Transcript Community changes: Succession

Ecological
Succession
Succession
 Primary succession:
 development of a new community
with no previous life.
 No soil is initially present.
 Very slow!
 Examples:
 Bare rock, volcanic island
Primary succession
1. Lichens colonize the bare rock.
Lichens are a mutualistic relationship
between fungi and algae.
2. Dead and decaying lichen forms a
layer of soil for grasslike plants to
grow.
3. Dead plants add to organic soil, so
mosses and larger plants can grow.
Secondary succession
 Existing community is cleared
by a disturbance, but soil is
present.
1. Weeds, like annual grasses,
dandelions, colonize first.
Seeds are carried by wind or
animals. Grow quickly, but die
each year.
2. Perennial grasses and shrubs
colonize later. Grow slower, but
last longer.
3. Large trees, like oak, eventually
colonize
 Pioneer species: first species
to predominate in succession.
Tend to be small, and grow
quickly.
 Climax community: stable
point that remains constant
until a disturbance occurs.
Summarize
1. How are populations related
to communities?
2. Describe the difference
between a habitat and a
niche.
3. An abandoned farm would
be an example of primary or
secondary succession?