Lyell in 1836, who had referred to the origin of species as the “mystery of mysteries” (Costa, 2009).

The controversy behind Wallace’s influence on Darwin seems to have been resolved (watch the appended video). In the introduction, Darwin explicitly acknowledges that he was “induced” to write by Wallace’s research paper send to him from Malay archipelago.

The third thing that Darwin mentions is this work by Robert Chamber “vestiges of creation”. Costa (2009) explains Chambers view as saltational vs. gradualism as espoused by Darwin. Chapter one was his attempt to prove this point and provide an exhaustive evidence for variation under domestication.

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Domesticated?

We, a bunch of nine, discussed for an hour on this chapter. Borrowing from Darwin, I would like to call this chapter the “Origin of domestic races”.

Darwin goes to stunning details on variation under domestication borrowing examples from plants to pigeons. Why take so much pain? It was his attempt to get across the message that domestic races share a genealogical relationship, an end product of human mediated accumulative selection that is artificial selection (Costa 2009). To cite Reznick (2010) “This opening chapter presents the raw material that Darwin needs for his subsequent arguments about natural selection to work. The changeability of organisms under artificial selection proves that the availability of heritable variation and amount of change that is possible are easily sufficient to account for the diversity of living things that are present in the world today, given the age of the earth and the vast amount of time that has been available for natural selection to act.

One last point, keep at the back of your mind the distinction between natural selection and speciation. Researchers including Ernst Mayr and recently, Jerry Coyne have argued that Darwin’s origin of species doesn’t quite address the issue of speciation. Let’s deduce it for ourself first hand if that’s the case!

Rupees 1,27,41831.28 check

Rupees 1,27,41831.28 check

Meet you all next Wednesday 5:30 pm Friday 5.45 pm in either the Lotka Volterra lab or the Class room. I will post all the soft copies of references to ESS. Pick it up from them.

References:

  1. Charles Darwin, 1859, On the origin of species by means of natural selection or the preservation of the favoured races in the struggle for life. John Murray.
  2. James T. Costa, 2009, The Annotated Origin. Facsimile of the first edition on the origin of species.
  3. David N. Reznick, 2010, “The “Origin” Then and Now: An Interpretive Guide to the “Origin of Species”, Princeton University.

On the origin of the book reading group

We had a pretty good turnout for the first meeting where we discussed how to go about reading On the origin of species. We are starting off next week, Thursday (24th Jan), at 5.30 pm in Lotka-Voltera lab the class room.

We will start by discussing the first chapter – Variation under domestication. Mahesh Ramadoss (not from CES) would be leading the discussion to make sure we don’t miss out on any important topics. The person leading could shortlist possible topics of discussions to keep the discussion going. But everyone is expected to read the chapter and contribute in the discussion.

As of now we are not sticking to any particular edition, but it would be nice to know how your edition is different from the others. It would be great if someone takes up the effort to write about the discussion and summing up the chapter on the ESS webpage after every session. We could rotate and take turns on this as well.

You can look for the edition of your interest here.

Book Reading Group

When in class 9, there was a book fair in Bagalkot, my home town. Although any fair was new and exciting to us, a book fair wasn’t exactly celebrated. On visiting it with a few of my friends, the only familiar author I found there was Darwin. I knew I had heard that name somewhere in my biology class.

Since then, I have made several failed attempts to read On the Origin of Species and have not gone past some of the paragraph long sentences without feeling like a moron. On discussing this with a few people at CES we realised that a lot of people have gone through this exercise of attempting to read the book. So how about starting a book reading group where we can discuss On the Origin of Species chapter by chapter? We could take some ideas from here.

If this works well we could discuss other interesting books. So please do comment on

  • the idea (whether it would last till we reach the end of the book)
  • ways in which we could discuss the chapters
  • Probably we could also post excerpts from each session on the blog

If you are interested to join the book reading group, please leave your mail id here or mail us at ess@ces.iisc.ernet.in  so that we can let you know when we plan to meet.

That’s All! (à la Annette Hanshaw)