July 2005 Archives

An excerpt from my first lab notebook, unearthed in a bout of organization.

5/8/2001
10 p.m.

And lo, the octopus was curled in the rear left bottom corner of the tank, and the crab was dead.
And there was no sign of any sand crabs yet living.
And the octopus had interesting, rather long papillae over it eyes.
And it darkened in color, and rearranged itself, an arm curling out here or there, then tucked tidily away again . . .

And I went to dig crabs from the beach at this ungodly hour.
Then thought better of going alone, and bade the octopus wait for the morrow.

Thanks to an excellent comment by Morgana on my last post, I have managed to broaden somewhat my initially narrow view of the Biologies to consider the vast array of medicine-relate biology departments and programs. (Not medicine itself, mind you. There I know so little I dare not tread.) Thus, for the moment I'm going to stop talking about eco/evo and mole/cell.

Instead, to discuss statistics, which was the original aim of this essay, I will focus on a distinction that I am actually making up as I write(!). I think there may be two fundamentally different approaches to biological questions--or really, two different questions.

1. How does it work?
2. Why does it work?

This is reminiscent of a lesson commonly taught in introductory classes on proximate vs. ultimate causes. Suppose an octopus is caught and devoured by an eel. You ask, perhaps plaintively, "Why did the octopus die?" The proximate cause involves tissue damage, blood loss, and cessation of brain function due to the teeth and digestive juices of the eel. Ultimately, however, the octopus died because it was too slow to escape, because it received poor genetic material from its parents, because its parents, due to the stochasticity* of the environment, lived in a year when eels were scarce and thus they survived despite their slowness . . .

Obviously, the causality of any one event is almost infinitely zoomable in either direction. Nevertheless the set of causes can be divided into two fairly distinct categories. First is the proximate, the how, the mechanistic explanations: how strong must the eel's teeth be to tear the skin; how potent must the chemicals in its saliva and stomach be to lyse the octopus' cells; etc. Second is the ultimate, the why, the big-picture stuff: why the environment brings eels and octopuses together, why predation and escape responses have developed over evolutionary time, etc.

These two sets of questions, or answers, which clearly complement each other, can be pursued by two equally complementary sets of techniques. The techniques for answering mechanistic questions tend to involve laboratories and microscopes, dissecting tools and fluorescent tags**. The techniques for answering big-picture questions are usually field studies and computer models, scuba gear and Matlab. Ecologist count things. They count lots of things, and they do it many times. And then they do a whole lot of data processing.

Which bring me back to statistics, and the somewhat counterintuitive conclusion that, while the eco/evo crowd is stigmatized as pursuing a "soft" science, they present their data in terms of huge sample sizes and incredibly hardcore statistical analysis. Meanwhile, cellular papers can be published with key figures that are simply photographs of stained gels, described qualitatively in the text and used to defend or refute a hypothesis of the author's choice. This is not to say that such data is invalid, but it is rarely quantified and sometimes not even replicated, and is nevertheless published. Ecology papers can't get away with that--and I bet epidemiology ones can't either.

* One of my favorite words. It's right up there with viscoelastoplastic (sound it out slowly--isn't it delicious?), which is, for this summer at least, my absolute favorite word. To be discussed at a later date.

** This reminds me that I was going to make an (obscure and terrible) joke about FISH in the last entry, but didn't get around to it. FISH stands for Fluorescent In Situ Hybridization, which is a way to track genetic material in a cell by adding fluorescent material that can match up, or hybridize, with the stuff you want to look at. However, this lovely acronym could just as well (and more appropriately) describe what happens when two different species of GloFish get together and produce an equally fluorescent offspring.

There is a long-standing tradition of separating the biology department at institutions of higher learning in twain. Insiders generally refer to the two halves as mole/cell and eco/evo. The former has nothing to do with moles, star-nosed or naked; the abbreviations stand for Molecular/Cellular and Ecology/Evolution, respectively.

Of course, the distinction is not precisely the same at all universities. The departments at my undergraduate institution were Molecular, Cellular, and Developmental Biology and Ecology, Evolution, and Marine Biology. The six biological disciplines thus represented could be lined up for a child's game of "which does not belong?" and many biologists would probably pick Marine Biology as the odd one out. None of the other five disciplines specify a study system--there is no Alpine Biology, or Interstitial* Biology.

