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Ecological succession
Ecosystem Stability
The interrelationships and interdependencies of organisms affect the development of stable
ecosystems. The types of animal communities found in an ecosystem are dependent upon the kinds of
plants and other producer organisms in that ecosystem.
Succession
The environment may be
A Typical New York State Succession
altered in substantial ways
through the activities of
humans, other living things,
or when natural disasters
occur, such as climate
changes and volcanic
eruptions. Although these
changes are sometimes
occur very quickly, in most
cases species replace
others gradually, resulting in long-term changes in ecosystems. These gradual long-term changes in
altered ecosystems are called ecological successions. Ecosystems tend to change with time until a
stable system is formed. The type of succession, which occurs in an ecosystem, depends upon
climatic and other limitations of a given geographical area.
Pioneer organisms are the first organisms to
reoccupy an area, which has been disturbed by
a disruption. Typical pioneers in a succession
include grasses in a plowed field or lichens on
rocks. These pioneer organisms modify their
environment, ultimately creating conditions
which are less favorable for themselves, but
establishing conditions under which more
advanced organisms can live. Over time, the
succession occurs in a series of plant stages,
which leads to a stable final community, which is
very similar to the plant community, which
originally existed in the ecosystem. This final
stable plant community is called a climax
community. This community may reach a point
of stability that can last for hundreds or thousands of years.
A Pond Succession Sequence
It has been observed that when natural disasters occur, such as a floods or fires, the damaged
ecosystem is likely to recover in a series of successional stages that eventually result in a stable
system similar to the original one that occupied the area.
Material cycles
The atoms and molecules
on the Earth cycle among
the living and nonliving
components of the
biosphere. Some of the
water molecules, which
are used in
photosynthesis, are
returned to the
environment. The change
of water from the liquid to
the gas state is called
evaporation, while the
water lost to the
atmosphere by the
activities of plants is
referred to as
transpiration water loss.
This water vapor
eventually condenses to
form clouds, and is
returned to the earth as
precipitation. This process is called the water cycle. The processes of cell respiration and excretion
also release some water to the environment as well.
The Water Cycle
The Carbon-Oxygen Cycle
Carbon dioxide molecules are used
in the process of photosynthesis to
form energy-rich organic sugar
compounds. These carbon dioxide
molecules are returned to the
environment by the process of cell
respiration, when the energy from
these compounds is eventually
released by cells. Some carbon is
also returned to the environment by
the decomposition of dead
organisms.
Oxygen is required by many living
things to release the energy in their
food in the process of aerobic
cellular respiration. Oxygen is
released to the environment as a
waste product of the process of
photosynthesis.
Other compounds, such as nitrogen, are cycled in the environment when organisms synthesize
proteins from simpler compounds and then return these nitrogen compounds to the environment when
they die and decompose.
Name: _______________________________________ Date: __________ Period: __________
Cycles and Succession Activity
_______________________
Define and explain:
1. Precipitation
2. Evaporation
3. Condensation
4. Infiltration
5. Runoff
6. Transpiration
______________________
Define and explain:
1. Photosynthesis
2. Respiration
3. Combustion
Define and Explain:
1. Nitrogen fixation
2. Why does nitrogen need to be
“fixed” by bacteria?
Define and Explain:
1. Primary Species
2. Climax community
3. Is this picture primary or
secondary succession?
4. Why? (provide facts and
details)
5. What is the difference
between primary and
secondary succession?