Duke has beat Arizona four times and the Wildcats beat the Blue Devils three times. Is that right? I don’t follow basketball very much, but I do like watching games. And the same scientific principles apply to sports as to ecology.
Since each game is a separate event when you think like a statistician, the past record does not determine who will win tonight’s game. For the communities of similar plants that live around Tucson, the weather each year is also a separate event. The amount of rain last year does not determine this year’s rain.
But if the factors that control the outcome are similar to past years, we can figure out the probability of that outcome. For example, if we measure wind speeds and directions over the oceans, we can estimate the probability that this year will be wetter than usual in Arizona. That would benefit many of the wildflower species. The wind patterns can be related to the amount of rainfall, and meteorlogists look for the factors that cause the relationship, like the physics of the wind patterns’ directions. Likewise, if Arizona had never beat Duke, we might wonder if Arizona recruited less talented players, or practiced less, or had an ineffective coach. Fortunately, that’s not the case! We have a real shot at winning tonight, based on the factors that predict outcomes.
Of course, that “historical range of variation,” or the set of past experiences, could always be changing in some specific way. For example, a team might get better over thirty years as a coach gains experience, and his winning record attracts better players. In ecology, many habitats have become more and more “fragmented,” or broken up by roads and houses over the last thirty years. On a longer time scale, as a school gets more established and wealthy over a century or two, its sports might also improve. Ecologically, as greenhouse gasses warm the earth, the physics of those wind currents might change, and we will have a harder time predicting our rainfall in Arizona.
So here’s to hoping Arizona wins tonight! There are whole fields of science that deal with why I’m hoping that (neuroscience and psychology), which I won’t get into.
(I should also mention that Duke has a pretty awesome Ecology program, too.)