Ecosystems are dynamic communities of living organisms that interact with each other and their non-living environment. Primary succession occurs when organisms first colonize an area that previously had no ecosystem, such as new volcanic land, and gradually establish equilibrium over hundreds of years through pioneer species that establish soil. Secondary succession more rapidly restores an existing ecosystem after a disturbance like fire or logging by taking advantage of existing soil and seeds. Both types of succession help maintain equilibrium in ecosystems over time.

1. Ecosystems
An ecosystem consists of all the living
organisms in a given area, along with the
abiotic factors that influence them.
Ecosystems are
dynamic, continually
changing as the
organisms within them
interact with one
another and the ever
changing environment.

2. Ecosystems
Ecosystems are dynamic, continually
changing as the organisms within them
interact with one another and the ever
changing environment.
Energy and nutrients
generally flow between
organisms within the
same ecosystem, and
little is lost to the
outside.

3. Biotic and abiotic factors
An ecosystem is formed of biotic and abiotic
components.
Biological organisms are part of their
ecosystem’s biotic component. The organisms
within an ecosystem
all affect one another,
acting as either an
energy source, or a
competitor.

4. Biotic and abiotic factors
The abiotic
component is the
non-biological part of
an ecosystem. This
includes the climate,
light level and
rainfall.
Some abiotic factors, such as the dirt, can be
altered by the presence of organisms.

5.  Organism – complex system of organs that
function as a whole
One FJH student
 Population – group of same species that live
together in a same area for the same time, they
compete for food, mates, and nesting place
All FJH students
 Communities – All the populations of different
species that live and interact in an area, different
population in a community depend on each
other
FISD all schools in Friendswood

6.  Ecosystem – community of organisms
and its abiotic environment, how
organisms interact with each other,
climate, and soil affect organisms
The city of Friendswood
 Biome – A biome is a large area on the
Earth's surface that is defined by the
types of animals and plants living there.
A biome can be partially defined by the
local climate patterns.
 Biosphere – whole area of Earth
where life exists includes, every
ecosystem
Earth

7. Succession

8. Succession
Succession is the
gradual change in a
community over time.
During succession
the organisms within
an ecosystem
change its abiotic
conditions.
This allows better
adapted organisms to
colonize the area,
replacing its current
inhabitants.
Primary succession occurs when
organisms colonize a lifeless habitat.
Secondary succession occurs
when organisms recolonize
a devastated
ecosystem.

9. A series of predictable changes that
occur in a community over time due to
events in the environment.
The changes may happen suddenly
or very slowly.

11.  The series of changes that occur in an
area where no ecosystem previously
existed.
 Eventually,
primary
succession
will lead to
equilibrium.

12. Primary Succession – the
series of changes that
occur in an area where no
ecosystem previously
existed.

13. An area of rock
uncovered by a
melting ice sheet
A new island formed
by the eruption of an
undersea volcano
Human made ponds

14. The first species
to populate an
area are the
pioneer species.
They break up rock
and begin soil
formation

15. Primary Succession
•Soil starts to form as lichens and
the forces of weather and erosion
help break down rocks into smaller
pieces
•When lichens die, they
decompose, adding small amounts
of organic matter to the rock to
make soil

16. A combination of
fungus and algae

19. Lichen pictures

20. Mosses break down rock
and add more soil

21. Grasses and small
plants – protect the
soil and add more
nutrients

22. •The simple plants die, adding more
organic material
•The soil layer thickens, and grasses,
wildflowers, and other plants begin to
take over

23. •These plants die, and they add
more nutrients to the soil
•Shrubs and trees can survive now
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24. •Insects, small birds, and mammals have
begun to move in
•What was once bare rock now supports
a variety of life
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25. Larger plants with deep roots
continue to break up rock and
make more soil.
A diverse forest ecosystem
takes hundreds of years

26. 1. Ground is solid rock
2. Rock begins to weather, pioneer
species begin
3. Weeds and grasses grow in soil making thicker, richer soil
4. Eventually trees and shrubs sprout community of organisms develops
5. Ecosystem reaches equilibrium

28. Reaching a stable community
can take centuries.

29. Equilibrium

31. Secondary Succession
The series of
changes that occur
after a disturbance
in an existing
ecosystem.
It can occur more
rapidly than
primary succession.

32. Secondary Succession
Begins in a place that already has
soil and was once the home of
living organisms
Occurs faster and has different
pioneer species than primary
succession

34. Natural disturbances:
Fires, hurricanes,
and tornadoes
Human disturbances:
A pasture
abandoned by a
farmer
Logging, or mining

35. Secondary Succession –
The series of changes that
occur after a disturbance
in an existing ecosystem.

37. 1. Varies depending on the type of
2.
3.
4.
5.
disturbance
A disturbed area returns to its
previous condition, eventually reaches
equilibrium
Soil and seeds are already present
Organisms move in
There is a quick recovery of the
ecosystem

38. Climax Community
•A stable group of plants and
animals that is the end result of
the succession process
•Does not always mean big trees
– Grasses in prairies
– Cacti in deserts
• Equilibrium restored
• State of balance
• No sudden changes
in community

39. Secondary succession usually
requires less time to form a
climax community, since soil is
already in place.

41. Succession Review

42. What
happens
to the
ecosyste
m
Length of
Time
Example
Primary
Creates a new
ecosystem
Secondary
Restores a
previous
ecosystem
May take a long time
to reach equilibrium
A shorter time to
reach equilibrium
New land created by
An area
volcanic eruption
destroyed by fire

44. Equilibrium

45. How do primary and secondary succession help
maintain equilibrium in an ecosystem?
Answer:
By fostering stability, over time, in the number and
species of organisms in a community.

46. What is a pioneer species?
Answer:
The first species to populate an area.

47. Identify two natural disturbances and
two human disturbances that can
result in secondary succession.
Answer:
Natural Disturbances: fire, hurricanes,
volcanoes, tornadoes. Human
Disturbances: farming, logging,
mining.

48. Grass poking through the cracks in the
sidewalk is an example of succession. Is
this primary or secondary succession?
Answer:
Secondary Succession; before the
sidewalk was built, an ecosystem
existed there.

49. Primary Succession occurs where no
previous ecosystem exists and
establishes equilibrium.
Secondary succession occurs after a
disturbance restores equilibrium.