Wednesday 26 November 2014

Taxing Taxonomy and Confusing Cladistics

Home Base

I was having a fascinating conversation with a group of entomologists on facebook the other day about termites. During the conversation a young gentleman named Agal mentioned that he was totally confused about the orders of insects. He is not alone, with the advent of DNA analysis and genome sequencing we’re beginning to realise that the natural world is even more complex than we thought. I heard one scientist lamenting that he wasn’t even sure what a species was anymore. So I though it time we had one of our little chats in the courtyard with a glass in one hand and a plate of nibbles in the other and have a little look at the world of the taxonomist.

Rosa canina A Rose by any other name?
A quick intro: Back in the old days scientists used Latin to describe the things they saw such as this Rock Rose with great, unwieldy descriptions such as Rosa sylvestris alba cum rubore, folio glabro meaning a whitish red wild rose with shiny leaves.  The trouble was, no two scientists described things the same way so there was a mass of information that couldn’t be organized. To try and get some sense into all this  a Swiss botanist named Gaspard Bauhin tried to cut these narratives down to just two descriptive words and in 1623 published his 'Pinax Theatri  Botanici' containing some six thousand plant species many of them using this two word system which we now know as the Binomial Nomenclature. So our flower over there known as the wild rose in English, Άγριο Τριαντάφυλλο in Greek,  or Heckenrose in German is known by every botanist around the world, regardless of native language, as Rosa canina. Which, I hope, answers the oft asked question: “Why do scientists have to use such long and complicated names?”

Who? Carl Linnaeus? Oh yes, him – Swedish botanist with a genital fixation. He certainly expanded on Bauhin’s work in his Systema Naturae of 1735 and he is known as the father of modern taxonomy. Definitely more famous but personally I think that‘s because he was a much better self-publicist than Bauhin.

Leopard Snake
So where does all this get us? We now have this delightful two name system called the Binomial Nomenclature so we all agree on what we’re looking at. Only we don’t. This Leopard Snake for instance has been known as Zamenis situla since 2006. Between 1993 and 2006 it was Elaphe situla and prior to that it enjoyed no less than six other synonyms starting with Coluber situla in 1758 (that man Linnaeus again – it means bucket snake). In practical terms what this means is that professional and amateur naturalists alike spend an inordinate amount of time simply trying to put a name to things, which, when you think about it, is one heck of a waste of time when we should be looking at how the natural world all fits together and functions. More specifically we need to know how we are supposed to fit comfortably into the big picture as a species rather than ram our way through it, destroying it as we go, which we are doing at the moment.

MiSeq Genomic Sequencer from Illumina
So how do we get around all this time wasting? Come with me and enter the seemingly labyrinthine world of cladistics. You may need a ball of string.  Traditional taxonomy involves looking at things and grouping them together based on shared, observable, characteristics. (If it looks like a duck and swims like a duck…it’s a duck). Cladistics on the other hand groups things together based on characteristics shared by a common ancestor.  So out will go the old classifications of species, genus, family, etc. (although they are still retained for practical purposes at the moment) and in come unspecified divisions called ranks and long, branching diagrams called cladograms (this is where the ball of string comes in handy). Now you can’t see these ancestral links so this is where DNA testing enters the picture.  The basic ideal is that you can take a plant leaf or insect wing, stick it in your home genomic sequencer and get an on-screen result giving you the name of the specimen and a pretty picture for visual confirmation from a free world database. That’s my dream anyway. And maybe it’s not so far away. I contacted the company which makes the desk top MiSeq genomic sequencer and they’re presently looking at a number of applications so one day in the not too distant future… who knows?

So where does that leave us as amateur naturalists? Well, I think we should continue to enjoy the world around us and still organize our notes down to family level but maybe we shouldn’t spend too much time worrying about the exact species. There are still a lot of observations to be made in the fields of phenology (when things happen) and ethology (animal and plant behavior in the wild) where the amateur naturalist can make a significant contribution. So until next week – happy hunting and let’s have some of your phenological and ethological observations in the Naturalists Group on Facebook.

A quick note on last week’s blog: what I thought was a freshwater mussel turned out to be a freshwater crustacean called a Seed Shrimp and I have updated the blog accordingly.

Special thanks this week to Steve Lenton at (an excellent site) for letting me use his picture of Rosa canina and Manos and the team at Progressive Computers in Ierapetra without whom this blog would not have been published as my computer had a major meltdown yesterday. Thanks for the speedy repair guys. 

Naturalists (the facebook page that accompanies this blog)

1 comment:

  1. “So I though it time...” (5th sentence) SHOULD READ: “So I thought it time...” [INS ‘t’]


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