My current institution appears to be equally poor at basic kindergarten skills, for their Biosciences department is separated into Cell, Molecular, Developmental, and Plant Biology and Ecology and Evolutionary Biology. Plants are an excellent and admirable system in which to address all kinds of biological questions, from the cellular to the evolutionary, but I fail to see how they merit explicit mention in the titles here given.

But I digress. I wish to address the existence of this dichotomy at all, and discuss its merits and abuses. First, some web-surfing has provided additional substance to my argument for its existence:

Harvard: Molecular and Cellular Biology + Organismic and Evolutionary Biology
Yale: Molecular, Cellular and Developmental Biology + Ecology and Evolutionary Biology
UC Berkeley: Molecular and Cell Biology + Integrative Biology

(Said web-surfing has also, I confess, provided several somewhat more complex divisions, which are equally interesting to me and which I hope to explore further at a later time.)

This division is played out on the academic stage with more or less animosity, depending on the players, but there can be no doubt that there are two strongly separated camps of biology. They tend to have different mailing lists, different seminars, different funding, and often very different outlooks on science and life. The stereotypes: Mole/cell biologists are narrow-minded, technique-obsessed fly-counters and yeast-spreaders**, driven by medical funding, with no interest in the big picture and no grasp of how life works in the real world. Meanwhile, eco/evo biologists are tree-hugging, touchy-feely, pot-smoking hippies who failed chemistry and use science as an excuse to hike in the rainforest and dive in the tropics.

The truth? Well, there's a reason we know much more about the ecology of tropical than polar regions. Biologists are not stupid.

Seriously, though, there are unquestionable differences in technique and perspective due to differences in training. If you want to study cells but haven't been exposed to the enormous variety of techniques available, it's a lot of work to play catch-up and learn what the cellular biologists mean when they suggest you try polyclonal antibody staining or FISH. Conversely, if you haven't taken a full Evolution course and done reading on evolutionary theory, it's difficult to make accurate statements about evolution even in the simplest context.

These differences cannot be avoided, nor need they be. The lamentable aspect of the schism lies in the not infrequent refusal of parties on either side to show any appreciation for the work done by their colleagues in the Other Half of Biology. That you may not understand it, is to be expected. That it may not even interest you, can be forgiven. But that you may despise and ridicule it, for shame! Have we no common decency nor respect?

Saddest of all, I feel, is that by closing their eyes to developments in fields other than their own, a number of excellent scientists lose the potential for excellent collaborations, for new insights into their own work based on a completely different perspective. Sometimes questions can be answered with techniques you never knew existed. This is why I'm so excited when I see people working on the ecology and evolution of Drosophila, or examining on a cellular level just which proteins allow mussels to live where they do.

And thus, returning to my home institution, I must applaud their relatively recent introduction of a third track within the Biosciences Department: Integrative/Organismal/Marine Biology. (Although I must also point out once again that One Of These Is Not Like The Others). Integrating biological studies from the very small (molecules and cells) to the very large (populations and ecosystems) lands us necessarily in the middle ground of whole organisms--the whole reason that most people, including myself, get interested in biology in the first place. We like critters! This "medium scale" has the added advantage of being on a human scale, making biology much more accessible to the layperson even as it serves as the bridge between the two academic disciplines into which biology has been split.

At least, that's the idea. It turns out that this track is having an identity crisis, and isn't really sure what it means to be Integrative/Organismal. Consequently the few students it contains seem to go back to allying themselves with Mole/Cell or Eco/Evo, thereby propagating the split.

To be continued.

Which group of scientists presents more quantitative data? Which do you think uses more statistics to back it up? Tune in next time to find out the (maybe) surprising answers!

* Interstitial refers to the space between sediment grains. The organisms living in this space are referred to as the meiofauna. Included in the meiofauna are the ever-adorable water bears.

** Drosophila (fruit flies) and Saccharomyces (baker's yeast) are popular model organisms for molecular and cellular studies.