Chapter 3

Not generally contained without boundaries Energy or material moves into or out of the system

A set of components or parts that function together to act as a whole Components may themselves be systems (subsystems) Systems respond to inputs and have outputs

No such movements take place ( there are few pure closed systems)

The steady star that all natural systems move towards wight influence of people Seldom attained or maintained very long

A dynamic equilibrium Material of energy is entering and leaving the system in equal amounts Opposing processes occur at equal rates

The time it takes for a given part of he total reservoir of a particular material to be cycled through the system The equation for average residence time is : ART= size/rate of transfer

Output of the system also acts as input Leads to further change n the system Vicious cycle (destabilizing)

System's response is in the opposite direction to the output Self regulating (stabilizing)

Growth occurs at a constant rate per time period N=Noe^kt

The time necessary for the quantity being measured to double Approximately equal to 70!divided by the annual percentage growth rate

The consequences of exponential growth and it’s accompanying positive feedback can be dramatic

The time between a stimulus and the response of a system If there is a long delay between stimulus and response, the. The resulting changes are much more difficult to recognize.

Consequences that may not be easily rectified on a human scale of decades of a few hundred years

Everything effects everything else Earth and it’s ecosystems are complex entities in which any action may have numerous effects

Process that operate today operated in the past Observations of processes today can explain events that occurred in the past and left evidence The present is the key to the past The study of past and present processes is the key to the future

All the organisms of all species living in an area or region up to and including the biosphere

The part of a planet where life exists The planetary system that includes and sustains life

A community of organisms and it’s local non living environment in which matter (chemical elements) cycle and energy flows Sustained life on earth is a characteristic of ecosystems Van be natural or artificial

Named for Gaia, the Greek goddess Mother Earth The surface environment of the Earth, with respect to such factors as the Atmospheric composition of gases Acidity- alkalinity of waters Surface temperature Are actively regulated by sensing, growth, metabolism, and other activities of the biota