Even landscape has a utilitarian purpose: the exchange of gases in the environment and a healthy planetary ecosystem.

The asteroid strikes Earth, critically damaging the planetary ecosystem.

The degenerating planetary ecosystem becomes reflected in man's health.

Throughout history, the Earth's atmosphere and biogeochemical cycles have been in a dynamic equilibrium with planetary ecosystems.

In a planetary ecosystem, plant life is an essential biological component.

The atmosphere of the Earth serves as a key factor in sustaining the planetary ecosystem.

They form an essential part of the planetary ecosystem.

The conversion of the planetary ecosystem is not yet complete, Captain.

Storms here, always violent, had become even more so since the Titans altered the planetary ecosystem to suit themselves.

If biodiversity declines, the absorptive capacity of the planetary ecosystem will decline as well.