Download HONORS LIVING ENVIRONMENT MS. ETRI TOPIC 23: ECOLOGY

HONORS LIVING ENVIRONMENT
MS. ETRI
TOPIC 23: ECOLOGY
PART 4: ECOLOGICAL SUCCESSION AND POPULATION GROWTH
ECOLOGICAL SUCCESSION: the gradual process by which ecosystems change and develop over time.

Nothing remains the same and habitats are constantly changing.

Due to the processes of
living, growing and
reproducing, organisms
interact with and affect
the environment within
an area, gradually
changing it.
TWO TYPES OF SUCCESSION:
1. PRIMARY SUCCESSION
o
The series of community changes which occur on an entirely new habitat which has never
been colonized before.
o
Occurs on newly exposed surfaces with no sign of life.
o
EXAMPLE: The initial development of plant or animal communities in an area where no soil
initially exists (such as caused by a lava flow following volcanic eruption).
o
The primary succession is important in pioneering the area to create conditions favorable for the
growth of other forms of plants and animals.
o
PIONEER SPECIES: the first organisms to populate a given location.3
HONORS LIVING ENVIRONMENT
2. SECONDARY SUCCESSION
o
MS. ETRI
The series of community changes which take place on a previously colonized, but disturbed or
damaged habitat.
o
Occurs on preexisting soil after the primary succession has been disrupted or destroyed due
to a disturbance that reduced the population of the initial inhabitants.
o
EXAMPLE: The development of new inhabitants to replace the previous community of plants
and animals that has been disrupted or disturbed by an event (e.g. forest fire, flood, harvesting,
epidemic disease, pest attack, etc.)
o
CLIMAX COMMUNITY: The permanent plant and animal species make up a stable or climax
community in which the populations remain the same or constant—they are in balance with one
another.