Mathematics and natural history
After a mathematics master’s degree at Brown, MacArthur earned his Yale doctorate under Hutchinson in 1957. He taught at Pennsylvania before moving to Princeton, combining quantitative analysis with patient field observation.
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Niche division and abundance
His 1958 warbler study examined niche division among similar birds. The earlier broken-stick model compared species-abundance patterns generated by explicit hypotheses; MacArthur later abandoned its particular competition hypothesis rather than treating it as universal.
References: [1]
Dynamic island diversity
The Theory of Island Biogeography (1967), written with Wilson, related species numbers to immigration and local extinction and examined island size and isolation. Relatively stable richness could coexist with continued turnover of species.
Explicit, testable simplification
His wider work addressed species packing, resources and community organization. Models made assumptions and consequences explicit for comparison with observations, rather than providing a complete description of every ecosystem.