Transcript CP Ecology Notes Part 4

Succession
Part 4
Brainstorm
How do Ecosystems Form?
Succession

Ecosystems are constantly changing in
response to natural and human activities
or events.
Succession

Ecosystems are constantly changing in
response to natural and human activities
or events.

Sometimes, an ecosystem changes in
response to an abrupt disturbance.
Succession

Ecosystems are constantly changing in
response to natural and human activities
or events.

Sometimes, an ecosystem changes in
response to an abrupt disturbance.

At other times, change occurs as a more
gradual response to natural fluctuations in
the environment.
Succession

Ecosystems are constantly changing in
response to natural and human activities
or events.
Natural Events
Human Events
Succession

Ecosystems are constantly changing in
response to natural and human activities
or events.
Natural Events
-
Fires
Volcanic eruptions
Retreated Glacier
Flood
Storms
Fallen tree
Human Events
Succession

Ecosystems are constantly changing in
response to natural and human activities
or events.
Natural Events
Human Events
-
- Logging
- Land Clearing for
Construction
- Live-stock Grazing
in Farming
Fires
Volcanic eruptions
Retreated Glacier
Flood
Storms
Fallen tree
What is ecological succession?

The series of predictable changes that
occurs in a community over time, due to
natural or human disturbances is called
ecological succession.

There are two types of succession:

There are two types of succession:
1. Primary Succession

There are two types of succession:
1. Primary Succession
2. Secondary Succession
Primary Succession

Succession that occurs on surfaces where
no soil exists.
Primary Succession

Succession that occurs on surfaces where
no soil exists.
Examples:
 Retreating Glaciers
 Volcanic Eruptions
Primary Succession
The
first species to populate the area are called
pioneer species.
Primary Succession
The

first species to populate the area are called
pioneer species.
Pioneer species
physically break up
the rocks, extract
minerals, and
provide organic
matter that will
decompose and
become the soil for
later species.
Pioneer Species

Pioneer species share some of the following
characteristics, which allow them to be the
first to grow in an area.
– Reproduce quickly
– Mechanisms for distant seed dispersal (birds,
insects, wind
– Shade Intolerant
– Need little or no soil
– Survive in harsh environments
– Need little water
Pioneer Species

Example of pioneer species:
– Lichen
Two organisms (algae and fungus)
Stages of Primary Succession
1. Primary succession begins when lichens
populate bare rock. Because lichens are
the first species to live where no life has
lived in the past, they are called pioneer
species. As the lichens grow, they help
break up the rocks and when they die
their organic material helps to form soil in
which plants can grow.
Stages of Primary Succession
2. Mosses may grow next
and then grasses and
small weeds will root in
the soil trapping soil and
organic matter that blows
their way. In addition, the
decomposition of grasses
and weeds will accelerate
the soil formation process.
Important NOTE

As the vegetation begins to
grow, animals begin to arrive
in the area.

These animals also die,
decompose, and add to the
soil being formed for other
plants to take root and more
organisms arrive as their
habitats form.
Important NOTE

As the vegetation begins to
grow, animals begin to arrive
in the area.

These animals also die,
decompose, and add to the
soil being formed for other
plants to take root and more
organisms arrive as their
habitats form.
Stages of Primary Succession
3. Small shrubs and pine
trees can now grow
amongst the grasses and
weeds.
Stages of Primary Succession
4. The community then moves
from a scrubby one to a pine
dominated forest.
Stages of Primary Succession
5. Hardwood trees such
as Maple, Beech and
Oak grow in the shade
of the pines and
eventually grow taller
than the pines shading
them and ultimately
resulting in their death
and replacement by
the hardwood forest.
This is called the climax community. If nothing
changes, which in nature is highly unlikely, this
community will be stable.
PRIMARY
SUCCESSION
EXAMPLES
Secondary Succession

What happens if a community is
disturbed at some stage of
succession?
Secondary Succession

What happens if a community is
disturbed at some stage of
succession?

If a community is disturbed, without
removing the soil, it will be set back to an
earlier stage and succession will start over
from there.
Secondary Succession

Secondary succession proceeds much quicker
than primary succession, because there is soil
present and often even seeds.
Secondary Succession

Secondary succession proceeds much quicker
than primary succession, because there is soil
present and often even seeds.

Results after a disturbance such as:
– abandoning a plowed field
– a wildfire or clear cutting a forest
Secondary Succession

Secondary succession proceeds much quicker
than primary succession, because there is soil
present and often even seeds.

Results after a disturbance such as:
– abandoning a plowed field
– a wildfire or clear cutting a forest
Secondary Succession

Secondary succession proceeds much quicker
than primary succession, because there is soil
present and often even seeds.

Results after a disturbance such as:
– abandoning a plowed field
– a wildfire or clear cutting a forest

Pioneer species: Grasses and weeds.
Secondary Succession
Primary or Secondary Succession?
Primary or Secondary Succession?

_____ As these plants live and die, the soil continues
to develop to the point that grasses can successfully
grow and grassland community forms.

_____ The shrub community may be replaced by a
forest.

_____ Bare rock is first colonized by lichens* and
bacteria.

_____ Over time, the soil level increases to point that
shrubs can grow in the grassland. The grassland is
replaced by a shrub community.

_____ The small amount of soil formed by the
lichens* is colonized by mosses and ferns, which do
not have roots and require little soil.

__3__ As these plants live and die, the soil continues
to develop to the point that grasses can successfully
grow and grassland community forms.

__5___ The shrub community may be replaced by a
forest.
 __1__ Bare rock is first colonized by lichens* and
bacteria.

__4__ Over time, the soil level increases to point that
shrubs can grow in the grassland. The grassland is
replaced by a shrub community.

__2___ The small amount of soil formed by the
lichens* is colonized by mosses and ferns, which do
not have roots and require little soil.
Arrange the species below in order of
their appearance in succession from
bare rock to forest:
Softwoods (conifer)
Lichen
Moss
Ferns
Hardwoods (oak)
Arrange the species below in order of
their appearance in succession from
bare rock to forest:
Lichen
Softwoods (conifer)
Moss
Ferns
Hardwoods (oak)
Arrange the species below in order of
their appearance in succession from
bare rock to forest:
Lichen
Moss
Softwoods (conifer)
Ferns
Hardwoods (oak)
Arrange the species below in order of
their appearance in succession from
bare rock to forest:
Lichen
Moss
Ferns
Softwoods (conifer)
Hardwoods (oak)