6.3a The interrelationships and interdependencies of organisms affect the development
of stable ecosystems.
6.3b Through ecological succession, all ecosystems progress through a sequence of
changes during which one ecological community modifies the environment, making it
more suitable for another community. These long-term gradual changes result in the
community reaching a point of stability that can last for hundreds or thousands of years.
6.3c A stable ecosystem can be altered, either rapidly or slowly, through the activities of
organisms (including humans), or through climatic changes or natural disasters. The
altered ecosystem can usually recover through gradual changes back to a point of long-