2.3 Ecosystems are always changing Population size changes in response to food supply Predation Seasons birth rates

A limiting factor, such as water, light, or food, can affect population survival and growth. The carrying capacity of an environment is the maximum population it can support. At carrying capacity a population stops growing.

Ecosystems change over time. Succession is a gradual series of changes that take place in an ecosystem after a disturbance. There are two types of succession Primary Secondary

Primary - starts from an environment that is mostly empty of life. Examples - After the retreat of a glacier, for example, or on new rock produced by a volcano, life can begin to return

Pioneer species - 1st species that moves into the barren environment and begin the task of creating soil. Examples: moss, lichen

Secondary - occurs in areas that have soil with roots and seeds below the surface. life already survives. may begin after a fire or flood disturbs the ecosystem.