Download Ecological Succession

Ecological Succession
3.
4.
Objectives
1.
Explain what succession is
2.
Explain the process of ecological succession
Explain the role that plants play in maintaining biodiversity
Explain how organisms survive after their ecosystem has
been disturbed.
Definitions…
Succession: The gradual change in the number and
type of species, that make up a community, over
time.
Primary Succession: Succession in an area that has
no plants, animals, or soil.
Pioneer Species: The first species to colonize an
area during succession.
Secondary Succession: Succession in an
ecosystem that has been disturbed by a natural
event or human activity.
Ecosystem: All living and non living components in
an area.
Ecological Succession…
• Succession is influenced by..
1) Biotic (living) factors
2) Abiotic (nonliving) factors
Succession occurs in stages or steps.
However, these steps are not always
distinct and can often blend into each
other..
Primary Succession…
• Takes place on
completely barren
rock.
•
•
•
•
•
•
No plants
No animals
No soil
No shade
No shelter
Nothing!!!!
…and then
Pioneer organisms start to grow.
Grasses, lichens start to grow on rocks.
Forms soil and creates conditions that allow more
vegetation to grow.
Still no shade or
shelter.
• Mosses and other small plants start to colonize
the area. They help keep water in soil and
reduce erosion.
• Attract insects, birds and other small animals
which feed on plants and eventually decompose
to build more soil.
Soil becomes
thicker and full
of nutrients.
Plants provide
some shelter to
small organisms.
• Small plants and soft
wood trees (pine trees
and larger shrubs) grow.
• These plants can survive
in harsh conditions.
• Roots break up rock and
help add more nutrients
to soil when they
decompose.
• Organisms slowly change
the biotic and abiotic
•Plants provide shelter
for more species of
factors.
insects, birds and small
mammals.
• Bigger plants and
hard wood trees
grow.
• Provide more
shelter and shade.
• Provide food and
habitat for a wider
range of mammals. • Soil continues to
become deeper and
• Their droppings
richer. Plants moderate
and remains enrich
temperature, wind and
the soil.
moisture in area.
Climax Community
• A relatively stable population.
• All ages of plants and hard wood trees
grow. Many shrubs, saplings and
herbaceous plants grow.
• High biodiversity.
• Complex food webs.
• Diversity of plant life provides food and
habitat for a wide range of other
organisms.
Ecological Succession
• As succession proceeds the biodiversity of
the community increases.
Secondary Succession
Happens more quickly. It usually happens after
an existing community has been disturbed by
natural events or human activity.
Community grows from pre-existing soil.
Competition and Forest Fires…
• Succession is a long-term process driven
by various types of competition.
• Read page hand out on ‘Succession’
Using your resources answer the questions
given.