Variation

“TIME OUT!!!”

No, this isn’t a basketball game we were attending, but rather a desperate attempt by a clueless group discussion leader to bring a house to order. Little short of a parliamentary session, if you’d like an Indian analogy.

There was much variation in opinion within the group Friday last when we were discussing the second chapter of “The Origin of Species”, the larger group slowly diversifying into sub-groups and sub-sub-groups, with much confused looks on faces. Let me try and explain some of this confusion..

The second chapter “Variation under Nature” is where Darwin uses the classification of life (the Linnaean classification system) as

Darwin’s Shells Image from http://www.guardian.co.uk

a means to describe his theory of the origin of species, in a very brief way. The presence of “varieties” within a group of organisms was the baseline for the origin of “a new and distinct species” by “Divergence of Character”, was Darwin’s argument. Now here was where the confusion began… what did he mean by a “variety”?

In chapter one Darwin uses the terms “species” and “variety” without defining the terms (yes, I know, we researchers are hung up on definitions) leaving a lot of room for assumption. In the second chapter, he goes into great detail on the distinction between species and variety, and tries his best in defining what he means by a variety. I say tries his best because we were still confused even after all that discussion around the subject,  leading to confusion number one. The confusion wasn’t limited to us though.. Darwin also surmises that taxonomists (of his day) are a confused bunch over the topic, not being able to decide how much of a difference is necessary to distinguish variety from a species. However, he does mention his own definition of a variety as a form the characteristics of which “…. can be inherited for at least some few generations.“. This is an important point that he brings forth in the discussion, that of inheritance, which is, of course, a repeated theme in the book, but gets first mention here. It also got us thinking about whether he was alluding to epigenetics, and if he meant that forms otherwise just exhibited phenotypic plasticity. That got us arguing for at least a half-hour. We were just in the first para, by the way.

chapter2 2nd

Variety

On to confusion number two, and a jump to the concluding para of the chapter (as you can see, we were an organised bunch). Darwin talks about genera, how large genera have the most variation, and “larger genera thus tend to become larger”. But then he also says that “larger genera also tend to break up into smaller genera”. Now, pray tell, if this does happen, how do the large genera remain large?!

The gist of the chapter seemed to clear, but his justifications need more reading into, perhaps. We’ll be continuing with the confusions, sorry, discussion, this Wednesday, the 6th of February at 5.30 pm in the Tea Room. Do join us to add to the confusion. 🙂

Chapter 3 will be discussed most probably, on Wednesday next week on February 20th.

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2 comments

  1. Aparna Lajmi

    Hey Nandita, it was good fun reading your blog. Though the discussion was pretty intense I seem to have forgotten what my stand was. Darn. Have to read it again.

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