10% rule (efficiency between trophic levels): limits how long an ecosystem's food chain can be
Predator/prey
cost benefit analysis (i.e. foraging) -- cost is risk of being eaten or
killed along the way, benefit is energy/nourishment obtained: limits
distribution of predator v. prey
Immigration/Emigration with other populations and ecosystems
Island
biogeography: size of land and distance from another
population/ecosystem (mainland): limits population size and variability
on island
