Learning the Ropes

Physics has laws. Universal truths that all physical bodies obey. The law of gravitation is followed by grains of sand and galaxies alike. As a Zoology undergraduate at the University of Sheffield, I quickly learnt that things are not so simple in the biological world. There are no laws that all living things rigidly adhere to. Cat owners are well aware of this fact. There are no forces, no set of equations, that fully describe the menagerie of behaviors exhibited by Earth’s biodiversity. The best we can do in Biology, therefore, are rules. General truisms or conventions, patterns that are pervasive enough in nature to be notable, but far from universal.

The species-area relationship is one such rule, whereby larger areas tend to contain more species. This is a very intuitive idea, one that is borne out by common sense and personal observation. And yet, a million and one caveats and qualifications emerge that prevent this observed trend from being an immutable law. Different ecosystems of the same size – a desert and a tropical rainforest, say – can contain vastly unequal species’ richness. Species communities on islands are subject to atypical dispersal and colonization dynamics that prevent a direct comparison with continental landmasses. Someone counting beetles will come up with a different result from someone counting butterflies. And the list goes on. Even if you manage to avoid all these confounds, limiting your investigation to one group of organisms in one ecosystem on one continent, you will still find small areas with a surprisingly large number of species and large areas maddeningly empty. There are always exceptions to rules.

Dr. Brooks's fellowship is under the supervision of Prof. Olaf Jensen at UW-Madison's Center for Limnology.