by John Hulme
Brother Timothy was not the only person to have pointed out the weakness of unsure starting conditions before carrying out important experiments.
Classification, or - Putting things into groups.
In the seventeenth century naturalists began trying to name living organisms, plants and animals, in some systematic way. Common names were fine, but often vague, confusing, changed from one region to the next and the same creature could have more than one name depending on who was doing the naming.
To get away from this confusion these naturalists used Latin (the language of culture and education at that time), and gave each plant or animal they could find a descriptive name that accurately said something about the organism. These names were supposed to be unambiguous, but to make them accurate, they often had to use five or six Latin words, a length that quickly became cumbersome and hard to remember.
A different system was needed.
That different system was invented by a Swedish botanist Carolus Linnaeus. He realized that all objects could be grouped (note: in principle the system of classification devised by Linnaeus could be applied to stamps, coins, chairs, cars, or almost anything, but we will restrict our discussion to living organisms).
For example, it was obvious to Linnaeus that "all living organisms" represented one large group of objects, which could then be divided into two smaller groups; "plants" and "animals".
This way of doing things seems just common sense and remarkably easy, but it contains two important concepts:
- defining the groups (i.e. "plants" and "animals"), and
- deciding what factors determine where a particular organism is placed (i.e. "all plants are green", and "no animal is green")
Taxonomy, is the process of devising and defining the various groups. In Linnaeus' case, deciding that he needed two groups which he called 'Kingdoms', the "Animal Kingdom" and the "Plant Kingdom".
This is not as easy as it looks. Although it seems obvious at the level of multicellular organisms that some are green (plants) and some move around (animals), at the microscopic level some organisms are both green and move around! Where to they go?
Linnaeus took the idea of groups even further. After he had divided all organisms into two groups (the 'Kingdoms') he took each Kingdom and divided it up even further into smaller groups (which he called "Phyla"). All animals (those in the "Animal Kingdom"), could be divided up into those animals with a stiff rod up their backs (Chordata), and those that didn't (such as the sponges).
Now he had one set of groups nested inside a larger group, and he continued subdividing each smaller group into even smaller and smaller groups, until there was only one creature that would fit into the final, smallest category. At this point he had to stop.
Defining these groups unambiguously started to become a problem for Linnaeus, and it has been a problem ever since. When defining the groups do you either,
- try to make the groups as large as possible (lumping as many organisms together as you can), or,
- split the groups up into many small categories (so as to make each group as unique as possible).
The taxonomic "wars" between the 'lumpers' and the 'splitters' continues to this day.
Once the groups have been established and the criteria for membership defined, it then becomes possible to take any creature and ask a series of questions. The answers to these questions then automatically places that creature into the next subgroup, where the questions start again. For example,
Humans -
First question - **Plant or Animal?** - answer, humans are multicellular, heterotrophic creatures, so, they belong in the "Animal Kingdom".
Second question - **Stiff rod in their back?** - answer, yes, so they belong in the "Chordata" phylum (the name given by Linnaeus to this level of subgroup).
Third question - **Spinal chord surrounded by bone?** - answer, yes, so they belong in the "Vertebrata" subphylum.
And so on.
Today you could go on subdividing into the "Class", then the "Order", then the "Family", then the "Genus" and finally into the "Species". When you finally arrive at these last two groups (the Genus and the Species) you can go no further, so the system stops here.
Nomenclature In the system devised by Linnaeus, the last two names used for each creature, the Genus name and the Species name, are put together to form the scientific name of that organism. In the case of humans the Genus name is "Homo" and the Species name is "sapiens", so these two are put together and the scientific name for humans becomes Homo sapiens. (Note: italics are used for these names and the Genus name is capitalized).
Because each creature is given a "two word name", this is often called the binomial system. Since the time of Linnaeus this system has been expanded and improved, but the controversy concerning the taxa (groups) has not gone away. Linnaeus only had two "Kingdoms", today most people use a system based on five Kingdoms, while some prefer four and others, six. No one system is 'right' or 'wrong', just different.
Classification. Any system of classification (or 'grouping') tries to put objects into the same group if they share characteristics in common, and tries to put different objects into different groups if the differ from one another. Sounds easy? Try it some time!
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Statistics
Even today, many biologists have a hard time with statistics. There is no denying the power of numbers and the impeccable arguments that derive from quantitative analysis, but abstract ratios on a notepad don't seem to impress as much as having the living organism on the laboratory bench.
In this fictionalized story Mendel runs into trouble when he starts reporting his numbers and the mathematical arguments that stem from them. In real life, Mendel would have had similar difficulties. Few of the biologists present would have followed his statistical analysis (simple as it was), and few of the mathematicians would have followed the underlying biological principles (revolutionary as they were). He was caught between the proverbial rock and a hard place.
Fictional Brother Timothy immediately jumps on a loop hole. To any member of Mendel's audience who knew anything about statistics, any ratio reported from a small sample of plants might show a random "fluctuation" that could be almost any value. Mendel actually gives an example (which I have put into the mouth of Brother Timothy) where 32 yellow seeds were reported and only 1 green seed; a ratio of 32 : 1, not anywhere near 3:1! However, to biologists not versed in statistics, this might appear to be a contradictory result and invalidate Mendel's arguments and explanations.
Mendel considered that such "fluctuations" were just a normal part of studying biological phenomena using statistical principles, and that, as the reported numbers became larger and larger, so his ratios became closer and closer to the value 3 : 1. (Obviously Brother Timothy did not agree, but then he had other motives!).
Actually, Mendel never reports observing a "pure" 3:1 ratio for any experiment, plant or pea pod. He also never tells his audience how many plants he should have used in order to see this magical ratio or at what confidence level his numbers should be treated. A lot is taken for granted. He repeatedly reports ratios close to 3 : 1 and implies that this ratio should in fact be considered the "real" ratio even though he cannot justify his argument. Today a modern audience would have been as hard on him as I have made the fictional team of Brother Timothy and Heir Grunewald.
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About the Author
John Hulme is a retired Professor, now living and writing in Florida. He was educated in England - a long time ago - and arrived on the shores of New York carrying a single suitcase and lots of ideas. He has written several hardcover science books and was an early user of the fledgling internet as a teaching tool. Before retirement he wrote a set of fictional science stories about Gregor Mendel - the person who discovered genetics, which he has now converted into ebooks. Since retirement he
has started on a long-cherished writing project of historical fiction - which you can now read for yourself.
In the “Shaftsman” Series -
The letters of a Roman Soldier written about the time of Julius Caesar.
Iron Shaft: Primus - the first letter and introduction
Iron Shaft: Secundus - how he joined the Tenth Legion, and got his nickname
Iron Shaft: Tertius - how he helped the Druids, and saved Caesar
Iron Shaft: Quaternus - poison, pearls, Druids and skulls
Iron Shaft: Quintus - how Caesar got his ships
Other works by John Hulme are:
In the “Mendel” Series -
A fictionalized account of the life and times of Gregor Mendel - the discoverer of genetics.
Brother Gregory: Gene One - a famous lecture, birth of genetics, a failure
Brother Gregory: Gene Two - visitors to the Monastery, Brother Timothy plots
Brother Gregory: Gene Three - Mendel’s Sparrows
Brother Gregory: Gene Four - the Saint, the Sinner and the Scientist
Brother Gregory: Gene Five - and the bending of light
Brother Gregory: Gene Seven - and the circles of carbon
The Bones of Saint Hugh - how the bones of an English Saint arrive in Brno
Short Stories -
The Night After Christmas - which was inspired by a real incident
As It Was Told - A short story collection
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