The lower breakeven point has also opened new suburban niches in areas where other McDonald's and plenty of competitors are just a short drive away.

"The best places to look would be places with lots of species, like rain forests, and islands, because isolation opens new niches."

This event precipitated a worldwide firestorm that ended the reign of dinosaurs and opened new ecological niches for primates, leading to the eventual emergence of Homo sapiens.

But the small, furry descendants of the therapsids kept the mammal-like design alive until the demise of the dinosaurs opened new evolutionary niches that eventually led the way to man.

It ushered most species into oblivion but opened ecological niches for a host of others, including the dinosaurs of the Mesozoic era that followed.

Those were moved to open niches newly made in the front wall of Leopold's Vault.

Fire creates a heterogenous ecosystem age and canopy structure, and the altered soil nutrient supply and cleared canopy structure opens new ecological niches for seedling establishment.

While Levi's jeans and Dockers khakis are facing more competition from private-label brands, Levi Strauss is using its deep pockets and marketing muscle to open new niches.

To those who argue that extinctions are useful because they open biological niches into which new species can evolve, Mr. Eldredge has a response: evolution itself is not necessarily good.

The reduction in service is expected to open niches for an ambitious regional carrier, WestJet Airlines of Calgary.