Multiple levels of understanding

Now, the title of this entry sounds philosophical, and is a bit misleading. Let me assure you that I have no intention of digressing into philosophy here (at least this time). This entry is the net result of a series of thoughts that I have had about trying to understand biological systems. In fact, after reading it, I think many people would say, "Hey! I already knew that! So what's the point?" Well, read it and judge for yourself.

As a side note, I must say, that this article is likely to contain many inaccuracies as to dates and titles of publications. Perhaps some facts are wrong as well. I invite anyone to correct me if they believe I am mistaken at any point and would positively welcome anyone who does.

I think that there are many, many ways of looking at biological systems; multiple levels, or layers if you will, of understanding.

The highest (and by highest, I mean most high-level, and not necessarily the best) level is the study and understanding of behaviour. I call this the highest level, because it is the sum total of what that organism is. By the way, this is called ethology. Now, the study of behaviour was probably the first thing that our ancestors (by ancestors, I mean humanoids from way, way back, possibly even before the evolution of modern man) systematically studied biology. Why? Because this gave them an understanding of how to get lunch and how not to become lunch. So, our ancestors probably observed, over the course of a few weeks, months, or years, how certain animals would take flight if you made a noise, while certain others weren't bothered. Still others would charge you with horns parallel to the ground and maul you to death if you weren't careful. They must have observed how deer and other herbivores congregated at water holes in the summers and how they hibernated in the winters. They would also have seen how wolves, tigers and other predators were dangerous to themselves and their children and devised strategies to keep them away. Maybe this involved pushing a boulder in front of the cave where you slept at night, an extremely effective strategy against large predators; but if the predator had been really good at digging, it wouldn't have worked. So, primitive man really was quite an ethologist, the need to survive meant that he had to be. Primitive man was also a taxonomist (one who classifies animals), but the real spark that set off the study of taxonomy was Carl Linnaeus, the man who invented the binomial nomenclature that we use, with some modifications, even today.

Later on, humans must have started studying anatomy. This might initially just have taken the form of, "The hooves of all deer are difficult to eat, but the haunches, now they taste good!" Eventually, this would have got more generalised to, "Hey, all animals have intestines, and all intestines taste like crap!". And finally, much, much later, humans started figuring out what each organ actually does. This took longer than you might think, even the ancient Greeks thought that the heart was the organ that did the thinking, and that the brain was just so much grey goo (and that was only a couple of millenia ago!). This understanding of the anatomy of an organism then, is the second highest level of understanding we can have. And what an important step it was! Because the next level was understanding how these organs work.

Understanding how organs do what they do is called physiology. While most people look upon physiology as a relatively mature science, I disagree. Physiology as a systematic science has an age measured in mere centuries, while the earliest humanoid fossils date back a 6 or 7 million years! Even the earliest fossils of modern humans are two hundred and fifty thousand years old. A lot has been understood about physiology in the last few centuries, but we still aren't remotely close to understanding everything about it. We have however, understood enough about it, that we have been able to go one step further, to the next level of understanding, cellular biology.

The study of cellular biology was pioneered by Robert Hooke, the inventor of the compound microscope, who published a work, "Micrografia" in 1665. Micrografia contained many, many drawings and descriptions of life when viewed through a compound microscope. It was Hooke who first coined the term "cell". Another person of note was Antony van Leeuwenhoek, a contemprary of Hooke's, who made unparalleled (at that time) compound microscopes that allowed him to observe microorganisms, which he called "animalcules". He too wrote a book with fantastic illustrations of his observations with a microscope. A nice history of Robert Hooke, along with some illustrations from Micrografia, can be found at http://www.ucmp.berkeley.edu/history/hooke.html and of Leeuwenhoek at http://www.ucmp.berkeley.edu/history/leeuwenhoek.html . Cellular biology has really kicked off since then, with bucketloads of information now available on cells, their structure and how they interact with each other. It is also important to note that later, more detailed studies, continuing even to the present, have given us a profound insight into that very unit of life, the smallest thing that can be said to be living, the cell. The next level of understanding, in my opinion, though many may disagree with the exact placing of it in the heirarchy, is the study of inheritance (genetics) and evolution.

Now, the study of genetics, or inheritance was fueled by two seminal works, Gregor Mendel's 1865 publication, "Experiments on plant hybridization" and Charles Darwin's 1859 publication "On the origin of species by means of natural selection". Now both these, as you can see, were published less than 200 years ago, and we are still working on our understanding of these two questions, i.e. how organisms transmit their genetic data to their children and how organisms evolve. Far more recently, Griffith and Avery in 1928 and 1944 respectively, proved that DNA is the genetic material. In parallel with the study of genetics, another discipline was emerging, the study of the chemistry of life, or biochemistry.

All living beings have a huge number of molecules in them. Many of these molecules are huge, so huge in fact, that very few molecules outside the living world ever attain that size. For example, proteins have molecular weights in the hundreds of thousands or even millions of units, while a hydrogen molecule (not a hydrogen atom!) has a molecular weight of 2! Such molecules are called macromolecules. Even the smaller molecules found in organisms, with a few exceptions, tend to be rather large compared to molecules found outside the living world. The size of macromolecules has had rather an unfortunate side-effect i.e. until recently, we couldn't understand a lot about their chemistry. We could see them react with various things and postulate how they reacted, but why the molecule was shaped like it was and what were the chemical factors contributing to its shape, for example, were questions that we couldn't answer. Luckily, with the advent of computers, this has changed, and we are slowly unravelling the mysteries of macromolecule structure. For those that are not professional biologists or chemists, a useful analogy would be to try and imagine the function of each atom in a chair or a table and trying to figure out how each atom contributes to the overall properties of the chair! Which leads me to the next level of understanding, the chemical/physical one.

What I mean by a chemical/physical level of understanding is trying to figure out how properties and laws from chemistry (especially physical chemistry) and physics affect all the higher levels of organisation. We have discovered over a long time, many properties of the world around us from gravity to the general structure of an atom. We have also shown that these properties apply to every single entity (living or non-living) in the universe. What we rarely consider, is how these affect life in general. This is because, as I said, life is composed of such complex interactions between these properties, that separating them often becomes downright difficult. We are now, with super powerful computers, slowly beginning to understand what exactly is going on.

Finally, the last level of understanding (so far at least), is that of sub-atomic physics. Now, I will not dwell too much on this level, partly because we are now leaving my comfort zone and partly because this is where it gets really really complicated. Suffice to say it can sometimes be useful to look at certain biological systems in a sub-atomic sense. Indeed, sometimes it is the only way of truly understanding some systems.

Now, why have I waffled on and on about these so-called "levels of understanding"? It's because I think that very few people are ever encouraged to think about or even made aware of these multiple levels at school, college or even university. It is (at least for me) impossible to think about all these levels at once, it gives me a headache! But what I do try to do, is try to think about them sequentially, over a period of days, or even weeks. For example, if I am studying biochemistry, I try and see how whatever I am studying would affect the behaviour, classification, anatomy, physiology, cell biology of the organism. I also try and see how it evolved and how they are passed on to subsequent generations. Finally, I try and take a look at the levels below the one I'm currently studying to see how I can better understand what exactly is going on. It is by no means necessary for each person to look at each and every one of these levels when they're studying biology, but looking at multiple levels, instead of just the one that interests you, deepens both your understanding of the level that you are studying, as well your love and enthusiasm for the subject. It did for me. And that, my friends, is how biology should be taught, not as a science in isolation, but as one facet of a many-sided structure.