As you finish up your March Madness bracket, keep in mind the laws of the jungle. It turns out win-loss records in basketball, and population statistics in ecology, look almost exactly alike.
"Just like there are a few dominant species in a jungle, there are a few dominant teams in college basketball," said Yale ecologist Robert Warren, lead author of a new study in the journal PLoS One. "And all the rest do OK."
Warren compared basketball stats and ecology stats to get a new look at a longstanding puzzle in ecology. For some reason, environments from the tropics to the tundra seem to have the same distribution of species. Most have a few species with a lot of members, and a lot of species with very few members.
Recently, some ecologists have tried to use statistical analysis to find one overarching explanation for why populations shake out the way they do. The standard idea for the last 150 years was Darwin's survival of the fittest: The most common creatures were the ones who survived, ate and reproduced.
But a new idea, called neutral theory, suggests that "while species might be different, it all comes out in the wash," Warren said. As far as population statistics are concerned, competition between species doesn't matter.
The theory bothered Warren, a lifelong college basketball fan. "If that were true, then there's no difference between Duke and Arkansas State," he said. It could be that similar statistical patterns naturally show up in a large enough data set, whether the data is related to ecology or not.
"I was thinking, I wish I had a data set where I knew what structured it," he said. "If I knew one that was structured by competition, that would really address this issue. And clearly, college basketball is structured by competition."
Warren and colleagues at Yale examined the win/loss records from 327 NCAA Division I teams from 2004 to 2008. They treated each team as a species, and each win as a member of that species who survived. Then they analyzed the records using a common method for assessing biodiversity and drew a curve that described the number of wins per team. The curve was not statistically different from similar curves describing species abundance in the wild.
Then the researchers made a random data set, in which it was just as likely for, say, Savannah State to have a lot of wins like North Carolina.
The curve looked almost identical.
"But we know college basketball is not random," Warren said. "If it were, what would be the fun of filling out your bracket?"
The fact that ecological communities, college basketball wins and random data all show the same pattern -- even though the data have different underlying explanations -- suggests that you can't tell what drives population diversity just by fitting a model to the curve, Warren said. The reason why some teams have a lot of basketball wins and others don't is well-known: Teams compete on every level, from hours of practice to coaches' salaries to recruitment.
But the reason why some species succeed and others fail is still a mystery. And since a recent study warned that the world might already be in the middle of the next mass extinction, knowing what keeps species afloat may be critical for saving them.
"Here we are at the verge of a very large extinction event, and we're kind of spinning our wheels. We still don't know what explains biodiversity," Warren said. "We need to get out there and figure out what's going on."
The finding doesn't say anything about whether neutral theory or survival of the fittest is correct, points out ecologist Jeff Lake of Michigan State University, who was not involved in the new work.
"But it really does provide a caution to us as biologists to not read too much into simple pattern observations," he said. "That’s a very worthwhile point to be making."
Images: 1) flickr/kthypryn 2) flickr/BenSpark 3) Robert Warren/PLoS One 4)flickr/Hamed Saber
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