Download 2.3 Ecosystems are always changing

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.